eCryptfs: Handle unrecognized tag 3 cipher codes

Returns an error when an unrecognized cipher code is present in a tag 3
packet or an ecryptfs_crypt_stat cannot be initialized.  Also sets an
crypt_stat->tfm error pointer to NULL to ensure that it will not be
incorrectly freed in ecryptfs_destroy_crypt_stat().

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, 8 insertions, 3 deletions

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 931f715827ac..f92370aa5704 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -795,6 +795,7 @@ int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
         kfree(full_alg_name);
         if (IS_ERR(crypt_stat->tfm)) {
                 rc = PTR_ERR(crypt_stat->tfm);
+                crypt_stat->tfm = NULL;
                 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
                                 "Error initializing cipher [%s]\n",
                                 crypt_stat->cipher);
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
index f9965139c430..3a61f056acf6 100644
--- a/fs/ecryptfs/keystore.c
+++ b/fs/ecryptfs/keystore.c
@@ -1316,8 +1316,10 @@ parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
                 rc = -EINVAL;
                 goto out_free;
         }
-        ecryptfs_cipher_code_to_string(crypt_stat->cipher,
-                                       (u16)data[(*packet_size)]);
+        rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
+                                            (u16)data[(*packet_size)]);
+        if (rc)
+                goto out_free;
         /* A little extra work to differentiate among the AES key
          * sizes; see RFC2440 */
         switch(data[(*packet_size)++]) {
@@ -1328,7 +1330,9 @@ parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
                 crypt_stat->key_size =
                         (*new_auth_tok)->session_key.encrypted_key_size;
         }
-        ecryptfs_init_crypt_ctx(crypt_stat);
+        rc = ecryptfs_init_crypt_ctx(crypt_stat);
+        if (rc)
+                goto out_free;
         if (unlikely(data[(*packet_size)++] != 0x03)) {
                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
                 rc = -ENOSYS;