[PATCH] dm-crypt: Reject sector_size feature if device length is not aligned to it

[Milan Broz <gmazyland@gmail.com>]

If a crypt mapping uses optional sector_size feature, additional
restrictions to mapped device segment size must be applied in constructor,
otherwise the device activation will fail later.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
---
 drivers/md/dm-crypt.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 54aef8ed97db..488ecd0b1bd0 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2584,6 +2584,10 @@ static int crypt_ctr_optional(struct dm_target *ti, unsigned int argc, char **ar
 				ti->error = "Invalid feature value for sector_size";
 				return -EINVAL;
 			}
+			if (ti->len & ((cc->sector_size >> SECTOR_SHIFT) - 1)) {
+				ti->error = "Device size is not multiple of sector_size feature";
+				return -EINVAL;
+			}
 			cc->sector_shift = __ffs(cc->sector_size) - SECTOR_SHIFT;
 		} else if (!strcasecmp(opt_string, "iv_large_sectors"))
 			set_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags);
-- 
2.14.1