From af2681828af5f2b42e12e8b16ba0cf113cf486c8 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 3 Apr 2008 12:52:19 -0700 Subject: [PATCH] [ICMP]: Ensure that ICMP relookup maintains status quo The ICMP relookup path is only meant to modify behaviour when appropriate IPsec policies are in place and marked as requiring relookups. It is certainly not meant to modify behaviour when IPsec policies don't exist at all. However, due to an oversight on the error paths existing behaviour may in fact change should one of the relookup steps fail. This patch corrects this by redirecting all errors on relookup failures to the previous code path. That is, if the initial xfrm_lookup let the packet pass, we will stand by that decision should the relookup fail due to an error. This should be safe from a security point-of-view because compliant systems must install a default deny policy so the packet would'nt have passed in that case. Many thanks to Julian Anastasov for pointing out this error. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/ipv4/icmp.c | 24 +++++++++++++----------- net/ipv6/icmp.c | 22 ++++++++++++---------- 2 files changed, 25 insertions(+), 21 deletions(-) diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index a944e8053e2..40508babad8 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -591,7 +591,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info) } if (xfrm_decode_session_reverse(skb_in, &fl, AF_INET)) - goto ende; + goto relookup_failed; if (inet_addr_type(net, fl.fl4_src) == RTN_LOCAL) err = __ip_route_output_key(net, &rt2, &fl); @@ -601,7 +601,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info) fl2.fl4_dst = fl.fl4_src; if (ip_route_output_key(net, &rt2, &fl2)) - goto ende; + goto relookup_failed; /* Ugh! */ odst = skb_in->dst; @@ -614,21 +614,23 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info) } if (err) - goto ende; + goto relookup_failed; err = xfrm_lookup((struct dst_entry **)&rt2, &fl, NULL, XFRM_LOOKUP_ICMP); - if (err == -ENOENT) { + switch (err) { + case 0: + dst_release(&rt->u.dst); + rt = rt2; + break; + case -EPERM: + goto ende; + default: +relookup_failed: if (!rt) goto out_unlock; - goto route_done; + break; } - - dst_release(&rt->u.dst); - rt = rt2; - - if (err) - goto out_unlock; } route_done: diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index f204a7275a0..893287ecc62 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -436,24 +436,26 @@ void icmpv6_send(struct sk_buff *skb, int type, int code, __u32 info, } if (xfrm_decode_session_reverse(skb, &fl2, AF_INET6)) - goto out_dst_release; + goto relookup_failed; if (ip6_dst_lookup(sk, &dst2, &fl)) - goto out_dst_release; + goto relookup_failed; err = xfrm_lookup(&dst2, &fl, sk, XFRM_LOOKUP_ICMP); - if (err == -ENOENT) { + switch (err) { + case 0: + dst_release(dst); + dst = dst2; + break; + case -EPERM: + goto out_dst_release; + default: +relookup_failed: if (!dst) goto out; - goto route_done; + break; } - dst_release(dst); - dst = dst2; - - if (err) - goto out; - route_done: if (ipv6_addr_is_multicast(&fl.fl6_dst)) hlimit = np->mcast_hops; -- 2.41.1