From: Ilpo Järvinen Date: Thu, 29 Nov 2007 12:07:58 +0000 (+1100) Subject: TCP: MTUprobe: fix potential sk_send_head corruption X-Git-Tag: v2.6.23.10~16 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5fb62a184b2f0ea0e3aa2baeed2a01b71844368d;p=thirdparty%2Fkernel%2Fstable.git TCP: MTUprobe: fix potential sk_send_head corruption [TCP] MTUprobe: fix potential sk_send_head corruption [ Upstream commit: 6e42141009ff18297fe19d19296738b742f861db ] When the abstraction functions got added, conversion here was made incorrectly. As a result, the skb may end up pointing to skb which got included to the probe skb and then was freed. For it to trigger, however, skb_transmit must fail sending as well. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller Cc: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- diff --git a/include/net/tcp.h b/include/net/tcp.h index 54053de0bdd7c..704d51e1f5432 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1256,6 +1256,9 @@ static inline void tcp_insert_write_queue_before(struct sk_buff *new, struct sock *sk) { __skb_insert(new, skb->prev, skb, &sk->sk_write_queue); + + if (sk->sk_send_head == skb) + sk->sk_send_head = new; } static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 666d8a58d14a3..097165fab7fbd 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -1287,7 +1287,6 @@ static int tcp_mtu_probe(struct sock *sk) skb = tcp_send_head(sk); tcp_insert_write_queue_before(nskb, skb, sk); - tcp_advance_send_head(sk, skb); TCP_SKB_CB(nskb)->seq = TCP_SKB_CB(skb)->seq; TCP_SKB_CB(nskb)->end_seq = TCP_SKB_CB(skb)->seq + probe_size;