[PATCH v2 2/2] fsck: avoid looking at NULL blob->object
- From
Jeff King <peff@peff.net>
- Date
- Jun 9, 2018, 09:31 UTC
- Message-ID
- <20180609093141.GB8942@sigill.intra.peff.net>
- In-Reply-To
- <20180609093028.GA8864@sigill.intra.peff.net>
Commit 159e7b080b (fsck: detect gitmodules files, 2018-05-02) taught fsck to look at the content of .gitmodules files. If the object turns out not to be a blob at all, we just complain and punt on checking the content. And since this was such an obvious and trivial code path, I didn't even bother to add a test.
Except it _does_ do one non-trivial thing, which is call the report() function, which wants us to pass a pointer to a "struct object". Which we don't have (we have only a "struct object_id"). So we erroneously pass a NULL object to report(), which gets dereferenced and causes a segfault.
It seems like we could refactor report() to just take the object_id itself. But we pass the object pointer along to a callback function, and indeed this ends up in builtin/fsck.c's objreport() which does want to look at other parts of the object (like the type).
So instead, let's just use lookup_unknown_object() to get the real "struct object", and pass that.
Signed-off-by: Jeff King <peff@peff.net> --- fsck.c | 3 ++- t/t7415-submodule-names.sh | 18 ++++++++++++++++++ 2 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/fsck.c b/fsck.c index bcae2c30e6..48e7e36869 100644 --- a/fsck.c +++ b/fsck.c @@ -1036,7 +1036,8 @@ int fsck_finish(struct fsck_options *options) blob = lookup_blob(oid); if (!blob) { - ret |= report(options, &blob->object, + struct object *obj = lookup_unknown_object(oid->hash); + ret |= report(options, obj, FSCK_MSG_GITMODULES_BLOB, "non-blob found at .gitmodules"); continue; diff --git a/t/t7415-submodule-names.sh b/t/t7415-submodule-names.sh index e2aae587ae..d7868c11fa 100755 --- a/t/t7415-submodule-names.sh +++ b/t/t7415-submodule-names.sh @@ -150,4 +150,22 @@ test_expect_success 'fsck detects symlinked .gitmodules file' ' ) ' +test_expect_success 'fsck detects non-blob .gitmodules' ' + git init non-blob && + ( + cd non-blob && + + # As above, make the funny tree directly to avoid index + # restrictions. + mkdir subdir && + cp ../.gitmodules subdir/file && + git add subdir/file && + git commit -m ok && + tree=$(git ls-tree HEAD | sed s/subdir/.gitmodules/ | git mktree) && + + test_must_fail git fsck 2>output && + grep gitmodulesBlob output + ) +' + test_done
-- 2.18.0.rc1.446.g4486251e51