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authorDmitry Vyukov <dvyukov@google.com>2016-11-30 15:54:16 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-11-30 16:32:52 -0800
commit828347f8f9a558cf1af2faa46387a26564f2ac3e (patch)
tree4acb63366cc89b3e87e85805530911300dd4ab19 /mm/kasan/kasan.c
parent045d599a286bc01daa3510d59272440a17b23c2e (diff)
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 <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: <stable@vger.kernel.org> [4.0+] 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.c19
1 files changed, 19 insertions, 0 deletions
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)