From 828347f8f9a558cf1af2faa46387a26564f2ac3e Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Wed, 30 Nov 2016 15:54:16 -0800 Subject: kasan: support use-after-scope detection Gcc revision 241896 implements use-after-scope detection. Will be available in gcc 7. Support it in KASAN. Gcc emits 2 new callbacks to poison/unpoison large stack objects when they go in/out of scope. Implement the callbacks and add a test. [dvyukov@google.com: v3] Link: http://lkml.kernel.org/r/1479998292-144502-1-git-send-email-dvyukov@google.com Link: http://lkml.kernel.org/r/1479226045-145148-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov Acked-by: Andrey Ryabinin Cc: Alexander Potapenko Cc: [4.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/kasan/kasan.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'mm/kasan/kasan.c') diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 70c009741aab..0e9505f66ec1 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -764,6 +764,25 @@ EXPORT_SYMBOL(__asan_storeN_noabort); void __asan_handle_no_return(void) {} EXPORT_SYMBOL(__asan_handle_no_return); +/* Emitted by compiler to poison large objects when they go out of scope. */ +void __asan_poison_stack_memory(const void *addr, size_t size) +{ + /* + * Addr is KASAN_SHADOW_SCALE_SIZE-aligned and the object is surrounded + * by redzones, so we simply round up size to simplify logic. + */ + kasan_poison_shadow(addr, round_up(size, KASAN_SHADOW_SCALE_SIZE), + KASAN_USE_AFTER_SCOPE); +} +EXPORT_SYMBOL(__asan_poison_stack_memory); + +/* Emitted by compiler to unpoison large objects when they go into scope. */ +void __asan_unpoison_stack_memory(const void *addr, size_t size) +{ + kasan_unpoison_shadow(addr, size); +} +EXPORT_SYMBOL(__asan_unpoison_stack_memory); + #ifdef CONFIG_MEMORY_HOTPLUG static int kasan_mem_notifier(struct notifier_block *nb, unsigned long action, void *data) -- cgit v1.2.3