From: Andrzej Hunt <ajrhunt@xxxxxxxxxx>
preprocess_options() allocates new strings for help messages for
OPTION_ALIAS. Therefore we also need to clean those help messages up
when freeing the returned options.
First introduced in:
7c280589cf (parse-options: teach "git cmd -h" to show alias as alias, 2020-03-16)
The preprocessed options themselves no longer contain any indication
that a given option is/was an alias: the easiest and fastest way to
figure it out is to look back at the original options. Alternatively we
could iterate over the alias_groups list - but that would require nested
looping and is likely to be a (little) less efficient.
As far as I can tell, parse_options() is only ever used once per
command, and the help messages are small - hence this leak has very
little impact.
This leak was found while running t0001. LSAN output can be found below:
Direct leak of 65 byte(s) in 1 object(s) allocated from:
#0 0x49a859 in realloc /home/abuild/rpmbuild/BUILD/llvm-11.0.0.src/build/../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:164:3
#1 0x9aae36 in xrealloc /home/ahunt/oss-fuzz/git/wrapper.c:126:8
#2 0x939d8d in strbuf_grow /home/ahunt/oss-fuzz/git/strbuf.c:98:2
#3 0x93b936 in strbuf_vaddf /home/ahunt/oss-fuzz/git/strbuf.c:392:3
#4 0x93b7ff in strbuf_addf /home/ahunt/oss-fuzz/git/strbuf.c:333:2
#5 0x86747e in preprocess_options /home/ahunt/oss-fuzz/git/parse-options.c:666:3
#6 0x866ed2 in parse_options /home/ahunt/oss-fuzz/git/parse-options.c:847:17
#7 0x51c4a7 in cmd_clone /home/ahunt/oss-fuzz/git/builtin/clone.c:989:9
#8 0x4cd60d in run_builtin /home/ahunt/oss-fuzz/git/git.c:453:11
#9 0x4cb2da in handle_builtin /home/ahunt/oss-fuzz/git/git.c:704:3
#10 0x4ccc37 in run_argv /home/ahunt/oss-fuzz/git/git.c:771:4
#11 0x4cac29 in cmd_main /home/ahunt/oss-fuzz/git/git.c:902:19
#12 0x69c9fe in main /home/ahunt/oss-fuzz/git/common-main.c:52:11
#13 0x7fdac42d4349 in __libc_start_main (/lib64/libc.so.6+0x24349)
Signed-off-by: Andrzej Hunt <ajrhunt@xxxxxxxxxx>
---
parse-options.c | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)
diff --git a/parse-options.c b/parse-options.c
index fbea16eaf5c2..3fe1dacc08cb 100644
--- a/parse-options.c
+++ b/parse-options.c
@@ -625,6 +625,8 @@ static int show_gitcomp(const struct option *opts, int show_all)
*
* Right now this is only used to preprocess and substitute
* OPTION_ALIAS.
+ *
+ * The returned options should be freed using free_preprocessed_options.
*/
static struct option *preprocess_options(struct parse_opt_ctx_t *ctx,
const struct option *options)
@@ -693,6 +695,21 @@ static struct option *preprocess_options(struct parse_opt_ctx_t *ctx,
return newopt;
}
+static void free_preprocessed_options(const struct option ** preprocessed_options, const struct option *original_options)
+{
+ int i;
+
+ if (!*preprocessed_options) {
+ return;
+ }
+ for (i = 0; original_options[i].type != OPTION_END; i++) {
+ if (original_options[i].type == OPTION_ALIAS) {
+ free((void *)(*preprocessed_options)[i].help);
+ }
+ }
+ free((void *)*preprocessed_options);
+}
+
static int usage_with_options_internal(struct parse_opt_ctx_t *,
const char * const *,
const struct option *, int, int);
@@ -838,15 +855,17 @@ int parse_options(int argc, const char **argv, const char *prefix,
int flags)
{
struct parse_opt_ctx_t ctx;
- struct option *real_options;
+ const struct option *preprocessed_options, *original_options = NULL;
disallow_abbreviated_options =
git_env_bool("GIT_TEST_DISALLOW_ABBREVIATED_OPTIONS", 0);
memset(&ctx, 0, sizeof(ctx));
- real_options = preprocess_options(&ctx, options);
- if (real_options)
- options = real_options;
+ preprocessed_options = preprocess_options(&ctx, options);
+ if (preprocessed_options) {
+ original_options = options;
+ options = preprocessed_options;
+ }
parse_options_start_1(&ctx, argc, argv, prefix, options, flags);
switch (parse_options_step(&ctx, options, usagestr)) {
case PARSE_OPT_HELP:
@@ -870,7 +889,7 @@ int parse_options(int argc, const char **argv, const char *prefix,
}
precompose_argv_prefix(argc, argv, NULL);
- free(real_options);
+ free_preprocessed_options(&preprocessed_options, original_options);
free(ctx.alias_groups);
return parse_options_end(&ctx);
}
--
gitgitgadget
