ecryptfs: Fix memory leakage in keystore.c

commit 3edc8376 upstream.

In 'decrypt_pki_encrypted_session_key' function:

Initializes 'payload' pointer and releases it on exit.
Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/ecryptfs/keystore.c

@@ -1149,7 +1149,7 @@ decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
 	struct ecryptfs_msg_ctx *msg_ctx;
 	struct ecryptfs_message *msg = NULL;
 	char *auth_tok_sig;
-	char *payload;
+	char *payload = NULL;
 	size_t payload_len;
 	int rc;
 
@@ -1204,6 +1204,7 @@ decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
 out:
 	if (msg)
 		kfree(msg);
+	kfree(payload);
 	return rc;
 }