diff options
| author | Zhengchao Shao <shaozhengchao@huawei.com> | 2022-07-15 14:55:59 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-09-05 11:31:28 +0300 |
| commit | 72f2dc8993f10262092745a88cb2dd0fef094f23 (patch) | |
| tree | a3c1a79341dce727a6d6000e36652cc35ec4afae | |
| parent | d81bd6671f45fde4c3ac7fd7733c6e3082ae9d8e (diff) | |
| download | linux-72f2dc8993f10262092745a88cb2dd0fef094f23.tar.xz | |
bpf: Don't redirect packets with invalid pkt_len
commit fd1894224407c484f652ad456e1ce423e89bb3eb upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/skbuff.h | 8 | ||||
| -rw-r--r-- | net/bpf/test_run.c | 3 | ||||
| -rw-r--r-- | net/core/dev.c | 1 |
3 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index d3d10556f0fa..2f41364a6791 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2624,6 +2624,14 @@ static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset) #endif /* NET_SKBUFF_DATA_USES_OFFSET */ +static inline void skb_assert_len(struct sk_buff *skb) +{ +#ifdef CONFIG_DEBUG_NET + if (WARN_ONCE(!skb->len, "%s\n", __func__)) + DO_ONCE_LITE(skb_dump, KERN_ERR, skb, false); +#endif /* CONFIG_DEBUG_NET */ +} + /* * Add data to an sk_buff */ diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 56f059b3c242..42f8de4ebbd7 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; diff --git a/net/core/dev.c b/net/core/dev.c index a77a979a4bf7..ecaeb3ef8e5c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4168,6 +4168,7 @@ int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev) bool again = false; skb_reset_mac_header(skb); + skb_assert_len(skb); if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_SCHED_TSTAMP)) __skb_tstamp_tx(skb, NULL, NULL, skb->sk, SCM_TSTAMP_SCHED); |