* [PATCH v5 01/23] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()"
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:13 ` [tip:x86/mm] x86/alternatives: Add text_poke_kgdb() to not assert the lock when debugging tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 02/23] x86/jump_label: Use text_poke_early() during early init Nadav Amit
` (22 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Kees Cook,
Dave Hansen, Masami Hiramatsu
text_mutex is currently expected to be held before text_poke() is
called, but kgdb does not take the mutex, and instead *supposedly*
ensures the lock is not taken and will not be acquired by any other core
while text_poke() is running.
The reason for the "supposedly" comment is that it is not entirely clear
that this would be the case if gdb_do_roundup is zero.
Create two wrapper functions, text_poke() and text_poke_kgdb(), which do
or do not run the lockdep assertion respectively.
While we are at it, change the return code of text_poke() to something
meaningful. One day, callers might actually respect it and the existing
BUG_ON() when patching fails could be removed. For kgdb, the return
value can actually be used.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 9222f606506c ("x86/alternatives: Lockdep-enforce text_mutex in text_poke*()")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/include/asm/text-patching.h | 1 +
arch/x86/kernel/alternative.c | 52 ++++++++++++++++++++--------
arch/x86/kernel/kgdb.c | 11 +++---
3 files changed, 45 insertions(+), 19 deletions(-)
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index e85ff65c43c3..f8fc8e86cf01 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -35,6 +35,7 @@ extern void *text_poke_early(void *addr, const void *opcode, size_t len);
* inconsistent instruction while you patch.
*/
extern void *text_poke(void *addr, const void *opcode, size_t len);
+extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len);
extern int poke_int3_handler(struct pt_regs *regs);
extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
extern int after_bootmem;
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 9a79c7808f9c..0a814d73547a 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -679,18 +679,7 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode,
return addr;
}
-/**
- * text_poke - Update instructions on a live kernel
- * @addr: address to modify
- * @opcode: source of the copy
- * @len: length to copy
- *
- * Only atomic text poke/set should be allowed when not doing early patching.
- * It means the size must be writable atomically and the address must be aligned
- * in a way that permits an atomic write. It also makes sure we fit on a single
- * page.
- */
-void *text_poke(void *addr, const void *opcode, size_t len)
+static void *__text_poke(void *addr, const void *opcode, size_t len)
{
unsigned long flags;
char *vaddr;
@@ -703,8 +692,6 @@ void *text_poke(void *addr, const void *opcode, size_t len)
*/
BUG_ON(!after_bootmem);
- lockdep_assert_held(&text_mutex);
-
if (!core_kernel_text((unsigned long)addr)) {
pages[0] = vmalloc_to_page(addr);
pages[1] = vmalloc_to_page(addr + PAGE_SIZE);
@@ -733,6 +720,43 @@ void *text_poke(void *addr, const void *opcode, size_t len)
return addr;
}
+/**
+ * text_poke - Update instructions on a live kernel
+ * @addr: address to modify
+ * @opcode: source of the copy
+ * @len: length to copy
+ *
+ * Only atomic text poke/set should be allowed when not doing early patching.
+ * It means the size must be writable atomically and the address must be aligned
+ * in a way that permits an atomic write. It also makes sure we fit on a single
+ * page.
+ */
+void *text_poke(void *addr, const void *opcode, size_t len)
+{
+ lockdep_assert_held(&text_mutex);
+
+ return __text_poke(addr, opcode, len);
+}
+
+/**
+ * text_poke_kgdb - Update instructions on a live kernel by kgdb
+ * @addr: address to modify
+ * @opcode: source of the copy
+ * @len: length to copy
+ *
+ * Only atomic text poke/set should be allowed when not doing early patching.
+ * It means the size must be writable atomically and the address must be aligned
+ * in a way that permits an atomic write. It also makes sure we fit on a single
+ * page.
+ *
+ * Context: should only be used by kgdb, which ensures no other core is running,
+ * despite the fact it does not hold the text_mutex.
+ */
+void *text_poke_kgdb(void *addr, const void *opcode, size_t len)
+{
+ return __text_poke(addr, opcode, len);
+}
+
static void do_sync_core(void *info)
{
sync_core();
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 4ff6b4cdb941..2b203ee5b879 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -759,13 +759,13 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
if (!err)
return err;
/*
- * It is safe to call text_poke() because normal kernel execution
+ * It is safe to call text_poke_kgdb() because normal kernel execution
* is stopped on all cores, so long as the text_mutex is not locked.
*/
if (mutex_is_locked(&text_mutex))
return -EBUSY;
- text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
- BREAK_INSTR_SIZE);
+ text_poke_kgdb((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
+ BREAK_INSTR_SIZE);
err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
if (err)
return err;
@@ -784,12 +784,13 @@ int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
if (bpt->type != BP_POKE_BREAKPOINT)
goto knl_write;
/*
- * It is safe to call text_poke() because normal kernel execution
+ * It is safe to call text_poke_kgdb() because normal kernel execution
* is stopped on all cores, so long as the text_mutex is not locked.
*/
if (mutex_is_locked(&text_mutex))
goto knl_write;
- text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE);
+ text_poke_kgdb((void *)bpt->bpt_addr, bpt->saved_instr,
+ BREAK_INSTR_SIZE);
err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE))
goto knl_write;
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/alternatives: Add text_poke_kgdb() to not assert the lock when debugging
2019-04-26 0:11 ` [PATCH v5 01/23] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Nadav Amit
@ 2019-04-30 11:13 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:13 UTC (permalink / raw)
To: linux-tip-commits
Cc: tglx, hpa, akpm, luto, bp, mhiramat, riel, ard.biesheuvel,
linux-kernel, namit, linux_dti, will.deacon, dave.hansen,
kristen, kernel-hardening, peterz, rick.p.edgecombe, mingo,
keescook, deneen.t.dock, jkosina, torvalds
Commit-ID: e836673c9b4966bc78e38aeda25f7022c57f0e90
Gitweb: https://git.kernel.org/tip/e836673c9b4966bc78e38aeda25f7022c57f0e90
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:21 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:47 +0200
x86/alternatives: Add text_poke_kgdb() to not assert the lock when debugging
text_mutex is currently expected to be held before text_poke() is
called, but kgdb does not take the mutex, and instead *supposedly*
ensures the lock is not taken and will not be acquired by any other core
while text_poke() is running.
The reason for the "supposedly" comment is that it is not entirely clear
that this would be the case if gdb_do_roundup is zero.
Create two wrapper functions, text_poke() and text_poke_kgdb(), which do
or do not run the lockdep assertion respectively.
While we are at it, change the return code of text_poke() to something
meaningful. One day, callers might actually respect it and the existing
BUG_ON() when patching fails could be removed. For kgdb, the return
value can actually be used.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 9222f606506c ("x86/alternatives: Lockdep-enforce text_mutex in text_poke*()")
Link: https://lkml.kernel.org/r/20190426001143.4983-2-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/text-patching.h | 1 +
arch/x86/kernel/alternative.c | 52 ++++++++++++++++++++++++++----------
arch/x86/kernel/kgdb.c | 11 ++++----
3 files changed, 45 insertions(+), 19 deletions(-)
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index e85ff65c43c3..f8fc8e86cf01 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -35,6 +35,7 @@ extern void *text_poke_early(void *addr, const void *opcode, size_t len);
* inconsistent instruction while you patch.
*/
extern void *text_poke(void *addr, const void *opcode, size_t len);
+extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len);
extern int poke_int3_handler(struct pt_regs *regs);
extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
extern int after_bootmem;
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 9a79c7808f9c..0a814d73547a 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -679,18 +679,7 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode,
return addr;
}
-/**
- * text_poke - Update instructions on a live kernel
- * @addr: address to modify
- * @opcode: source of the copy
- * @len: length to copy
- *
- * Only atomic text poke/set should be allowed when not doing early patching.
- * It means the size must be writable atomically and the address must be aligned
- * in a way that permits an atomic write. It also makes sure we fit on a single
- * page.
- */
-void *text_poke(void *addr, const void *opcode, size_t len)
+static void *__text_poke(void *addr, const void *opcode, size_t len)
{
unsigned long flags;
char *vaddr;
@@ -703,8 +692,6 @@ void *text_poke(void *addr, const void *opcode, size_t len)
*/
BUG_ON(!after_bootmem);
- lockdep_assert_held(&text_mutex);
-
if (!core_kernel_text((unsigned long)addr)) {
pages[0] = vmalloc_to_page(addr);
pages[1] = vmalloc_to_page(addr + PAGE_SIZE);
@@ -733,6 +720,43 @@ void *text_poke(void *addr, const void *opcode, size_t len)
return addr;
}
+/**
+ * text_poke - Update instructions on a live kernel
+ * @addr: address to modify
+ * @opcode: source of the copy
+ * @len: length to copy
+ *
+ * Only atomic text poke/set should be allowed when not doing early patching.
+ * It means the size must be writable atomically and the address must be aligned
+ * in a way that permits an atomic write. It also makes sure we fit on a single
+ * page.
+ */
+void *text_poke(void *addr, const void *opcode, size_t len)
+{
+ lockdep_assert_held(&text_mutex);
+
+ return __text_poke(addr, opcode, len);
+}
+
+/**
+ * text_poke_kgdb - Update instructions on a live kernel by kgdb
+ * @addr: address to modify
+ * @opcode: source of the copy
+ * @len: length to copy
+ *
+ * Only atomic text poke/set should be allowed when not doing early patching.
+ * It means the size must be writable atomically and the address must be aligned
+ * in a way that permits an atomic write. It also makes sure we fit on a single
+ * page.
+ *
+ * Context: should only be used by kgdb, which ensures no other core is running,
+ * despite the fact it does not hold the text_mutex.
+ */
+void *text_poke_kgdb(void *addr, const void *opcode, size_t len)
+{
+ return __text_poke(addr, opcode, len);
+}
+
static void do_sync_core(void *info)
{
sync_core();
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 4ff6b4cdb941..2b203ee5b879 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -759,13 +759,13 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
if (!err)
return err;
/*
- * It is safe to call text_poke() because normal kernel execution
+ * It is safe to call text_poke_kgdb() because normal kernel execution
* is stopped on all cores, so long as the text_mutex is not locked.
*/
if (mutex_is_locked(&text_mutex))
return -EBUSY;
- text_poke((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
- BREAK_INSTR_SIZE);
+ text_poke_kgdb((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
+ BREAK_INSTR_SIZE);
err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
if (err)
return err;
@@ -784,12 +784,13 @@ int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
if (bpt->type != BP_POKE_BREAKPOINT)
goto knl_write;
/*
- * It is safe to call text_poke() because normal kernel execution
+ * It is safe to call text_poke_kgdb() because normal kernel execution
* is stopped on all cores, so long as the text_mutex is not locked.
*/
if (mutex_is_locked(&text_mutex))
goto knl_write;
- text_poke((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE);
+ text_poke_kgdb((void *)bpt->bpt_addr, bpt->saved_instr,
+ BREAK_INSTR_SIZE);
err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE))
goto knl_write;
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 02/23] x86/jump_label: Use text_poke_early() during early init
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
2019-04-26 0:11 ` [PATCH v5 01/23] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:15 ` [tip:x86/mm] " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 03/23] x86/mm: Introduce temporary mm structs Nadav Amit
` (21 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Kees Cook,
Dave Hansen, Masami Hiramatsu
There is no apparent reason not to use text_poke_early() during
early-init, since no patching of code that might be on the stack is done
and only a single core is running.
This is required for the next patches that would set a temporary mm for
text poking, and this mm is only initialized after some static-keys are
enabled/disabled.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/jump_label.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index f99bd26bd3f1..e7d8c636b228 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -50,7 +50,12 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
jmp.offset = jump_entry_target(entry) -
(jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
- if (early_boot_irqs_disabled)
+ /*
+ * As long as only a single processor is running and the code is still
+ * not marked as RO, text_poke_early() can be used; Checking that
+ * system_state is SYSTEM_BOOTING guarantees it.
+ */
+ if (system_state == SYSTEM_BOOTING)
poker = text_poke_early;
if (type == JUMP_LABEL_JMP) {
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/jump_label: Use text_poke_early() during early init
2019-04-26 0:11 ` [PATCH v5 02/23] x86/jump_label: Use text_poke_early() during early init Nadav Amit
@ 2019-04-30 11:15 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:15 UTC (permalink / raw)
To: linux-tip-commits
Cc: riel, akpm, kernel-hardening, torvalds, hpa, mingo, linux-kernel,
dave.hansen, kristen, bp, tglx, linux_dti, will.deacon, keescook,
deneen.t.dock, namit, mhiramat, rick.p.edgecombe, ard.biesheuvel,
peterz, luto
Commit-ID: 1fd8de46d01d95f875c12684a6a03559831e8b4c
Gitweb: https://git.kernel.org/tip/1fd8de46d01d95f875c12684a6a03559831e8b4c
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:22 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:49 +0200
x86/jump_label: Use text_poke_early() during early init
There is no apparent reason not to use text_poke_early() during
early-init, since no patching of code that might be on the stack is done
and only a single core is running.
This is required for the next patches that would set a temporary mm for
text poking, and this mm is only initialized after some static-keys are
enabled/disabled.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-3-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/jump_label.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index f99bd26bd3f1..e7d8c636b228 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -50,7 +50,12 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
jmp.offset = jump_entry_target(entry) -
(jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
- if (early_boot_irqs_disabled)
+ /*
+ * As long as only a single processor is running and the code is still
+ * not marked as RO, text_poke_early() can be used; Checking that
+ * system_state is SYSTEM_BOOTING guarantees it.
+ */
+ if (system_state == SYSTEM_BOOTING)
poker = text_poke_early;
if (type == JUMP_LABEL_JMP) {
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 03/23] x86/mm: Introduce temporary mm structs
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
2019-04-26 0:11 ` [PATCH v5 01/23] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Nadav Amit
2019-04-26 0:11 ` [PATCH v5 02/23] x86/jump_label: Use text_poke_early() during early init Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:16 ` [tip:x86/mm] " tip-bot for Andy Lutomirski
2019-04-26 0:11 ` [PATCH v5 04/23] x86/mm: Save debug registers when loading a temporary mm Nadav Amit
` (20 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Kees Cook, Dave Hansen,
Nadav Amit
From: Andy Lutomirski <luto@kernel.org>
Using a dedicated page-table for temporary PTEs prevents other cores
from using - even speculatively - these PTEs, thereby providing two
benefits:
(1) Security hardening: an attacker that gains kernel memory writing
abilities cannot easily overwrite sensitive data.
(2) Avoiding TLB shootdowns: the PTEs do not need to be flushed in
remote page-tables.
To do so a temporary mm_struct can be used. Mappings which are private
for this mm can be set in the userspace part of the address-space.
During the whole time in which the temporary mm is loaded, interrupts
must be disabled.
The first use-case for temporary mm struct, which will follow, is for
poking the kernel text.
[ Commit message was written by Nadav Amit ]
Cc: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/include/asm/mmu_context.h | 33 ++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 19d18fae6ec6..24dc3b810970 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -356,4 +356,37 @@ static inline unsigned long __get_current_cr3_fast(void)
return cr3;
}
+typedef struct {
+ struct mm_struct *mm;
+} temp_mm_state_t;
+
+/*
+ * Using a temporary mm allows to set temporary mappings that are not accessible
+ * by other CPUs. Such mappings are needed to perform sensitive memory writes
+ * that override the kernel memory protections (e.g., W^X), without exposing the
+ * temporary page-table mappings that are required for these write operations to
+ * other CPUs. Using a temporary mm also allows to avoid TLB shootdowns when the
+ * mapping is torn down.
+ *
+ * Context: The temporary mm needs to be used exclusively by a single core. To
+ * harden security IRQs must be disabled while the temporary mm is
+ * loaded, thereby preventing interrupt handler bugs from overriding
+ * the kernel memory protection.
+ */
+static inline temp_mm_state_t use_temporary_mm(struct mm_struct *mm)
+{
+ temp_mm_state_t temp_state;
+
+ lockdep_assert_irqs_disabled();
+ temp_state.mm = this_cpu_read(cpu_tlbstate.loaded_mm);
+ switch_mm_irqs_off(NULL, mm, current);
+ return temp_state;
+}
+
+static inline void unuse_temporary_mm(temp_mm_state_t prev_state)
+{
+ lockdep_assert_irqs_disabled();
+ switch_mm_irqs_off(NULL, prev_state.mm, current);
+}
+
#endif /* _ASM_X86_MMU_CONTEXT_H */
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/mm: Introduce temporary mm structs
2019-04-26 0:11 ` [PATCH v5 03/23] x86/mm: Introduce temporary mm structs Nadav Amit
@ 2019-04-30 11:16 ` tip-bot for Andy Lutomirski
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Andy Lutomirski @ 2019-04-30 11:16 UTC (permalink / raw)
To: linux-tip-commits
Cc: tglx, linux-kernel, will.deacon, mhiramat, hpa, torvalds, peterz,
mingo, kernel-hardening, dave.hansen, kristen, riel, linux_dti,
namit, ard.biesheuvel, luto, keescook, rick.p.edgecombe, bp,
akpm, deneen.t.dock
Commit-ID: cefa929c034eb5d9c15c50088235a0093a219687
Gitweb: https://git.kernel.org/tip/cefa929c034eb5d9c15c50088235a0093a219687
Author: Andy Lutomirski <luto@kernel.org>
AuthorDate: Thu, 25 Apr 2019 17:11:23 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:50 +0200
x86/mm: Introduce temporary mm structs
Using a dedicated page-table for temporary PTEs prevents other cores
from using - even speculatively - these PTEs, thereby providing two
benefits:
(1) Security hardening: an attacker that gains kernel memory writing
abilities cannot easily overwrite sensitive data.
(2) Avoiding TLB shootdowns: the PTEs do not need to be flushed in
remote page-tables.
To do so a temporary mm_struct can be used. Mappings which are private
for this mm can be set in the userspace part of the address-space.
During the whole time in which the temporary mm is loaded, interrupts
must be disabled.
The first use-case for temporary mm struct, which will follow, is for
poking the kernel text.
[ Commit message was written by Nadav Amit ]
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-4-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/mmu_context.h | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 19d18fae6ec6..24dc3b810970 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -356,4 +356,37 @@ static inline unsigned long __get_current_cr3_fast(void)
return cr3;
}
+typedef struct {
+ struct mm_struct *mm;
+} temp_mm_state_t;
+
+/*
+ * Using a temporary mm allows to set temporary mappings that are not accessible
+ * by other CPUs. Such mappings are needed to perform sensitive memory writes
+ * that override the kernel memory protections (e.g., W^X), without exposing the
+ * temporary page-table mappings that are required for these write operations to
+ * other CPUs. Using a temporary mm also allows to avoid TLB shootdowns when the
+ * mapping is torn down.
+ *
+ * Context: The temporary mm needs to be used exclusively by a single core. To
+ * harden security IRQs must be disabled while the temporary mm is
+ * loaded, thereby preventing interrupt handler bugs from overriding
+ * the kernel memory protection.
+ */
+static inline temp_mm_state_t use_temporary_mm(struct mm_struct *mm)
+{
+ temp_mm_state_t temp_state;
+
+ lockdep_assert_irqs_disabled();
+ temp_state.mm = this_cpu_read(cpu_tlbstate.loaded_mm);
+ switch_mm_irqs_off(NULL, mm, current);
+ return temp_state;
+}
+
+static inline void unuse_temporary_mm(temp_mm_state_t prev_state)
+{
+ lockdep_assert_irqs_disabled();
+ switch_mm_irqs_off(NULL, prev_state.mm, current);
+}
+
#endif /* _ASM_X86_MMU_CONTEXT_H */
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 04/23] x86/mm: Save debug registers when loading a temporary mm
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (2 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 03/23] x86/mm: Introduce temporary mm structs Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:17 ` [tip:x86/mm] " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 05/23] fork: Provide a function for copying init_mm Nadav Amit
` (19 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit
Prevent user watchpoints from mistakenly firing while the temporary mm
is being used. As the addresses of the temporary mm might overlap those
of the user-process, this is necessary to prevent wrong signals or worse
things from happening.
Cc: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/include/asm/mmu_context.h | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 24dc3b810970..93dff1963337 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -13,6 +13,7 @@
#include <asm/tlbflush.h>
#include <asm/paravirt.h>
#include <asm/mpx.h>
+#include <asm/debugreg.h>
extern atomic64_t last_mm_ctx_id;
@@ -380,6 +381,21 @@ static inline temp_mm_state_t use_temporary_mm(struct mm_struct *mm)
lockdep_assert_irqs_disabled();
temp_state.mm = this_cpu_read(cpu_tlbstate.loaded_mm);
switch_mm_irqs_off(NULL, mm, current);
+
+ /*
+ * If breakpoints are enabled, disable them while the temporary mm is
+ * used. Userspace might set up watchpoints on addresses that are used
+ * in the temporary mm, which would lead to wrong signals being sent or
+ * crashes.
+ *
+ * Note that breakpoints are not disabled selectively, which also causes
+ * kernel breakpoints (e.g., perf's) to be disabled. This might be
+ * undesirable, but still seems reasonable as the code that runs in the
+ * temporary mm should be short.
+ */
+ if (hw_breakpoint_active())
+ hw_breakpoint_disable();
+
return temp_state;
}
@@ -387,6 +403,13 @@ static inline void unuse_temporary_mm(temp_mm_state_t prev_state)
{
lockdep_assert_irqs_disabled();
switch_mm_irqs_off(NULL, prev_state.mm, current);
+
+ /*
+ * Restore the breakpoints if they were disabled before the temporary mm
+ * was loaded.
+ */
+ if (hw_breakpoint_active())
+ hw_breakpoint_restore();
}
#endif /* _ASM_X86_MMU_CONTEXT_H */
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/mm: Save debug registers when loading a temporary mm
2019-04-26 0:11 ` [PATCH v5 04/23] x86/mm: Save debug registers when loading a temporary mm Nadav Amit
@ 2019-04-30 11:17 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:17 UTC (permalink / raw)
To: linux-tip-commits
Cc: bp, tglx, hpa, rick.p.edgecombe, peterz, mingo, akpm,
will.deacon, luto, ard.biesheuvel, deneen.t.dock, linux-kernel,
namit, riel, kristen, linux_dti, torvalds, dave.hansen,
kernel-hardening
Commit-ID: d97080ebed7811a53c931032a284166ee46b9565
Gitweb: https://git.kernel.org/tip/d97080ebed7811a53c931032a284166ee46b9565
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:24 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:50 +0200
x86/mm: Save debug registers when loading a temporary mm
Prevent user watchpoints from mistakenly firing while the temporary mm
is being used. As the addresses of the temporary mm might overlap those
of the user-process, this is necessary to prevent wrong signals or worse
things from happening.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-5-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/mmu_context.h | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 24dc3b810970..93dff1963337 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -13,6 +13,7 @@
#include <asm/tlbflush.h>
#include <asm/paravirt.h>
#include <asm/mpx.h>
+#include <asm/debugreg.h>
extern atomic64_t last_mm_ctx_id;
@@ -380,6 +381,21 @@ static inline temp_mm_state_t use_temporary_mm(struct mm_struct *mm)
lockdep_assert_irqs_disabled();
temp_state.mm = this_cpu_read(cpu_tlbstate.loaded_mm);
switch_mm_irqs_off(NULL, mm, current);
+
+ /*
+ * If breakpoints are enabled, disable them while the temporary mm is
+ * used. Userspace might set up watchpoints on addresses that are used
+ * in the temporary mm, which would lead to wrong signals being sent or
+ * crashes.
+ *
+ * Note that breakpoints are not disabled selectively, which also causes
+ * kernel breakpoints (e.g., perf's) to be disabled. This might be
+ * undesirable, but still seems reasonable as the code that runs in the
+ * temporary mm should be short.
+ */
+ if (hw_breakpoint_active())
+ hw_breakpoint_disable();
+
return temp_state;
}
@@ -387,6 +403,13 @@ static inline void unuse_temporary_mm(temp_mm_state_t prev_state)
{
lockdep_assert_irqs_disabled();
switch_mm_irqs_off(NULL, prev_state.mm, current);
+
+ /*
+ * Restore the breakpoints if they were disabled before the temporary mm
+ * was loaded.
+ */
+ if (hw_breakpoint_active())
+ hw_breakpoint_restore();
}
#endif /* _ASM_X86_MMU_CONTEXT_H */
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 05/23] fork: Provide a function for copying init_mm
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (3 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 04/23] x86/mm: Save debug registers when loading a temporary mm Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:18 ` [tip:x86/mm] " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 06/23] x86/alternative: Initialize temporary mm for patching Nadav Amit
` (18 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Kees Cook,
Dave Hansen
Provide a function for copying init_mm. This function will be later used
for setting a temporary mm.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
include/linux/sched/task.h | 1 +
kernel/fork.c | 24 ++++++++++++++++++------
2 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 2e97a2227045..f1227f2c38a4 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -76,6 +76,7 @@ extern void exit_itimers(struct signal_struct *);
extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
struct task_struct *fork_idle(int);
+struct mm_struct *copy_init_mm(void);
extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
diff --git a/kernel/fork.c b/kernel/fork.c
index 9dcd18aa210b..099cca8f701c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1298,13 +1298,20 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
complete_vfork_done(tsk);
}
-/*
- * Allocate a new mm structure and copy contents from the
- * mm structure of the passed in task structure.
+/**
+ * dup_mm() - duplicates an existing mm structure
+ * @tsk: the task_struct with which the new mm will be associated.
+ * @oldmm: the mm to duplicate.
+ *
+ * Allocates a new mm structure and duplicates the provided @oldmm structure
+ * content into it.
+ *
+ * Return: the duplicated mm or NULL on failure.
*/
-static struct mm_struct *dup_mm(struct task_struct *tsk)
+static struct mm_struct *dup_mm(struct task_struct *tsk,
+ struct mm_struct *oldmm)
{
- struct mm_struct *mm, *oldmm = current->mm;
+ struct mm_struct *mm;
int err;
mm = allocate_mm();
@@ -1371,7 +1378,7 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
}
retval = -ENOMEM;
- mm = dup_mm(tsk);
+ mm = dup_mm(tsk, current->mm);
if (!mm)
goto fail_nomem;
@@ -2186,6 +2193,11 @@ struct task_struct *fork_idle(int cpu)
return task;
}
+struct mm_struct *copy_init_mm(void)
+{
+ return dup_mm(NULL, &init_mm);
+}
+
/*
* Ok, this is the main fork-routine.
*
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] fork: Provide a function for copying init_mm
2019-04-26 0:11 ` [PATCH v5 05/23] fork: Provide a function for copying init_mm Nadav Amit
@ 2019-04-30 11:18 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:18 UTC (permalink / raw)
To: linux-tip-commits
Cc: peterz, luto, mhiramat, kristen, linux-kernel, hpa,
deneen.t.dock, namit, tglx, torvalds, dave.hansen, mingo,
linux_dti, kernel-hardening, will.deacon, rick.p.edgecombe, riel,
keescook, akpm, bp, ard.biesheuvel
Commit-ID: 13585fa0668c724efab9635aaeef6ec390217415
Gitweb: https://git.kernel.org/tip/13585fa0668c724efab9635aaeef6ec390217415
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:25 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:51 +0200
fork: Provide a function for copying init_mm
Provide a function for copying init_mm. This function will be later used
for setting a temporary mm.
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-6-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/sched/task.h | 1 +
kernel/fork.c | 24 ++++++++++++++++++------
2 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 2e97a2227045..f1227f2c38a4 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -76,6 +76,7 @@ extern void exit_itimers(struct signal_struct *);
extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
struct task_struct *fork_idle(int);
+struct mm_struct *copy_init_mm(void);
extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
diff --git a/kernel/fork.c b/kernel/fork.c
index 44fba5e5e916..fbe9dfcd8680 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1299,13 +1299,20 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
complete_vfork_done(tsk);
}
-/*
- * Allocate a new mm structure and copy contents from the
- * mm structure of the passed in task structure.
+/**
+ * dup_mm() - duplicates an existing mm structure
+ * @tsk: the task_struct with which the new mm will be associated.
+ * @oldmm: the mm to duplicate.
+ *
+ * Allocates a new mm structure and duplicates the provided @oldmm structure
+ * content into it.
+ *
+ * Return: the duplicated mm or NULL on failure.
*/
-static struct mm_struct *dup_mm(struct task_struct *tsk)
+static struct mm_struct *dup_mm(struct task_struct *tsk,
+ struct mm_struct *oldmm)
{
- struct mm_struct *mm, *oldmm = current->mm;
+ struct mm_struct *mm;
int err;
mm = allocate_mm();
@@ -1372,7 +1379,7 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk)
}
retval = -ENOMEM;
- mm = dup_mm(tsk);
+ mm = dup_mm(tsk, current->mm);
if (!mm)
goto fail_nomem;
@@ -2187,6 +2194,11 @@ struct task_struct *fork_idle(int cpu)
return task;
}
+struct mm_struct *copy_init_mm(void)
+{
+ return dup_mm(NULL, &init_mm);
+}
+
/*
* Ok, this is the main fork-routine.
*
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 06/23] x86/alternative: Initialize temporary mm for patching
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (4 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 05/23] fork: Provide a function for copying init_mm Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-26 0:11 ` [PATCH v5 07/23] x86/alternative: Use temporary mm for text poking Nadav Amit
` (17 subsequent siblings)
23 siblings, 0 replies; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Kees Cook,
Dave Hansen
To prevent improper use of the PTEs that are used for text patching, the
next patches will use a temporary mm struct. Initailize it by copying
the init mm.
The address that will be used for patching is taken from the lower area
that is usually used for the task memory. Doing so prevents the need to
frequently synchronize the temporary-mm (e.g., when BPF programs are
installed), since different PGDs are used for the task memory.
Finally, randomize the address of the PTEs to harden against exploits
that use these PTEs.
Cc: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/include/asm/pgtable.h | 3 +++
arch/x86/include/asm/text-patching.h | 2 ++
arch/x86/kernel/alternative.c | 3 +++
arch/x86/mm/init_64.c | 36 ++++++++++++++++++++++++++++
init/main.c | 3 +++
5 files changed, 47 insertions(+)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 5cfbbb6d458d..6b6bfdfe83aa 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1038,6 +1038,9 @@ static inline void __meminit init_trampoline_default(void)
/* Default trampoline pgd value */
trampoline_pgd_entry = init_top_pgt[pgd_index(__PAGE_OFFSET)];
}
+
+void __init poking_init(void);
+
# ifdef CONFIG_RANDOMIZE_MEMORY
void __meminit init_trampoline(void);
# else
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index f8fc8e86cf01..a75eed841eed 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -39,5 +39,7 @@ extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len);
extern int poke_int3_handler(struct pt_regs *regs);
extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
extern int after_bootmem;
+extern __ro_after_init struct mm_struct *poking_mm;
+extern __ro_after_init unsigned long poking_addr;
#endif /* _ASM_X86_TEXT_PATCHING_H */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 0a814d73547a..11d5c710a94f 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -679,6 +679,9 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode,
return addr;
}
+__ro_after_init struct mm_struct *poking_mm;
+__ro_after_init unsigned long poking_addr;
+
static void *__text_poke(void *addr, const void *opcode, size_t len)
{
unsigned long flags;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index bccff68e3267..125c8c48aa24 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -53,6 +53,7 @@
#include <asm/init.h>
#include <asm/uv/uv.h>
#include <asm/setup.h>
+#include <asm/text-patching.h>
#include "mm_internal.h"
@@ -1383,6 +1384,41 @@ unsigned long memory_block_size_bytes(void)
return memory_block_size_probed;
}
+/*
+ * Initialize an mm_struct to be used during poking and a pointer to be used
+ * during patching.
+ */
+void __init poking_init(void)
+{
+ spinlock_t *ptl;
+ pte_t *ptep;
+
+ poking_mm = copy_init_mm();
+ BUG_ON(!poking_mm);
+
+ /*
+ * Randomize the poking address, but make sure that the following page
+ * will be mapped at the same PMD. We need 2 pages, so find space for 3,
+ * and adjust the address if the PMD ends after the first one.
+ */
+ poking_addr = TASK_UNMAPPED_BASE;
+ if (IS_ENABLED(CONFIG_RANDOMIZE_BASE))
+ poking_addr += (kaslr_get_random_long("Poking") & PAGE_MASK) %
+ (TASK_SIZE - TASK_UNMAPPED_BASE - 3 * PAGE_SIZE);
+
+ if (((poking_addr + PAGE_SIZE) & ~PMD_MASK) == 0)
+ poking_addr += PAGE_SIZE;
+
+ /*
+ * We need to trigger the allocation of the page-tables that will be
+ * needed for poking now. Later, poking may be performed in an atomic
+ * section, which might cause allocation to fail.
+ */
+ ptep = get_locked_pte(poking_mm, poking_addr, &ptl);
+ BUG_ON(!ptep);
+ pte_unmap_unlock(ptep, ptl);
+}
+
#ifdef CONFIG_SPARSEMEM_VMEMMAP
/*
* Initialise the sparsemem vmemmap using huge-pages at the PMD level.
diff --git a/init/main.c b/init/main.c
index 598e278b46f7..949eed8015ec 100644
--- a/init/main.c
+++ b/init/main.c
@@ -504,6 +504,8 @@ void __init __weak thread_stack_cache_init(void)
void __init __weak mem_encrypt_init(void) { }
+void __init __weak poking_init(void) { }
+
bool initcall_debug;
core_param(initcall_debug, initcall_debug, bool, 0644);
@@ -737,6 +739,7 @@ asmlinkage __visible void __init start_kernel(void)
taskstats_init_early();
delayacct_init();
+ poking_init();
check_bugs();
acpi_subsystem_init();
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [PATCH v5 07/23] x86/alternative: Use temporary mm for text poking
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (5 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 06/23] x86/alternative: Initialize temporary mm for patching Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:20 ` [tip:x86/mm] x86/alternatives: " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 08/23] x86/kgdb: Avoid redundant comparison of patched code Nadav Amit
` (16 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Kees Cook,
Dave Hansen, Masami Hiramatsu
text_poke() can potentially compromise security as it sets temporary
PTEs in the fixmap. These PTEs might be used to rewrite the kernel code
from other cores accidentally or maliciously, if an attacker gains the
ability to write onto kernel memory.
Moreover, since remote TLBs are not flushed after the temporary PTEs are
removed, the time-window in which the code is writable is not limited if
the fixmap PTEs - maliciously or accidentally - are cached in the TLB.
To address these potential security hazards, use a temporary mm for
patching the code.
Finally, text_poke() is also not conservative enough when mapping pages,
as it always tries to map 2 pages, even when a single one is sufficient.
So try to be more conservative, and do not map more than needed.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/include/asm/fixmap.h | 2 -
arch/x86/kernel/alternative.c | 108 +++++++++++++++++++++++++++-------
arch/x86/xen/mmu_pv.c | 2 -
3 files changed, 86 insertions(+), 26 deletions(-)
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 50ba74a34a37..9da8cccdf3fb 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -103,8 +103,6 @@ enum fixed_addresses {
#ifdef CONFIG_PARAVIRT
FIX_PARAVIRT_BOOTMAP,
#endif
- FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
- FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
#ifdef CONFIG_X86_INTEL_MID
FIX_LNW_VRTC,
#endif
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 11d5c710a94f..599203876c32 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -12,6 +12,7 @@
#include <linux/slab.h>
#include <linux/kdebug.h>
#include <linux/kprobes.h>
+#include <linux/mmu_context.h>
#include <asm/text-patching.h>
#include <asm/alternative.h>
#include <asm/sections.h>
@@ -684,41 +685,104 @@ __ro_after_init unsigned long poking_addr;
static void *__text_poke(void *addr, const void *opcode, size_t len)
{
+ bool cross_page_boundary = offset_in_page(addr) + len > PAGE_SIZE;
+ struct page *pages[2] = {NULL};
+ temp_mm_state_t prev;
unsigned long flags;
- char *vaddr;
- struct page *pages[2];
- int i;
+ pte_t pte, *ptep;
+ spinlock_t *ptl;
+ pgprot_t pgprot;
/*
- * While boot memory allocator is runnig we cannot use struct
- * pages as they are not yet initialized.
+ * While boot memory allocator is running we cannot use struct pages as
+ * they are not yet initialized. There is no way to recover.
*/
BUG_ON(!after_bootmem);
if (!core_kernel_text((unsigned long)addr)) {
pages[0] = vmalloc_to_page(addr);
- pages[1] = vmalloc_to_page(addr + PAGE_SIZE);
+ if (cross_page_boundary)
+ pages[1] = vmalloc_to_page(addr + PAGE_SIZE);
} else {
pages[0] = virt_to_page(addr);
WARN_ON(!PageReserved(pages[0]));
- pages[1] = virt_to_page(addr + PAGE_SIZE);
+ if (cross_page_boundary)
+ pages[1] = virt_to_page(addr + PAGE_SIZE);
}
- BUG_ON(!pages[0]);
+ /*
+ * If something went wrong, crash and burn since recovery paths are not
+ * implemented.
+ */
+ BUG_ON(!pages[0] || (cross_page_boundary && !pages[1]));
+
local_irq_save(flags);
- set_fixmap(FIX_TEXT_POKE0, page_to_phys(pages[0]));
- if (pages[1])
- set_fixmap(FIX_TEXT_POKE1, page_to_phys(pages[1]));
- vaddr = (char *)fix_to_virt(FIX_TEXT_POKE0);
- memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len);
- clear_fixmap(FIX_TEXT_POKE0);
- if (pages[1])
- clear_fixmap(FIX_TEXT_POKE1);
- local_flush_tlb();
- sync_core();
- /* Could also do a CLFLUSH here to speed up CPU recovery; but
- that causes hangs on some VIA CPUs. */
- for (i = 0; i < len; i++)
- BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]);
+
+ /*
+ * Map the page without the global bit, as TLB flushing is done with
+ * flush_tlb_mm_range(), which is intended for non-global PTEs.
+ */
+ pgprot = __pgprot(pgprot_val(PAGE_KERNEL) & ~_PAGE_GLOBAL);
+
+ /*
+ * The lock is not really needed, but this allows to avoid open-coding.
+ */
+ ptep = get_locked_pte(poking_mm, poking_addr, &ptl);
+
+ /*
+ * This must not fail; preallocated in poking_init().
+ */
+ VM_BUG_ON(!ptep);
+
+ pte = mk_pte(pages[0], pgprot);
+ set_pte_at(poking_mm, poking_addr, ptep, pte);
+
+ if (cross_page_boundary) {
+ pte = mk_pte(pages[1], pgprot);
+ set_pte_at(poking_mm, poking_addr + PAGE_SIZE, ptep + 1, pte);
+ }
+
+ /*
+ * Loading the temporary mm behaves as a compiler barrier, which
+ * guarantees that the PTE will be set at the time memcpy() is done.
+ */
+ prev = use_temporary_mm(poking_mm);
+
+ kasan_disable_current();
+ memcpy((u8 *)poking_addr + offset_in_page(addr), opcode, len);
+ kasan_enable_current();
+
+ /*
+ * Ensure that the PTE is only cleared after the instructions of memcpy
+ * were issued by using a compiler barrier.
+ */
+ barrier();
+
+ pte_clear(poking_mm, poking_addr, ptep);
+ if (cross_page_boundary)
+ pte_clear(poking_mm, poking_addr + PAGE_SIZE, ptep + 1);
+
+ /*
+ * Loading the previous page-table hierarchy requires a serializing
+ * instruction that already allows the core to see the updated version.
+ * Xen-PV is assumed to serialize execution in a similar manner.
+ */
+ unuse_temporary_mm(prev);
+
+ /*
+ * Flushing the TLB might involve IPIs, which would require enabled
+ * IRQs, but not if the mm is not used, as it is in this point.
+ */
+ flush_tlb_mm_range(poking_mm, poking_addr, poking_addr +
+ (cross_page_boundary ? 2 : 1) * PAGE_SIZE,
+ PAGE_SHIFT, false);
+
+ /*
+ * If the text does not match what we just wrote then something is
+ * fundamentally screwy; there's nothing we can really do about that.
+ */
+ BUG_ON(memcmp(addr, opcode, len));
+
+ pte_unmap_unlock(ptep, ptl);
local_irq_restore(flags);
return addr;
}
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index a21e1734fc1f..beb44e22afdf 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2318,8 +2318,6 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
#elif defined(CONFIG_X86_VSYSCALL_EMULATION)
case VSYSCALL_PAGE:
#endif
- case FIX_TEXT_POKE0:
- case FIX_TEXT_POKE1:
/* All local page mappings */
pte = pfn_pte(phys, prot);
break;
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/alternatives: Use temporary mm for text poking
2019-04-26 0:11 ` [PATCH v5 07/23] x86/alternative: Use temporary mm for text poking Nadav Amit
@ 2019-04-30 11:20 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:20 UTC (permalink / raw)
To: linux-tip-commits
Cc: kernel-hardening, ard.biesheuvel, torvalds, akpm, mingo,
linux-kernel, riel, namit, linux_dti, keescook, bp, hpa,
mhiramat, kristen, dave.hansen, luto, deneen.t.dock, peterz,
tglx, rick.p.edgecombe, will.deacon
Commit-ID: b3fd8e83ada0d51b71a84297480187e2d40e5ded
Gitweb: https://git.kernel.org/tip/b3fd8e83ada0d51b71a84297480187e2d40e5ded
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:27 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:52 +0200
x86/alternatives: Use temporary mm for text poking
text_poke() can potentially compromise security as it sets temporary
PTEs in the fixmap. These PTEs might be used to rewrite the kernel code
from other cores accidentally or maliciously, if an attacker gains the
ability to write onto kernel memory.
Moreover, since remote TLBs are not flushed after the temporary PTEs are
removed, the time-window in which the code is writable is not limited if
the fixmap PTEs - maliciously or accidentally - are cached in the TLB.
To address these potential security hazards, use a temporary mm for
patching the code.
Finally, text_poke() is also not conservative enough when mapping pages,
as it always tries to map 2 pages, even when a single one is sufficient.
So try to be more conservative, and do not map more than needed.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-8-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/fixmap.h | 2 -
arch/x86/kernel/alternative.c | 108 +++++++++++++++++++++++++++++++++---------
arch/x86/xen/mmu_pv.c | 2 -
3 files changed, 86 insertions(+), 26 deletions(-)
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 50ba74a34a37..9da8cccdf3fb 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -103,8 +103,6 @@ enum fixed_addresses {
#ifdef CONFIG_PARAVIRT
FIX_PARAVIRT_BOOTMAP,
#endif
- FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
- FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
#ifdef CONFIG_X86_INTEL_MID
FIX_LNW_VRTC,
#endif
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 11d5c710a94f..599203876c32 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -12,6 +12,7 @@
#include <linux/slab.h>
#include <linux/kdebug.h>
#include <linux/kprobes.h>
+#include <linux/mmu_context.h>
#include <asm/text-patching.h>
#include <asm/alternative.h>
#include <asm/sections.h>
@@ -684,41 +685,104 @@ __ro_after_init unsigned long poking_addr;
static void *__text_poke(void *addr, const void *opcode, size_t len)
{
+ bool cross_page_boundary = offset_in_page(addr) + len > PAGE_SIZE;
+ struct page *pages[2] = {NULL};
+ temp_mm_state_t prev;
unsigned long flags;
- char *vaddr;
- struct page *pages[2];
- int i;
+ pte_t pte, *ptep;
+ spinlock_t *ptl;
+ pgprot_t pgprot;
/*
- * While boot memory allocator is runnig we cannot use struct
- * pages as they are not yet initialized.
+ * While boot memory allocator is running we cannot use struct pages as
+ * they are not yet initialized. There is no way to recover.
*/
BUG_ON(!after_bootmem);
if (!core_kernel_text((unsigned long)addr)) {
pages[0] = vmalloc_to_page(addr);
- pages[1] = vmalloc_to_page(addr + PAGE_SIZE);
+ if (cross_page_boundary)
+ pages[1] = vmalloc_to_page(addr + PAGE_SIZE);
} else {
pages[0] = virt_to_page(addr);
WARN_ON(!PageReserved(pages[0]));
- pages[1] = virt_to_page(addr + PAGE_SIZE);
+ if (cross_page_boundary)
+ pages[1] = virt_to_page(addr + PAGE_SIZE);
}
- BUG_ON(!pages[0]);
+ /*
+ * If something went wrong, crash and burn since recovery paths are not
+ * implemented.
+ */
+ BUG_ON(!pages[0] || (cross_page_boundary && !pages[1]));
+
local_irq_save(flags);
- set_fixmap(FIX_TEXT_POKE0, page_to_phys(pages[0]));
- if (pages[1])
- set_fixmap(FIX_TEXT_POKE1, page_to_phys(pages[1]));
- vaddr = (char *)fix_to_virt(FIX_TEXT_POKE0);
- memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len);
- clear_fixmap(FIX_TEXT_POKE0);
- if (pages[1])
- clear_fixmap(FIX_TEXT_POKE1);
- local_flush_tlb();
- sync_core();
- /* Could also do a CLFLUSH here to speed up CPU recovery; but
- that causes hangs on some VIA CPUs. */
- for (i = 0; i < len; i++)
- BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]);
+
+ /*
+ * Map the page without the global bit, as TLB flushing is done with
+ * flush_tlb_mm_range(), which is intended for non-global PTEs.
+ */
+ pgprot = __pgprot(pgprot_val(PAGE_KERNEL) & ~_PAGE_GLOBAL);
+
+ /*
+ * The lock is not really needed, but this allows to avoid open-coding.
+ */
+ ptep = get_locked_pte(poking_mm, poking_addr, &ptl);
+
+ /*
+ * This must not fail; preallocated in poking_init().
+ */
+ VM_BUG_ON(!ptep);
+
+ pte = mk_pte(pages[0], pgprot);
+ set_pte_at(poking_mm, poking_addr, ptep, pte);
+
+ if (cross_page_boundary) {
+ pte = mk_pte(pages[1], pgprot);
+ set_pte_at(poking_mm, poking_addr + PAGE_SIZE, ptep + 1, pte);
+ }
+
+ /*
+ * Loading the temporary mm behaves as a compiler barrier, which
+ * guarantees that the PTE will be set at the time memcpy() is done.
+ */
+ prev = use_temporary_mm(poking_mm);
+
+ kasan_disable_current();
+ memcpy((u8 *)poking_addr + offset_in_page(addr), opcode, len);
+ kasan_enable_current();
+
+ /*
+ * Ensure that the PTE is only cleared after the instructions of memcpy
+ * were issued by using a compiler barrier.
+ */
+ barrier();
+
+ pte_clear(poking_mm, poking_addr, ptep);
+ if (cross_page_boundary)
+ pte_clear(poking_mm, poking_addr + PAGE_SIZE, ptep + 1);
+
+ /*
+ * Loading the previous page-table hierarchy requires a serializing
+ * instruction that already allows the core to see the updated version.
+ * Xen-PV is assumed to serialize execution in a similar manner.
+ */
+ unuse_temporary_mm(prev);
+
+ /*
+ * Flushing the TLB might involve IPIs, which would require enabled
+ * IRQs, but not if the mm is not used, as it is in this point.
+ */
+ flush_tlb_mm_range(poking_mm, poking_addr, poking_addr +
+ (cross_page_boundary ? 2 : 1) * PAGE_SIZE,
+ PAGE_SHIFT, false);
+
+ /*
+ * If the text does not match what we just wrote then something is
+ * fundamentally screwy; there's nothing we can really do about that.
+ */
+ BUG_ON(memcmp(addr, opcode, len));
+
+ pte_unmap_unlock(ptep, ptl);
local_irq_restore(flags);
return addr;
}
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index a21e1734fc1f..beb44e22afdf 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -2318,8 +2318,6 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
#elif defined(CONFIG_X86_VSYSCALL_EMULATION)
case VSYSCALL_PAGE:
#endif
- case FIX_TEXT_POKE0:
- case FIX_TEXT_POKE1:
/* All local page mappings */
pte = pfn_pte(phys, prot);
break;
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 08/23] x86/kgdb: Avoid redundant comparison of patched code
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (6 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 07/23] x86/alternative: Use temporary mm for text poking Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:20 ` [tip:x86/mm] " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 09/23] x86/ftrace: Set trampoline pages as executable Nadav Amit
` (15 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit
text_poke() already ensures that the written value is the correct one
and fails if that is not the case. There is no need for an additional
comparison. Remove it.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/kgdb.c | 14 +-------------
1 file changed, 1 insertion(+), 13 deletions(-)
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 2b203ee5b879..13b13311b792 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -747,7 +747,6 @@ void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
{
int err;
- char opc[BREAK_INSTR_SIZE];
bpt->type = BP_BREAKPOINT;
err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
@@ -766,11 +765,6 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
return -EBUSY;
text_poke_kgdb((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
BREAK_INSTR_SIZE);
- err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
- if (err)
- return err;
- if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE))
- return -EINVAL;
bpt->type = BP_POKE_BREAKPOINT;
return err;
@@ -778,9 +772,6 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
{
- int err;
- char opc[BREAK_INSTR_SIZE];
-
if (bpt->type != BP_POKE_BREAKPOINT)
goto knl_write;
/*
@@ -791,10 +782,7 @@ int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
goto knl_write;
text_poke_kgdb((void *)bpt->bpt_addr, bpt->saved_instr,
BREAK_INSTR_SIZE);
- err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
- if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE))
- goto knl_write;
- return err;
+ return 0;
knl_write:
return probe_kernel_write((char *)bpt->bpt_addr,
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/kgdb: Avoid redundant comparison of patched code
2019-04-26 0:11 ` [PATCH v5 08/23] x86/kgdb: Avoid redundant comparison of patched code Nadav Amit
@ 2019-04-30 11:20 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:20 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux_dti, kristen, bp, deneen.t.dock, linux-kernel, peterz,
akpm, riel, namit, mingo, rick.p.edgecombe, tglx, dave.hansen,
ard.biesheuvel, hpa, torvalds, luto, will.deacon,
kernel-hardening
Commit-ID: 86a22057127d1c0462a18901421bf1ff89491392
Gitweb: https://git.kernel.org/tip/86a22057127d1c0462a18901421bf1ff89491392
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:28 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:53 +0200
x86/kgdb: Avoid redundant comparison of patched code
text_poke() already ensures that the written value is the correct one
and fails if that is not the case. There is no need for an additional
comparison. Remove it.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-9-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/kgdb.c | 14 +-------------
1 file changed, 1 insertion(+), 13 deletions(-)
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 2b203ee5b879..13b13311b792 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -747,7 +747,6 @@ void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
{
int err;
- char opc[BREAK_INSTR_SIZE];
bpt->type = BP_BREAKPOINT;
err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
@@ -766,11 +765,6 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
return -EBUSY;
text_poke_kgdb((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr,
BREAK_INSTR_SIZE);
- err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
- if (err)
- return err;
- if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE))
- return -EINVAL;
bpt->type = BP_POKE_BREAKPOINT;
return err;
@@ -778,9 +772,6 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
{
- int err;
- char opc[BREAK_INSTR_SIZE];
-
if (bpt->type != BP_POKE_BREAKPOINT)
goto knl_write;
/*
@@ -791,10 +782,7 @@ int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
goto knl_write;
text_poke_kgdb((void *)bpt->bpt_addr, bpt->saved_instr,
BREAK_INSTR_SIZE);
- err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE);
- if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE))
- goto knl_write;
- return err;
+ return 0;
knl_write:
return probe_kernel_write((char *)bpt->bpt_addr,
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 09/23] x86/ftrace: Set trampoline pages as executable
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (7 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 08/23] x86/kgdb: Avoid redundant comparison of patched code Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:21 ` [tip:x86/mm] " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 10/23] x86/kprobes: Set instruction page " Nadav Amit
` (14 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit
Since alloc_module() will not set the pages as executable soon, set
ftrace trampoline pages as executable after they are allocated.
For the time being, do not change ftrace to use the text_poke()
interface. As a result, ftrace still breaks W^X.
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/ftrace.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index ef49517f6bb2..53ba1aa3a01f 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -730,6 +730,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
unsigned long end_offset;
unsigned long op_offset;
unsigned long offset;
+ unsigned long npages;
unsigned long size;
unsigned long retq;
unsigned long *ptr;
@@ -762,6 +763,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
return 0;
*tramp_size = size + RET_SIZE + sizeof(void *);
+ npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE);
/* Copy ftrace_caller onto the trampoline memory */
ret = probe_kernel_read(trampoline, (void *)start_offset, size);
@@ -806,6 +808,12 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
/* ALLOC_TRAMP flags lets us know we created it */
ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
+ /*
+ * Module allocation needs to be completed by making the page
+ * executable. The page is still writable, which is a security hazard,
+ * but anyhow ftrace breaks W^X completely.
+ */
+ set_memory_x((unsigned long)trampoline, npages);
return (unsigned long)trampoline;
fail:
tramp_free(trampoline, *tramp_size);
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/ftrace: Set trampoline pages as executable
2019-04-26 0:11 ` [PATCH v5 09/23] x86/ftrace: Set trampoline pages as executable Nadav Amit
@ 2019-04-30 11:21 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:21 UTC (permalink / raw)
To: linux-tip-commits
Cc: bp, linux-kernel, kernel-hardening, luto, ard.biesheuvel, akpm,
linux_dti, dave.hansen, tglx, torvalds, rick.p.edgecombe,
will.deacon, rostedt, namit, deneen.t.dock, kristen, peterz,
mingo, hpa, riel
Commit-ID: 3c0dab44e22782359a0a706cbce72de99a22aa75
Gitweb: https://git.kernel.org/tip/3c0dab44e22782359a0a706cbce72de99a22aa75
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:29 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:53 +0200
x86/ftrace: Set trampoline pages as executable
Since alloc_module() will not set the pages as executable soon, set
ftrace trampoline pages as executable after they are allocated.
For the time being, do not change ftrace to use the text_poke()
interface. As a result, ftrace still breaks W^X.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-10-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/ftrace.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index ef49517f6bb2..53ba1aa3a01f 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -730,6 +730,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
unsigned long end_offset;
unsigned long op_offset;
unsigned long offset;
+ unsigned long npages;
unsigned long size;
unsigned long retq;
unsigned long *ptr;
@@ -762,6 +763,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
return 0;
*tramp_size = size + RET_SIZE + sizeof(void *);
+ npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE);
/* Copy ftrace_caller onto the trampoline memory */
ret = probe_kernel_read(trampoline, (void *)start_offset, size);
@@ -806,6 +808,12 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
/* ALLOC_TRAMP flags lets us know we created it */
ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
+ /*
+ * Module allocation needs to be completed by making the page
+ * executable. The page is still writable, which is a security hazard,
+ * but anyhow ftrace breaks W^X completely.
+ */
+ set_memory_x((unsigned long)trampoline, npages);
return (unsigned long)trampoline;
fail:
tramp_free(trampoline, *tramp_size);
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 10/23] x86/kprobes: Set instruction page as executable
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (8 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 09/23] x86/ftrace: Set trampoline pages as executable Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:22 ` [tip:x86/mm] " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 11/23] x86/module: Avoid breaking W^X while loading modules Nadav Amit
` (13 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit
Set the page as executable after allocation. This patch is a
preparatory patch for a following patch that makes module allocated
pages non-executable.
While at it, do some small cleanup of what appears to be unnecessary
masking.
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/kprobes/core.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index a034cb808e7e..1591852d3ac4 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -431,8 +431,20 @@ void *alloc_insn_page(void)
void *page;
page = module_alloc(PAGE_SIZE);
- if (page)
- set_memory_ro((unsigned long)page & PAGE_MASK, 1);
+ if (!page)
+ return NULL;
+
+ /*
+ * First make the page read-only, and only then make it executable to
+ * prevent it from being W+X in between.
+ */
+ set_memory_ro((unsigned long)page, 1);
+
+ /*
+ * TODO: Once additional kernel code protection mechanisms are set, ensure
+ * that the page was not maliciously altered and it is still zeroed.
+ */
+ set_memory_x((unsigned long)page, 1);
return page;
}
@@ -440,8 +452,12 @@ void *alloc_insn_page(void)
/* Recover page to RW mode before releasing it */
void free_insn_page(void *page)
{
- set_memory_nx((unsigned long)page & PAGE_MASK, 1);
- set_memory_rw((unsigned long)page & PAGE_MASK, 1);
+ /*
+ * First make the page non-executable, and only then make it writable to
+ * prevent it from being W+X in between.
+ */
+ set_memory_nx((unsigned long)page, 1);
+ set_memory_rw((unsigned long)page, 1);
module_memfree(page);
}
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/kprobes: Set instruction page as executable
2019-04-26 0:11 ` [PATCH v5 10/23] x86/kprobes: Set instruction page " Nadav Amit
@ 2019-04-30 11:22 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:22 UTC (permalink / raw)
To: linux-tip-commits
Cc: peterz, namit, mingo, akpm, tglx, rick.p.edgecombe, hpa,
ard.biesheuvel, dave.hansen, torvalds, kristen, linux_dti, bp,
deneen.t.dock, riel, luto, will.deacon, kernel-hardening,
linux-kernel
Commit-ID: 7298e24f904224fa79eb8fd7e0fbd78950ccf2db
Gitweb: https://git.kernel.org/tip/7298e24f904224fa79eb8fd7e0fbd78950ccf2db
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:30 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:54 +0200
x86/kprobes: Set instruction page as executable
Set the page as executable after allocation. This patch is a
preparatory patch for a following patch that makes module allocated
pages non-executable.
While at it, do some small cleanup of what appears to be unnecessary
masking.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-11-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/kprobes/core.c | 24 ++++++++++++++++++++----
1 file changed, 20 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index fed46ddb1eef..06058c44ab57 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -431,8 +431,20 @@ void *alloc_insn_page(void)
void *page;
page = module_alloc(PAGE_SIZE);
- if (page)
- set_memory_ro((unsigned long)page & PAGE_MASK, 1);
+ if (!page)
+ return NULL;
+
+ /*
+ * First make the page read-only, and only then make it executable to
+ * prevent it from being W+X in between.
+ */
+ set_memory_ro((unsigned long)page, 1);
+
+ /*
+ * TODO: Once additional kernel code protection mechanisms are set, ensure
+ * that the page was not maliciously altered and it is still zeroed.
+ */
+ set_memory_x((unsigned long)page, 1);
return page;
}
@@ -440,8 +452,12 @@ void *alloc_insn_page(void)
/* Recover page to RW mode before releasing it */
void free_insn_page(void *page)
{
- set_memory_nx((unsigned long)page & PAGE_MASK, 1);
- set_memory_rw((unsigned long)page & PAGE_MASK, 1);
+ /*
+ * First make the page non-executable, and only then make it writable to
+ * prevent it from being W+X in between.
+ */
+ set_memory_nx((unsigned long)page, 1);
+ set_memory_rw((unsigned long)page, 1);
module_memfree(page);
}
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 11/23] x86/module: Avoid breaking W^X while loading modules
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (9 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 10/23] x86/kprobes: Set instruction page " Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:22 ` [tip:x86/mm] x86/modules: " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 12/23] x86/jump-label: Remove support for custom poker Nadav Amit
` (12 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Kees Cook,
Dave Hansen, Masami Hiramatsu, Jessica Yu
When modules and BPF filters are loaded, there is a time window in
which some memory is both writable and executable. An attacker that has
already found another vulnerability (e.g., a dangling pointer) might be
able to exploit this behavior to overwrite kernel code. Prevent having
writable executable PTEs in this stage.
In addition, avoiding having W+X mappings can also slightly simplify the
patching of modules code on initialization (e.g., by alternatives and
static-key), as would be done in the next patch. This was actually the
main motivation for this patch.
To avoid having W+X mappings, set them initially as RW (NX) and after
they are set as RO set them as X as well. Setting them as executable is
done as a separate step to avoid one core in which the old PTE is cached
(hence writable), and another which sees the updated PTE (executable),
which would break the W^X protection.
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/alternative.c | 28 +++++++++++++++++++++-------
arch/x86/kernel/module.c | 2 +-
include/linux/filter.h | 1 +
kernel/module.c | 5 +++++
4 files changed, 28 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 599203876c32..3d2b6b6fb20c 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -668,15 +668,29 @@ void __init alternative_instructions(void)
* handlers seeing an inconsistent instruction while you patch.
*/
void *__init_or_module text_poke_early(void *addr, const void *opcode,
- size_t len)
+ size_t len)
{
unsigned long flags;
- local_irq_save(flags);
- memcpy(addr, opcode, len);
- local_irq_restore(flags);
- sync_core();
- /* Could also do a CLFLUSH here to speed up CPU recovery; but
- that causes hangs on some VIA CPUs. */
+
+ if (boot_cpu_has(X86_FEATURE_NX) &&
+ is_module_text_address((unsigned long)addr)) {
+ /*
+ * Modules text is marked initially as non-executable, so the
+ * code cannot be running and speculative code-fetches are
+ * prevented. Just change the code.
+ */
+ memcpy(addr, opcode, len);
+ } else {
+ local_irq_save(flags);
+ memcpy(addr, opcode, len);
+ local_irq_restore(flags);
+ sync_core();
+
+ /*
+ * Could also do a CLFLUSH here to speed up CPU recovery; but
+ * that causes hangs on some VIA CPUs.
+ */
+ }
return addr;
}
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index b052e883dd8c..cfa3106faee4 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -87,7 +87,7 @@ void *module_alloc(unsigned long size)
p = __vmalloc_node_range(size, MODULE_ALIGN,
MODULES_VADDR + get_module_load_offset(),
MODULES_END, GFP_KERNEL,
- PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
+ PAGE_KERNEL, 0, NUMA_NO_NODE,
__builtin_return_address(0));
if (p && (kasan_module_alloc(p, size) < 0)) {
vfree(p);
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 6074aa064b54..14ec3bdad9a9 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -746,6 +746,7 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
{
set_memory_ro((unsigned long)hdr, hdr->pages);
+ set_memory_x((unsigned long)hdr, hdr->pages);
}
static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
diff --git a/kernel/module.c b/kernel/module.c
index 0b9aa8ab89f0..2b2845ae983e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1950,8 +1950,13 @@ void module_enable_ro(const struct module *mod, bool after_init)
return;
frob_text(&mod->core_layout, set_memory_ro);
+ frob_text(&mod->core_layout, set_memory_x);
+
frob_rodata(&mod->core_layout, set_memory_ro);
+
frob_text(&mod->init_layout, set_memory_ro);
+ frob_text(&mod->init_layout, set_memory_x);
+
frob_rodata(&mod->init_layout, set_memory_ro);
if (after_init)
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/modules: Avoid breaking W^X while loading modules
2019-04-26 0:11 ` [PATCH v5 11/23] x86/module: Avoid breaking W^X while loading modules Nadav Amit
@ 2019-04-30 11:22 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:22 UTC (permalink / raw)
To: linux-tip-commits
Cc: bp, ard.biesheuvel, deneen.t.dock, jeyu, torvalds, linux_dti,
rick.p.edgecombe, kernel-hardening, keescook, mhiramat,
dave.hansen, luto, peterz, namit, luto, kristen, mingo, tglx,
riel, linux-kernel, will.deacon, akpm, hpa
Commit-ID: f2c65fb3221adc6b73b0549fc7ba892022db9797
Gitweb: https://git.kernel.org/tip/f2c65fb3221adc6b73b0549fc7ba892022db9797
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:31 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:55 +0200
x86/modules: Avoid breaking W^X while loading modules
When modules and BPF filters are loaded, there is a time window in
which some memory is both writable and executable. An attacker that has
already found another vulnerability (e.g., a dangling pointer) might be
able to exploit this behavior to overwrite kernel code. Prevent having
writable executable PTEs in this stage.
In addition, avoiding having W+X mappings can also slightly simplify the
patching of modules code on initialization (e.g., by alternatives and
static-key), as would be done in the next patch. This was actually the
main motivation for this patch.
To avoid having W+X mappings, set them initially as RW (NX) and after
they are set as RO set them as X as well. Setting them as executable is
done as a separate step to avoid one core in which the old PTE is cached
(hence writable), and another which sees the updated PTE (executable),
which would break the W^X protection.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: https://lkml.kernel.org/r/20190426001143.4983-12-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/alternative.c | 28 +++++++++++++++++++++-------
arch/x86/kernel/module.c | 2 +-
include/linux/filter.h | 1 +
kernel/module.c | 5 +++++
4 files changed, 28 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 599203876c32..3d2b6b6fb20c 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -668,15 +668,29 @@ void __init alternative_instructions(void)
* handlers seeing an inconsistent instruction while you patch.
*/
void *__init_or_module text_poke_early(void *addr, const void *opcode,
- size_t len)
+ size_t len)
{
unsigned long flags;
- local_irq_save(flags);
- memcpy(addr, opcode, len);
- local_irq_restore(flags);
- sync_core();
- /* Could also do a CLFLUSH here to speed up CPU recovery; but
- that causes hangs on some VIA CPUs. */
+
+ if (boot_cpu_has(X86_FEATURE_NX) &&
+ is_module_text_address((unsigned long)addr)) {
+ /*
+ * Modules text is marked initially as non-executable, so the
+ * code cannot be running and speculative code-fetches are
+ * prevented. Just change the code.
+ */
+ memcpy(addr, opcode, len);
+ } else {
+ local_irq_save(flags);
+ memcpy(addr, opcode, len);
+ local_irq_restore(flags);
+ sync_core();
+
+ /*
+ * Could also do a CLFLUSH here to speed up CPU recovery; but
+ * that causes hangs on some VIA CPUs.
+ */
+ }
return addr;
}
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index b052e883dd8c..cfa3106faee4 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -87,7 +87,7 @@ void *module_alloc(unsigned long size)
p = __vmalloc_node_range(size, MODULE_ALIGN,
MODULES_VADDR + get_module_load_offset(),
MODULES_END, GFP_KERNEL,
- PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
+ PAGE_KERNEL, 0, NUMA_NO_NODE,
__builtin_return_address(0));
if (p && (kasan_module_alloc(p, size) < 0)) {
vfree(p);
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 6074aa064b54..14ec3bdad9a9 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -746,6 +746,7 @@ static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
{
set_memory_ro((unsigned long)hdr, hdr->pages);
+ set_memory_x((unsigned long)hdr, hdr->pages);
}
static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
diff --git a/kernel/module.c b/kernel/module.c
index 0b9aa8ab89f0..2b2845ae983e 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1950,8 +1950,13 @@ void module_enable_ro(const struct module *mod, bool after_init)
return;
frob_text(&mod->core_layout, set_memory_ro);
+ frob_text(&mod->core_layout, set_memory_x);
+
frob_rodata(&mod->core_layout, set_memory_ro);
+
frob_text(&mod->init_layout, set_memory_ro);
+ frob_text(&mod->init_layout, set_memory_x);
+
frob_rodata(&mod->init_layout, set_memory_ro);
if (after_init)
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 12/23] x86/jump-label: Remove support for custom poker
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (10 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 11/23] x86/module: Avoid breaking W^X while loading modules Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:23 ` [tip:x86/mm] x86/jump-label: Remove support for custom text poker tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 13/23] x86/alternative: Remove the return value of text_poke_*() Nadav Amit
` (11 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Kees Cook,
Dave Hansen, Masami Hiramatsu
There are only two types of poking: early and breakpoint based. The use
of a function pointer to perform poking complicates the code and is
probably inefficient due to the use of indirect branches.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/jump_label.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index e7d8c636b228..e631c358f7f4 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -37,7 +37,6 @@ static void bug_at(unsigned char *ip, int line)
static void __ref __jump_label_transform(struct jump_entry *entry,
enum jump_label_type type,
- void *(*poker)(void *, const void *, size_t),
int init)
{
union jump_code_union jmp;
@@ -50,14 +49,6 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
jmp.offset = jump_entry_target(entry) -
(jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
- /*
- * As long as only a single processor is running and the code is still
- * not marked as RO, text_poke_early() can be used; Checking that
- * system_state is SYSTEM_BOOTING guarantees it.
- */
- if (system_state == SYSTEM_BOOTING)
- poker = text_poke_early;
-
if (type == JUMP_LABEL_JMP) {
if (init) {
expect = default_nop; line = __LINE__;
@@ -80,16 +71,19 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
bug_at((void *)jump_entry_code(entry), line);
/*
- * Make text_poke_bp() a default fallback poker.
+ * As long as only a single processor is running and the code is still
+ * not marked as RO, text_poke_early() can be used; Checking that
+ * system_state is SYSTEM_BOOTING guarantees it. It will be set to
+ * SYSTEM_SCHEDULING before other cores are awaken and before the
+ * code is write-protected.
*
* At the time the change is being done, just ignore whether we
* are doing nop -> jump or jump -> nop transition, and assume
* always nop being the 'currently valid' instruction
- *
*/
- if (poker) {
- (*poker)((void *)jump_entry_code(entry), code,
- JUMP_LABEL_NOP_SIZE);
+ if (init || system_state == SYSTEM_BOOTING) {
+ text_poke_early((void *)jump_entry_code(entry), code,
+ JUMP_LABEL_NOP_SIZE);
return;
}
@@ -101,7 +95,7 @@ void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
{
mutex_lock(&text_mutex);
- __jump_label_transform(entry, type, NULL, 0);
+ __jump_label_transform(entry, type, 0);
mutex_unlock(&text_mutex);
}
@@ -131,5 +125,5 @@ __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry,
jlstate = JL_STATE_NO_UPDATE;
}
if (jlstate == JL_STATE_UPDATE)
- __jump_label_transform(entry, type, text_poke_early, 1);
+ __jump_label_transform(entry, type, 1);
}
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/jump-label: Remove support for custom text poker
2019-04-26 0:11 ` [PATCH v5 12/23] x86/jump-label: Remove support for custom poker Nadav Amit
@ 2019-04-30 11:23 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:23 UTC (permalink / raw)
To: linux-tip-commits
Cc: luto, bp, dave.hansen, linux-kernel, akpm, tglx, mhiramat,
kernel-hardening, deneen.t.dock, linux_dti, hpa, riel, mingo,
kristen, keescook, namit, peterz, will.deacon, ard.biesheuvel,
rick.p.edgecombe, torvalds
Commit-ID: bb0a008d6a2c543efc11313b448d2f26f91dc4f8
Gitweb: https://git.kernel.org/tip/bb0a008d6a2c543efc11313b448d2f26f91dc4f8
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:32 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:55 +0200
x86/jump-label: Remove support for custom text poker
There are only two types of text poking: early and breakpoint based. The use
of a function pointer to perform text poking complicates the code and is
probably inefficient due to the use of indirect branches.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-13-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/jump_label.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index e7d8c636b228..e631c358f7f4 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -37,7 +37,6 @@ static void bug_at(unsigned char *ip, int line)
static void __ref __jump_label_transform(struct jump_entry *entry,
enum jump_label_type type,
- void *(*poker)(void *, const void *, size_t),
int init)
{
union jump_code_union jmp;
@@ -50,14 +49,6 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
jmp.offset = jump_entry_target(entry) -
(jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
- /*
- * As long as only a single processor is running and the code is still
- * not marked as RO, text_poke_early() can be used; Checking that
- * system_state is SYSTEM_BOOTING guarantees it.
- */
- if (system_state == SYSTEM_BOOTING)
- poker = text_poke_early;
-
if (type == JUMP_LABEL_JMP) {
if (init) {
expect = default_nop; line = __LINE__;
@@ -80,16 +71,19 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
bug_at((void *)jump_entry_code(entry), line);
/*
- * Make text_poke_bp() a default fallback poker.
+ * As long as only a single processor is running and the code is still
+ * not marked as RO, text_poke_early() can be used; Checking that
+ * system_state is SYSTEM_BOOTING guarantees it. It will be set to
+ * SYSTEM_SCHEDULING before other cores are awaken and before the
+ * code is write-protected.
*
* At the time the change is being done, just ignore whether we
* are doing nop -> jump or jump -> nop transition, and assume
* always nop being the 'currently valid' instruction
- *
*/
- if (poker) {
- (*poker)((void *)jump_entry_code(entry), code,
- JUMP_LABEL_NOP_SIZE);
+ if (init || system_state == SYSTEM_BOOTING) {
+ text_poke_early((void *)jump_entry_code(entry), code,
+ JUMP_LABEL_NOP_SIZE);
return;
}
@@ -101,7 +95,7 @@ void arch_jump_label_transform(struct jump_entry *entry,
enum jump_label_type type)
{
mutex_lock(&text_mutex);
- __jump_label_transform(entry, type, NULL, 0);
+ __jump_label_transform(entry, type, 0);
mutex_unlock(&text_mutex);
}
@@ -131,5 +125,5 @@ __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry,
jlstate = JL_STATE_NO_UPDATE;
}
if (jlstate == JL_STATE_UPDATE)
- __jump_label_transform(entry, type, text_poke_early, 1);
+ __jump_label_transform(entry, type, 1);
}
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 13/23] x86/alternative: Remove the return value of text_poke_*()
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (11 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 12/23] x86/jump-label: Remove support for custom poker Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:24 ` [tip:x86/mm] x86/alternatives: " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 14/23] x86/mm/cpa: Add set_direct_map_ functions Nadav Amit
` (10 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Kees Cook,
Dave Hansen, Masami Hiramatsu
The return value of text_poke_early() and text_poke_bp() is useless.
Remove it.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/include/asm/text-patching.h | 4 ++--
arch/x86/kernel/alternative.c | 11 ++++-------
2 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index a75eed841eed..c90678fd391a 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -18,7 +18,7 @@ static inline void apply_paravirt(struct paravirt_patch_site *start,
#define __parainstructions_end NULL
#endif
-extern void *text_poke_early(void *addr, const void *opcode, size_t len);
+extern void text_poke_early(void *addr, const void *opcode, size_t len);
/*
* Clear and restore the kernel write-protection flag on the local CPU.
@@ -37,7 +37,7 @@ extern void *text_poke_early(void *addr, const void *opcode, size_t len);
extern void *text_poke(void *addr, const void *opcode, size_t len);
extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len);
extern int poke_int3_handler(struct pt_regs *regs);
-extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
+extern void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
extern int after_bootmem;
extern __ro_after_init struct mm_struct *poking_mm;
extern __ro_after_init unsigned long poking_addr;
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 3d2b6b6fb20c..18f959975ea0 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -265,7 +265,7 @@ static void __init_or_module add_nops(void *insns, unsigned int len)
extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
extern s32 __smp_locks[], __smp_locks_end[];
-void *text_poke_early(void *addr, const void *opcode, size_t len);
+void text_poke_early(void *addr, const void *opcode, size_t len);
/*
* Are we looking at a near JMP with a 1 or 4-byte displacement.
@@ -667,8 +667,8 @@ void __init alternative_instructions(void)
* instructions. And on the local CPU you need to be protected again NMI or MCE
* handlers seeing an inconsistent instruction while you patch.
*/
-void *__init_or_module text_poke_early(void *addr, const void *opcode,
- size_t len)
+void __init_or_module text_poke_early(void *addr, const void *opcode,
+ size_t len)
{
unsigned long flags;
@@ -691,7 +691,6 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode,
* that causes hangs on some VIA CPUs.
*/
}
- return addr;
}
__ro_after_init struct mm_struct *poking_mm;
@@ -893,7 +892,7 @@ NOKPROBE_SYMBOL(poke_int3_handler);
* replacing opcode
* - sync cores
*/
-void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
+void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
{
unsigned char int3 = 0xcc;
@@ -935,7 +934,5 @@ void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
* the writing of the new instruction.
*/
bp_patching_in_progress = false;
-
- return addr;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/alternatives: Remove the return value of text_poke_*()
2019-04-26 0:11 ` [PATCH v5 13/23] x86/alternative: Remove the return value of text_poke_*() Nadav Amit
@ 2019-04-30 11:24 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:24 UTC (permalink / raw)
To: linux-tip-commits
Cc: mhiramat, torvalds, kernel-hardening, tglx, rick.p.edgecombe,
ard.biesheuvel, will.deacon, linux-kernel, hpa, kristen, akpm,
linux_dti, dave.hansen, deneen.t.dock, namit, riel, mingo, luto,
keescook, peterz, bp
Commit-ID: 0a203df5cf0eb709be4f190314e262b72d7e5b76
Gitweb: https://git.kernel.org/tip/0a203df5cf0eb709be4f190314e262b72d7e5b76
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:33 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:56 +0200
x86/alternatives: Remove the return value of text_poke_*()
The return value of text_poke_early() and text_poke_bp() is useless.
Remove it.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-14-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/text-patching.h | 4 ++--
arch/x86/kernel/alternative.c | 11 ++++-------
2 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index a75eed841eed..c90678fd391a 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -18,7 +18,7 @@ static inline void apply_paravirt(struct paravirt_patch_site *start,
#define __parainstructions_end NULL
#endif
-extern void *text_poke_early(void *addr, const void *opcode, size_t len);
+extern void text_poke_early(void *addr, const void *opcode, size_t len);
/*
* Clear and restore the kernel write-protection flag on the local CPU.
@@ -37,7 +37,7 @@ extern void *text_poke_early(void *addr, const void *opcode, size_t len);
extern void *text_poke(void *addr, const void *opcode, size_t len);
extern void *text_poke_kgdb(void *addr, const void *opcode, size_t len);
extern int poke_int3_handler(struct pt_regs *regs);
-extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
+extern void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
extern int after_bootmem;
extern __ro_after_init struct mm_struct *poking_mm;
extern __ro_after_init unsigned long poking_addr;
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 3d2b6b6fb20c..18f959975ea0 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -265,7 +265,7 @@ static void __init_or_module add_nops(void *insns, unsigned int len)
extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
extern s32 __smp_locks[], __smp_locks_end[];
-void *text_poke_early(void *addr, const void *opcode, size_t len);
+void text_poke_early(void *addr, const void *opcode, size_t len);
/*
* Are we looking at a near JMP with a 1 or 4-byte displacement.
@@ -667,8 +667,8 @@ void __init alternative_instructions(void)
* instructions. And on the local CPU you need to be protected again NMI or MCE
* handlers seeing an inconsistent instruction while you patch.
*/
-void *__init_or_module text_poke_early(void *addr, const void *opcode,
- size_t len)
+void __init_or_module text_poke_early(void *addr, const void *opcode,
+ size_t len)
{
unsigned long flags;
@@ -691,7 +691,6 @@ void *__init_or_module text_poke_early(void *addr, const void *opcode,
* that causes hangs on some VIA CPUs.
*/
}
- return addr;
}
__ro_after_init struct mm_struct *poking_mm;
@@ -893,7 +892,7 @@ NOKPROBE_SYMBOL(poke_int3_handler);
* replacing opcode
* - sync cores
*/
-void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
+void text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
{
unsigned char int3 = 0xcc;
@@ -935,7 +934,5 @@ void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler)
* the writing of the new instruction.
*/
bp_patching_in_progress = false;
-
- return addr;
}
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 14/23] x86/mm/cpa: Add set_direct_map_ functions
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (12 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 13/23] x86/alternative: Remove the return value of text_poke_*() Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-26 16:40 ` Linus Torvalds
2019-04-30 11:24 ` [tip:x86/mm] x86/mm/cpa: Add set_direct_map_*() functions tip-bot for Rick Edgecombe
2019-04-26 0:11 ` [PATCH v5 15/23] mm: Make hibernate handle unmapped pages Nadav Amit
` (9 subsequent siblings)
23 siblings, 2 replies; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe
From: Rick Edgecombe <rick.p.edgecombe@intel.com>
Add two new functions set_direct_map_default_noflush() and
set_direct_map_invalid_noflush() for setting the direct map alias for the
page to its default valid permissions and to an invalid state that cannot
be cached in a TLB, respectively. These functions do not flush the TLB.
Note, __kernel_map_pages() does something similar but flushes the TLB and
doesn't reset the permission bits to default on all architectures.
Also add an ARCH config ARCH_HAS_SET_DIRECT_MAP for specifying whether
these have an actual implementation or a default empty one.
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/Kconfig | 4 ++++
arch/x86/Kconfig | 1 +
arch/x86/include/asm/set_memory.h | 3 +++
arch/x86/mm/pageattr.c | 14 +++++++++++---
include/linux/set_memory.h | 11 +++++++++++
5 files changed, 30 insertions(+), 3 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 3ab446bd12ef..5e43fcbad4ca 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -249,6 +249,10 @@ config ARCH_HAS_FORTIFY_SOURCE
config ARCH_HAS_SET_MEMORY
bool
+# Select if arch has all set_direct_map_invalid/default() functions
+config ARCH_HAS_SET_DIRECT_MAP
+ bool
+
# Select if arch init_task must go in the __init_task_data section
config ARCH_TASK_STRUCT_ON_STACK
bool
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2ec5e850b807..45d788354376 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -66,6 +66,7 @@ config X86
select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
select ARCH_HAS_SET_MEMORY
+ select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_STRICT_MODULE_RWX
select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index 07a25753e85c..ae7b909dc242 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -85,6 +85,9 @@ int set_pages_nx(struct page *page, int numpages);
int set_pages_ro(struct page *page, int numpages);
int set_pages_rw(struct page *page, int numpages);
+int set_direct_map_invalid_noflush(struct page *page);
+int set_direct_map_default_noflush(struct page *page);
+
extern int kernel_set_to_readonly;
void set_kernel_text_rw(void);
void set_kernel_text_ro(void);
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 4c570612e24e..3574550192c6 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -2209,8 +2209,6 @@ int set_pages_rw(struct page *page, int numpages)
return set_memory_rw(addr, numpages);
}
-#ifdef CONFIG_DEBUG_PAGEALLOC
-
static int __set_pages_p(struct page *page, int numpages)
{
unsigned long tempaddr = (unsigned long) page_address(page);
@@ -2249,6 +2247,17 @@ static int __set_pages_np(struct page *page, int numpages)
return __change_page_attr_set_clr(&cpa, 0);
}
+int set_direct_map_invalid_noflush(struct page *page)
+{
+ return __set_pages_np(page, 1);
+}
+
+int set_direct_map_default_noflush(struct page *page)
+{
+ return __set_pages_p(page, 1);
+}
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
if (PageHighMem(page))
@@ -2282,7 +2291,6 @@ void __kernel_map_pages(struct page *page, int numpages, int enable)
}
#ifdef CONFIG_HIBERNATION
-
bool kernel_page_present(struct page *page)
{
unsigned int level;
diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
index 2a986d282a97..b5071497b8cb 100644
--- a/include/linux/set_memory.h
+++ b/include/linux/set_memory.h
@@ -17,6 +17,17 @@ static inline int set_memory_x(unsigned long addr, int numpages) { return 0; }
static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
#endif
+#ifndef CONFIG_ARCH_HAS_SET_DIRECT_MAP
+static inline int set_direct_map_invalid_noflush(struct page *page)
+{
+ return 0;
+}
+static inline int set_direct_map_default_noflush(struct page *page)
+{
+ return 0;
+}
+#endif
+
#ifndef set_mce_nospec
static inline int set_mce_nospec(unsigned long pfn)
{
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* Re: [PATCH v5 14/23] x86/mm/cpa: Add set_direct_map_ functions
2019-04-26 0:11 ` [PATCH v5 14/23] x86/mm/cpa: Add set_direct_map_ functions Nadav Amit
@ 2019-04-26 16:40 ` Linus Torvalds
2019-04-26 16:43 ` Nadav Amit
2019-04-30 11:24 ` [tip:x86/mm] x86/mm/cpa: Add set_direct_map_*() functions tip-bot for Rick Edgecombe
1 sibling, 1 reply; 49+ messages in thread
From: Linus Torvalds @ 2019-04-26 16:40 UTC (permalink / raw)
To: Nadav Amit
Cc: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar,
lkml, the arch/x86 maintainers, H. Peter Anvin, Thomas Gleixner,
Nadav Amit, Dave Hansen, linux_dti, linux-integrity, LSM List,
Andrew Morton, kernel-hardening, Linux-MM, Will Deacon,
Ard Biesheuvel, kristen, deneen.t.dock, Rick Edgecombe
Nadav,
I get
dmarc=fail (p=QUARANTINE sp=NONE dis=QUARANTINE) header.from=vmware.com
for these emails, because they lack the vmware DKIM signature.
It clearly did go through some vmware mail servers, but apparently not
the *right* external vmware SMTP gateway.
Please check with vmware MIS what the right SMTP setup for git-send-email is.
Linus
On Fri, Apr 26, 2019 at 12:32 AM Nadav Amit <namit@vmware.com> wrote:
>
> From: Rick Edgecombe <rick.p.edgecombe@intel.com>
>
> Add two new functions set_direct_map_default_noflush() and
> set_direct_map_invalid_noflush() for setting the direct map alias for the
> page to its default valid permissions and to an invalid state that cannot
> be cached in a TLB, respectively. These functions do not flush the TLB.
...
^ permalink raw reply [flat|nested] 49+ messages in thread* Re: [PATCH v5 14/23] x86/mm/cpa: Add set_direct_map_ functions
2019-04-26 16:40 ` Linus Torvalds
@ 2019-04-26 16:43 ` Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 16:43 UTC (permalink / raw)
To: Linus Torvalds
Cc: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar,
lkml, the arch/x86 maintainers, H. Peter Anvin, Thomas Gleixner,
Dave Hansen, Damian Tometzki, linux-integrity, LSM List,
Andrew Morton, Kernel Hardening, Linux-MM, Will Deacon,
Ard Biesheuvel, kristen, deneen.t.dock, Rick Edgecombe
> On Apr 26, 2019, at 9:40 AM, Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
> Nadav,
>
> I get
>
> dmarc=fail (p=QUARANTINE sp=NONE dis=QUARANTINE) header.from=vmware.com
>
> for these emails, because they lack the vmware DKIM signature.
>
> It clearly did go through some vmware mail servers, but apparently not
> the *right* external vmware SMTP gateway.
>
> Please check with vmware MIS what the right SMTP setup for git-send-email is.
Err.. Sorry for that. For the time being I’ll use gmail instead.
^ permalink raw reply [flat|nested] 49+ messages in thread
* [tip:x86/mm] x86/mm/cpa: Add set_direct_map_*() functions
2019-04-26 0:11 ` [PATCH v5 14/23] x86/mm/cpa: Add set_direct_map_ functions Nadav Amit
2019-04-26 16:40 ` Linus Torvalds
@ 2019-04-30 11:24 ` tip-bot for Rick Edgecombe
1 sibling, 0 replies; 49+ messages in thread
From: tip-bot for Rick Edgecombe @ 2019-04-30 11:24 UTC (permalink / raw)
To: linux-tip-commits
Cc: riel, will.deacon, luto, kristen, deneen.t.dock, dave.hansen,
mingo, torvalds, tglx, peterz, ard.biesheuvel, linux-kernel,
akpm, rick.p.edgecombe, kernel-hardening, linux_dti, bp,
nadav.amit, hpa
Commit-ID: d253ca0c3865a8d9a8c01143cf20425e0be4d0ce
Gitweb: https://git.kernel.org/tip/d253ca0c3865a8d9a8c01143cf20425e0be4d0ce
Author: Rick Edgecombe <rick.p.edgecombe@intel.com>
AuthorDate: Thu, 25 Apr 2019 17:11:34 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:56 +0200
x86/mm/cpa: Add set_direct_map_*() functions
Add two new functions set_direct_map_default_noflush() and
set_direct_map_invalid_noflush() for setting the direct map alias for the
page to its default valid permissions and to an invalid state that cannot
be cached in a TLB, respectively. These functions do not flush the TLB.
Note, __kernel_map_pages() does something similar but flushes the TLB and
doesn't reset the permission bits to default on all architectures.
Also add an ARCH config ARCH_HAS_SET_DIRECT_MAP for specifying whether
these have an actual implementation or a default empty one.
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-15-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/Kconfig | 4 ++++
arch/x86/Kconfig | 1 +
arch/x86/include/asm/set_memory.h | 3 +++
arch/x86/mm/pageattr.c | 14 +++++++++++---
include/linux/set_memory.h | 11 +++++++++++
5 files changed, 30 insertions(+), 3 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index 33687dddd86a..88e5a92a9e58 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -249,6 +249,10 @@ config ARCH_HAS_FORTIFY_SOURCE
config ARCH_HAS_SET_MEMORY
bool
+# Select if arch has all set_direct_map_invalid/default() functions
+config ARCH_HAS_SET_DIRECT_MAP
+ bool
+
# Select if arch init_task must go in the __init_task_data section
config ARCH_TASK_STRUCT_ON_STACK
bool
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index bd6f93ce0633..cee3f22ce8d1 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -65,6 +65,7 @@ config X86
select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
select ARCH_HAS_UACCESS_MCSAFE if X86_64 && X86_MCE
select ARCH_HAS_SET_MEMORY
+ select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_STRICT_MODULE_RWX
select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE
diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index 07a25753e85c..ae7b909dc242 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -85,6 +85,9 @@ int set_pages_nx(struct page *page, int numpages);
int set_pages_ro(struct page *page, int numpages);
int set_pages_rw(struct page *page, int numpages);
+int set_direct_map_invalid_noflush(struct page *page);
+int set_direct_map_default_noflush(struct page *page);
+
extern int kernel_set_to_readonly;
void set_kernel_text_rw(void);
void set_kernel_text_ro(void);
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 4c570612e24e..3574550192c6 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -2209,8 +2209,6 @@ int set_pages_rw(struct page *page, int numpages)
return set_memory_rw(addr, numpages);
}
-#ifdef CONFIG_DEBUG_PAGEALLOC
-
static int __set_pages_p(struct page *page, int numpages)
{
unsigned long tempaddr = (unsigned long) page_address(page);
@@ -2249,6 +2247,17 @@ static int __set_pages_np(struct page *page, int numpages)
return __change_page_attr_set_clr(&cpa, 0);
}
+int set_direct_map_invalid_noflush(struct page *page)
+{
+ return __set_pages_np(page, 1);
+}
+
+int set_direct_map_default_noflush(struct page *page)
+{
+ return __set_pages_p(page, 1);
+}
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
if (PageHighMem(page))
@@ -2282,7 +2291,6 @@ void __kernel_map_pages(struct page *page, int numpages, int enable)
}
#ifdef CONFIG_HIBERNATION
-
bool kernel_page_present(struct page *page)
{
unsigned int level;
diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
index 2a986d282a97..b5071497b8cb 100644
--- a/include/linux/set_memory.h
+++ b/include/linux/set_memory.h
@@ -17,6 +17,17 @@ static inline int set_memory_x(unsigned long addr, int numpages) { return 0; }
static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
#endif
+#ifndef CONFIG_ARCH_HAS_SET_DIRECT_MAP
+static inline int set_direct_map_invalid_noflush(struct page *page)
+{
+ return 0;
+}
+static inline int set_direct_map_default_noflush(struct page *page)
+{
+ return 0;
+}
+#endif
+
#ifndef set_mce_nospec
static inline int set_mce_nospec(unsigned long pfn)
{
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 15/23] mm: Make hibernate handle unmapped pages
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (13 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 14/23] x86/mm/cpa: Add set_direct_map_ functions Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:25 ` [tip:x86/mm] mm/hibernation: Make hibernation " tip-bot for Rick Edgecombe
2019-04-26 0:11 ` [PATCH v5 16/23] vmalloc: Add flag for free of special permsissions Nadav Amit
` (8 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Rafael J. Wysocki, Pavel Machek
From: Rick Edgecombe <rick.p.edgecombe@intel.com>
Make hibernate handle unmapped pages on the direct map when
CONFIG_ARCH_HAS_SET_ALIAS is set. These functions allow for setting pages
to invalid configurations, so now hibernate should check if the pages have
valid mappings and handle if they are unmapped when doing a hibernate
save operation.
Previously this checking was already done when CONFIG_DEBUG_PAGEALLOC
was configured. It does not appear to have a big hibernating performance
impact. The speed of the saving operation before this change was measured
as 819.02 MB/s, and after was measured at 813.32 MB/s.
Before:
[ 4.670938] PM: Wrote 171996 kbytes in 0.21 seconds (819.02 MB/s)
After:
[ 4.504714] PM: Wrote 178932 kbytes in 0.22 seconds (813.32 MB/s)
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Borislav Petkov <bp@alien8.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/mm/pageattr.c | 4 ----
include/linux/mm.h | 18 ++++++------------
kernel/power/snapshot.c | 5 +++--
mm/page_alloc.c | 7 +++++--
4 files changed, 14 insertions(+), 20 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 3574550192c6..daf4d645e537 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -2257,7 +2257,6 @@ int set_direct_map_default_noflush(struct page *page)
return __set_pages_p(page, 1);
}
-#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
if (PageHighMem(page))
@@ -2302,11 +2301,8 @@ bool kernel_page_present(struct page *page)
pte = lookup_address((unsigned long)page_address(page), &level);
return (pte_val(*pte) & _PAGE_PRESENT);
}
-
#endif /* CONFIG_HIBERNATION */
-#endif /* CONFIG_DEBUG_PAGEALLOC */
-
int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,
unsigned numpages, unsigned long page_flags)
{
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6b10c21630f5..083d7b4863ed 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2610,37 +2610,31 @@ static inline void kernel_poison_pages(struct page *page, int numpages,
int enable) { }
#endif
-#ifdef CONFIG_DEBUG_PAGEALLOC
extern bool _debug_pagealloc_enabled;
-extern void __kernel_map_pages(struct page *page, int numpages, int enable);
static inline bool debug_pagealloc_enabled(void)
{
- return _debug_pagealloc_enabled;
+ return IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) && _debug_pagealloc_enabled;
}
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP)
+extern void __kernel_map_pages(struct page *page, int numpages, int enable);
+
static inline void
kernel_map_pages(struct page *page, int numpages, int enable)
{
- if (!debug_pagealloc_enabled())
- return;
-
__kernel_map_pages(page, numpages, enable);
}
#ifdef CONFIG_HIBERNATION
extern bool kernel_page_present(struct page *page);
#endif /* CONFIG_HIBERNATION */
-#else /* CONFIG_DEBUG_PAGEALLOC */
+#else /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */
static inline void
kernel_map_pages(struct page *page, int numpages, int enable) {}
#ifdef CONFIG_HIBERNATION
static inline bool kernel_page_present(struct page *page) { return true; }
#endif /* CONFIG_HIBERNATION */
-static inline bool debug_pagealloc_enabled(void)
-{
- return false;
-}
-#endif /* CONFIG_DEBUG_PAGEALLOC */
+#endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */
#ifdef __HAVE_ARCH_GATE_AREA
extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index f08a1e4ee1d4..bc9558ab1e5b 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1342,8 +1342,9 @@ static inline void do_copy_page(long *dst, long *src)
* safe_copy_page - Copy a page in a safe way.
*
* Check if the page we are going to copy is marked as present in the kernel
- * page tables (this always is the case if CONFIG_DEBUG_PAGEALLOC is not set
- * and in that case kernel_page_present() always returns 'true').
+ * page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or
+ * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present()
+ * always returns 'true'.
*/
static void safe_copy_page(void *dst, struct page *s_page)
{
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d96ca5bc555b..34a70681a4af 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1131,7 +1131,9 @@ static __always_inline bool free_pages_prepare(struct page *page,
}
arch_free_page(page, order);
kernel_poison_pages(page, 1 << order, 0);
- kernel_map_pages(page, 1 << order, 0);
+ if (debug_pagealloc_enabled())
+ kernel_map_pages(page, 1 << order, 0);
+
kasan_free_nondeferred_pages(page, order);
return true;
@@ -2001,7 +2003,8 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
set_page_refcounted(page);
arch_alloc_page(page, order);
- kernel_map_pages(page, 1 << order, 1);
+ if (debug_pagealloc_enabled())
+ kernel_map_pages(page, 1 << order, 1);
kasan_alloc_pages(page, order);
kernel_poison_pages(page, 1 << order, 1);
set_page_owner(page, order, gfp_flags);
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] mm/hibernation: Make hibernation handle unmapped pages
2019-04-26 0:11 ` [PATCH v5 15/23] mm: Make hibernate handle unmapped pages Nadav Amit
@ 2019-04-30 11:25 ` tip-bot for Rick Edgecombe
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Rick Edgecombe @ 2019-04-30 11:25 UTC (permalink / raw)
To: linux-tip-commits
Cc: hpa, tglx, linux_dti, peterz, rick.p.edgecombe, kristen, luto,
mingo, dave.hansen, rjw, ard.biesheuvel, nadav.amit, akpm,
kernel-hardening, bp, riel, deneen.t.dock, pavel, torvalds,
linux-kernel, will.deacon
Commit-ID: d63326928611600ad65baff54a70f53b02b3cdfe
Gitweb: https://git.kernel.org/tip/d63326928611600ad65baff54a70f53b02b3cdfe
Author: Rick Edgecombe <rick.p.edgecombe@intel.com>
AuthorDate: Thu, 25 Apr 2019 17:11:35 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:57 +0200
mm/hibernation: Make hibernation handle unmapped pages
Make hibernate handle unmapped pages on the direct map when
CONFIG_ARCH_HAS_SET_ALIAS=y is set. These functions allow for setting pages
to invalid configurations, so now hibernate should check if the pages have
valid mappings and handle if they are unmapped when doing a hibernate
save operation.
Previously this checking was already done when CONFIG_DEBUG_PAGEALLOC=y
was configured. It does not appear to have a big hibernating performance
impact. The speed of the saving operation before this change was measured
as 819.02 MB/s, and after was measured at 813.32 MB/s.
Before:
[ 4.670938] PM: Wrote 171996 kbytes in 0.21 seconds (819.02 MB/s)
After:
[ 4.504714] PM: Wrote 178932 kbytes in 0.22 seconds (813.32 MB/s)
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-16-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/mm/pageattr.c | 4 ----
include/linux/mm.h | 18 ++++++------------
kernel/power/snapshot.c | 5 +++--
mm/page_alloc.c | 7 +++++--
4 files changed, 14 insertions(+), 20 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 3574550192c6..daf4d645e537 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -2257,7 +2257,6 @@ int set_direct_map_default_noflush(struct page *page)
return __set_pages_p(page, 1);
}
-#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
if (PageHighMem(page))
@@ -2302,11 +2301,8 @@ bool kernel_page_present(struct page *page)
pte = lookup_address((unsigned long)page_address(page), &level);
return (pte_val(*pte) & _PAGE_PRESENT);
}
-
#endif /* CONFIG_HIBERNATION */
-#endif /* CONFIG_DEBUG_PAGEALLOC */
-
int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address,
unsigned numpages, unsigned long page_flags)
{
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6b10c21630f5..083d7b4863ed 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2610,37 +2610,31 @@ static inline void kernel_poison_pages(struct page *page, int numpages,
int enable) { }
#endif
-#ifdef CONFIG_DEBUG_PAGEALLOC
extern bool _debug_pagealloc_enabled;
-extern void __kernel_map_pages(struct page *page, int numpages, int enable);
static inline bool debug_pagealloc_enabled(void)
{
- return _debug_pagealloc_enabled;
+ return IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) && _debug_pagealloc_enabled;
}
+#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_ARCH_HAS_SET_DIRECT_MAP)
+extern void __kernel_map_pages(struct page *page, int numpages, int enable);
+
static inline void
kernel_map_pages(struct page *page, int numpages, int enable)
{
- if (!debug_pagealloc_enabled())
- return;
-
__kernel_map_pages(page, numpages, enable);
}
#ifdef CONFIG_HIBERNATION
extern bool kernel_page_present(struct page *page);
#endif /* CONFIG_HIBERNATION */
-#else /* CONFIG_DEBUG_PAGEALLOC */
+#else /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */
static inline void
kernel_map_pages(struct page *page, int numpages, int enable) {}
#ifdef CONFIG_HIBERNATION
static inline bool kernel_page_present(struct page *page) { return true; }
#endif /* CONFIG_HIBERNATION */
-static inline bool debug_pagealloc_enabled(void)
-{
- return false;
-}
-#endif /* CONFIG_DEBUG_PAGEALLOC */
+#endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_DIRECT_MAP */
#ifdef __HAVE_ARCH_GATE_AREA
extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index f08a1e4ee1d4..bc9558ab1e5b 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1342,8 +1342,9 @@ static inline void do_copy_page(long *dst, long *src)
* safe_copy_page - Copy a page in a safe way.
*
* Check if the page we are going to copy is marked as present in the kernel
- * page tables (this always is the case if CONFIG_DEBUG_PAGEALLOC is not set
- * and in that case kernel_page_present() always returns 'true').
+ * page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or
+ * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present()
+ * always returns 'true'.
*/
static void safe_copy_page(void *dst, struct page *s_page)
{
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c02cff1ed56e..59661106da16 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1144,7 +1144,9 @@ static __always_inline bool free_pages_prepare(struct page *page,
}
arch_free_page(page, order);
kernel_poison_pages(page, 1 << order, 0);
- kernel_map_pages(page, 1 << order, 0);
+ if (debug_pagealloc_enabled())
+ kernel_map_pages(page, 1 << order, 0);
+
kasan_free_nondeferred_pages(page, order);
return true;
@@ -2014,7 +2016,8 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
set_page_refcounted(page);
arch_alloc_page(page, order);
- kernel_map_pages(page, 1 << order, 1);
+ if (debug_pagealloc_enabled())
+ kernel_map_pages(page, 1 << order, 1);
kasan_alloc_pages(page, order);
kernel_poison_pages(page, 1 << order, 1);
set_page_owner(page, order, gfp_flags);
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 16/23] vmalloc: Add flag for free of special permsissions
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (14 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 15/23] mm: Make hibernate handle unmapped pages Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:26 ` [tip:x86/mm] mm/vmalloc: Add flag for freeing " tip-bot for Rick Edgecombe
2019-04-26 0:11 ` [PATCH v5 17/23] modules: Use vmalloc special flag Nadav Amit
` (7 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe
From: Rick Edgecombe <rick.p.edgecombe@intel.com>
Add a new flag VM_FLUSH_RESET_PERMS, for enabling vfree operations to
immediately clear executable TLB entries before freeing pages, and handle
resetting permissions on the directmap. This flag is useful for any kind
of memory with elevated permissions, or where there can be related
permissions changes on the directmap. Today this is RO+X and RO memory.
Although this enables directly vfreeing non-writeable memory now,
non-writable memory cannot be freed in an interrupt because the allocation
itself is used as a node on deferred free list. So when RO memory needs to
be freed in an interrupt the code doing the vfree needs to have its own
work queue, as was the case before the deferred vfree list was added to
vmalloc.
For architectures with set_direct_map_ implementations this whole operation
can be done with one TLB flush when centralized like this. For others with
directmap permissions, currently only arm64, a backup method using
set_memory functions is used to reset the directmap. When arm64 adds
set_direct_map_ functions, this backup can be removed.
When the TLB is flushed to both remove TLB entries for the vmalloc range
mapping and the direct map permissions, the lazy purge operation could be
done to try to save a TLB flush later. However today vm_unmap_aliases
could flush a TLB range that does not include the directmap. So a helper
is added with extra parameters that can allow both the vmalloc address and
the direct mapping to be flushed during this operation. The behavior of the
normal vm_unmap_aliases function is unchanged.
Cc: Borislav Petkov <bp@alien8.de>
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Suggested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
include/linux/vmalloc.h | 15 ++++++
mm/vmalloc.c | 113 +++++++++++++++++++++++++++++++++-------
2 files changed, 109 insertions(+), 19 deletions(-)
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 398e9c95cd61..c6eebb839552 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -21,6 +21,11 @@ struct notifier_block; /* in notifier.h */
#define VM_UNINITIALIZED 0x00000020 /* vm_struct is not fully initialized */
#define VM_NO_GUARD 0x00000040 /* don't add guard page */
#define VM_KASAN 0x00000080 /* has allocated kasan shadow memory */
+/*
+ * Memory with VM_FLUSH_RESET_PERMS cannot be freed in an interrupt or with
+ * vfree_atomic().
+ */
+#define VM_FLUSH_RESET_PERMS 0x00000100 /* Reset direct map and flush TLB on unmap */
/* bits [20..32] reserved for arch specific ioremap internals */
/*
@@ -142,6 +147,13 @@ extern int map_kernel_range_noflush(unsigned long start, unsigned long size,
pgprot_t prot, struct page **pages);
extern void unmap_kernel_range_noflush(unsigned long addr, unsigned long size);
extern void unmap_kernel_range(unsigned long addr, unsigned long size);
+static inline void set_vm_flush_reset_perms(void *addr)
+{
+ struct vm_struct *vm = find_vm_area(addr);
+
+ if (vm)
+ vm->flags |= VM_FLUSH_RESET_PERMS;
+}
#else
static inline int
map_kernel_range_noflush(unsigned long start, unsigned long size,
@@ -157,6 +169,9 @@ static inline void
unmap_kernel_range(unsigned long addr, unsigned long size)
{
}
+static inline void set_vm_flush_reset_perms(void *addr)
+{
+}
#endif
/* Allocate/destroy a 'vmalloc' VM area. */
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index e86ba6e74b50..e5e9e1fcac01 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -18,6 +18,7 @@
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
+#include <linux/set_memory.h>
#include <linux/debugobjects.h>
#include <linux/kallsyms.h>
#include <linux/list.h>
@@ -1059,24 +1060,9 @@ static void vb_free(const void *addr, unsigned long size)
spin_unlock(&vb->lock);
}
-/**
- * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
- *
- * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
- * to amortize TLB flushing overheads. What this means is that any page you
- * have now, may, in a former life, have been mapped into kernel virtual
- * address by the vmap layer and so there might be some CPUs with TLB entries
- * still referencing that page (additional to the regular 1:1 kernel mapping).
- *
- * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
- * be sure that none of the pages we have control over will have any aliases
- * from the vmap layer.
- */
-void vm_unmap_aliases(void)
+static void _vm_unmap_aliases(unsigned long start, unsigned long end, int flush)
{
- unsigned long start = ULONG_MAX, end = 0;
int cpu;
- int flush = 0;
if (unlikely(!vmap_initialized))
return;
@@ -1113,6 +1099,27 @@ void vm_unmap_aliases(void)
flush_tlb_kernel_range(start, end);
mutex_unlock(&vmap_purge_lock);
}
+
+/**
+ * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
+ *
+ * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
+ * to amortize TLB flushing overheads. What this means is that any page you
+ * have now, may, in a former life, have been mapped into kernel virtual
+ * address by the vmap layer and so there might be some CPUs with TLB entries
+ * still referencing that page (additional to the regular 1:1 kernel mapping).
+ *
+ * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
+ * be sure that none of the pages we have control over will have any aliases
+ * from the vmap layer.
+ */
+void vm_unmap_aliases(void)
+{
+ unsigned long start = ULONG_MAX, end = 0;
+ int flush = 0;
+
+ _vm_unmap_aliases(start, end, flush);
+}
EXPORT_SYMBOL_GPL(vm_unmap_aliases);
/**
@@ -1505,6 +1512,72 @@ struct vm_struct *remove_vm_area(const void *addr)
return NULL;
}
+static inline void set_area_direct_map(const struct vm_struct *area,
+ int (*set_direct_map)(struct page *page))
+{
+ int i;
+
+ for (i = 0; i < area->nr_pages; i++)
+ if (page_address(area->pages[i]))
+ set_direct_map(area->pages[i]);
+}
+
+/* Handle removing and resetting vm mappings related to the vm_struct. */
+static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
+{
+ unsigned long addr = (unsigned long)area->addr;
+ unsigned long start = ULONG_MAX, end = 0;
+ int flush_reset = area->flags & VM_FLUSH_RESET_PERMS;
+ int i;
+
+ /*
+ * The below block can be removed when all architectures that have
+ * direct map permissions also have set_direct_map_() implementations.
+ * This is concerned with resetting the direct map any an vm alias with
+ * execute permissions, without leaving a RW+X window.
+ */
+ if (flush_reset && !IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
+ set_memory_nx(addr, area->nr_pages);
+ set_memory_rw(addr, area->nr_pages);
+ }
+
+ remove_vm_area(area->addr);
+
+ /* If this is not VM_FLUSH_RESET_PERMS memory, no need for the below. */
+ if (!flush_reset)
+ return;
+
+ /*
+ * If not deallocating pages, just do the flush of the VM area and
+ * return.
+ */
+ if (!deallocate_pages) {
+ vm_unmap_aliases();
+ return;
+ }
+
+ /*
+ * If execution gets here, flush the vm mapping and reset the direct
+ * map. Find the start and end range of the direct mappings to make sure
+ * the vm_unmap_aliases() flush includes the direct map.
+ */
+ for (i = 0; i < area->nr_pages; i++) {
+ if (page_address(area->pages[i])) {
+ start = min(addr, start);
+ end = max(addr, end);
+ }
+ }
+
+ /*
+ * Set direct map to something invalid so that it won't be cached if
+ * there are any accesses after the TLB flush, then flush the TLB and
+ * reset the direct map permissions to the default.
+ */
+ set_area_direct_map(area, set_direct_map_invalid_noflush);
+ _vm_unmap_aliases(start, end, 1);
+ set_area_direct_map(area, set_direct_map_default_noflush);
+}
+
static void __vunmap(const void *addr, int deallocate_pages)
{
struct vm_struct *area;
@@ -1526,7 +1599,8 @@ static void __vunmap(const void *addr, int deallocate_pages)
debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
- remove_vm_area(addr);
+ vm_remove_mappings(area, deallocate_pages);
+
if (deallocate_pages) {
int i;
@@ -1961,8 +2035,9 @@ EXPORT_SYMBOL(vzalloc_node);
*/
void *vmalloc_exec(unsigned long size)
{
- return __vmalloc_node(size, 1, GFP_KERNEL, PAGE_KERNEL_EXEC,
- NUMA_NO_NODE, __builtin_return_address(0));
+ return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
+ GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS,
+ NUMA_NO_NODE, __builtin_return_address(0));
}
#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] mm/vmalloc: Add flag for freeing of special permsissions
2019-04-26 0:11 ` [PATCH v5 16/23] vmalloc: Add flag for free of special permsissions Nadav Amit
@ 2019-04-30 11:26 ` tip-bot for Rick Edgecombe
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Rick Edgecombe @ 2019-04-30 11:26 UTC (permalink / raw)
To: linux-tip-commits
Cc: rick.p.edgecombe, mingo, will.deacon, riel, hpa, torvalds,
linux_dti, nadav.amit, ard.biesheuvel, tglx, akpm, dave.hansen,
linux-kernel, kristen, peterz, bp, kernel-hardening,
deneen.t.dock, luto
Commit-ID: 868b104d7379e28013e9d48bdd2db25e0bdcf751
Gitweb: https://git.kernel.org/tip/868b104d7379e28013e9d48bdd2db25e0bdcf751
Author: Rick Edgecombe <rick.p.edgecombe@intel.com>
AuthorDate: Thu, 25 Apr 2019 17:11:36 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:58 +0200
mm/vmalloc: Add flag for freeing of special permsissions
Add a new flag VM_FLUSH_RESET_PERMS, for enabling vfree operations to
immediately clear executable TLB entries before freeing pages, and handle
resetting permissions on the directmap. This flag is useful for any kind
of memory with elevated permissions, or where there can be related
permissions changes on the directmap. Today this is RO+X and RO memory.
Although this enables directly vfreeing non-writeable memory now,
non-writable memory cannot be freed in an interrupt because the allocation
itself is used as a node on deferred free list. So when RO memory needs to
be freed in an interrupt the code doing the vfree needs to have its own
work queue, as was the case before the deferred vfree list was added to
vmalloc.
For architectures with set_direct_map_ implementations this whole operation
can be done with one TLB flush when centralized like this. For others with
directmap permissions, currently only arm64, a backup method using
set_memory functions is used to reset the directmap. When arm64 adds
set_direct_map_ functions, this backup can be removed.
When the TLB is flushed to both remove TLB entries for the vmalloc range
mapping and the direct map permissions, the lazy purge operation could be
done to try to save a TLB flush later. However today vm_unmap_aliases
could flush a TLB range that does not include the directmap. So a helper
is added with extra parameters that can allow both the vmalloc address and
the direct mapping to be flushed during this operation. The behavior of the
normal vm_unmap_aliases function is unchanged.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Suggested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-17-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/vmalloc.h | 15 +++++++
mm/vmalloc.c | 113 ++++++++++++++++++++++++++++++++++++++++--------
2 files changed, 109 insertions(+), 19 deletions(-)
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 398e9c95cd61..c6eebb839552 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -21,6 +21,11 @@ struct notifier_block; /* in notifier.h */
#define VM_UNINITIALIZED 0x00000020 /* vm_struct is not fully initialized */
#define VM_NO_GUARD 0x00000040 /* don't add guard page */
#define VM_KASAN 0x00000080 /* has allocated kasan shadow memory */
+/*
+ * Memory with VM_FLUSH_RESET_PERMS cannot be freed in an interrupt or with
+ * vfree_atomic().
+ */
+#define VM_FLUSH_RESET_PERMS 0x00000100 /* Reset direct map and flush TLB on unmap */
/* bits [20..32] reserved for arch specific ioremap internals */
/*
@@ -142,6 +147,13 @@ extern int map_kernel_range_noflush(unsigned long start, unsigned long size,
pgprot_t prot, struct page **pages);
extern void unmap_kernel_range_noflush(unsigned long addr, unsigned long size);
extern void unmap_kernel_range(unsigned long addr, unsigned long size);
+static inline void set_vm_flush_reset_perms(void *addr)
+{
+ struct vm_struct *vm = find_vm_area(addr);
+
+ if (vm)
+ vm->flags |= VM_FLUSH_RESET_PERMS;
+}
#else
static inline int
map_kernel_range_noflush(unsigned long start, unsigned long size,
@@ -157,6 +169,9 @@ static inline void
unmap_kernel_range(unsigned long addr, unsigned long size)
{
}
+static inline void set_vm_flush_reset_perms(void *addr)
+{
+}
#endif
/* Allocate/destroy a 'vmalloc' VM area. */
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index e86ba6e74b50..e5e9e1fcac01 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -18,6 +18,7 @@
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
+#include <linux/set_memory.h>
#include <linux/debugobjects.h>
#include <linux/kallsyms.h>
#include <linux/list.h>
@@ -1059,24 +1060,9 @@ static void vb_free(const void *addr, unsigned long size)
spin_unlock(&vb->lock);
}
-/**
- * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
- *
- * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
- * to amortize TLB flushing overheads. What this means is that any page you
- * have now, may, in a former life, have been mapped into kernel virtual
- * address by the vmap layer and so there might be some CPUs with TLB entries
- * still referencing that page (additional to the regular 1:1 kernel mapping).
- *
- * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
- * be sure that none of the pages we have control over will have any aliases
- * from the vmap layer.
- */
-void vm_unmap_aliases(void)
+static void _vm_unmap_aliases(unsigned long start, unsigned long end, int flush)
{
- unsigned long start = ULONG_MAX, end = 0;
int cpu;
- int flush = 0;
if (unlikely(!vmap_initialized))
return;
@@ -1113,6 +1099,27 @@ void vm_unmap_aliases(void)
flush_tlb_kernel_range(start, end);
mutex_unlock(&vmap_purge_lock);
}
+
+/**
+ * vm_unmap_aliases - unmap outstanding lazy aliases in the vmap layer
+ *
+ * The vmap/vmalloc layer lazily flushes kernel virtual mappings primarily
+ * to amortize TLB flushing overheads. What this means is that any page you
+ * have now, may, in a former life, have been mapped into kernel virtual
+ * address by the vmap layer and so there might be some CPUs with TLB entries
+ * still referencing that page (additional to the regular 1:1 kernel mapping).
+ *
+ * vm_unmap_aliases flushes all such lazy mappings. After it returns, we can
+ * be sure that none of the pages we have control over will have any aliases
+ * from the vmap layer.
+ */
+void vm_unmap_aliases(void)
+{
+ unsigned long start = ULONG_MAX, end = 0;
+ int flush = 0;
+
+ _vm_unmap_aliases(start, end, flush);
+}
EXPORT_SYMBOL_GPL(vm_unmap_aliases);
/**
@@ -1505,6 +1512,72 @@ struct vm_struct *remove_vm_area(const void *addr)
return NULL;
}
+static inline void set_area_direct_map(const struct vm_struct *area,
+ int (*set_direct_map)(struct page *page))
+{
+ int i;
+
+ for (i = 0; i < area->nr_pages; i++)
+ if (page_address(area->pages[i]))
+ set_direct_map(area->pages[i]);
+}
+
+/* Handle removing and resetting vm mappings related to the vm_struct. */
+static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
+{
+ unsigned long addr = (unsigned long)area->addr;
+ unsigned long start = ULONG_MAX, end = 0;
+ int flush_reset = area->flags & VM_FLUSH_RESET_PERMS;
+ int i;
+
+ /*
+ * The below block can be removed when all architectures that have
+ * direct map permissions also have set_direct_map_() implementations.
+ * This is concerned with resetting the direct map any an vm alias with
+ * execute permissions, without leaving a RW+X window.
+ */
+ if (flush_reset && !IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
+ set_memory_nx(addr, area->nr_pages);
+ set_memory_rw(addr, area->nr_pages);
+ }
+
+ remove_vm_area(area->addr);
+
+ /* If this is not VM_FLUSH_RESET_PERMS memory, no need for the below. */
+ if (!flush_reset)
+ return;
+
+ /*
+ * If not deallocating pages, just do the flush of the VM area and
+ * return.
+ */
+ if (!deallocate_pages) {
+ vm_unmap_aliases();
+ return;
+ }
+
+ /*
+ * If execution gets here, flush the vm mapping and reset the direct
+ * map. Find the start and end range of the direct mappings to make sure
+ * the vm_unmap_aliases() flush includes the direct map.
+ */
+ for (i = 0; i < area->nr_pages; i++) {
+ if (page_address(area->pages[i])) {
+ start = min(addr, start);
+ end = max(addr, end);
+ }
+ }
+
+ /*
+ * Set direct map to something invalid so that it won't be cached if
+ * there are any accesses after the TLB flush, then flush the TLB and
+ * reset the direct map permissions to the default.
+ */
+ set_area_direct_map(area, set_direct_map_invalid_noflush);
+ _vm_unmap_aliases(start, end, 1);
+ set_area_direct_map(area, set_direct_map_default_noflush);
+}
+
static void __vunmap(const void *addr, int deallocate_pages)
{
struct vm_struct *area;
@@ -1526,7 +1599,8 @@ static void __vunmap(const void *addr, int deallocate_pages)
debug_check_no_locks_freed(area->addr, get_vm_area_size(area));
debug_check_no_obj_freed(area->addr, get_vm_area_size(area));
- remove_vm_area(addr);
+ vm_remove_mappings(area, deallocate_pages);
+
if (deallocate_pages) {
int i;
@@ -1961,8 +2035,9 @@ EXPORT_SYMBOL(vzalloc_node);
*/
void *vmalloc_exec(unsigned long size)
{
- return __vmalloc_node(size, 1, GFP_KERNEL, PAGE_KERNEL_EXEC,
- NUMA_NO_NODE, __builtin_return_address(0));
+ return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
+ GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS,
+ NUMA_NO_NODE, __builtin_return_address(0));
}
#if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32)
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 17/23] modules: Use vmalloc special flag
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (15 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 16/23] vmalloc: Add flag for free of special permsissions Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:26 ` [tip:x86/mm] " tip-bot for Rick Edgecombe
2019-04-26 0:11 ` [PATCH v5 18/23] bpf: " Nadav Amit
` (6 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Jessica Yu, Steven Rostedt
From: Rick Edgecombe <rick.p.edgecombe@intel.com>
Use new flag for handling freeing of special permissioned memory in vmalloc
and remove places where memory was set RW before freeing which is no longer
needed.
Since freeing of VM_FLUSH_RESET_PERMS memory is not supported in an
interrupt by vmalloc, the freeing of init sections is moved to a work
queue. Instead of call_rcu it now uses synchronize_rcu() in the work
queue.
Lastly, there is now a WARN_ON in module_memfree since it should not be
called in an interrupt with special memory as is required for
VM_FLUSH_RESET_PERMS.
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
kernel/module.c | 77 +++++++++++++++++++++++++------------------------
1 file changed, 39 insertions(+), 38 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index 2b2845ae983e..a9020bdd4cf6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -98,6 +98,10 @@ DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
static LIST_HEAD(modules);
+/* Work queue for freeing init sections in success case */
+static struct work_struct init_free_wq;
+static struct llist_head init_free_list;
+
#ifdef CONFIG_MODULES_TREE_LOOKUP
/*
@@ -1949,6 +1953,8 @@ void module_enable_ro(const struct module *mod, bool after_init)
if (!rodata_enabled)
return;
+ set_vm_flush_reset_perms(mod->core_layout.base);
+ set_vm_flush_reset_perms(mod->init_layout.base);
frob_text(&mod->core_layout, set_memory_ro);
frob_text(&mod->core_layout, set_memory_x);
@@ -1972,15 +1978,6 @@ static void module_enable_nx(const struct module *mod)
frob_writable_data(&mod->init_layout, set_memory_nx);
}
-static void module_disable_nx(const struct module *mod)
-{
- frob_rodata(&mod->core_layout, set_memory_x);
- frob_ro_after_init(&mod->core_layout, set_memory_x);
- frob_writable_data(&mod->core_layout, set_memory_x);
- frob_rodata(&mod->init_layout, set_memory_x);
- frob_writable_data(&mod->init_layout, set_memory_x);
-}
-
/* Iterate through all modules and set each module's text as RW */
void set_all_modules_text_rw(void)
{
@@ -2024,23 +2021,8 @@ void set_all_modules_text_ro(void)
}
mutex_unlock(&module_mutex);
}
-
-static void disable_ro_nx(const struct module_layout *layout)
-{
- if (rodata_enabled) {
- frob_text(layout, set_memory_rw);
- frob_rodata(layout, set_memory_rw);
- frob_ro_after_init(layout, set_memory_rw);
- }
- frob_rodata(layout, set_memory_x);
- frob_ro_after_init(layout, set_memory_x);
- frob_writable_data(layout, set_memory_x);
-}
-
#else
-static void disable_ro_nx(const struct module_layout *layout) { }
static void module_enable_nx(const struct module *mod) { }
-static void module_disable_nx(const struct module *mod) { }
#endif
#ifdef CONFIG_LIVEPATCH
@@ -2120,6 +2102,11 @@ static void free_module_elf(struct module *mod)
void __weak module_memfree(void *module_region)
{
+ /*
+ * This memory may be RO, and freeing RO memory in an interrupt is not
+ * supported by vmalloc.
+ */
+ WARN_ON(in_interrupt());
vfree(module_region);
}
@@ -2171,7 +2158,6 @@ static void free_module(struct module *mod)
mutex_unlock(&module_mutex);
/* This may be empty, but that's OK */
- disable_ro_nx(&mod->init_layout);
module_arch_freeing_init(mod);
module_memfree(mod->init_layout.base);
kfree(mod->args);
@@ -2181,7 +2167,6 @@ static void free_module(struct module *mod)
lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size);
/* Finally, free the core (containing the module structure) */
- disable_ro_nx(&mod->core_layout);
module_memfree(mod->core_layout.base);
}
@@ -3420,17 +3405,34 @@ static void do_mod_ctors(struct module *mod)
/* For freeing module_init on success, in case kallsyms traversing */
struct mod_initfree {
- struct rcu_head rcu;
+ struct llist_node node;
void *module_init;
};
-static void do_free_init(struct rcu_head *head)
+static void do_free_init(struct work_struct *w)
{
- struct mod_initfree *m = container_of(head, struct mod_initfree, rcu);
- module_memfree(m->module_init);
- kfree(m);
+ struct llist_node *pos, *n, *list;
+ struct mod_initfree *initfree;
+
+ list = llist_del_all(&init_free_list);
+
+ synchronize_rcu();
+
+ llist_for_each_safe(pos, n, list) {
+ initfree = container_of(pos, struct mod_initfree, node);
+ module_memfree(initfree->module_init);
+ kfree(initfree);
+ }
}
+static int __init modules_wq_init(void)
+{
+ INIT_WORK(&init_free_wq, do_free_init);
+ init_llist_head(&init_free_list);
+ return 0;
+}
+module_init(modules_wq_init);
+
/*
* This is where the real work happens.
*
@@ -3507,7 +3509,6 @@ static noinline int do_init_module(struct module *mod)
#endif
module_enable_ro(mod, true);
mod_tree_remove_init(mod);
- disable_ro_nx(&mod->init_layout);
module_arch_freeing_init(mod);
mod->init_layout.base = NULL;
mod->init_layout.size = 0;
@@ -3518,14 +3519,18 @@ static noinline int do_init_module(struct module *mod)
* We want to free module_init, but be aware that kallsyms may be
* walking this with preempt disabled. In all the failure paths, we
* call synchronize_rcu(), but we don't want to slow down the success
- * path, so use actual RCU here.
+ * path. module_memfree() cannot be called in an interrupt, so do the
+ * work and call synchronize_rcu() in a work queue.
+ *
* Note that module_alloc() on most architectures creates W+X page
* mappings which won't be cleaned up until do_free_init() runs. Any
* code such as mark_rodata_ro() which depends on those mappings to
* be cleaned up needs to sync with the queued work - ie
* rcu_barrier()
*/
- call_rcu(&freeinit->rcu, do_free_init);
+ if (llist_add(&freeinit->node, &init_free_list))
+ schedule_work(&init_free_wq);
+
mutex_unlock(&module_mutex);
wake_up_all(&module_wq);
@@ -3822,10 +3827,6 @@ static int load_module(struct load_info *info, const char __user *uargs,
module_bug_cleanup(mod);
mutex_unlock(&module_mutex);
- /* we can't deallocate the module until we clear memory protection */
- module_disable_ro(mod);
- module_disable_nx(mod);
-
ddebug_cleanup:
ftrace_release_mod(mod);
dynamic_debug_remove(mod, info->debug);
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] modules: Use vmalloc special flag
2019-04-26 0:11 ` [PATCH v5 17/23] modules: Use vmalloc special flag Nadav Amit
@ 2019-04-30 11:26 ` tip-bot for Rick Edgecombe
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Rick Edgecombe @ 2019-04-30 11:26 UTC (permalink / raw)
To: linux-tip-commits
Cc: tglx, bp, mingo, deneen.t.dock, peterz, will.deacon, linux_dti,
linux-kernel, kernel-hardening, kristen, rostedt, akpm,
dave.hansen, rick.p.edgecombe, nadav.amit, ard.biesheuvel, luto,
hpa, jeyu, torvalds, riel
Commit-ID: 1a7b7d9220819afe79d1ec5d759fe4349bd2453e
Gitweb: https://git.kernel.org/tip/1a7b7d9220819afe79d1ec5d759fe4349bd2453e
Author: Rick Edgecombe <rick.p.edgecombe@intel.com>
AuthorDate: Thu, 25 Apr 2019 17:11:37 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:58 +0200
modules: Use vmalloc special flag
Use new flag for handling freeing of special permissioned memory in vmalloc
and remove places where memory was set RW before freeing which is no longer
needed.
Since freeing of VM_FLUSH_RESET_PERMS memory is not supported in an
interrupt by vmalloc, the freeing of init sections is moved to a work
queue. Instead of call_rcu it now uses synchronize_rcu() in the work
queue.
Lastly, there is now a WARN_ON in module_memfree since it should not be
called in an interrupt with special memory as is required for
VM_FLUSH_RESET_PERMS.
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-18-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/module.c | 77 +++++++++++++++++++++++++++++----------------------------
1 file changed, 39 insertions(+), 38 deletions(-)
diff --git a/kernel/module.c b/kernel/module.c
index 2b2845ae983e..a9020bdd4cf6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -98,6 +98,10 @@ DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
static LIST_HEAD(modules);
+/* Work queue for freeing init sections in success case */
+static struct work_struct init_free_wq;
+static struct llist_head init_free_list;
+
#ifdef CONFIG_MODULES_TREE_LOOKUP
/*
@@ -1949,6 +1953,8 @@ void module_enable_ro(const struct module *mod, bool after_init)
if (!rodata_enabled)
return;
+ set_vm_flush_reset_perms(mod->core_layout.base);
+ set_vm_flush_reset_perms(mod->init_layout.base);
frob_text(&mod->core_layout, set_memory_ro);
frob_text(&mod->core_layout, set_memory_x);
@@ -1972,15 +1978,6 @@ static void module_enable_nx(const struct module *mod)
frob_writable_data(&mod->init_layout, set_memory_nx);
}
-static void module_disable_nx(const struct module *mod)
-{
- frob_rodata(&mod->core_layout, set_memory_x);
- frob_ro_after_init(&mod->core_layout, set_memory_x);
- frob_writable_data(&mod->core_layout, set_memory_x);
- frob_rodata(&mod->init_layout, set_memory_x);
- frob_writable_data(&mod->init_layout, set_memory_x);
-}
-
/* Iterate through all modules and set each module's text as RW */
void set_all_modules_text_rw(void)
{
@@ -2024,23 +2021,8 @@ void set_all_modules_text_ro(void)
}
mutex_unlock(&module_mutex);
}
-
-static void disable_ro_nx(const struct module_layout *layout)
-{
- if (rodata_enabled) {
- frob_text(layout, set_memory_rw);
- frob_rodata(layout, set_memory_rw);
- frob_ro_after_init(layout, set_memory_rw);
- }
- frob_rodata(layout, set_memory_x);
- frob_ro_after_init(layout, set_memory_x);
- frob_writable_data(layout, set_memory_x);
-}
-
#else
-static void disable_ro_nx(const struct module_layout *layout) { }
static void module_enable_nx(const struct module *mod) { }
-static void module_disable_nx(const struct module *mod) { }
#endif
#ifdef CONFIG_LIVEPATCH
@@ -2120,6 +2102,11 @@ static void free_module_elf(struct module *mod)
void __weak module_memfree(void *module_region)
{
+ /*
+ * This memory may be RO, and freeing RO memory in an interrupt is not
+ * supported by vmalloc.
+ */
+ WARN_ON(in_interrupt());
vfree(module_region);
}
@@ -2171,7 +2158,6 @@ static void free_module(struct module *mod)
mutex_unlock(&module_mutex);
/* This may be empty, but that's OK */
- disable_ro_nx(&mod->init_layout);
module_arch_freeing_init(mod);
module_memfree(mod->init_layout.base);
kfree(mod->args);
@@ -2181,7 +2167,6 @@ static void free_module(struct module *mod)
lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size);
/* Finally, free the core (containing the module structure) */
- disable_ro_nx(&mod->core_layout);
module_memfree(mod->core_layout.base);
}
@@ -3420,17 +3405,34 @@ static void do_mod_ctors(struct module *mod)
/* For freeing module_init on success, in case kallsyms traversing */
struct mod_initfree {
- struct rcu_head rcu;
+ struct llist_node node;
void *module_init;
};
-static void do_free_init(struct rcu_head *head)
+static void do_free_init(struct work_struct *w)
{
- struct mod_initfree *m = container_of(head, struct mod_initfree, rcu);
- module_memfree(m->module_init);
- kfree(m);
+ struct llist_node *pos, *n, *list;
+ struct mod_initfree *initfree;
+
+ list = llist_del_all(&init_free_list);
+
+ synchronize_rcu();
+
+ llist_for_each_safe(pos, n, list) {
+ initfree = container_of(pos, struct mod_initfree, node);
+ module_memfree(initfree->module_init);
+ kfree(initfree);
+ }
}
+static int __init modules_wq_init(void)
+{
+ INIT_WORK(&init_free_wq, do_free_init);
+ init_llist_head(&init_free_list);
+ return 0;
+}
+module_init(modules_wq_init);
+
/*
* This is where the real work happens.
*
@@ -3507,7 +3509,6 @@ static noinline int do_init_module(struct module *mod)
#endif
module_enable_ro(mod, true);
mod_tree_remove_init(mod);
- disable_ro_nx(&mod->init_layout);
module_arch_freeing_init(mod);
mod->init_layout.base = NULL;
mod->init_layout.size = 0;
@@ -3518,14 +3519,18 @@ static noinline int do_init_module(struct module *mod)
* We want to free module_init, but be aware that kallsyms may be
* walking this with preempt disabled. In all the failure paths, we
* call synchronize_rcu(), but we don't want to slow down the success
- * path, so use actual RCU here.
+ * path. module_memfree() cannot be called in an interrupt, so do the
+ * work and call synchronize_rcu() in a work queue.
+ *
* Note that module_alloc() on most architectures creates W+X page
* mappings which won't be cleaned up until do_free_init() runs. Any
* code such as mark_rodata_ro() which depends on those mappings to
* be cleaned up needs to sync with the queued work - ie
* rcu_barrier()
*/
- call_rcu(&freeinit->rcu, do_free_init);
+ if (llist_add(&freeinit->node, &init_free_list))
+ schedule_work(&init_free_wq);
+
mutex_unlock(&module_mutex);
wake_up_all(&module_wq);
@@ -3822,10 +3827,6 @@ static int load_module(struct load_info *info, const char __user *uargs,
module_bug_cleanup(mod);
mutex_unlock(&module_mutex);
- /* we can't deallocate the module until we clear memory protection */
- module_disable_ro(mod);
- module_disable_nx(mod);
-
ddebug_cleanup:
ftrace_release_mod(mod);
dynamic_debug_remove(mod, info->debug);
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 18/23] bpf: Use vmalloc special flag
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (16 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 17/23] modules: Use vmalloc special flag Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:27 ` [tip:x86/mm] " tip-bot for Rick Edgecombe
2019-04-26 0:11 ` [PATCH v5 19/23] x86/ftrace: " Nadav Amit
` (5 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Daniel Borkmann,
Alexei Starovoitov
From: Rick Edgecombe <rick.p.edgecombe@intel.com>
Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set RW
before freeing which is no longer needed. Don't track if the memory is RO
anymore because it is now tracked in vmalloc.
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
include/linux/filter.h | 17 +++--------------
kernel/bpf/core.c | 1 -
2 files changed, 3 insertions(+), 15 deletions(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 14ec3bdad9a9..7d3abde3f183 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -20,6 +20,7 @@
#include <linux/set_memory.h>
#include <linux/kallsyms.h>
#include <linux/if_vlan.h>
+#include <linux/vmalloc.h>
#include <net/sch_generic.h>
@@ -503,7 +504,6 @@ struct bpf_prog {
u16 pages; /* Number of allocated pages */
u16 jited:1, /* Is our filter JIT'ed? */
jit_requested:1,/* archs need to JIT the prog */
- undo_set_mem:1, /* Passed set_memory_ro() checkpoint */
gpl_compatible:1, /* Is filter GPL compatible? */
cb_access:1, /* Is control block accessed? */
dst_needed:1, /* Do we need dst entry? */
@@ -733,27 +733,17 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default)
static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
{
- fp->undo_set_mem = 1;
+ set_vm_flush_reset_perms(fp);
set_memory_ro((unsigned long)fp, fp->pages);
}
-static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
-{
- if (fp->undo_set_mem)
- set_memory_rw((unsigned long)fp, fp->pages);
-}
-
static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
{
+ set_vm_flush_reset_perms(hdr);
set_memory_ro((unsigned long)hdr, hdr->pages);
set_memory_x((unsigned long)hdr, hdr->pages);
}
-static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
-{
- set_memory_rw((unsigned long)hdr, hdr->pages);
-}
-
static inline struct bpf_binary_header *
bpf_jit_binary_hdr(const struct bpf_prog *fp)
{
@@ -789,7 +779,6 @@ void __bpf_prog_free(struct bpf_prog *fp);
static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
{
- bpf_prog_unlock_ro(fp);
__bpf_prog_free(fp);
}
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index ff09d32a8a1b..c605397c79f0 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -848,7 +848,6 @@ void __weak bpf_jit_free(struct bpf_prog *fp)
if (fp->jited) {
struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
- bpf_jit_binary_unlock_ro(hdr);
bpf_jit_binary_free(hdr);
WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] bpf: Use vmalloc special flag
2019-04-26 0:11 ` [PATCH v5 18/23] bpf: " Nadav Amit
@ 2019-04-30 11:27 ` tip-bot for Rick Edgecombe
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Rick Edgecombe @ 2019-04-30 11:27 UTC (permalink / raw)
To: linux-tip-commits
Cc: peterz, daniel, will.deacon, torvalds, akpm, dave.hansen, bp,
deneen.t.dock, rick.p.edgecombe, tglx, kernel-hardening,
linux_dti, ard.biesheuvel, luto, mingo, hpa, riel, nadav.amit,
ast, kristen, linux-kernel
Commit-ID: d53d2f78ceadba081fc7785570798c3c8d50a718
Gitweb: https://git.kernel.org/tip/d53d2f78ceadba081fc7785570798c3c8d50a718
Author: Rick Edgecombe <rick.p.edgecombe@intel.com>
AuthorDate: Thu, 25 Apr 2019 17:11:38 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:59 +0200
bpf: Use vmalloc special flag
Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set RW
before freeing which is no longer needed. Don't track if the memory is RO
anymore because it is now tracked in vmalloc.
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-19-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/filter.h | 17 +++--------------
kernel/bpf/core.c | 1 -
2 files changed, 3 insertions(+), 15 deletions(-)
diff --git a/include/linux/filter.h b/include/linux/filter.h
index 14ec3bdad9a9..7d3abde3f183 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -20,6 +20,7 @@
#include <linux/set_memory.h>
#include <linux/kallsyms.h>
#include <linux/if_vlan.h>
+#include <linux/vmalloc.h>
#include <net/sch_generic.h>
@@ -503,7 +504,6 @@ struct bpf_prog {
u16 pages; /* Number of allocated pages */
u16 jited:1, /* Is our filter JIT'ed? */
jit_requested:1,/* archs need to JIT the prog */
- undo_set_mem:1, /* Passed set_memory_ro() checkpoint */
gpl_compatible:1, /* Is filter GPL compatible? */
cb_access:1, /* Is control block accessed? */
dst_needed:1, /* Do we need dst entry? */
@@ -733,27 +733,17 @@ bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default)
static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
{
- fp->undo_set_mem = 1;
+ set_vm_flush_reset_perms(fp);
set_memory_ro((unsigned long)fp, fp->pages);
}
-static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
-{
- if (fp->undo_set_mem)
- set_memory_rw((unsigned long)fp, fp->pages);
-}
-
static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
{
+ set_vm_flush_reset_perms(hdr);
set_memory_ro((unsigned long)hdr, hdr->pages);
set_memory_x((unsigned long)hdr, hdr->pages);
}
-static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
-{
- set_memory_rw((unsigned long)hdr, hdr->pages);
-}
-
static inline struct bpf_binary_header *
bpf_jit_binary_hdr(const struct bpf_prog *fp)
{
@@ -789,7 +779,6 @@ void __bpf_prog_free(struct bpf_prog *fp);
static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
{
- bpf_prog_unlock_ro(fp);
__bpf_prog_free(fp);
}
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index ff09d32a8a1b..c605397c79f0 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -848,7 +848,6 @@ void __weak bpf_jit_free(struct bpf_prog *fp)
if (fp->jited) {
struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
- bpf_jit_binary_unlock_ro(hdr);
bpf_jit_binary_free(hdr);
WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 19/23] x86/ftrace: Use vmalloc special flag
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (17 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 18/23] bpf: " Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:28 ` [tip:x86/mm] " tip-bot for Rick Edgecombe
2019-04-26 0:11 ` [PATCH v5 20/23] x86/kprobes: " Nadav Amit
` (4 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe
From: Rick Edgecombe <rick.p.edgecombe@intel.com>
Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set NX
and RW before freeing which is no longer needed.
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/ftrace.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 53ba1aa3a01f..0caf8122d680 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -678,12 +678,8 @@ static inline void *alloc_tramp(unsigned long size)
{
return module_alloc(size);
}
-static inline void tramp_free(void *tramp, int size)
+static inline void tramp_free(void *tramp)
{
- int npages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
- set_memory_nx((unsigned long)tramp, npages);
- set_memory_rw((unsigned long)tramp, npages);
module_memfree(tramp);
}
#else
@@ -692,7 +688,7 @@ static inline void *alloc_tramp(unsigned long size)
{
return NULL;
}
-static inline void tramp_free(void *tramp, int size) { }
+static inline void tramp_free(void *tramp) { }
#endif
/* Defined as markers to the end of the ftrace default trampolines */
@@ -808,6 +804,8 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
/* ALLOC_TRAMP flags lets us know we created it */
ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
+ set_vm_flush_reset_perms(trampoline);
+
/*
* Module allocation needs to be completed by making the page
* executable. The page is still writable, which is a security hazard,
@@ -816,7 +814,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
set_memory_x((unsigned long)trampoline, npages);
return (unsigned long)trampoline;
fail:
- tramp_free(trampoline, *tramp_size);
+ tramp_free(trampoline);
return 0;
}
@@ -947,7 +945,7 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
if (!ops || !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
return;
- tramp_free((void *)ops->trampoline, ops->trampoline_size);
+ tramp_free((void *)ops->trampoline);
ops->trampoline = 0;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/ftrace: Use vmalloc special flag
2019-04-26 0:11 ` [PATCH v5 19/23] x86/ftrace: " Nadav Amit
@ 2019-04-30 11:28 ` tip-bot for Rick Edgecombe
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Rick Edgecombe @ 2019-04-30 11:28 UTC (permalink / raw)
To: linux-tip-commits
Cc: hpa, bp, torvalds, tglx, mingo, akpm, nadav.amit, will.deacon,
peterz, rostedt, linux_dti, dave.hansen, linux-kernel,
rick.p.edgecombe, ard.biesheuvel, kernel-hardening, kristen,
riel, deneen.t.dock, luto
Commit-ID: 7fdfe1e40b225b1d163f9afed2fa3f04442dbaad
Gitweb: https://git.kernel.org/tip/7fdfe1e40b225b1d163f9afed2fa3f04442dbaad
Author: Rick Edgecombe <rick.p.edgecombe@intel.com>
AuthorDate: Thu, 25 Apr 2019 17:11:39 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:38:00 +0200
x86/ftrace: Use vmalloc special flag
Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set NX
and RW before freeing which is no longer needed.
Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-20-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/ftrace.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 53ba1aa3a01f..0caf8122d680 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -678,12 +678,8 @@ static inline void *alloc_tramp(unsigned long size)
{
return module_alloc(size);
}
-static inline void tramp_free(void *tramp, int size)
+static inline void tramp_free(void *tramp)
{
- int npages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
- set_memory_nx((unsigned long)tramp, npages);
- set_memory_rw((unsigned long)tramp, npages);
module_memfree(tramp);
}
#else
@@ -692,7 +688,7 @@ static inline void *alloc_tramp(unsigned long size)
{
return NULL;
}
-static inline void tramp_free(void *tramp, int size) { }
+static inline void tramp_free(void *tramp) { }
#endif
/* Defined as markers to the end of the ftrace default trampolines */
@@ -808,6 +804,8 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
/* ALLOC_TRAMP flags lets us know we created it */
ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
+ set_vm_flush_reset_perms(trampoline);
+
/*
* Module allocation needs to be completed by making the page
* executable. The page is still writable, which is a security hazard,
@@ -816,7 +814,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
set_memory_x((unsigned long)trampoline, npages);
return (unsigned long)trampoline;
fail:
- tramp_free(trampoline, *tramp_size);
+ tramp_free(trampoline);
return 0;
}
@@ -947,7 +945,7 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
if (!ops || !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
return;
- tramp_free((void *)ops->trampoline, ops->trampoline_size);
+ tramp_free((void *)ops->trampoline);
ops->trampoline = 0;
}
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 20/23] x86/kprobes: Use vmalloc special flag
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (18 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 19/23] x86/ftrace: " Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:28 ` [tip:x86/mm] " tip-bot for Rick Edgecombe
2019-04-26 0:11 ` [PATCH v5 21/23] x86/alternative: Comment about module removal races Nadav Amit
` (3 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Masami Hiramatsu
From: Rick Edgecombe <rick.p.edgecombe@intel.com>
Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set NX
and RW before freeing which is no longer needed.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/kprobes/core.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 1591852d3ac4..136695e4434a 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -434,6 +434,7 @@ void *alloc_insn_page(void)
if (!page)
return NULL;
+ set_vm_flush_reset_perms(page);
/*
* First make the page read-only, and only then make it executable to
* prevent it from being W+X in between.
@@ -452,12 +453,6 @@ void *alloc_insn_page(void)
/* Recover page to RW mode before releasing it */
void free_insn_page(void *page)
{
- /*
- * First make the page non-executable, and only then make it writable to
- * prevent it from being W+X in between.
- */
- set_memory_nx((unsigned long)page, 1);
- set_memory_rw((unsigned long)page, 1);
module_memfree(page);
}
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/kprobes: Use vmalloc special flag
2019-04-26 0:11 ` [PATCH v5 20/23] x86/kprobes: " Nadav Amit
@ 2019-04-30 11:28 ` tip-bot for Rick Edgecombe
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Rick Edgecombe @ 2019-04-30 11:28 UTC (permalink / raw)
To: linux-tip-commits
Cc: deneen.t.dock, luto, akpm, rick.p.edgecombe, nadav.amit,
linux-kernel, bp, peterz, linux_dti, dave.hansen,
kernel-hardening, hpa, torvalds, will.deacon, tglx, riel,
ard.biesheuvel, mhiramat, kristen, mingo
Commit-ID: 241a1f22380646bc4d1dd18e5bc246877513da68
Gitweb: https://git.kernel.org/tip/241a1f22380646bc4d1dd18e5bc246877513da68
Author: Rick Edgecombe <rick.p.edgecombe@intel.com>
AuthorDate: Thu, 25 Apr 2019 17:11:40 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:38:01 +0200
x86/kprobes: Use vmalloc special flag
Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special
permissioned memory in vmalloc and remove places where memory was set NX
and RW before freeing which is no longer needed.
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-21-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/kprobes/core.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 06058c44ab57..800593f4ddf7 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -434,6 +434,7 @@ void *alloc_insn_page(void)
if (!page)
return NULL;
+ set_vm_flush_reset_perms(page);
/*
* First make the page read-only, and only then make it executable to
* prevent it from being W+X in between.
@@ -452,12 +453,6 @@ void *alloc_insn_page(void)
/* Recover page to RW mode before releasing it */
void free_insn_page(void *page)
{
- /*
- * First make the page non-executable, and only then make it writable to
- * prevent it from being W+X in between.
- */
- set_memory_nx((unsigned long)page, 1);
- set_memory_rw((unsigned long)page, 1);
module_memfree(page);
}
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 21/23] x86/alternative: Comment about module removal races
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (19 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 20/23] x86/kprobes: " Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:29 ` [tip:x86/mm] x86/alternatives: Add comment " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 22/23] mm/tlb: Provide default nmi_uaccess_okay() Nadav Amit
` (2 subsequent siblings)
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Masami Hiramatsu
Add a comment to clarify that users of text_poke() must ensure that
no races with module removal take place.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/alternative.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 18f959975ea0..7b9b49dfc05a 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -810,6 +810,11 @@ static void *__text_poke(void *addr, const void *opcode, size_t len)
* It means the size must be writable atomically and the address must be aligned
* in a way that permits an atomic write. It also makes sure we fit on a single
* page.
+ *
+ * Note that the caller must ensure that if the modified code is part of a
+ * module, the module would not be removed during poking. This can be achieved
+ * by registering a module notifier, and ordering module removal and patching
+ * trough a mutex.
*/
void *text_poke(void *addr, const void *opcode, size_t len)
{
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] x86/alternatives: Add comment about module removal races
2019-04-26 0:11 ` [PATCH v5 21/23] x86/alternative: Comment about module removal races Nadav Amit
@ 2019-04-30 11:29 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:29 UTC (permalink / raw)
To: linux-tip-commits
Cc: ard.biesheuvel, bp, dave.hansen, linux_dti, riel, akpm,
deneen.t.dock, linux-kernel, torvalds, kristen, hpa, will.deacon,
mingo, mhiramat, tglx, rick.p.edgecombe, luto, kernel-hardening,
peterz, namit
Commit-ID: 3950746d9d8ef981c1cb842384e0e86e8d1aad76
Gitweb: https://git.kernel.org/tip/3950746d9d8ef981c1cb842384e0e86e8d1aad76
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:41 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:38:01 +0200
x86/alternatives: Add comment about module removal races
Add a comment to clarify that users of text_poke() must ensure that
no races with module removal take place.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-22-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/alternative.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 18f959975ea0..7b9b49dfc05a 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -810,6 +810,11 @@ static void *__text_poke(void *addr, const void *opcode, size_t len)
* It means the size must be writable atomically and the address must be aligned
* in a way that permits an atomic write. It also makes sure we fit on a single
* page.
+ *
+ * Note that the caller must ensure that if the modified code is part of a
+ * module, the module would not be removed during poking. This can be achieved
+ * by registering a module notifier, and ordering module removal and patching
+ * trough a mutex.
*/
void *text_poke(void *addr, const void *opcode, size_t len)
{
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 22/23] mm/tlb: Provide default nmi_uaccess_okay()
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (20 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 21/23] x86/alternative: Comment about module removal races Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:14 ` [tip:x86/mm] " tip-bot for Nadav Amit
2019-04-26 0:11 ` [PATCH v5 23/23] bpf: Fail bpf_probe_write_user() while mm is switched Nadav Amit
2019-04-26 12:36 ` [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Peter Zijlstra
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit
x86 has an nmi_uaccess_okay(), but other architectures do not.
Arch-independent code might need to know whether access to user
addresses is ok in an NMI context or in other code whose execution
context is unknown. Specifically, this function is needed for
bpf_probe_write_user().
Add a default implementation of nmi_uaccess_okay() for architectures
that do not have such a function.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/include/asm/tlbflush.h | 2 ++
include/asm-generic/tlb.h | 9 +++++++++
2 files changed, 11 insertions(+)
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 90926e8dd1f8..dee375831962 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -274,6 +274,8 @@ static inline bool nmi_uaccess_okay(void)
return true;
}
+#define nmi_uaccess_okay nmi_uaccess_okay
+
/* Initialize cr4 shadow for this CPU. */
static inline void cr4_init_shadow(void)
{
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index b9edc7608d90..480e5b2a5748 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -21,6 +21,15 @@
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
+/*
+ * Blindly accessing user memory from NMI context can be dangerous
+ * if we're in the middle of switching the current user task or switching
+ * the loaded mm.
+ */
+#ifndef nmi_uaccess_okay
+# define nmi_uaccess_okay() true
+#endif
+
#ifdef CONFIG_MMU
/*
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] mm/tlb: Provide default nmi_uaccess_okay()
2019-04-26 0:11 ` [PATCH v5 22/23] mm/tlb: Provide default nmi_uaccess_okay() Nadav Amit
@ 2019-04-30 11:14 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:14 UTC (permalink / raw)
To: linux-tip-commits
Cc: namit, torvalds, akpm, hpa, peterz, ard.biesheuvel, dave.hansen,
kristen, linux_dti, kernel-hardening, bp, riel, rick.p.edgecombe,
mingo, will.deacon, tglx, luto, linux-kernel, deneen.t.dock
Commit-ID: 5932c9fd19e6e5ac84756c5c32fe5155d9a6b458
Gitweb: https://git.kernel.org/tip/5932c9fd19e6e5ac84756c5c32fe5155d9a6b458
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:42 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:48 +0200
mm/tlb: Provide default nmi_uaccess_okay()
x86 has an nmi_uaccess_okay(), but other architectures do not.
Arch-independent code might need to know whether access to user
addresses is ok in an NMI context or in other code whose execution
context is unknown. Specifically, this function is needed for
bpf_probe_write_user().
Add a default implementation of nmi_uaccess_okay() for architectures
that do not have such a function.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-23-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/tlbflush.h | 2 ++
include/asm-generic/tlb.h | 9 +++++++++
2 files changed, 11 insertions(+)
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index f4204bf377fc..e9eae3d6ef02 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -274,6 +274,8 @@ static inline bool nmi_uaccess_okay(void)
return true;
}
+#define nmi_uaccess_okay nmi_uaccess_okay
+
/* Initialize cr4 shadow for this CPU. */
static inline void cr4_init_shadow(void)
{
diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 6be86c1c5c58..075b353cae86 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -20,6 +20,15 @@
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
+/*
+ * Blindly accessing user memory from NMI context can be dangerous
+ * if we're in the middle of switching the current user task or switching
+ * the loaded mm.
+ */
+#ifndef nmi_uaccess_okay
+# define nmi_uaccess_okay() true
+#endif
+
#ifdef CONFIG_MMU
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
^ permalink raw reply related [flat|nested] 49+ messages in thread
* [PATCH v5 23/23] bpf: Fail bpf_probe_write_user() while mm is switched
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (21 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 22/23] mm/tlb: Provide default nmi_uaccess_okay() Nadav Amit
@ 2019-04-26 0:11 ` Nadav Amit
2019-04-30 11:15 ` [tip:x86/mm] " tip-bot for Nadav Amit
2019-04-26 12:36 ` [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Peter Zijlstra
23 siblings, 1 reply; 49+ messages in thread
From: Nadav Amit @ 2019-04-26 0:11 UTC (permalink / raw)
To: Peter Zijlstra, Borislav Petkov, Andy Lutomirski, Ingo Molnar
Cc: linux-kernel, x86, hpa, Thomas Gleixner, Nadav Amit, Dave Hansen,
linux_dti, linux-integrity, linux-security-module, akpm,
kernel-hardening, linux-mm, will.deacon, ard.biesheuvel, kristen,
deneen.t.dock, Rick Edgecombe, Nadav Amit, Daniel Borkmann,
Alexei Starovoitov
When using a temporary mm, bpf_probe_write_user() should not be able to
write to user memory, since user memory addresses may be used to map
kernel memory. Detect these cases and fail bpf_probe_write_user() in
such cases.
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Reported-by: Jann Horn <jannh@google.com>
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
kernel/trace/bpf_trace.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d64c00afceb5..94b0e37d90ef 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -14,6 +14,8 @@
#include <linux/syscalls.h>
#include <linux/error-injection.h>
+#include <asm/tlb.h>
+
#include "trace_probe.h"
#include "trace.h"
@@ -163,6 +165,10 @@ BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
* access_ok() should prevent writing to non-user memory, but in
* some situations (nommu, temporary switch, etc) access_ok() does
* not provide enough validation, hence the check on KERNEL_DS.
+ *
+ * nmi_uaccess_okay() ensures the probe is not run in an interim
+ * state, when the task or mm are switched. This is specifically
+ * required to prevent the use of temporary mm.
*/
if (unlikely(in_interrupt() ||
@@ -170,6 +176,8 @@ BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
return -EPERM;
if (unlikely(uaccess_kernel()))
return -EPERM;
+ if (unlikely(!nmi_uaccess_okay()))
+ return -EPERM;
if (!access_ok(unsafe_ptr, size))
return -EPERM;
--
2.17.1
^ permalink raw reply related [flat|nested] 49+ messages in thread* [tip:x86/mm] bpf: Fail bpf_probe_write_user() while mm is switched
2019-04-26 0:11 ` [PATCH v5 23/23] bpf: Fail bpf_probe_write_user() while mm is switched Nadav Amit
@ 2019-04-30 11:15 ` tip-bot for Nadav Amit
0 siblings, 0 replies; 49+ messages in thread
From: tip-bot for Nadav Amit @ 2019-04-30 11:15 UTC (permalink / raw)
To: linux-tip-commits
Cc: luto, namit, linux_dti, ard.biesheuvel, will.deacon, jannh, riel,
rick.p.edgecombe, kernel-hardening, torvalds, linux-kernel,
daniel, deneen.t.dock, tglx, ast, akpm, mingo, kristen, peterz,
bp, hpa, dave.hansen
Commit-ID: c7b6f29b6257532792fc722b68fcc0e00b5a856c
Gitweb: https://git.kernel.org/tip/c7b6f29b6257532792fc722b68fcc0e00b5a856c
Author: Nadav Amit <namit@vmware.com>
AuthorDate: Thu, 25 Apr 2019 17:11:43 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 30 Apr 2019 12:37:48 +0200
bpf: Fail bpf_probe_write_user() while mm is switched
When using a temporary mm, bpf_probe_write_user() should not be able to
write to user memory, since user memory addresses may be used to map
kernel memory. Detect these cases and fail bpf_probe_write_user() in
such cases.
Suggested-by: Jann Horn <jannh@google.com>
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-24-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/trace/bpf_trace.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index d64c00afceb5..94b0e37d90ef 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -14,6 +14,8 @@
#include <linux/syscalls.h>
#include <linux/error-injection.h>
+#include <asm/tlb.h>
+
#include "trace_probe.h"
#include "trace.h"
@@ -163,6 +165,10 @@ BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
* access_ok() should prevent writing to non-user memory, but in
* some situations (nommu, temporary switch, etc) access_ok() does
* not provide enough validation, hence the check on KERNEL_DS.
+ *
+ * nmi_uaccess_okay() ensures the probe is not run in an interim
+ * state, when the task or mm are switched. This is specifically
+ * required to prevent the use of temporary mm.
*/
if (unlikely(in_interrupt() ||
@@ -170,6 +176,8 @@ BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
return -EPERM;
if (unlikely(uaccess_kernel()))
return -EPERM;
+ if (unlikely(!nmi_uaccess_okay()))
+ return -EPERM;
if (!access_ok(unsafe_ptr, size))
return -EPERM;
^ permalink raw reply related [flat|nested] 49+ messages in thread
* Re: [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns
2019-04-26 0:11 [PATCH v5 00/23] x86: text_poke() fixes and executable lockdowns Nadav Amit
` (22 preceding siblings ...)
2019-04-26 0:11 ` [PATCH v5 23/23] bpf: Fail bpf_probe_write_user() while mm is switched Nadav Amit
@ 2019-04-26 12:36 ` Peter Zijlstra
23 siblings, 0 replies; 49+ messages in thread
From: Peter Zijlstra @ 2019-04-26 12:36 UTC (permalink / raw)
To: Nadav Amit
Cc: Borislav Petkov, Andy Lutomirski, Ingo Molnar, linux-kernel, x86,
hpa, Thomas Gleixner, Nadav Amit, Dave Hansen, linux_dti,
linux-integrity, linux-security-module, akpm, kernel-hardening,
linux-mm, will.deacon, ard.biesheuvel, kristen, deneen.t.dock,
Rick Edgecombe
On Thu, Apr 25, 2019 at 05:11:20PM -0700, Nadav Amit wrote:
> Yet another version, per PeterZ request, addressing the latest feedback.
>
Well, I would've been OK with just an updated to the one patch, but
thanks. Let me see if I can get all that to apply :-)
^ permalink raw reply [flat|nested] 49+ messages in thread