[PATCH 5/7] submodule: handle NULL value when parsing submodule.*.branch
- From
Jeff King <peff@peff.net>
- Date
- Dec 7, 2023, 07:11 UTC
- Message-ID
- <20231207071129.GE1276005@coredump.intra.peff.net>
- In-Reply-To
- <20231207071030.GA1275835@coredump.intra.peff.net>
We record the submodule branch config value as a string, so config that uses an implicit bool like:
[submodule "foo"] branch
will cause us to segfault. Note that unlike most other config-parsing bugs of this class, this can be triggered by parsing a bogus .gitmodules file (which we might do after cloning a malicious repository).
I don't think the security implications are important, though. It's always a strict NULL dereference, not an out-of-bounds read or write. So we should reliably kill the process. That may be annoying, but the impact is limited to the attacker preventing the victim from successfully using "git clone --recurse-submodules", etc, on the malicious repo.
The "branch" entry is the only one with this problem; other strings like "path" and "url" already check for NULL.
Signed-off-by: Jeff King <peff@peff.net> --- submodule-config.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/submodule-config.c b/submodule-config.c index 6a48fd12f6..f4dd482abc 100644 --- a/submodule-config.c +++ b/submodule-config.c @@ -516,7 +516,9 @@ static int parse_config(const char *var, const char *value, submodule->recommend_shallow = git_config_bool(var, value); } else if (!strcmp(item.buf, "branch")) { - if (!me->overwrite && submodule->branch) + if (!value) + ret = config_error_nonbool(var); + else if (!me->overwrite && submodule->branch) warn_multiple_config(me->treeish_name, submodule->name, "branch"); else {
-- 2.43.0.664.ga12c899002