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authorEric Dumazet <edumazet@google.com>2013-05-24 05:49:58 +0000
committerDavid S. Miller <davem@davemloft.net>2013-05-25 23:26:30 -0700
commita622260254ee481747cceaaa8609985b29a31565 (patch)
treef93bf1a22f058b9fb55aed01a346102e57357940 /net
parent0d8c3e77e7fba8c84c871b43f35029daa92acc17 (diff)
ip_tunnel: fix kernel panic with icmp_dest_unreach
Daniel Petre reported crashes in icmp_dst_unreach() with following call graph: #3 [ffff88003fc03938] __stack_chk_fail at ffffffff81037f77 #4 [ffff88003fc03948] icmp_send at ffffffff814d5fec #5 [ffff88003fc03ae8] ipv4_link_failure at ffffffff814a1795 #6 [ffff88003fc03af8] ipgre_tunnel_xmit at ffffffff814e7965 #7 [ffff88003fc03b78] dev_hard_start_xmit at ffffffff8146e032 #8 [ffff88003fc03bc8] sch_direct_xmit at ffffffff81487d66 #9 [ffff88003fc03c08] __qdisc_run at ffffffff81487efd #10 [ffff88003fc03c48] dev_queue_xmit at ffffffff8146e5a7 #11 [ffff88003fc03c88] ip_finish_output at ffffffff814ab596 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>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ip_tunnel.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index e4147ec1665a..be2f8da0ae8e 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -503,6 +503,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
+ memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
dst = tnl_params->daddr;
if (dst == 0) {
/* NBMA tunnel */
@@ -658,7 +659,6 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
skb_dst_drop(skb);
skb_dst_set(skb, &rt->dst);
- memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
/* Push down and install the IP header. */
skb_push(skb, sizeof(struct iphdr));