diff options
| author | Marco Elver <elver@google.com> | 2022-01-14 14:04:54 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-01-15 16:30:26 +0200 |
| commit | bed0a9b591492bb285ea88cd221e0412031396ca (patch) | |
| tree | 63bba3f5748459fcfad15372d3361871a32a3fb1 /mm | |
| parent | e5f4728767d2ec9e3eb122c74e224242d21ee650 (diff) | |
kasan: add ability to detect double-kmem_cache_destroy()
Because mm/slab_common.c is not instrumented with software KASAN modes,
it is not possible to detect use-after-free of the kmem_cache passed
into kmem_cache_destroy(). In particular, because of the s->refcount--
and subsequent early return if non-zero, KASAN would never be able to
see the double-free via kmem_cache_free(kmem_cache, s). To be able to
detect a double-kmem_cache_destroy(), check accessibility of the
kmem_cache, and in case of failure return early.
While KASAN_HW_TAGS is able to detect such bugs, by checking
accessibility and returning early we fail more gracefully and also avoid
corrupting reused objects (where tags mismatch).
A recent case of a double-kmem_cache_destroy() was detected by KFENCE:
https://lkml.kernel.org/r/0000000000003f654905c168b09d@google.com, which
was not detectable by software KASAN modes.
Link: https://lkml.kernel.org/r/20211119142219.1519617-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/slab_common.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c index b7c431819cdb..f02c32bd05ab 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -489,7 +489,7 @@ void slab_kmem_cache_release(struct kmem_cache *s) void kmem_cache_destroy(struct kmem_cache *s) { - if (unlikely(!s)) + if (unlikely(!s) || !kasan_check_byte(s)) return; cpus_read_lock(); |