From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
