From 673498b8ed4c4d4b7221c5309d891c5eac2b7528 Mon Sep 17 00:00:00 2001 From: Stefan Tomanek Date: Tue, 10 Dec 2013 23:21:25 +0100 Subject: [PATCH] inet: fix NULL pointer Oops in fib(6)_rule_suppress This changes ensures that the routing entry investigated by the suppress function actually does point to a device struct before following that pointer, fixing a possible kernel oops situation when verifying the interface group associated with a routing table entry. According to Daniel Golle, this Oops can be triggered by a user process trying to establish an outgoing IPv6 connection while having no real IPv6 connectivity set up (only autoassigned link-local addresses). Fixes: 6ef94cfafba15 ("fib_rules: add route suppression based on ifgroup") Reported-by: Daniel Golle Tested-by: Daniel Golle Signed-off-by: Stefan Tomanek Signed-off-by: David S. Miller --- net/ipv4/fib_rules.c | 5 ++++- net/ipv6/fib6_rules.c | 6 +++++- 2 files changed, 9 insertions(+), 2 deletions(-) --- a/net/ipv4/fib_rules.c +++ b/net/ipv4/fib_rules.c @@ -104,7 +104,10 @@ errout: static bool fib4_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) { struct fib_result *result = (struct fib_result *) arg->result; - struct net_device *dev = result->fi->fib_dev; + struct net_device *dev = NULL; + + if (result->fi) + dev = result->fi->fib_dev; /* do not accept result if the route does * not meet the required prefix length --- a/net/ipv6/fib6_rules.c +++ b/net/ipv6/fib6_rules.c @@ -122,7 +122,11 @@ out: static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg) { struct rt6_info *rt = (struct rt6_info *) arg->result; - struct net_device *dev = rt->rt6i_idev->dev; + struct net_device *dev = NULL; + + if (rt->rt6i_idev) + dev = rt->rt6i_idev->dev; + /* do not accept result if the route does * not meet the required prefix length */