dm_target_crypt - Fix compatibility with Linux

* The sector number that Linux' dm-crypt passes to its iv generators
  is offset another -block_offset sectors, so that the actual sector
  number is the one on the dm device, not the underlying device.

* Also fix the plain iv generator, which is supposed to be a "32-bit
  little-endian version of the sector number"

* Now our dm_target_crypt can read Linux' crypt disks. This was tested
  with an image using aes-cbc-essiv:sha256 and aes-cbc-plain.

diff --git a/sys/dev/disk/dm/dm_target_crypt.c b/sys/dev/disk/dm/dm_target_crypt.c
index 7973eaa..5beccf1 100644 (file)
--- a/sys/dev/disk/dm/dm_target_crypt.c
+++ b/sys/dev/disk/dm/dm_target_crypt.c
@@ -365,7 +365,7 @@ plain_ivgen(dm_target_crypt_config_t *priv, u_int8_t *iv,
            size_t iv_len, off_t sector, void *opaque)
 {
        bzero(iv, iv_len);
-       *((off_t *)iv) = htole64(sector + priv->iv_offset);
+       *((uint32_t *)iv) = htole32((uint32_t)(sector + priv->iv_offset));
        dmtc_crypto_dispatch(opaque);
 }
 
@@ -588,7 +588,7 @@ dm_target_crypt_init(dm_dev_t * dmv, void **target_config, char *params)
        /* Save length of param string */
        priv->params_len = len;
        priv->block_offset = block_offset;
-       priv->iv_offset = iv_offset;
+       priv->iv_offset = iv_offset - block_offset;
 
        *target_config = priv;