[PATCH v2] gre: Avoid kernel panic by clearing IPCB before dst_link_failure called
From: Bernie Harris <hidden>
Date: 2016-02-16 01:10:35
Also in:
stable
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
skb->cb may contain data from previous layers (in the observed case the qdisc layer). In the observed scenario, the data was misinterpreted as ip header options, which later caused the ihl to be set to an invalid value (<5). This resulted in an infinite loop in the mips implementation of ip_fast_csum. This patch clears IPCB before dst_link_failure is called from the functions ip_tunnel_xmit and ip6gre_xmit2, similar to what commit 11c21a30 does for an ipv4 case. Signed-off-by: Bernie Harris <redacted> --- net/ipv4/ip_tunnel.c | 1 + net/ipv6/ip6_gre.c | 2 ++ 2 files changed, 3 insertions(+)
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 89e8861..946091a 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c@@ -799,6 +799,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, #if IS_ENABLED(CONFIG_IPV6) tx_error_icmp: + memset(IPCB(skb), 0, sizeof(*IPCB(skb))); dst_link_failure(skb); #endif tx_error:
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index f37f18b..93fc6f9 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c@@ -678,6 +678,7 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb, tunnel->err_time + IP6TUNNEL_ERR_TIMEO)) { tunnel->err_count--; + memset(IPCB(skb), 0, sizeof(*IPCB(skb))); dst_link_failure(skb); } else tunnel->err_count = 0;
@@ -761,6 +762,7 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb, return 0; tx_err_link_failure: stats->tx_carrier_errors++; + memset(IPCB(skb), 0, sizeof(*IPCB(skb))); dst_link_failure(skb); tx_err_dst_release: dst_release(dst);
--
2.7.1