From d208328765a0ab425e36b5b828285f3337a85451 Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Mon, 24 Sep 2012 18:12:23 +0000 Subject: gre: fix handling of key 0 GRE driver incorrectly uses zero as a flag value. Zero is a perfectly valid value for key, and the tunnel should match packets with no key only with tunnels created without key, and vice versa. This is a slightly visible change since previously it might be possible to construct a working tunnel that sent key 0 and received only because of the key wildcard of zero. I.e the sender sent key of zero, but tunnel was defined without key. Note: using gre key 0 requires iproute2 utilities v3.2 or later. The original utility code was broken as well. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/ipv4/ip_gre.c | 44 ++++++++++++++++++++++++++++++++++---------- 1 file changed, 34 insertions(+), 10 deletions(-) (limited to 'net') diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index f233c1da207..0d4c3832d49 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -214,11 +214,25 @@ static struct rtnl_link_stats64 *ipgre_get_stats64(struct net_device *dev, return tot; } +/* Does key in tunnel parameters match packet */ +static bool ipgre_key_match(const struct ip_tunnel_parm *p, + __u32 flags, __be32 key) +{ + if (p->i_flags & GRE_KEY) { + if (flags & GRE_KEY) + return key == p->i_key; + else + return false; /* key expected, none present */ + } else + return !(flags & GRE_KEY); +} + /* Given src, dst and key, find appropriate for input tunnel. */ static struct ip_tunnel *ipgre_tunnel_lookup(struct net_device *dev, __be32 remote, __be32 local, - __be32 key, __be16 gre_proto) + __u32 flags, __be32 key, + __be16 gre_proto) { struct net *net = dev_net(dev); int link = dev->ifindex; @@ -233,10 +247,12 @@ static struct ip_tunnel *ipgre_tunnel_lookup(struct net_device *dev, for_each_ip_tunnel_rcu(ign->tunnels_r_l[h0 ^ h1]) { if (local != t->parms.iph.saddr || remote != t->parms.iph.daddr || - key != t->parms.i_key || !(t->dev->flags & IFF_UP)) continue; + if (!ipgre_key_match(&t->parms, flags, key)) + continue; + if (t->dev->type != ARPHRD_IPGRE && t->dev->type != dev_type) continue; @@ -257,10 +273,12 @@ static struct ip_tunnel *ipgre_tunnel_lookup(struct net_device *dev, for_each_ip_tunnel_rcu(ign->tunnels_r[h0 ^ h1]) { if (remote != t->parms.iph.daddr || - key != t->parms.i_key || !(t->dev->flags & IFF_UP)) continue; + if (!ipgre_key_match(&t->parms, flags, key)) + continue; + if (t->dev->type != ARPHRD_IPGRE && t->dev->type != dev_type) continue; @@ -283,10 +301,12 @@ static struct ip_tunnel *ipgre_tunnel_lookup(struct net_device *dev, if ((local != t->parms.iph.saddr && (local != t->parms.iph.daddr || !ipv4_is_multicast(local))) || - key != t->parms.i_key || !(t->dev->flags & IFF_UP)) continue; + if (!ipgre_key_match(&t->parms, flags, key)) + continue; + if (t->dev->type != ARPHRD_IPGRE && t->dev->type != dev_type) continue; @@ -489,6 +509,7 @@ static void ipgre_err(struct sk_buff *skb, u32 info) const int code = icmp_hdr(skb)->code; struct ip_tunnel *t; __be16 flags; + __be32 key = 0; flags = p[0]; if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) { @@ -505,6 +526,9 @@ static void ipgre_err(struct sk_buff *skb, u32 info) if (skb_headlen(skb) < grehlen) return; + if (flags & GRE_KEY) + key = *(((__be32 *)p) + (grehlen / 4) - 1); + switch (type) { default: case ICMP_PARAMETERPROB: @@ -535,9 +559,8 @@ static void ipgre_err(struct sk_buff *skb, u32 info) rcu_read_lock(); t = ipgre_tunnel_lookup(skb->dev, iph->daddr, iph->saddr, - flags & GRE_KEY ? - *(((__be32 *)p) + (grehlen / 4) - 1) : 0, - p[1]); + flags, key, p[1]); + if (t == NULL) goto out; @@ -642,9 +665,10 @@ static int ipgre_rcv(struct sk_buff *skb) gre_proto = *(__be16 *)(h + 2); rcu_read_lock(); - if ((tunnel = ipgre_tunnel_lookup(skb->dev, - iph->saddr, iph->daddr, key, - gre_proto))) { + tunnel = ipgre_tunnel_lookup(skb->dev, + iph->saddr, iph->daddr, flags, key, + gre_proto); + if (tunnel) { struct pcpu_tstats *tstats; secpath_reset(skb); -- cgit v1.2.3