From 032a480202245e384fdbcac92da720d697384d8e Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Tue, 31 Oct 2017 14:32:38 +0100 Subject: [PATCH] ipv4: fix validate_source for VRF setup David reported breakages of VRF scenarios due to the commit 6e617de84e87 ("net: avoid a full fib lookup when rp_filter is disabled."): the local addresses based test is too strict when VRFs are in place. With this change we fall-back to a full lookup when custom fib rules are in place; so that we address the VRF use case and possibly other similar issues in non trivial setups. v1 -> v2: - fix build breakage when CONFIG_IP_MULTIPLE_TABLES is not defined, reported by the kbuild test robot Reported-by: David Ahern Fixes: 6e617de84e87 ("net: avoid a full fib lookup when rp_filter is disabled.") Signed-off-by: Paolo Abeni Acked-by: David Ahern Signed-off-by: David S. Miller --- net/ipv4/fib_frontend.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index f02819134ba2..f52d27a422c3 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -73,6 +73,11 @@ static int __net_init fib4_rules_init(struct net *net) fib_free_table(main_table); return -ENOMEM; } + +static bool fib4_has_custom_rules(struct net *net) +{ + return false; +} #else struct fib_table *fib_new_table(struct net *net, u32 id) @@ -128,6 +133,11 @@ struct fib_table *fib_get_table(struct net *net, u32 id) } return NULL; } + +static bool fib4_has_custom_rules(struct net *net) +{ + return net->ipv4.fib_has_custom_rules; +} #endif /* CONFIG_IP_MULTIPLE_TABLES */ static void fib_replace_table(struct net *net, struct fib_table *old, @@ -405,10 +415,12 @@ int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst, (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) { if (IN_DEV_ACCEPT_LOCAL(idev)) goto ok; - /* if no local routes are added from user space we can check - * for local addresses looking-up the ifaddr table + /* with custom local routes in place, checking local addresses + * only will be too optimistic, with custom rules, checking + * local addresses only can be too strict, e.g. due to vrf */ - if (net->ipv4.fib_has_custom_local_routes) + if (net->ipv4.fib_has_custom_local_routes || + fib4_has_custom_rules(net)) goto full_check; if (inet_lookup_ifaddr_rcu(net, src)) return -EINVAL; -- GitLab