builtin/upload-archive: fix leaking args passed to write_archive()

In git-upload-archive(1), we pass an array of arguments to
`write_archive()` to tell it what exactly to do. We don't ever clear the
vector though, causing a memory leak. Furthermore though, the call to
`write_archive()` may cause contents of the array to be modified, which
would cause us to leak memory to allocated strings held by it.

Fix the issue by having `write_archive()` create a shallow copy of
`argv` before parsing the arguments. Like this, we won't modify the
caller's array and can easily `strvec_clear()` it to plug these memory
leaks.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

archive.c

@@ -736,6 +736,7 @@ int write_archive(int argc, const char **argv, const char *prefix,
 	struct pretty_print_describe_status describe_status = {0};
 	struct pretty_print_context ctx = {0};
 	struct archiver_args args;
+	const char **argv_copy;
 	int rc;
 
 	git_config_get_bool("uploadarchive.allowunreachable", &remote_allow_unreachable);
@@ -749,6 +750,14 @@ int write_archive(int argc, const char **argv, const char *prefix,
 	args.repo = repo;
 	args.prefix = prefix;
 	string_list_init_dup(&args.extra_files);
+
+	/*
+	 * `parse_archive_args()` modifies contents of `argv`, which is what we
+	 * want. Our callers may not want it though, so we create a copy here.
+	 */
+	DUP_ARRAY(argv_copy, argv, argc);
+	argv = argv_copy;
+
 	argc = parse_archive_args(argc, argv, &ar, &args, name_hint, remote);
 	if (!startup_info->have_repository) {
 		/*
@@ -767,6 +776,7 @@ int write_archive(int argc, const char **argv, const char *prefix,
 	string_list_clear_func(&args.extra_files, extra_file_info_clear);
 	free(args.refname);
 	clear_pathspec(&args.pathspec);
+	free(argv_copy);
 
 	return rc;
 }

builtin/upload-archive.c

@@ -22,6 +22,7 @@ int cmd_upload_archive_writer(int argc, const char **argv, const char *prefix)
 {
 	struct strvec sent_argv = STRVEC_INIT;
 	const char *arg_cmd = "argument ";
+	int ret;
 
 	if (argc != 2 || !strcmp(argv[1], "-h"))
 		usage(upload_archive_usage);
@@ -46,8 +47,11 @@ int cmd_upload_archive_writer(int argc, const char **argv, const char *prefix)
 	}
 
 	/* parse all options sent by the client */
-	return write_archive(sent_argv.nr, sent_argv.v, prefix,
-			     the_repository, NULL, 1);
+	ret = write_archive(sent_argv.nr, sent_argv.v, prefix,
+			    the_repository, NULL, 1);
+
+	strvec_clear(&sent_argv);
+	return ret;
 }
 
 __attribute__((format (printf, 1, 2)))