eCryptfs: modified size of keysig in the ecryptfs_key_sig structure

The size of the 'keysig' array is incremented of one byte in order to make
room for the NULL character. The 'keysig' variable is used, in the function
ecryptfs_generate_key_packet_set(), to find an authentication token with
the given signature and is printed a debug message if it cannot be
retrieved.
Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

fs/ecryptfs/ecryptfs_kernel.h

@@ -233,7 +233,7 @@ ecryptfs_get_key_payload_data(struct key *key)
 
 struct ecryptfs_key_sig {
 	struct list_head crypt_stat_list;
-	char keysig[ECRYPTFS_SIG_SIZE_HEX];
+	char keysig[ECRYPTFS_SIG_SIZE_HEX + 1];
 };
 
 struct ecryptfs_filename {

fs/ecryptfs/keystore.c

@@ -2425,6 +2425,7 @@ int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
 		return -ENOMEM;
 	}
 	memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
+	new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
 	/* Caller must hold keysig_list_mutex */
 	list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);