From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: kernel-hardening@lists.openwall.com
Cc: linux-arm-kernel@lists.infradead.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Arnd Bergmann <arnd@arndb.de>, Nicolas Pitre <nico@linaro.org>,
Russell King <linux@armlinux.org.uk>,
Kees Cook <keescook@chromium.org>,
Thomas Garnier <thgarnie@google.com>,
Marc Zyngier <marc.zyngier@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Tony Lindgren <tony@atomide.com>,
Matt Fleming <matt@codeblueprint.co.uk>,
Dave Martin <dave.martin@arm.com>
Subject: [kernel-hardening] [PATCH 15/30] ARM: kernel: switch to relative exception tables
Date: Mon, 14 Aug 2017 13:53:56 +0100 [thread overview]
Message-ID: <20170814125411.22604-16-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20170814125411.22604-1-ard.biesheuvel@linaro.org>
To avoid having to relocate the contents of extable entries at
runtime when running with KASLR enabled, wire up the existing
support for emitting them as relative references. This ensures
these quantities are invariant under runtime relocation.
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/arm/include/asm/Kbuild | 1 -
arch/arm/include/asm/assembler.h | 6 +++---
arch/arm/include/asm/extable.h | 20 ++++++++++++++++++
arch/arm/include/asm/futex.h | 2 +-
arch/arm/include/asm/uaccess.h | 8 +++----
arch/arm/include/asm/word-at-a-time.h | 2 +-
arch/arm/kernel/entry-armv.S | 6 +++---
arch/arm/kernel/swp_emulate.c | 4 ++--
arch/arm/lib/backtrace.S | 8 +++----
arch/arm/lib/getuser.S | 22 ++++++++++----------
arch/arm/lib/putuser.S | 12 +++++------
arch/arm/mm/alignment.c | 14 ++++++-------
arch/arm/mm/extable.c | 2 +-
arch/arm/nwfpe/entry.S | 2 +-
scripts/sortextable.c | 2 +-
15 files changed, 65 insertions(+), 46 deletions(-)
diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
index 721ab5ecfb9b..f2d67fa34eb3 100644
--- a/arch/arm/include/asm/Kbuild
+++ b/arch/arm/include/asm/Kbuild
@@ -3,7 +3,6 @@ generic-y += current.h
generic-y += early_ioremap.h
generic-y += emergency-restart.h
generic-y += exec.h
-generic-y += extable.h
generic-y += irq_regs.h
generic-y += kdebug.h
generic-y += local.h
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 3176bf7dcbd9..09b6b28f2595 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -247,7 +247,7 @@
9999: x; \
.pushsection __ex_table,"a"; \
.align 3; \
- .long 9999b,9001f; \
+ .long 9999b - ., 9001f - .; \
.popsection
#ifdef CONFIG_SMP
@@ -383,7 +383,7 @@ THUMB( orr \reg , \reg , #PSR_T_BIT )
.pushsection __ex_table,"a"
.align 3
- .long 9999b, \abort
+ .long 9999b - ., \abort - .
.popsection
.endm
@@ -424,7 +424,7 @@ THUMB( orr \reg , \reg , #PSR_T_BIT )
.pushsection __ex_table,"a"
.align 3
- .long 9999b, \abort
+ .long 9999b - ., \abort - .
.popsection
.endr
.endm
diff --git a/arch/arm/include/asm/extable.h b/arch/arm/include/asm/extable.h
new file mode 100644
index 000000000000..3610cc116a86
--- /dev/null
+++ b/arch/arm/include/asm/extable.h
@@ -0,0 +1,20 @@
+#ifndef __ASM_EXTABLE_H
+#define __ASM_EXTABLE_H
+
+/*
+ * The exception table consists of pairs of relative offsets: the first
+ * is the relative offset to an instruction that is allowed to fault,
+ * and the second is the relative offset at which the program should
+ * continue. No registers are modified, so it is entirely up to the
+ * continuation code to figure out what to do.
+ */
+
+struct exception_table_entry
+{
+ int insn, fixup;
+};
+
+#define ARCH_HAS_RELATIVE_EXTABLE
+
+extern int fixup_exception(struct pt_regs *regs);
+#endif
diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h
index 6795368ad023..31760d0ab76b 100644
--- a/arch/arm/include/asm/futex.h
+++ b/arch/arm/include/asm/futex.h
@@ -11,7 +11,7 @@
"3:\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
- " .long 1b, 4f, 2b, 4f\n" \
+ " .long 1b - ., 4f - ., 2b - ., 4f - .\n" \
" .popsection\n" \
" .pushsection .text.fixup,\"ax\"\n" \
" .align 2\n" \
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 0bf2347495f1..62b9bb7d991a 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -295,7 +295,7 @@ do { \
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
- " .long 1b, 3b\n" \
+ " .long 1b - ., 3b - .\n" \
" .popsection" \
: "+r" (err), "=&r" (x) \
: "r" (addr), "i" (-EFAULT) \
@@ -385,7 +385,7 @@ do { \
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
- " .long 1b, 3b\n" \
+ " .long 1b - ., 3b - .\n" \
" .popsection" \
: "+r" (err) \
: "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
@@ -435,8 +435,8 @@ do { \
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
- " .long 1b, 4b\n" \
- " .long 2b, 4b\n" \
+ " .long 1b - ., 4b - .\n" \
+ " .long 2b - ., 4b - .\n" \
" .popsection" \
: "+r" (err), "+r" (__pu_addr) \
: "r" (x), "i" (-EFAULT) \
diff --git a/arch/arm/include/asm/word-at-a-time.h b/arch/arm/include/asm/word-at-a-time.h
index 5831dce4b51c..d433c686d9ca 100644
--- a/arch/arm/include/asm/word-at-a-time.h
+++ b/arch/arm/include/asm/word-at-a-time.h
@@ -86,7 +86,7 @@ static inline unsigned long load_unaligned_zeropad(const void *addr)
" .popsection\n"
" .pushsection __ex_table,\"a\"\n"
" .align 3\n"
- " .long 1b, 3b\n"
+ " .long 1b - ., 3b - .\n"
" .popsection"
: "=&r" (ret), "=&r" (offset)
: "r" (addr), "Qo" (*(unsigned long *)addr));
diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index c731f0d2b2af..1c7c12123b18 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -570,10 +570,10 @@ ENDPROC(__und_usr)
ret r9
.popsection
.pushsection __ex_table,"a"
- .long 1b, 4b
+ .long 1b - ., 4b - .
#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7
- .long 2b, 4b
- .long 3b, 4b
+ .long 2b - ., 4b - .
+ .long 3b - ., 4b - .
#endif
.popsection
diff --git a/arch/arm/kernel/swp_emulate.c b/arch/arm/kernel/swp_emulate.c
index 3bda08bee674..a783e9c0b266 100644
--- a/arch/arm/kernel/swp_emulate.c
+++ b/arch/arm/kernel/swp_emulate.c
@@ -50,8 +50,8 @@
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .align 3\n" \
- " .long 0b, 3b\n" \
- " .long 1b, 3b\n" \
+ " .long 0b - ., 3b - .\n" \
+ " .long 1b - ., 3b - .\n" \
" .previous" \
: "=&r" (res), "+r" (data), "=&r" (temp) \
: "r" (addr), "i" (-EAGAIN), "i" (-EFAULT) \
diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S
index 7d7952e5a3b1..84a8df7aa63c 100644
--- a/arch/arm/lib/backtrace.S
+++ b/arch/arm/lib/backtrace.S
@@ -107,10 +107,10 @@ ENDPROC(c_backtrace)
.pushsection __ex_table,"a"
.align 3
- .long 1001b, 1006b
- .long 1002b, 1006b
- .long 1003b, 1006b
- .long 1004b, 1006b
+ .long 1001b - ., 1006b - .
+ .long 1002b - ., 1006b - .
+ .long 1003b - ., 1006b - .
+ .long 1004b - ., 1006b - .
.popsection
.Lbad: .asciz "Backtrace aborted due to bad frame pointer <%p>\n"
diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S
index df73914e81c8..d47b4776d308 100644
--- a/arch/arm/lib/getuser.S
+++ b/arch/arm/lib/getuser.S
@@ -133,17 +133,17 @@ ENDPROC(__get_user_bad)
ENDPROC(__get_user_bad8)
.pushsection __ex_table, "a"
- .long 1b, __get_user_bad
- .long 2b, __get_user_bad
- .long 3b, __get_user_bad
- .long 4b, __get_user_bad
- .long 5b, __get_user_bad8
- .long 6b, __get_user_bad8
+ .long 1b - ., __get_user_bad - .
+ .long 2b - ., __get_user_bad - .
+ .long 3b - ., __get_user_bad - .
+ .long 4b - ., __get_user_bad - .
+ .long 5b - ., __get_user_bad8 - .
+ .long 6b - ., __get_user_bad8 - .
#ifdef __ARMEB__
- .long 7b, __get_user_bad
- .long 8b, __get_user_bad8
- .long 9b, __get_user_bad8
- .long 10b, __get_user_bad8
- .long 11b, __get_user_bad8
+ .long 7b - ., __get_user_bad - .
+ .long 8b - ., __get_user_bad8 - .
+ .long 9b - ., __get_user_bad8 - .
+ .long 10b - ., __get_user_bad8 - .
+ .long 11b - ., __get_user_bad8 - .
#endif
.popsection
diff --git a/arch/arm/lib/putuser.S b/arch/arm/lib/putuser.S
index 38d660d3705f..6b854197ff48 100644
--- a/arch/arm/lib/putuser.S
+++ b/arch/arm/lib/putuser.S
@@ -89,10 +89,10 @@ __put_user_bad:
ENDPROC(__put_user_bad)
.pushsection __ex_table, "a"
- .long 1b, __put_user_bad
- .long 2b, __put_user_bad
- .long 3b, __put_user_bad
- .long 4b, __put_user_bad
- .long 5b, __put_user_bad
- .long 6b, __put_user_bad
+ .long 1b - ., __put_user_bad - .
+ .long 2b - ., __put_user_bad - .
+ .long 3b - ., __put_user_bad - .
+ .long 4b - ., __put_user_bad - .
+ .long 5b - ., __put_user_bad - .
+ .long 6b - ., __put_user_bad - .
.popsection
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c
index 2c96190e018b..2c74cb826b6a 100644
--- a/arch/arm/mm/alignment.c
+++ b/arch/arm/mm/alignment.c
@@ -209,7 +209,7 @@ union offset_union {
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
- " .long 1b, 3b\n" \
+ " .long 1b - ., 3b - .\n" \
" .popsection\n" \
: "=r" (err), "=&r" (val), "=r" (addr) \
: "0" (err), "2" (addr))
@@ -269,8 +269,8 @@ union offset_union {
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
- " .long 1b, 4b\n" \
- " .long 2b, 4b\n" \
+ " .long 1b - ., 4b - .\n" \
+ " .long 2b - ., 4b - .\n" \
" .popsection\n" \
: "=r" (err), "=&r" (v), "=&r" (a) \
: "0" (err), "1" (v), "2" (a)); \
@@ -309,10 +309,10 @@ union offset_union {
" .popsection\n" \
" .pushsection __ex_table,\"a\"\n" \
" .align 3\n" \
- " .long 1b, 6b\n" \
- " .long 2b, 6b\n" \
- " .long 3b, 6b\n" \
- " .long 4b, 6b\n" \
+ " .long 1b - ., 6b - .\n" \
+ " .long 2b - ., 6b - .\n" \
+ " .long 3b - ., 6b - .\n" \
+ " .long 4b - ., 6b - .\n" \
" .popsection\n" \
: "=r" (err), "=&r" (v), "=&r" (a) \
: "0" (err), "1" (v), "2" (a)); \
diff --git a/arch/arm/mm/extable.c b/arch/arm/mm/extable.c
index f436f7439e46..6a8b85bf0cac 100644
--- a/arch/arm/mm/extable.c
+++ b/arch/arm/mm/extable.c
@@ -10,7 +10,7 @@ int fixup_exception(struct pt_regs *regs)
fixup = search_exception_tables(instruction_pointer(regs));
if (fixup) {
- regs->ARM_pc = fixup->fixup;
+ regs->ARM_pc = (unsigned long)&fixup->fixup + fixup->fixup;
#ifdef CONFIG_THUMB2_KERNEL
/* Clear the IT state to avoid nasty surprises in the fixup */
regs->ARM_cpsr &= ~PSR_IT_MASK;
diff --git a/arch/arm/nwfpe/entry.S b/arch/arm/nwfpe/entry.S
index 39c20afad7ed..c4fe13b31705 100644
--- a/arch/arm/nwfpe/entry.S
+++ b/arch/arm/nwfpe/entry.S
@@ -121,5 +121,5 @@ next:
.pushsection __ex_table,"a"
.align 3
- .long .Lx1, .Lfix
+ .long .Lx1 - ., .Lfix - .
.popsection
diff --git a/scripts/sortextable.c b/scripts/sortextable.c
index 365a907f98b3..56a4c6714da7 100644
--- a/scripts/sortextable.c
+++ b/scripts/sortextable.c
@@ -314,6 +314,7 @@ do_file(char const *const fname)
break;
case EM_S390:
+ case EM_ARM:
case EM_AARCH64:
case EM_PARISC:
case EM_PPC:
@@ -322,7 +323,6 @@ do_file(char const *const fname)
break;
case EM_ARCOMPACT:
case EM_ARCV2:
- case EM_ARM:
case EM_MICROBLAZE:
case EM_MIPS:
case EM_XTENSA:
--
2.11.0
next prev parent reply other threads:[~2017-08-14 12:53 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-14 12:53 [kernel-hardening] [PATCH 00/30] implement KASLR for ARM Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 01/30] asm-generic: add .data.rel.ro sections to __ro_after_init Ard Biesheuvel
2017-08-14 14:26 ` [kernel-hardening] " Arnd Bergmann
2017-08-14 12:53 ` [kernel-hardening] [PATCH 02/30] ARM: assembler: introduce adr_l, ldr_l and str_l macros Ard Biesheuvel
2017-08-14 15:29 ` [kernel-hardening] " Dave Martin
2017-08-14 15:38 ` Ard Biesheuvel
2017-08-14 15:50 ` Dave Martin
2017-08-14 16:18 ` Nicolas Pitre
2017-08-14 16:22 ` Ard Biesheuvel
2017-08-14 16:33 ` Nicolas Pitre
2017-08-14 16:42 ` Russell King - ARM Linux
2017-08-14 16:56 ` Ard Biesheuvel
2017-08-14 15:32 ` Dave Martin
2017-08-14 15:40 ` Ard Biesheuvel
2017-08-14 15:53 ` Dave Martin
2017-08-14 12:53 ` [kernel-hardening] [PATCH 03/30] ARM: head-common.S: use PC-relative insn sequence for __proc_info Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 04/30] ARM: head-common.S: use PC-relative insn sequence for idmap creation Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 05/30] ARM: head.S: use PC-relative insn sequence for secondary_data Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 06/30] ARM: kernel: use relative references for UP/SMP alternatives Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 07/30] ARM: head: use PC-relative insn sequence for __smp_alt Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 08/30] ARM: sleep.S: use PC-relative insn sequence for sleep_save_sp/mpidr_hash Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 09/30] ARM: head.S: use PC-relative insn sequences for __fixup_pv_table Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 10/30] ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 11/30] ARM: kvm: replace open coded VA->PA calculations with adr_l call Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 12/30] arm-soc: exynos: replace open coded VA->PA conversions Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 13/30] arm-soc: mvebu: replace open coded VA->PA conversion Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 14/30] arm-soc: various: replace open coded VA->PA calculation of pen_release Ard Biesheuvel
2017-08-14 12:53 ` Ard Biesheuvel [this message]
2017-08-14 12:53 ` [kernel-hardening] [PATCH 16/30] ARM: kernel: use relative phys-to-virt patch tables Ard Biesheuvel
2017-08-14 12:53 ` [kernel-hardening] [PATCH 17/30] arm-soc: tegra: make sleep asm code runtime relocatable Ard Biesheuvel
2017-08-14 14:42 ` [kernel-hardening] " Dave Martin
2017-08-14 14:49 ` Ard Biesheuvel
2017-08-14 15:29 ` Dave Martin
2017-08-14 12:53 ` [kernel-hardening] [PATCH 18/30] ARM: kernel: make vmlinux buildable as a PIE executable Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 19/30] ARM: kernel: use PC-relative symbol references in MMU switch code Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 20/30] ARM: kernel: use PC relative symbol references in suspend/resume code Ard Biesheuvel
2017-08-14 16:02 ` [kernel-hardening] " Nicolas Pitre
2017-08-14 18:14 ` Ard Biesheuvel
2017-08-14 18:37 ` Nicolas Pitre
2017-08-14 12:54 ` [kernel-hardening] [PATCH 21/30] ARM: mm: export default vmalloc base address Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 22/30] ARM: kernel: refer to swapper_pg_dir via its symbol Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 23/30] ARM: kernel: implement randomization of the kernel load address Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 24/30] ARM: decompressor: explicitly map decompressor binary cacheable Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 25/30] ARM: compressed: factor out zImage header and make it extensible Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 26/30] ARM: decompressor: add KASLR support Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 27/30] efi/libstub: add 'max' parameter to efi_random_alloc() Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 28/30] efi/libstub: check for vmalloc= command line argument Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 29/30] efi/libstub: arm: reserve bootloader supplied initrd in memory map Ard Biesheuvel
2017-08-18 11:48 ` [kernel-hardening] " Ard Biesheuvel
2017-08-21 10:37 ` Mark Rutland
2017-08-21 10:39 ` Ard Biesheuvel
2017-08-14 12:54 ` [kernel-hardening] [PATCH 30/30] efi/libstub: arm: implement KASLR Ard Biesheuvel
2017-08-14 15:30 ` [kernel-hardening] Re: [PATCH 00/30] implement KASLR for ARM Arnd Bergmann
2017-08-14 15:49 ` Ard Biesheuvel
2017-08-14 16:03 ` Arnd Bergmann
2017-08-14 16:28 ` Nicolas Pitre
2017-08-14 17:28 ` Ard Biesheuvel
2017-08-14 18:01 ` Nicolas Pitre
2017-08-14 18:08 ` Ard Biesheuvel
2017-08-14 16:16 ` Nicolas Pitre
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