From: Greg Kroah-Hartman <gre...@linuxfoundation.org>

From: Andrey Konovalov <andreyk...@google.com>

[ Upstream commit e66e1799a76621003e5b04c9c057826a2152e103 ]

Since the hardware tag-based KASAN mode might not have a redzone that
comes after an allocated object (when kasan.mode=prod is enabled), the
kasan_bitops_tags() test ends up corrupting the next object in memory.

Change the test so it always accesses the redzone that lies within the
allocated object's boundaries.

Link: 
https://linux-review.googlesource.com/id/I67f51d1ee48f0a8d0fe2658c2a39e4879fe0832a
Link: 
https://lkml.kernel.org/r/7d452ce4ae35bb1988d2c9244dfea56cf2cc9315.1610733117.git.andreyk...@google.com
Signed-off-by: Andrey Konovalov <andreyk...@google.com>
Reviewed-by: Marco Elver <el...@google.com>
Reviewed-by: Alexander Potapenko <gli...@google.com>
Cc: Andrey Ryabinin <aryabi...@virtuozzo.com>
Cc: Branislav Rankov <branislav.ran...@arm.com>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Dmitry Vyukov <dvyu...@google.com>
Cc: Evgenii Stepanov <euge...@google.com>
Cc: Kevin Brodsky <kevin.brod...@arm.com>
Cc: Peter Collingbourne <p...@google.com>
Cc: Vincenzo Frascino <vincenzo.frasc...@arm.com>
Cc: Will Deacon <will.dea...@arm.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 lib/test_kasan.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c
index 2947274cc2d3..5a2f104ca13f 100644
--- a/lib/test_kasan.c
+++ b/lib/test_kasan.c
@@ -737,13 +737,13 @@ static void kasan_bitops_tags(struct kunit *test)
                return;
        }
 
-       /* Allocation size will be rounded to up granule size, which is 16. */
-       bits = kzalloc(sizeof(*bits), GFP_KERNEL);
+       /* kmalloc-64 cache will be used and the last 16 bytes will be the 
redzone. */
+       bits = kzalloc(48, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits);
 
-       /* Do the accesses past the 16 allocated bytes. */
-       kasan_bitops_modify(test, BITS_PER_LONG, &bits[1]);
-       kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, 
&bits[1]);
+       /* Do the accesses past the 48 allocated bytes, but within the redone. 
*/
+       kasan_bitops_modify(test, BITS_PER_LONG, (void *)bits + 48);
+       kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, (void 
*)bits + 48);
 
        kfree(bits);
 }
-- 
2.30.1



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