diff options
| author | Andrey Konovalov <andreyknvl@google.com> | 2022-01-14 14:05:01 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-01-15 16:30:26 +0200 |
| commit | 26dca996ea7b1ac7008b6b6063fc88b849e3ac3e (patch) | |
| tree | cba343dcba067570b75226033f93f85de5310c17 | |
| parent | f98f966cd75002a71caec1b6d209da5762c0efac (diff) | |
kasan: fix quarantine conflicting with init_on_free
KASAN's quarantine might save its metadata inside freed objects. As
this happens after the memory is zeroed by the slab allocator when
init_on_free is enabled, the memory coming out of quarantine is not
properly zeroed.
This causes lib/test_meminit.c tests to fail with Generic KASAN.
Zero the metadata when the object is removed from quarantine.
Link: https://lkml.kernel.org/r/2805da5df4b57138fdacd671f5d227d58950ba54.1640037083.git.andreyknvl@google.com
Fixes: 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/kasan/quarantine.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c index d8ccff4c1275..47ed4fc33a29 100644 --- a/mm/kasan/quarantine.c +++ b/mm/kasan/quarantine.c @@ -132,12 +132,23 @@ static void *qlink_to_object(struct qlist_node *qlink, struct kmem_cache *cache) static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache) { void *object = qlink_to_object(qlink, cache); + struct kasan_free_meta *meta = kasan_get_free_meta(cache, object); unsigned long flags; if (IS_ENABLED(CONFIG_SLAB)) local_irq_save(flags); /* + * If init_on_free is enabled and KASAN's free metadata is stored in + * the object, zero the metadata. Otherwise, the object's memory will + * not be properly zeroed, as KASAN saves the metadata after the slab + * allocator zeroes the object. + */ + if (slab_want_init_on_free(cache) && + cache->kasan_info.free_meta_offset == 0) + memzero_explicit(meta, sizeof(*meta)); + + /* * As the object now gets freed from the quarantine, assume that its * free track is no longer valid. */ |