[PATCH 01/12] for_each_alternate_ref: handle failure from real_pathdup()
- From
Jeff King <peff@peff.net>
- Date
- Jan 24, 2017, 00:38 UTC
- Message-ID
- <20170124003827.l2rimgitsyxsvtly@sigill.intra.peff.net>
- In-Reply-To
- <20170124003729.j4ygjcgypdq7hceg@sigill.intra.peff.net>
In older versions of git, if real_path() failed to resolve the alternate object store path, we would die() with an error. However, since 4ac9006f8 (real_path: have callers use real_pathdup and strbuf_realpath, 2016-12-12) we use the real_pathdup() function, which may return NULL. Since we don't check the return value, we can segfault.
This is hard to trigger in practice, since we check that the path is accessible before creating the alternate_object_database struct. But it could be removed racily, or we could see a transient filesystem error.
We could restore the original behavior by switching back to xstrdup(real_path()). However, dying is probably not the best option here. This whole function is best-effort already; there might not even be a repository around the shared objects at all. And if the alternate store has gone away, there are no objects to show.
So let's just quietly return, as we would if we failed to open "refs/", or if upload-pack failed to start, etc.
Signed-off-by: Jeff King <peff@peff.net> --- transport.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/transport.c b/transport.c index c86ba2eb8..74d0e45bd 100644 --- a/transport.c +++ b/transport.c @@ -1215,6 +1215,8 @@ static int refs_from_alternate_cb(struct alternate_object_database *e, struct alternate_refs_data *cb = data; other = real_pathdup(e->path); + if (!other) + return 0; len = strlen(other); while (other[len-1] == '/')
-- 2.11.0.765.g454d2182f