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authorAndrey Konovalov <andreyknvl@google.com>2019-01-08 15:23:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-01-08 17:15:11 -0800
commit96fedce27e1356a2fff1c270710d9405848db562 (patch)
tree740a5d338824604bc88f4faa6398a17e8a8f0204
parenteb214f2dda31ffa989033b1e0f848ba0d3cb6188 (diff)
kasan: make tag based mode work with CONFIG_HARDENED_USERCOPY
With CONFIG_HARDENED_USERCOPY enabled __check_heap_object() compares and then subtracts a potentially tagged pointer with a non-tagged address of the page that this pointer belongs to, which leads to unexpected behavior. Untag the pointer in __check_heap_object() before doing any of these operations. Link: http://lkml.kernel.org/r/7e756a298d514c4482f52aea6151db34818d395d.1546540962.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/slub.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 36c0befeebd8..1e3d0ec4e200 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3846,6 +3846,8 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
unsigned int offset;
size_t object_size;
+ ptr = kasan_reset_tag(ptr);
+
/* Find object and usable object size. */
s = page->slab_cache;