dm: Check for device sector overflow if CONFIG_LBDAF is not set

[ Upstream commit ef87bfc2 ]

Reference to a device in device-mapper table contains offset in sectors.

If the sector_t is 32bit integer (CONFIG_LBDAF is not set), then
several device-mapper targets can overflow this offset and validity
check is then performed on a wrong offset and a wrong table is activated.

See for example (on 32bit without CONFIG_LBDAF) this overflow:

  # dmsetup create test --table "0 2048 linear /dev/sdg 4294967297"
  # dmsetup table test
  0 2048 linear 8:96 1

This patch adds explicit check for overflow if the offset is sector_t type.
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/md/dm-crypt.c

@@ -2780,7 +2780,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 
 	ret = -EINVAL;
-	if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) {
+	if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1 || tmpll != (sector_t)tmpll) {
 		ti->error = "Invalid device sector";
 		goto bad;
 	}

drivers/md/dm-delay.c

@@ -141,7 +141,7 @@ static int delay_class_ctr(struct dm_target *ti, struct delay_class *c, char **a
 	unsigned long long tmpll;
 	char dummy;
 
-	if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1) {
+	if (sscanf(argv[1], "%llu%c", &tmpll, &dummy) != 1 || tmpll != (sector_t)tmpll) {
 		ti->error = "Invalid device sector";
 		return -EINVAL;
 	}

drivers/md/dm-flakey.c

@@ -213,7 +213,7 @@ static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	devname = dm_shift_arg(&as);
 
 	r = -EINVAL;
-	if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1) {
+	if (sscanf(dm_shift_arg(&as), "%llu%c", &tmpll, &dummy) != 1 || tmpll != (sector_t)tmpll) {
 		ti->error = "Invalid device sector";
 		goto bad;
 	}

drivers/md/dm-linear.c

@@ -45,7 +45,7 @@ static int linear_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 
 	ret = -EINVAL;
-	if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1) {
+	if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1 || tmp != (sector_t)tmp) {
 		ti->error = "Invalid device sector";
 		goto bad;
 	}

drivers/md/dm-raid1.c

@@ -943,7 +943,8 @@ static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
 	char dummy;
 	int ret;
 
-	if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1) {
+	if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1 ||
+	    offset != (sector_t)offset) {
 		ti->error = "Invalid offset";
 		return -EINVAL;
 	}

drivers/md/dm-unstripe.c

@@ -78,7 +78,7 @@ static int unstripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto err;
 	}
 
-	if (sscanf(argv[4], "%llu%c", &start, &dummy) != 1) {
+	if (sscanf(argv[4], "%llu%c", &start, &dummy) != 1 || start != (sector_t)start) {
 		ti->error = "Invalid striped device offset";
 		goto err;
 	}