[dm-devel] [PATCH] dm-crypt: Fix parsing of extended IV arguments.
Milan Broz
gmazyland at gmail.com
Wed Jan 9 10:57:14 UTC 2019
The dm-crypt cipher specification in a mapping table is defined as
cipher[:keycount]-chainmode-ivmode[:ivopts] or with the new crypt API format
capi:cipher_api_spec-ivmode[:ivopts].
For ESSIV, the parameter includes hash specification, for example aes-cbc-essiv:sha256.
The implementation expected that additional IV option never includes another dash '-' character
Unfortunately, with SHA3, we have now names like sha3-256, so the mapping table parser fails:
dmsetup create test --table "0 8 crypt aes-cbc-essiv:sha3-256 9c1185a5c5e9fc54612808977ee8f5b9e 0 /dev/sdb 0"
or (new format)
dmsetup create test --table "0 8 crypt capi:cbc(aes)-essiv:sha3-256 9c1185a5c5e9fc54612808977ee8f5b9e 0 /dev/sdb 0"
device-mapper: crypt: Ignoring unexpected additional cipher options
device-mapper: table: 253:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
This patch fixes the dm-crypt constructor to ignore additional dash in IV options and also removes
bogus warning (that is ignored anyway).
[This patch should go into stable tree as well.]
Signed-off-by: Milan Broz <gmazyland at gmail.com>
---
drivers/md/dm-crypt.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 0ff22159a0ca..71bfb85f9652 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -2414,9 +2414,21 @@ static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key
* capi:cipher_api_spec-iv:ivopts
*/
tmp = &cipher_in[strlen("capi:")];
- cipher_api = strsep(&tmp, "-");
- *ivmode = strsep(&tmp, ":");
- *ivopts = tmp;
+
+ /* Separate IV options if present, it can contain another '-' in hash name */
+ *ivopts = strrchr(tmp, ':');
+ if (*ivopts) {
+ **ivopts = '\0';
+ (*ivopts)++;
+ }
+ /* Parse IV mode */
+ *ivmode = strrchr(tmp, '-');
+ if (*ivmode) {
+ **ivmode = '\0';
+ (*ivmode)++;
+ }
+ /* The rest is crypto API spec */
+ cipher_api = tmp;
if (*ivmode && !strcmp(*ivmode, "lmk"))
cc->tfms_count = 64;
@@ -2486,11 +2498,8 @@ static int crypt_ctr_cipher_old(struct dm_target *ti, char *cipher_in, char *key
goto bad_mem;
chainmode = strsep(&tmp, "-");
- *ivopts = strsep(&tmp, "-");
- *ivmode = strsep(&*ivopts, ":");
-
- if (tmp)
- DMWARN("Ignoring unexpected additional cipher options");
+ *ivmode = strsep(&tmp, ":");
+ *ivopts = tmp;
/*
* For compatibility with the original dm-crypt mapping format, if
--
2.20.1
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