From 047d711a7a3e6e9b84f19c594a8bb3af04384e69 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Fri, 20 May 2016 16:59:28 -0700 Subject: mm/kasan: add API to check memory regions commit 64f8ebaf115bcddc4aaa902f981c57ba6506bc42 upstream. Memory access coded in an assembly won't be seen by KASAN as a compiler can instrument only C code. Add kasan_check_[read,write]() API which is going to be used to check a certain memory range. Link: http://lkml.kernel.org/r/1462538722-1574-3-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin Acked-by: Alexander Potapenko Cc: Dmitry Vyukov Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 4.4: drop change in MAINTAINERS] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- include/linux/kasan-checks.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) create mode 100644 include/linux/kasan-checks.h (limited to 'include/linux') diff --git a/include/linux/kasan-checks.h b/include/linux/kasan-checks.h new file mode 100644 index 000000000000..b7f8aced7870 --- /dev/null +++ b/include/linux/kasan-checks.h @@ -0,0 +1,12 @@ +#ifndef _LINUX_KASAN_CHECKS_H +#define _LINUX_KASAN_CHECKS_H + +#ifdef CONFIG_KASAN +void kasan_check_read(const void *p, unsigned int size); +void kasan_check_write(const void *p, unsigned int size); +#else +static inline void kasan_check_read(const void *p, unsigned int size) { } +static inline void kasan_check_write(const void *p, unsigned int size) { } +#endif + +#endif -- cgit v1.2.3 From 36bd2ae6cc1887bd371ca259d433734ae68212f4 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Thu, 1 Feb 2018 21:00:48 +0300 Subject: compiler.h, kasan: Avoid duplicating __read_once_size_nocheck() commit bdb5ac801af3d81d36732c2f640d6a1d3df83826 upstream. Instead of having two identical __read_once_size_nocheck() functions with different attributes, consolidate all the difference in new macro __no_kasan_or_inline and use it. No functional changes. Signed-off-by: Andrey Ryabinin Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- include/linux/compiler.h | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'include/linux') diff --git a/include/linux/compiler.h b/include/linux/compiler.h index e5d349d65ae9..92a51e00b904 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -241,23 +241,21 @@ void __read_once_size(const volatile void *p, void *res, int size) #ifdef CONFIG_KASAN /* - * This function is not 'inline' because __no_sanitize_address confilcts + * We can't declare function 'inline' because __no_sanitize_address confilcts * with inlining. Attempt to inline it may cause a build failure. * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368 * '__maybe_unused' allows us to avoid defined-but-not-used warnings. */ -static __no_sanitize_address __maybe_unused -void __read_once_size_nocheck(const volatile void *p, void *res, int size) -{ - __READ_ONCE_SIZE; -} +# define __no_kasan_or_inline __no_sanitize_address __maybe_unused #else -static __always_inline +# define __no_kasan_or_inline __always_inline +#endif + +static __no_kasan_or_inline void __read_once_size_nocheck(const volatile void *p, void *res, int size) { __READ_ONCE_SIZE; } -#endif static __always_inline void __write_once_size(volatile void *p, void *res, int size) { -- cgit v1.2.3 From 203ba216f29bfc7378d3595f31daab74fa72f9d7 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Thu, 1 Feb 2018 21:00:49 +0300 Subject: compiler.h: Add read_word_at_a_time() function. commit 7f1e541fc8d57a143dd5df1d0a1276046e08c083 upstream. Sometimes we know that it's safe to do potentially out-of-bounds access because we know it won't cross a page boundary. Still, KASAN will report this as a bug. Add read_word_at_a_time() function which is supposed to be used in such cases. In read_word_at_a_time() KASAN performs relaxed check - only the first byte of access is validated. Signed-off-by: Andrey Ryabinin Signed-off-by: Linus Torvalds [bwh: Backported to 4.4: adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- include/linux/compiler.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/linux') diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 92a51e00b904..7cabe0cc8665 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -292,6 +292,7 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s * with an explicit memory barrier or atomic instruction that provides the * required ordering. */ +#include #define __READ_ONCE(x, check) \ ({ \ @@ -310,6 +311,13 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s */ #define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0) +static __no_kasan_or_inline +unsigned long read_word_at_a_time(const void *addr) +{ + kasan_check_read(addr, 1); + return *(unsigned long *)addr; +} + #define WRITE_ONCE(x, val) \ ({ \ union { typeof(x) __val; char __c[1]; } __u = \ -- cgit v1.2.3