[PATCH] route: fix ICMP redirect validation
From: Flavio Leitner <hidden>
Date: 2011-10-05 14:20:14
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
The commit f39925dbde7788cfb96419c0f092b086aa325c0f (ipv4: Cache learned redirect information in inetpeer.) removed some ICMP packet validations which are required by RFC 1122, section 3.2.2.2: ... A Redirect message SHOULD be silently discarded if the new gateway address it specifies is not on the same connected (sub-) net through which the Redirect arrived [INTRO:2, Appendix A], or if the source of the Redirect is not the current first-hop gateway for the specified destination (see Section 3.3.1). Signed-off-by: Flavio Leitner <redacted> --- net/ipv4/route.c | 47 ++++++++++++++++++++++++++++++++++++++++++----- 1 files changed, 42 insertions(+), 5 deletions(-)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 26c77e1..1c11f28 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c@@ -1308,7 +1308,12 @@ static void rt_del(unsigned hash, struct rtable *rt) void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, __be32 saddr, struct net_device *dev) { + int s, i; struct in_device *in_dev = __in_dev_get_rcu(dev); + struct rtable *rth; + struct rtable __rcu **rthp; + __be32 skeys[2] = { saddr, 0 }; + int ikeys[2] = { dev->ifindex, 0 }; struct inet_peer *peer; struct net *net;
@@ -1321,6 +1326,9 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, ipv4_is_zeronet(new_gw)) goto reject_redirect; + if (!rt_caching(net)) + goto reject_redirect;; + if (!IN_DEV_SHARED_MEDIA(in_dev)) { if (!inet_addr_onlink(in_dev, new_gw, old_gw)) goto reject_redirect;
@@ -1331,13 +1339,42 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw, goto reject_redirect; } - peer = inet_getpeer_v4(daddr, 1); - if (peer) { - peer->redirect_learned.a4 = new_gw; + for (s = 0; s < 2; s++) { + for (i = 0; i < 2; i++) { + unsigned int hash = rt_hash(daddr, skeys[s], + ikeys[i], rt_genid(net)); - inet_putpeer(peer); + rthp=&rt_hash_table[hash].chain; - atomic_inc(&__rt_peer_genid); + while ((rth = rcu_dereference(*rthp)) != NULL) { + + if (rth->rt_key_dst != daddr || + rth->rt_key_src != skeys[s] || + rth->rt_oif != ikeys[i] || + rt_is_input_route(rth) || + rt_is_expired(rth) || + !net_eq(dev_net(rth->dst.dev), net)) { + rthp = &rth->dst.rt_next; + continue; + } + + if (rth->rt_dst != daddr || + rth->rt_src != saddr || + rth->rt_gateway != old_gw || + rth->dst.dev != dev || + rth->dst.error) + break; + + peer = inet_getpeer_v4(daddr, 1); + if (peer) { + peer->redirect_learned.a4 = new_gw; + inet_putpeer(peer); + atomic_inc(&__rt_peer_genid); + } + + break; + } + } } return;
--
1.7.6