From: Yee Lee <yee.lee@xxxxxxxxxxxx>
Issue: when SLUB debug is on, hwtag kasan_unpoison() would overwrite
the redzone of object with unaligned size.
An additional memzero_explicit() path is added to replacing init by
hwtag instruction for those unaligned size at SLUB debug mode.
Signed-off-by: Yee Lee <yee.lee@xxxxxxxxxxxx>
---
mm/kasan/kasan.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 8f450bc28045..d1054f35838f 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -387,6 +387,12 @@ static inline void kasan_unpoison(const void *addr, size_t size, bool init)
if (WARN_ON((unsigned long)addr & KASAN_GRANULE_MASK))
return;
+#if IS_ENABLED(CONFIG_SLUB_DEBUG)
+ if (init && ((unsigned long)size & KASAN_GRANULE_MASK)) {
+ init = false;
+ memzero_explicit((void *)addr, size);
+ }
+#endif
size = round_up(size, KASAN_GRANULE_SIZE);
hw_set_mem_tag_range((void *)addr, size, tag, init);
--
2.18.0
