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authorAlexander Potapenko <glider@google.com>2021-05-22 17:41:56 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-22 15:09:07 -1000
commitf70b00496f2a0669fdb19a783e613bdbdedcf901 (patch)
treec8e67f9b8062c3ab2dccc36a2e7f0c6f2b0104b8 /mm/slub.c
parent4d1cd3b2c5c1c32826454de3a18c6183238d47ed (diff)
kasan: slab: always reset the tag in get_freepointer_safe()
With CONFIG_DEBUG_PAGEALLOC enabled, the kernel should also untag the object pointer, as done in get_freepointer(). Failing to do so reportedly leads to SLUB freelist corruptions that manifest as boot-time crashes. Link: https://lkml.kernel.org/r/20210514072228.534418-1-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Marco Elver <elver@google.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Elliot Berman <eberman@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 438fa8d4c970..3f96e099817a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -301,6 +301,7 @@ static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
if (!debug_pagealloc_enabled_static())
return get_freepointer(s, object);
+ object = kasan_reset_tag(object);
freepointer_addr = (unsigned long)object + s->offset;
copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p));
return freelist_ptr(s, p, freepointer_addr);