crypto: cts - Weed out non-CBC algorithms

The cts algorithm as currently implemented assumes the underlying
is a CBC-mode algorithm.  So this patch adds a check for that to
eliminate bogus combinations of cts with non-CBC modes.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 3 insertions, 0 deletions

diff --git a/crypto/cts.c b/crypto/cts.c
index 6a8089c4d4b4..e467ec0acf9f 100644
--- a/crypto/cts.c
+++ b/crypto/cts.c
@@ -290,6 +290,9 @@ static struct crypto_instance *crypto_cts_alloc(struct rtattr **tb)
         if (!is_power_of_2(alg->cra_blocksize))
                 goto out_put_alg;
 
+        if (strncmp(alg->cra_name, "cbc(", 4))
+                goto out_put_alg;
+
         inst = crypto_alloc_instance("cts", alg);
         if (IS_ERR(inst))
                 goto out_put_alg;