Commit d321599c authored by Alexander Potapenko's avatar Alexander Potapenko Committed by Linus Torvalds
Browse files

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: default avatarAlexander Potapenko <glider@google.com>
Signed-off-by: default avatarGreg Hackmann <ghackmann@google.com>
Signed-off-by: default avatarPaul Lawrence <paullawrence@google.com>
Signed-off-by: default avatarFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarAndrey 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 00a14294
......@@ -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)
......
......@@ -121,4 +121,48 @@ static inline void quarantine_reduce(void) { }
static inline void quarantine_remove_cache(struct kmem_cache *cache) { }
#endif
/*
* Exported functions for interfaces called from assembly or from generated
* code. Declarations here to avoid warning about missing declarations.
*/
asmlinkage void kasan_unpoison_task_stack_below(const void *watermark);
void __asan_register_globals(struct kasan_global *globals, size_t size);
void __asan_unregister_globals(struct kasan_global *globals, size_t size);
void __asan_loadN(unsigned long addr, size_t size);
void __asan_storeN(unsigned long addr, size_t size);
void __asan_handle_no_return(void);
void __asan_poison_stack_memory(const void *addr, size_t size);
void __asan_unpoison_stack_memory(const void *addr, size_t size);
void __asan_alloca_poison(unsigned long addr, size_t size);
void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom);
void __asan_load1(unsigned long addr);
void __asan_store1(unsigned long addr);
void __asan_load2(unsigned long addr);
void __asan_store2(unsigned long addr);
void __asan_load4(unsigned long addr);
void __asan_store4(unsigned long addr);
void __asan_load8(unsigned long addr);
void __asan_store8(unsigned long addr);
void __asan_load16(unsigned long addr);
void __asan_store16(unsigned long addr);
void __asan_load1_noabort(unsigned long addr);
void __asan_store1_noabort(unsigned long addr);
void __asan_load2_noabort(unsigned long addr);
void __asan_store2_noabort(unsigned long addr);
void __asan_load4_noabort(unsigned long addr);
void __asan_store4_noabort(unsigned long addr);
void __asan_load8_noabort(unsigned long addr);
void __asan_store8_noabort(unsigned long addr);
void __asan_load16_noabort(unsigned long addr);
void __asan_store16_noabort(unsigned long addr);
void __asan_set_shadow_00(const void *addr, size_t size);
void __asan_set_shadow_f1(const void *addr, size_t size);
void __asan_set_shadow_f2(const void *addr, size_t size);
void __asan_set_shadow_f3(const void *addr, size_t size);
void __asan_set_shadow_f5(const void *addr, size_t size);
void __asan_set_shadow_f8(const void *addr, size_t size);
#endif
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