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| author | Zhengchao Shao <shaozhengchao@huawei.com> | 2022-07-15 19:55:59 +0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-07-19 09:50:54 -0700 |
| commit | fd1894224407c484f652ad456e1ce423e89bb3eb (patch) | |
| tree | 9980e1d31ad073231806f842bea8c26e819e7e58 /net/bpf/test_run.c | |
| parent | 92f619735b7c4269fc6349a7ec13f09ffb558f77 (diff) | |
| download | lwn-fd1894224407c484f652ad456e1ce423e89bb3eb.tar.gz lwn-fd1894224407c484f652ad456e1ce423e89bb3eb.zip | |
bpf: Don't redirect packets with invalid pkt_len
Syzbot found an issue [1]: fq_codel_drop() try to drop a flow whitout any
skbs, that is, the flow->head is null.
The root cause, as the [2] says, is because that bpf_prog_test_run_skb()
run a bpf prog which redirects empty skbs.
So we should determine whether the length of the packet modified by bpf
prog or others like bpf_prog_test is valid before forwarding it directly.
LINK: [1] https://syzkaller.appspot.com/bug?id=0b84da80c2917757915afa89f7738a9d16ec96c5
LINK: [2] https://www.spinics.net/lists/netdev/msg777503.html
Reported-by: syzbot+7a12909485b94426aceb@syzkaller.appspotmail.com
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220715115559.139691-1-shaozhengchao@huawei.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/bpf/test_run.c')
| -rw-r--r-- | net/bpf/test_run.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 2ca96acbc50a..dc9dc0bedca0 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -955,6 +955,9 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb) { struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb; + if (!skb->len) + return -EINVAL; + if (!__skb) return 0; |