From: Alexander Potapenko <glider@xxxxxxxxxx> Subject: 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@xxxxxxxx: add declarations for internal functions] Link: http://lkml.kernel.org/r/20180105094112.2690475-1-arnd@xxxxxxxx [fengguang.wu@xxxxxxxxx: __asan_set_shadow_00 can be static] Link: http://lkml.kernel.org/r/20171223125943.GA74341@lkp-ib03 [ghackmann@xxxxxxxxxx: fix memset() parameters, and tweak commit message to describe new callbacks] Link: http://lkml.kernel.org/r/20171204191735.132544-6-paullawrence@xxxxxxxxxx Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> Signed-off-by: Greg Hackmann <ghackmann@xxxxxxxxxx> Signed-off-by: Paul Lawrence <paullawrence@xxxxxxxxxx> Signed-off-by: Fengguang Wu <fengguang.wu@xxxxxxxxx> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Cc: Matthias Kaehlcke <mka@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/kasan/kasan.c | 15 +++++++++++++++ mm/kasan/kasan.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 59 insertions(+) diff -puN mm/kasan/kasan.c~kasan-added-functions-for-unpoisoning-stack-variables mm/kasan/kasan.c --- a/mm/kasan/kasan.c~kasan-added-functions-for-unpoisoning-stack-variables +++ a/mm/kasan/kasan.c @@ -770,6 +770,21 @@ void __asan_allocas_unpoison(const void } 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) diff -puN mm/kasan/kasan.h~kasan-added-functions-for-unpoisoning-stack-variables mm/kasan/kasan.h --- a/mm/kasan/kasan.h~kasan-added-functions-for-unpoisoning-stack-variables +++ a/mm/kasan/kasan.h @@ -121,4 +121,48 @@ static inline void quarantine_reduce(voi 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 _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
