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