Re: [PATCH] xfs_io: fix memory leak in add_enckey

[Eric Biggers <ebiggers@google.com>]

On Thu, Nov 07, 2019 at 10:50:59AM -0600, Eric Sandeen wrote:
> Invalid arguments to add_enckey will leak the "arg" allocation,
> so fix that.
> 
> Fixes: ba71de04 ("xfs_io/encrypt: add 'add_enckey' command")
> Fixes-coverity-id: 1454644
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
> 
> diff --git a/io/encrypt.c b/io/encrypt.c
> index 17d61cfb..c6a4e190 100644
> --- a/io/encrypt.c
> +++ b/io/encrypt.c
> @@ -696,6 +696,7 @@ add_enckey_f(int argc, char **argv)
>  				goto out;
>  			break;
>  		default:
> +			free(arg);
>  			return command_usage(&add_enckey_cmd);
>  		}
>  	}
> 

The same leak happens later in the function too.  How about this instead:

diff --git a/io/encrypt.c b/io/encrypt.c
index 17d61cfb..de48c50c 100644
--- a/io/encrypt.c
+++ b/io/encrypt.c
@@ -678,6 +678,7 @@ add_enckey_f(int argc, char **argv)
 	int c;
 	struct fscrypt_add_key_arg *arg;
 	ssize_t raw_size;
+	int retval = 0;
 
 	arg = calloc(1, sizeof(*arg) + FSCRYPT_MAX_KEY_SIZE + 1);
 	if (!arg) {
@@ -696,14 +697,17 @@ add_enckey_f(int argc, char **argv)
 				goto out;
 			break;
 		default:
-			return command_usage(&add_enckey_cmd);
+			retval = command_usage(&add_enckey_cmd);
+			goto out;
 		}
 	}
 	argc -= optind;
 	argv += optind;
 
-	if (argc != 0)
-		return command_usage(&add_enckey_cmd);
+	if (argc != 0) {
+		retval = command_usage(&add_enckey_cmd);
+		goto out;
+	}
 
 	raw_size = read_until_limit_or_eof(STDIN_FILENO, arg->raw,
 					   FSCRYPT_MAX_KEY_SIZE + 1);
@@ -732,7 +736,7 @@ add_enckey_f(int argc, char **argv)
 out:
 	memset(arg->raw, 0, FSCRYPT_MAX_KEY_SIZE + 1);
 	free(arg);
-	return 0;
+	return retval;
 }
 
 static int