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authorAlexander Potapenko <glider@google.com>2018-02-07 02:36:20 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-07 05:32:42 +0300
commitd321599cf6b861beefe92327476b617435c7fc4a (patch)
tree8baa5c41552be1bdf011192cb0af20196422d3dd /mm/kasan/kasan.c
parent00a14294bb33af533f7ac002fb20623fdd8ea0d7 (diff)
downloadlinux-d321599cf6b861beefe92327476b617435c7fc4a.tar.xz
kasan: add functions for unpoisoning stack variables
As a code-size optimization, LLVM builds since r279383 may bulk-manipulate the shadow region when (un)poisoning large memory blocks. This requires new callbacks that simply do an uninstrumented memset(). This fixes linking the Clang-built kernel when using KASAN. [arnd@arndb.de: add declarations for internal functions] Link: http://lkml.kernel.org/r/20180105094112.2690475-1-arnd@arndb.de [fengguang.wu@intel.com: __asan_set_shadow_00 can be static] Link: http://lkml.kernel.org/r/20171223125943.GA74341@lkp-ib03 [ghackmann@google.com: fix memset() parameters, and tweak commit message to describe new callbacks] Link: http://lkml.kernel.org/r/20171204191735.132544-6-paullawrence@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Paul Lawrence <paullawrence@google.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kasan/kasan.c')
-rw-r--r--mm/kasan/kasan.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index d96b36088b2f..8aaee42fcfab 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -770,6 +770,21 @@ void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
}
EXPORT_SYMBOL(__asan_allocas_unpoison);
+/* Emitted by the compiler to [un]poison local variables. */
+#define DEFINE_ASAN_SET_SHADOW(byte) \
+ void __asan_set_shadow_##byte(const void *addr, size_t size) \
+ { \
+ __memset((void *)addr, 0x##byte, size); \
+ } \
+ EXPORT_SYMBOL(__asan_set_shadow_##byte)
+
+DEFINE_ASAN_SET_SHADOW(00);
+DEFINE_ASAN_SET_SHADOW(f1);
+DEFINE_ASAN_SET_SHADOW(f2);
+DEFINE_ASAN_SET_SHADOW(f3);
+DEFINE_ASAN_SET_SHADOW(f5);
+DEFINE_ASAN_SET_SHADOW(f8);
+
#ifdef CONFIG_MEMORY_HOTPLUG
static int __meminit kasan_mem_notifier(struct notifier_block *nb,
unsigned long action, void *data)