The patch titled
Subject: kasan: fix quarantine conflicting with init_on_free
has been added to the -mm tree. Its filename is
kasan-fix-quarantine-conflicting-with-init_on_free.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/kasan-fix-quarantine-conflicting-with-init_on_free.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/kasan-fix-quarantine-conflicting-with-init_on_free.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx
Fixes: 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options")
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kasan/quarantine.c | 11 +++++++++++
1 file changed, 11 insertions(+)
--- a/mm/kasan/quarantine.c~kasan-fix-quarantine-conflicting-with-init_on_free
+++ a/mm/kasan/quarantine.c
@@ -132,12 +132,23 @@ static void *qlink_to_object(struct qlis
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.
*/
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-fix-quarantine-conflicting-with-init_on_free.patch
