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authorZhengchao Shao <shaozhengchao@huawei.com>2022-07-15 19:55:59 +0800
committerAlexei Starovoitov <ast@kernel.org>2022-07-19 09:50:54 -0700
commitfd1894224407c484f652ad456e1ce423e89bb3eb (patch)
tree9980e1d31ad073231806f842bea8c26e819e7e58 /net/core
parent92f619735b7c4269fc6349a7ec13f09ffb558f77 (diff)
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/core')
-rw-r--r--net/core/dev.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 978ed0622d8f..e241a475036f 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);