eCryptfs: Filename encryption only supports password auth tokens

Returns -ENOTSUPP when attempting to use filename encryption with
something other than a password authentication token, such as a private
token from openssl.  Using filename encryption with a userspace eCryptfs
key module is a future goal.  Until then, this patch handles the
situation a little better than simply using a BUG_ON().

Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: ecryptfs-devel@lists.launchpad.net
Cc: stable <stable@kernel.org>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

fs/ecryptfs/crypto.c

@@ -1703,7 +1703,7 @@ ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
 	} else {
 		printk(KERN_ERR "%s: No support for requested filename "
 		       "encryption method in this release\n", __func__);
-		rc = -ENOTSUPP;
+		rc = -EOPNOTSUPP;
 		goto out;
 	}
 out:
@@ -2168,7 +2168,7 @@ int ecryptfs_encrypt_and_encode_filename(
 			(*encoded_name)[(*encoded_name_size)] = '\0';
 			(*encoded_name_size)++;
 		} else {
-			rc = -ENOTSUPP;
+			rc = -EOPNOTSUPP;
 		}
 		if (rc) {
 			printk(KERN_ERR "%s: Error attempting to encode "

fs/ecryptfs/keystore.c

@@ -612,7 +612,12 @@ ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
 	}
 	/* TODO: Support other key modules than passphrase for
 	 * filename encryption */
-	BUG_ON(s->auth_tok->token_type != ECRYPTFS_PASSWORD);
+	if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
+		rc = -EOPNOTSUPP;
+		printk(KERN_INFO "%s: Filename encryption only supports "
+		       "password tokens\n", __func__);
+		goto out_free_unlock;
+	}
 	sg_init_one(
 		&s->hash_sg,
 		(u8 *)s->auth_tok->token.password.session_key_encryption_key,
@@ -910,7 +915,12 @@ ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
 	}
 	/* TODO: Support other key modules than passphrase for
 	 * filename encryption */
-	BUG_ON(s->auth_tok->token_type != ECRYPTFS_PASSWORD);
+	if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
+		rc = -EOPNOTSUPP;
+		printk(KERN_INFO "%s: Filename encryption only supports "
+		       "password tokens\n", __func__);
+		goto out_free_unlock;
+	}
 	rc = crypto_blkcipher_setkey(
 		s->desc.tfm,
 		s->auth_tok->token.password.session_key_encryption_key,