From: Taylor Blau Date: Thu, 1 Aug 2024 17:06:54 +0000 (-0400) Subject: config.c: avoid segfault with --fixed-value and valueless config X-Git-Tag: v2.46.1~29^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=615d2de3b457272216d4179ceb82b3b2b86b1929;p=thirdparty%2Fgit.git config.c: avoid segfault with --fixed-value and valueless config When using `--fixed-value` with a key whose value is left empty (implied as being "true"), 'git config' may crash when invoked like either of: $ git config set --file=config --value=value --fixed-value \ section.key pattern $ git config --file=config --fixed-value section.key value pattern The original bugreport[1] bisects to 00bbdde141 (builtin/config: introduce "set" subcommand, 2024-05-06), which is a red-herring, since the original bugreport uses the new 'git config set' invocation. The behavior likely bisects back to c90702a1f6 (config: plumb --fixed-value into config API, 2020-11-25), which introduces the new --fixed-value option in the first place. Looking at the relevant frame from a failed process's coredump, the crash appears in config.c::matches() like so: (gdb) up #1 0x000055b3e8b06022 in matches (key=0x55b3ea894360 "section.key", value=0x0, store=0x7ffe99076eb0) at config.c:2884 2884 return !strcmp(store->fixed_value, value); where we are trying to compare the `--fixed-value` argument to `value`, which is NULL. Avoid attempting to match `--fixed-value` for configuration keys with no explicit value. A future patch could consider the empty value to mean "true", "yes", "on", etc. when invoked with `--type=bool`, but let's punt on that for now in the name of avoiding the segfault. [1]: https://lore.kernel.org/git/CANrWfmTek1xErBLrnoyhHN+gWU+rw14y6SQ+abZyzGoaBjmiKA@mail.gmail.com/ Reported-by: Han Jiang Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- diff --git a/config.c b/config.c index aa2888d301..53ecb2f32d 100644 --- a/config.c +++ b/config.c @@ -2876,7 +2876,7 @@ static int matches(const char *key, const char *value, { if (strcmp(key, store->key)) return 0; /* not ours */ - if (store->fixed_value) + if (store->fixed_value && value) return !strcmp(store->fixed_value, value); if (!store->value_pattern) return 1; /* always matches */ diff --git a/t/t1300-config.sh b/t/t1300-config.sh index f1d42b62b0..127671aa3f 100755 --- a/t/t1300-config.sh +++ b/t/t1300-config.sh @@ -2434,6 +2434,15 @@ test_expect_success '--get and --get-all with --fixed-value' ' test_must_fail git config --file=config --get-regexp --fixed-value fixed+ non-existent ' +test_expect_success '--fixed-value with value-less configuration' ' + test_when_finished rm -f config && + cat >config <<-\EOF && + [section] + key + EOF + git config --file=config --fixed-value section.key value pattern +' + test_expect_success 'includeIf.hasconfig:remote.*.url' ' git init hasremoteurlTest && test_when_finished "rm -rf hasremoteurlTest" &&