A malicious server can return ACK with non-existent SHA-1 or not a commit. lookup_commit() in this case may return NULL. Do not let fetch-pack crash by accessing NULL address in this case. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx> --- However it raises another question, what if the other end returns a valid commit, but not the one in "have" line fetch-pack sent? Are we OK with that? builtin/fetch-pack.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c index 4367984..3c871c2 100644 --- a/builtin/fetch-pack.c +++ b/builtin/fetch-pack.c @@ -395,6 +395,8 @@ static int find_common(int fd[2], unsigned char *result_sha1, case ACK_continue: { struct commit *commit = lookup_commit(result_sha1); + if (!commit) + die("invalid commit %s", sha1_to_hex(result_sha1)); if (args.stateless_rpc && ack == ACK_common && !(commit->object.flags & COMMON)) { -- 1.7.4.74.g639db -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html