[PATCH 1/3] fix xstrdup leak in parse_short_opt

["Lidong Yan via GitGitGadget" <gitgitgadget@gmail.com>]

From: Lidong Yan <502024330056@smail.nju.edu.cn>

Signed-off-by: Lidong Yan <502024330056@smail.nju.edu.cn>
---
 Makefile                             |  1 +
 parse-options.c                      | 17 +++++++++++++-
 parse-options.h                      | 12 ++++++++++
 t/helper/meson.build                 |  1 +
 t/helper/test-free-unknown-options.c | 35 ++++++++++++++++++++++++++++
 t/helper/test-tool.c                 |  1 +
 t/helper/test-tool.h                 |  1 +
 t/t0040-parse-options.sh             | 14 +++++++++++
 8 files changed, 81 insertions(+), 1 deletion(-)
 create mode 100644 t/helper/test-free-unknown-options.c

diff --git a/Makefile b/Makefile
index 8a7f1c76543f..af8ea677b820 100644
--- a/Makefile
+++ b/Makefile
@@ -822,6 +822,7 @@ TEST_BUILTINS_OBJS += test-online-cpus.o
 TEST_BUILTINS_OBJS += test-pack-mtimes.o
 TEST_BUILTINS_OBJS += test-parse-options.o
 TEST_BUILTINS_OBJS += test-parse-pathspec-file.o
+TEST_BUILTINS_OBJS += test-free-unknown-options.o
 TEST_BUILTINS_OBJS += test-partial-clone.o
 TEST_BUILTINS_OBJS += test-path-utils.o
 TEST_BUILTINS_OBJS += test-path-walk.o
diff --git a/parse-options.c b/parse-options.c
index a9a39ecaef6c..4279dfe4d313 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -638,6 +638,16 @@ static int has_subcommands(const struct option *options)
 	return 0;
 }
 
+static void set_strdup_fn(struct parse_opt_ctx_t *ctx, const struct option *options) {
+	for (; options->type != OPTION_END; options++)
+		;
+	if (options->value && options->strdup_fn) {
+		ctx->unknown_opts = options->value;
+		ctx->strdup_fn = options->strdup_fn;
+		return;
+	}
+}
+
 static void parse_options_start_1(struct parse_opt_ctx_t *ctx,
 				  int argc, const char **argv, const char *prefix,
 				  const struct option *options,
@@ -655,6 +665,7 @@ static void parse_options_start_1(struct parse_opt_ctx_t *ctx,
 	ctx->cpidx = ((flags & PARSE_OPT_KEEP_ARGV0) != 0);
 	ctx->flags = flags;
 	ctx->has_subcommands = has_subcommands(options);
+	set_strdup_fn(ctx, options);
 	if (!ctx->has_subcommands && (flags & PARSE_OPT_SUBCOMMAND_OPTIONAL))
 		BUG("Using PARSE_OPT_SUBCOMMAND_OPTIONAL without subcommands");
 	if (ctx->has_subcommands) {
@@ -981,7 +992,11 @@ enum parse_opt_result parse_options_step(struct parse_opt_ctx_t *ctx,
 					 *
 					 * This is leaky, too bad.
 					 */
-					ctx->argv[0] = xstrdup(ctx->opt - 1);
+					if (ctx->unknown_opts && ctx->strdup_fn) {
+						ctx->argv[0] = ctx->strdup_fn(ctx->unknown_opts, ctx->opt - 1);
+					} else {
+						ctx->argv[0] = xstrdup(ctx->opt - 1);
+					}
 					*(char *)ctx->argv[0] = '-';
 					goto unknown;
 				case PARSE_OPT_NON_OPTION:
diff --git a/parse-options.h b/parse-options.h
index 91c3e3c29b3d..af06a09abb8e 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -77,6 +77,8 @@ typedef enum parse_opt_result parse_opt_ll_cb(struct parse_opt_ctx_t *ctx,
 typedef int parse_opt_subcommand_fn(int argc, const char **argv,
 				    const char *prefix, struct repository *repo);
 
+typedef char *parse_opt_strdup_fn(void *value, const char *s);
+
 /*
  * `type`::
  *   holds the type of the option, you must have an OPTION_END last in your
@@ -165,6 +167,7 @@ struct option {
 	parse_opt_ll_cb *ll_callback;
 	intptr_t extra;
 	parse_opt_subcommand_fn *subcommand_fn;
+	parse_opt_strdup_fn *strdup_fn;
 };
 
 #define OPT_BIT_F(s, l, v, h, b, f) { \
@@ -388,6 +391,12 @@ static char *parse_options_noop_ignored_value MAYBE_UNUSED;
 }
 #define OPT_SUBCOMMAND(l, v, fn)    OPT_SUBCOMMAND_F((l), (v), (fn), 0)
 
+#define OPT_UNKNOWN(v, fn) { \
+	.type = OPTION_END, \
+	.value = (v), \
+	.strdup_fn = (fn), \
+}
+
 /*
  * parse_options() will filter out the processed options and leave the
  * non-option arguments in argv[]. argv0 is assumed program name and
@@ -496,6 +505,9 @@ struct parse_opt_ctx_t {
 	const char *prefix;
 	const char **alias_groups; /* must be in groups of 3 elements! */
 	struct parse_opt_cmdmode_list *cmdmode_list;
+
+	void *unknown_opts;
+	parse_opt_strdup_fn *strdup_fn;
 };
 
 void parse_options_start(struct parse_opt_ctx_t *ctx,
diff --git a/t/helper/meson.build b/t/helper/meson.build
index d2cabaa2bcfc..476e32781761 100644
--- a/t/helper/meson.build
+++ b/t/helper/meson.build
@@ -39,6 +39,7 @@ test_tool_sources = [
   'test-pack-mtimes.c',
   'test-parse-options.c',
   'test-parse-pathspec-file.c',
+  'test-free-unknown-options.c',
   'test-partial-clone.c',
   'test-path-utils.c',
   'test-path-walk.c',
diff --git a/t/helper/test-free-unknown-options.c b/t/helper/test-free-unknown-options.c
new file mode 100644
index 000000000000..9d658115ba8f
--- /dev/null
+++ b/t/helper/test-free-unknown-options.c
@@ -0,0 +1,35 @@
+#include "git-compat-util.h"
+#include "parse-options.h"
+#include "setup.h"
+#include "strvec.h"
+
+static const char *const free_unknown_options_usage[] = {
+    "test-tool free-unknown-options",
+    NULL
+};
+
+int cmd__free_unknown_options(int argc, const char **argv) {
+    struct strvec *unknown_opts = xmalloc(sizeof(struct strvec));
+    strvec_init(unknown_opts);
+    const char *prefix = setup_git_directory();
+
+    bool a, b;
+	struct option options[] = {
+		OPT_BOOL('a', "test-a", &a, N_("option a, only for test use")),
+	OPT_BOOL('b', "test-b", &b, N_("option b, only for test use")),
+	OPT_UNKNOWN(unknown_opts, (parse_opt_strdup_fn *)&strvec_push),
+	};
+
+    parse_options(argc, argv, prefix, options,
+	free_unknown_options_usage, PARSE_OPT_KEEP_UNKNOWN_OPT);
+
+    printf("a = %s\n", a? "true": "false");
+    printf("b = %s\n", b? "true": "false");
+
+    int i;
+    for (i = 0; i < unknown_opts->nr; i++) {
+	printf("free unknown option: %s\n", unknown_opts->v[i]);
+    }
+    strvec_clear(unknown_opts);
+    free(unknown_opts);
+}
\ No newline at end of file
diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c
index 50dc4dac4ed6..79ec4f9cda07 100644
--- a/t/helper/test-tool.c
+++ b/t/helper/test-tool.c
@@ -51,6 +51,7 @@ static struct test_cmd cmds[] = {
 	{ "parse-options-flags", cmd__parse_options_flags },
 	{ "parse-pathspec-file", cmd__parse_pathspec_file },
 	{ "parse-subcommand", cmd__parse_subcommand },
+	{ "free-unknown-options", cmd__free_unknown_options},
 	{ "partial-clone", cmd__partial_clone },
 	{ "path-utils", cmd__path_utils },
 	{ "path-walk", cmd__path_walk },
diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h
index 6d62a5b53d95..33fa7828b9f6 100644
--- a/t/helper/test-tool.h
+++ b/t/helper/test-tool.h
@@ -44,6 +44,7 @@ int cmd__parse_options(int argc, const char **argv);
 int cmd__parse_options_flags(int argc, const char **argv);
 int cmd__parse_pathspec_file(int argc, const char** argv);
 int cmd__parse_subcommand(int argc, const char **argv);
+int cmd__free_unknown_options(int argc, const char **argv);
 int cmd__partial_clone(int argc, const char **argv);
 int cmd__path_utils(int argc, const char **argv);
 int cmd__path_walk(int argc, const char **argv);
diff --git a/t/t0040-parse-options.sh b/t/t0040-parse-options.sh
index ca55ea8228c3..773f54103fd3 100755
--- a/t/t0040-parse-options.sh
+++ b/t/t0040-parse-options.sh
@@ -822,4 +822,18 @@ test_expect_success 'u16 limits range' '
 	test_grep "value 65536 for option .u16. not in range \[0,65535\]" err
 '
 
+cat >expect <<\EOF
+a = true
+b = true
+free unknown option: -c
+free unknown option: -d
+EOF
+
+test_expect_success 'free unknown options' '
+	test-tool free-unknown-options -ac -bd \
+	>output 2>output.err &&
+	test_cmp expect output &&
+	test_must_be_empty output.err
+'
+
 test_done
-- 
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