From: Mikulas Patocka mpatocka@redhat.com
commit 85e123c27d5cbc22cfdc01de1e2ca1d9003a02d0 upstream.
The code in dm-log rounds up bitset_size to 32 bits. It then uses find_next_zero_bit_le on the allocated region. find_next_zero_bit_le accesses the bitmap using unsigned long pointers. So, on 64-bit architectures, it may access 4 bytes beyond the allocated size.
Fix this bug by rounding up bitset_size to BITS_PER_LONG.
This bug was found by running the lvm2 testsuite with kasan.
Fixes: 29121bd0b00e ("[PATCH] dm mirror log: bitset_size fix") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Mike Snitzer snitzer@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/dm-log.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/drivers/md/dm-log.c +++ b/drivers/md/dm-log.c @@ -415,8 +415,7 @@ static int create_log_context(struct dm_ /* * Work out how many "unsigned long"s we need to hold the bitset. */ - bitset_size = dm_round_up(region_count, - sizeof(*lc->clean_bits) << BYTE_SHIFT); + bitset_size = dm_round_up(region_count, BITS_PER_LONG); bitset_size >>= BYTE_SHIFT;
lc->bitset_uint32_count = bitset_size / sizeof(*lc->clean_bits);