From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
commit 0d74e6a3b6421d98eeafbed26f29156d469bc0b5 upstream.
If the string opt_string is small, the function memcmp can access bytes
that are beyond the terminating nul character. In theory, it could cause
segfault, if opt_string were located just below some unmapped memory.
Change from memcmp to strncmp so that we don't read bytes beyond the end
of the string.
Cc: stable@xxxxxxxxxxxxxxx # v4.12+
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-integrity.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -2917,17 +2917,17 @@ static int dm_integrity_ctr(struct dm_ta
goto bad;
}
ic->sectors_per_block = val >> SECTOR_SHIFT;
- } else if (!memcmp(opt_string, "internal_hash:", strlen("internal_hash:"))) {
+ } else if (!strncmp(opt_string, "internal_hash:", strlen("internal_hash:"))) {
r = get_alg_and_key(opt_string, &ic->internal_hash_alg, &ti->error,
"Invalid internal_hash argument");
if (r)
goto bad;
- } else if (!memcmp(opt_string, "journal_crypt:", strlen("journal_crypt:"))) {
+ } else if (!strncmp(opt_string, "journal_crypt:", strlen("journal_crypt:"))) {
r = get_alg_and_key(opt_string, &ic->journal_crypt_alg, &ti->error,
"Invalid journal_crypt argument");
if (r)
goto bad;
- } else if (!memcmp(opt_string, "journal_mac:", strlen("journal_mac:"))) {
+ } else if (!strncmp(opt_string, "journal_mac:", strlen("journal_mac:"))) {
r = get_alg_and_key(opt_string, &ic->journal_mac_alg, &ti->error,
"Invalid journal_mac argument");
if (r)
