| Date | Mon, 12 May 2014 02:32:48 +0200 | From | Willy Tarreau <> | Subject | [ 048/143] ip_tunnel: fix kernel panic with icmp_dest_unreach |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
[ Upstream commit a622260254ee481747cceaaa8609985b29a31565 ]
Daniel Petre reported crashes in icmp_dst_unreach() with following call graph:
Daniel found a similar problem mentioned in http://lkml.indiana.edu/hypermail/linux/kernel/1007.0/00961.html
And indeed this is the root cause : skb->cb[] contains data fooling IP stack.
We must clear IPCB in ip_tunnel_xmit() sooner in case dst_link_failure() is called. Or else skb->cb[] might contain garbage from GSO segmentation layer.
A similar fix was tested on linux-3.9, but gre code was refactored in linux-3.10. I'll send patches for stable kernels as well.
Many thanks to Daniel for providing reports, patches and testing !
Reported-by: Daniel Petre <daniel.petre@rcs-rds.ro> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Willy Tarreau <w@1wt.eu> --- net/ipv4/ipip.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c index 860b5c5..49aa1ad 100644 --- a/net/ipv4/ipip.c +++ b/net/ipv4/ipip.c @@ -408,6 +408,7 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) if (tos&1) tos = old_iph->tos; + memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); if (!dst) { /* NBMA tunnel */ if ((rt = skb_rtable(skb)) == NULL) { @@ -494,7 +495,6 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) skb->transport_header = skb->network_header; skb_push(skb, sizeof(struct iphdr)); skb_reset_network_header(skb); - memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | IPSKB_REROUTED); skb_dst_drop(skb); -- 1.7.12.2.21.g234cd45.dirty
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