From: Peter Zijlstra <peterz@infradead.org>
To: torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com,
julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net,
mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com,
valentin.schneider@arm.com, brgerst@gmail.com,
jpoimboe@redhat.com, luto@kernel.org, bp@alien8.de,
dvlasenk@redhat.com
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
dvyukov@google.com, rostedt@goodmis.org
Subject: [PATCH 09/20] x86/uaccess,kasan: Fix KASAN vs SMAP
Date: Thu, 07 Mar 2019 12:45:20 +0100 [thread overview]
Message-ID: <20190307115159.881691431@infradead.org> (raw)
In-Reply-To: 20190307114511.870090179@infradead.org
KASAN inserts extra code for every LOAD/STORE emitted by te compiler.
Much of this code is simple and safe to run with AC=1, however the
kasan_report() function, called on error, is most certainly not safe
to call with AC=1.
Therefore wrap kasan_report() in user_access_{save,restore}; which for
x86 SMAP, saves/restores EFLAGS and clears AC before calling the real
function.
Also ensure all the functions are without __fentry__ hook. The
function tracer is also not safe.
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
mm/kasan/Makefile | 3 +++
mm/kasan/common.c | 10 ++++++++++
mm/kasan/report.c | 3 +--
3 files changed, 14 insertions(+), 2 deletions(-)
--- a/mm/kasan/Makefile
+++ b/mm/kasan/Makefile
@@ -2,11 +2,13 @@
KASAN_SANITIZE := n
UBSAN_SANITIZE_common.o := n
UBSAN_SANITIZE_generic.o := n
+UBSAN_SANITIZE_generic_report.o := n
UBSAN_SANITIZE_tags.o := n
KCOV_INSTRUMENT := n
CFLAGS_REMOVE_common.o = -pg
CFLAGS_REMOVE_generic.o = -pg
+CFLAGS_REMOVE_generic_report.o = -pg
CFLAGS_REMOVE_tags.o = -pg
# Function splitter causes unnecessary splits in __asan_load1/__asan_store1
@@ -14,6 +16,7 @@ CFLAGS_REMOVE_tags.o = -pg
CFLAGS_common.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
CFLAGS_generic.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
+CFLAGS_generic_report.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
CFLAGS_tags.o := $(call cc-option, -fno-conserve-stack -fno-stack-protector)
obj-$(CONFIG_KASAN) := common.o init.o report.o
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -34,6 +34,7 @@
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/bug.h>
+#include <linux/uaccess.h>
#include "kasan.h"
#include "../slab.h"
@@ -612,6 +613,15 @@ void kasan_free_shadow(const struct vm_s
vfree(kasan_mem_to_shadow(vm->addr));
}
+extern void __kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip);
+
+void kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip)
+{
+ unsigned long flags = user_access_save();
+ __kasan_report(addr, size, is_write, ip);
+ user_access_restore(flags);
+}
+
#ifdef CONFIG_MEMORY_HOTPLUG
static bool shadow_mapped(unsigned long addr)
{
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -281,8 +281,7 @@ void kasan_report_invalid_free(void *obj
end_report(&flags);
}
-void kasan_report(unsigned long addr, size_t size,
- bool is_write, unsigned long ip)
+void __kasan_report(unsigned long addr, size_t size, bool is_write, unsigned long ip)
{
struct kasan_access_info info;
void *tagged_addr;
next prev parent reply other threads:[~2019-03-07 11:54 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-07 11:45 [PATCH 00/20] objtool: UACCESS validation v3 Peter Zijlstra
2019-03-07 11:45 ` [PATCH 01/20] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-03-07 11:45 ` [PATCH 02/20] i915,uaccess: Fix redundant CLAC Peter Zijlstra
2019-03-07 11:45 ` [PATCH 03/20] x86/uaccess: Move copy_user_handle_tail into asm Peter Zijlstra
2019-03-08 18:53 ` Josh Poimboeuf
2019-03-08 19:48 ` Peter Zijlstra
2019-03-08 19:53 ` Josh Poimboeuf
2019-03-10 13:22 ` Peter Zijlstra
2019-03-07 11:45 ` [PATCH 04/20] x86/uaccess: Fix up the fixup Peter Zijlstra
2019-03-07 11:45 ` [PATCH 05/20] x86/uaccess/xen: Suppress SMAP warnings Peter Zijlstra
2019-03-07 12:22 ` Juergen Gross
2019-03-07 12:32 ` Peter Zijlstra
2019-03-07 12:36 ` Juergen Gross
2019-03-08 19:00 ` Josh Poimboeuf
2019-03-08 19:03 ` Josh Poimboeuf
2019-03-10 13:19 ` Peter Zijlstra
2019-03-11 17:59 ` Josh Poimboeuf
2019-03-08 19:50 ` Peter Zijlstra
2019-03-07 11:45 ` [PATCH 06/20] x86/uaccess: Always inline user_access_begin() Peter Zijlstra
2019-03-07 11:45 ` [PATCH 07/20] x86/uaccess: Always inline force_valid_ss() Peter Zijlstra
2019-03-07 13:50 ` Peter Zijlstra
2019-03-07 18:05 ` Andy Lutomirski
2019-03-07 18:59 ` Peter Zijlstra
2019-03-07 19:06 ` Andy Lutomirski
2019-03-07 11:45 ` [PATCH 08/20] x86/uaccess: Introduce user_access_{save,restore}() Peter Zijlstra
2019-03-07 11:45 ` Peter Zijlstra [this message]
2019-03-07 11:45 ` [PATCH 10/20] x86/uaccess,ubsan: Fix UBSAN vs SMAP Peter Zijlstra
2019-03-07 11:45 ` [PATCH 11/20] x86/uaccess,ftrace: Fix ftrace_likely_update() " Peter Zijlstra
2019-03-07 11:45 ` [PATCH 12/20] objtool: Set insn->func for alternatives Peter Zijlstra
2019-03-08 19:16 ` Josh Poimboeuf
2019-03-08 19:51 ` Peter Zijlstra
2019-03-07 11:45 ` [PATCH 13/20] objtool: Hande function aliases Peter Zijlstra
2019-03-08 19:23 ` Josh Poimboeuf
2019-03-08 19:52 ` Peter Zijlstra
2019-03-08 20:00 ` Josh Poimboeuf
2019-03-07 11:45 ` [PATCH 14/20] objtool: Rewrite add_ignores() Peter Zijlstra
2019-03-08 19:29 ` Josh Poimboeuf
2019-03-07 11:45 ` [PATCH 15/20] objtool: Add --backtrace support Peter Zijlstra
2019-03-08 19:33 ` Josh Poimboeuf
2019-03-07 11:45 ` [PATCH 16/20] objtool: Rewrite alt->skip_orig Peter Zijlstra
2019-03-08 20:15 ` Josh Poimboeuf
2019-03-08 21:34 ` Peter Zijlstra
2019-03-08 22:27 ` Josh Poimboeuf
2019-03-07 11:45 ` [PATCH 17/20] objtool: Fix sibling call detection Peter Zijlstra
2019-03-08 20:22 ` Josh Poimboeuf
2019-03-07 11:45 ` [PATCH 18/20] objtool: Add UACCESS validation Peter Zijlstra
2019-03-07 16:33 ` Linus Torvalds
2019-03-07 17:10 ` hpa
2019-03-07 17:41 ` Peter Zijlstra
2019-03-07 17:54 ` Linus Torvalds
2019-03-07 18:48 ` Peter Zijlstra
2019-03-07 18:51 ` hpa
2019-03-07 19:03 ` Peter Zijlstra
2019-03-08 15:01 ` Josh Poimboeuf
2019-03-08 15:07 ` Peter Zijlstra
2019-03-07 20:23 ` Peter Zijlstra
2019-03-07 20:40 ` Peter Zijlstra
2019-03-08 15:07 ` Josh Poimboeuf
2019-03-08 15:23 ` Peter Zijlstra
2019-03-07 20:15 ` Andrey Ryabinin
2019-03-07 20:33 ` Peter Zijlstra
2019-03-07 20:40 ` Andrey Ryabinin
2019-03-07 20:42 ` Peter Zijlstra
2019-03-08 21:02 ` Josh Poimboeuf
2019-03-08 21:31 ` Peter Zijlstra
2019-03-08 21:54 ` Josh Poimboeuf
2019-03-10 13:10 ` Peter Zijlstra
2019-03-11 18:01 ` Josh Poimboeuf
2019-03-07 11:45 ` [PATCH 19/20] objtool: uaccess PUSHF/POPF support Peter Zijlstra
2019-03-08 21:11 ` Josh Poimboeuf
2019-03-10 13:12 ` Peter Zijlstra
2019-03-07 11:45 ` [PATCH 20/20] objtool: Add Direction Flag validation Peter Zijlstra
2019-03-08 21:16 ` Josh Poimboeuf
2019-03-08 21:33 ` Peter Zijlstra
2019-03-08 21:56 ` Josh Poimboeuf
2019-03-10 13:13 ` Peter Zijlstra
2019-03-11 18:00 ` Josh Poimboeuf
2019-03-07 12:03 ` [PATCH 00/20] objtool: UACCESS validation v3 Peter Zijlstra
2019-03-07 12:55 ` Peter Zijlstra
2019-03-07 13:13 ` Peter Zijlstra
2019-03-07 16:47 ` Josh Poimboeuf
2019-03-07 16:50 ` Josh Poimboeuf
2019-03-07 17:00 ` Linus Torvalds
2019-03-07 17:17 ` Josh Poimboeuf
2019-03-07 17:38 ` Peter Zijlstra
2019-03-07 17:45 ` Linus Torvalds
2019-03-07 18:18 ` Steven Rostedt
2019-03-10 13:16 ` Peter Zijlstra
2019-04-19 10:08 ` [PATCH] compiler.h, tracing: Remove CONFIG_PROFILE_ALL_BRANCHES Ingo Molnar
2019-04-19 13:04 ` Steven Rostedt
2019-03-07 17:04 ` [PATCH 00/20] objtool: UACCESS validation v3 hpa
2019-03-07 17:18 ` Josh Poimboeuf
2019-03-07 17:29 ` hpa
2019-03-07 17:45 ` Josh Poimboeuf
2019-03-07 17:48 ` Linus Torvalds
2019-03-07 17:43 ` Peter Zijlstra
2019-03-07 17:48 ` Josh Poimboeuf
2019-04-03 8:21 ` [tip:core/objtool] tracing: Improve "if" macro code generation tip-bot for Josh Poimboeuf
2019-03-07 16:31 ` [PATCH 00/20] objtool: UACCESS validation v3 Linus Torvalds
2019-03-07 17:14 ` hpa
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