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authorAndrey Konovalov <andreyknvl@google.com>2018-12-28 11:30:35 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 23:11:43 +0300
commit772a2fa50ffb2f4282be8436da6e70530a2ac63c (patch)
tree21cc3befe7a9d1e8ccc8dd07ded02f90c3055ad0
parent21696c1613244f2ad4e9216c4f6e7804831a992c (diff)
downloadlinux-772a2fa50ffb2f4282be8436da6e70530a2ac63c.tar.xz
kasan, mm: perform untagged pointers comparison in krealloc
The krealloc function checks where the same buffer was reused or a new one allocated by comparing kernel pointers. Tag-based KASAN changes memory tag on the krealloc'ed chunk of memory and therefore also changes the pointer tag of the returned pointer. Therefore we need to perform comparison on untagged (with tags reset) pointers to check whether it's the same memory region or not. Link: http://lkml.kernel.org/r/14f6190d7846186a3506cd66d82446646fe65090.1544099024.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mark Rutland <mark.rutland@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/slab_common.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index a4a82fbdefd4..bc24100682b0 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1534,7 +1534,7 @@ void *krealloc(const void *p, size_t new_size, gfp_t flags)
}
ret = __do_krealloc(p, new_size, flags);
- if (ret && p != ret)
+ if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
kfree(p);
return ret;