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>

2 files changed, 14 insertions, 4 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index f92370aa570..bae20ad1a50 100644
--- a/fs/ecryptfs/crypto.c
+++ b/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 "
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index 3a61f056acf..17164e483ab 100644
--- a/fs/ecryptfs/keystore.c
+++ b/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,