dm crypt: reject sector_size feature if device length is not aligned to it

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.

Fixes: 8f0009a225 ("dm crypt: optionally support larger encryption sector size")
Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 75341fdca4b6..96ab46512e1f 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2585,6 +2585,10 @@ 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);