diff mbox series

[v6,11/18] khwasan, mm: perform untagged pointers comparison in krealloc

Message ID a13a41e3ca65116eb5614c4dd396b23182e98fed.1535462971.git.andreyknvl@google.com (mailing list archive)
State New, archived
Headers show
Series khwasan: kernel hardware assisted address sanitizer | expand

Commit Message

Andrey Konovalov Aug. 29, 2018, 11:35 a.m. UTC
The krealloc function checks where the same buffer was reused or a new one
allocated by comparing kernel pointers. KHWASAN changes memory tag on the
krealloc'ed chunk of memory and therefore also changes the pointer tag of
the returned pointer. Therefore we need to perform comparison on untagged
(with tags reset) pointers to check whether it's the same memory region or
not.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/slab_common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 3abfa0f86118..0d588dfebd7d 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1513,7 +1513,7 @@  void *krealloc(const void *p, size_t new_size, gfp_t flags)
 	}
 
 	ret = __do_krealloc(p, new_size, flags);
-	if (ret && p != ret)
+	if (ret && khwasan_reset_tag(p) != khwasan_reset_tag(ret))
 		kfree(p);
 
 	return ret;