| Message ID | 20090417092553.GA1601@gondor.apana.org.au |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Herbert Xu <herbert@gondor.apana.org.au> Date: Fri, 17 Apr 2009 17:25:53 +0800 > gro: Fix use after free in tcp_gro_receive > > After calling skb_gro_receive skb->len can no longer be relied > on since if the skb was merged using frags, then its pages will > have been removed and the length reduced. > > This caused tcp_gro_receive to prematurely end merging which > resulted in suboptimal performance with ixgbe. > > The fix is to store skb->len on the stack. > > Reported-by: Mark Wagner <mwagner@redhat.com> > Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Applied, thanks! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index fafbec8..1d7f49c 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2511,6 +2511,7 @@ struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) struct sk_buff *p; struct tcphdr *th; struct tcphdr *th2; + unsigned int len; unsigned int thlen; unsigned int flags; unsigned int mss = 1; @@ -2531,6 +2532,7 @@ struct sk_buff **tcp_gro_receive(struct sk_buff **head, struct sk_buff *skb) skb_gro_pull(skb, thlen); + len = skb_gro_len(skb); flags = tcp_flag_word(th); for (; (p = *head); head = &p->next) { @@ -2561,7 +2563,7 @@ found: mss = skb_shinfo(p)->gso_size; - flush |= (skb_gro_len(skb) > mss) | !skb_gro_len(skb); + flush |= (len > mss) | !len; flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq); if (flush || skb_gro_receive(head, skb)) { @@ -2574,7 +2576,7 @@ found: tcp_flag_word(th2) |= flags & (TCP_FLAG_FIN | TCP_FLAG_PSH); out_check_final: - flush = skb_gro_len(skb) < mss; + flush = len < mss; flush |= flags & (TCP_FLAG_URG | TCP_FLAG_PSH | TCP_FLAG_RST | TCP_FLAG_SYN | TCP_FLAG_FIN);
Hi: gro: Fix use after free in tcp_gro_receive After calling skb_gro_receive skb->len can no longer be relied on since if the skb was merged using frags, then its pages will have been removed and the length reduced. This caused tcp_gro_receive to prematurely end merging which resulted in suboptimal performance with ixgbe. The fix is to store skb->len on the stack. Reported-by: Mark Wagner <mwagner@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cheers,