dm crypt: omit parsing of the encapsulated cipher

Only the ESSIV IV generation mode used to use cc->cipher so it could
instantiate the bare cipher used to encrypt the IV. However, this is
now taken care of by the ESSIV template, and so no users of cc->cipher
remain. So remove it altogether.

Signed-off-by: Ard Biesheuvel <[e-mail]>
Tested-by: Milan Broz <[e-mail]>
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm-crypt.c

···
 	struct task_struct *write_thread;
 	struct rb_root write_tree;
 
-	char *cipher;
 	char *cipher_string;
 	char *cipher_auth;
 	char *key_string;
···
 	if (cc->dev)
 		dm_put_device(ti, cc->dev);
 
-	kzfree(cc->cipher);
 	kzfree(cc->cipher_string);
 	kzfree(cc->key_string);
 	kzfree(cc->cipher_auth);
···
 		ti->error = "Invalid IV mode";
 		return -EINVAL;
 	}
-
-	return 0;
-}
-
-/*
- * Workaround to parse cipher algorithm from crypto API spec.
- * The cc->cipher is currently used only in ESSIV.
- * This should be probably done by crypto-api calls (once available...)
- */
-static int crypt_ctr_blkdev_cipher(struct crypt_config *cc)
-{
-	const char *alg_name = NULL;
-	char *start, *end;
-
-	if (crypt_integrity_aead(cc)) {
-		alg_name = crypto_tfm_alg_name(crypto_aead_tfm(any_tfm_aead(cc)));
-		if (!alg_name)
-			return -EINVAL;
-		if (crypt_integrity_hmac(cc)) {
-			alg_name = strchr(alg_name, ',');
-			if (!alg_name)
-				return -EINVAL;
-		}
-		alg_name++;
-	} else {
-		alg_name = crypto_tfm_alg_name(crypto_skcipher_tfm(any_tfm(cc)));
-		if (!alg_name)
-			return -EINVAL;
-	}
-
-	start = strchr(alg_name, '(');
-	end = strchr(alg_name, ')');
-
-	if (!start && !end) {
-		cc->cipher = kstrdup(alg_name, GFP_KERNEL);
-		return cc->cipher ? 0 : -ENOMEM;
-	}
-
-	if (!start || !end || ++start >= end)
-		return -EINVAL;
-
-	cc->cipher = kzalloc(end - start + 1, GFP_KERNEL);
-	if (!cc->cipher)
-		return -ENOMEM;
-
-	strncpy(cc->cipher, start, end - start);
 
 	return 0;
 }
···
 	else
 		cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc));
 
-	ret = crypt_ctr_blkdev_cipher(cc);
-	if (ret < 0) {
-		ti->error = "Cannot allocate cipher string";
-		return -ENOMEM;
-	}
-
 	return 0;
 }
 
···
 		return -EINVAL;
 	}
 	cc->key_parts = cc->tfms_count;
-
-	cc->cipher = kstrdup(cipher, GFP_KERNEL);
-	if (!cc->cipher)
-		goto bad_mem;
 
 	chainmode = strsep(&tmp, "-");
 	*ivmode = strsep(&tmp, ":");