From b045d37bd68c20ca88123c2b363cac5e3dae815f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 3 Feb 2014 12:52:14 -0800 Subject: ip_tunnel: fix panic in ip_tunnel_xmit() Setting rt variable to NULL at the beginning of ip_tunnel_xmit() missed possible use of this variable as a scratch value. Also fixes a possible dst leak in tunnel_dst_check() : If we had to call tunnel_dst_reset(), we forgot to release the reference on dst. Merges tunnel_dst_get()/tunnel_dst_check() into a single tunnel_rtable_get() function for clarity. Many thanks to Tommi for his report and tests. Fixes: 7d442fab0a67 ("ipv4: Cache dst in tunnels") Reported-by: Tommi Rantala Signed-off-by: Eric Dumazet Tested-by: Tommi Rantala Cc: Tom Herbert Cc: Maciej Żenczykowski Signed-off-by: David S. Miller --- net/ipv4/ip_tunnel.c | 29 +++++++++++------------------ 1 file changed, 11 insertions(+), 18 deletions(-) (limited to 'net') diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index bd28f386bd02..50228be5c17b 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -101,28 +101,22 @@ static void tunnel_dst_reset_all(struct ip_tunnel *t) __tunnel_dst_set(per_cpu_ptr(t->dst_cache, i), NULL); } -static struct dst_entry *tunnel_dst_get(struct ip_tunnel *t) +static struct rtable *tunnel_rtable_get(struct ip_tunnel *t, u32 cookie) { struct dst_entry *dst; rcu_read_lock(); dst = rcu_dereference(this_cpu_ptr(t->dst_cache)->dst); - if (dst) + if (dst) { + if (dst->obsolete && dst->ops->check(dst, cookie) == NULL) { + rcu_read_unlock(); + tunnel_dst_reset(t); + return NULL; + } dst_hold(dst); - rcu_read_unlock(); - return dst; -} - -static struct dst_entry *tunnel_dst_check(struct ip_tunnel *t, u32 cookie) -{ - struct dst_entry *dst = tunnel_dst_get(t); - - if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) { - tunnel_dst_reset(t); - return NULL; } - - return dst; + rcu_read_unlock(); + return (struct rtable *)dst; } /* Often modified stats are per cpu, other are shared (netdev->stats) */ @@ -584,7 +578,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi4 fl4; u8 tos, ttl; __be16 df; - struct rtable *rt = NULL; /* Route to the other host */ + struct rtable *rt; /* Route to the other host */ unsigned int max_headroom; /* The extra header space needed */ __be32 dst; int err; @@ -657,8 +651,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, init_tunnel_flow(&fl4, protocol, dst, tnl_params->saddr, tunnel->parms.o_key, RT_TOS(tos), tunnel->parms.link); - if (connected) - rt = (struct rtable *)tunnel_dst_check(tunnel, 0); + rt = connected ? tunnel_rtable_get(tunnel, 0) : NULL; if (!rt) { rt = ip_route_output_key(tunnel->net, &fl4); -- cgit v1.2.3