From: Alex Hornung <ahornung@gmail.com>
Date: Sat, 21 Aug 2010 06:17:54 +0000 (+0100)
Subject: dm_target_crypt - Fix compatibility with Linux
X-Git-Tag: v2.9.0~466
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/7a89864aca790456f28133cb04924ae4b1364a46

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 7973eaad3f..5beccf131b 100644
--- 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;