[dm-devel] add IV generation method null
Ludwig Nussel
ludwig.nussel at suse.de
Thu Mar 1 15:16:32 UTC 2007
Alasdair G Kergon wrote:
> On Wed, Feb 28, 2007 at 03:47:54PM +0100, Ludwig Nussel wrote:
> > Any comments/objections on the patch? Is there any additional action
> > from my side required to get this into the mainline kernel?
>
> This comment ought to be more descriptive:
>
> null: For mounting legacy images only.
Ok, patch with better comment included.
> I'll include it in the next set of patches I send upstream.
Thanks! :-)
Add IV generation method 'null' to be able to read old filesystem
images created with SuSE's loop_fish2 module.
Signed-off-by: Ludwig Nussel <ludwig.nussel at suse.de>
Acked-By: Christophe Saout <christophe at saout.de>
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -103,6 +103,10 @@ static kmem_cache_t *_crypt_io_pool;
* encrypted with the bulk cipher using a salt as key. The salt
* should be derived from the bulk cipher's key via hashing.
*
+ * null: the initial vector is always zero. This method is for
+ * compatability with SuSE's obsolete loop_fish2 only. Do not
+ * use it for creating new content.
+ *
* plumb: unimplemented, see:
* http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
*/
@@ -203,6 +207,13 @@ static int crypt_iv_essiv_gen(struct cry
return 0;
}
+static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
+{
+ memset(iv, 0, cc->iv_size);
+
+ return 0;
+}
+
static struct crypt_iv_operations crypt_iv_plain_ops = {
.generator = crypt_iv_plain_gen
};
@@ -213,6 +224,9 @@ static struct crypt_iv_operations crypt_
.generator = crypt_iv_essiv_gen
};
+static struct crypt_iv_operations crypt_iv_null_ops = {
+ .generator = crypt_iv_null_gen
+};
static int
crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out,
@@ -594,6 +608,8 @@ static int crypt_ctr(struct dm_target *t
cc->iv_gen_ops = &crypt_iv_plain_ops;
else if (strcmp(ivmode, "essiv") == 0)
cc->iv_gen_ops = &crypt_iv_essiv_ops;
+ else if (strcmp(ivmode, "null") == 0)
+ cc->iv_gen_ops = &crypt_iv_null_ops;
else {
ti->error = "Invalid IV mode";
goto bad2;
cu
Ludwig
--
(o_ Ludwig Nussel
//\ SUSE Labs
V_/_ http://www.suse.de/
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nuernberg)
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