Messages in this thread Patch in this message | | | From | Paul Lawrence <> | Subject | [PATCH v3 5/5] kasan: added functions for unpoisoning stack variables | Date | Fri, 1 Dec 2017 13:36:43 -0800 |
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From: Alexander Potapenko <glider@google.com>
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.
Signed-off-by: Alexander Potapenko <glider@google.com> [ghackmann@google.com: fix memset() parameters, and tweak commit message to describe new callbacks] Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Paul Lawrence <paullawrence@google.com> --- mm/kasan/kasan.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
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) -- 2.15.0.531.g2ccb3012c9-goog
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