From ba233b34741a1dc88d1e94db7deeb7b079ef4b9a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 18 Oct 2017 14:20:30 -0700 Subject: [PATCH] tcp: fix tcp_send_syn_data() syn_data was allocated by sk_stream_alloc_skb(), meaning its destructor and _skb_refdst fields are mangled. We need to call tcp_skb_tsorted_anchor_cleanup() before calling kfree_skb() or kernel crashes. Bug was reported by syzkaller bot. Fixes: e2080072ed2d ("tcp: new list for sent but unacked skbs for RACK recovery") Signed-off-by: Eric Dumazet Reported-by: Dmitry Vyukov Acked-by: Yuchung Cheng Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 53dc1267c85e..988733f289c8 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3383,6 +3383,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn) int copied = copy_from_iter(skb_put(syn_data, space), space, &fo->data->msg_iter); if (unlikely(!copied)) { + tcp_skb_tsorted_anchor_cleanup(syn_data); kfree_skb(syn_data); goto fallback; } -- 2.30.2