[IPV6]: Fix crash in ip6_del_rt

ip6_null_entry doesn't have rt6i_table set, when trying to delete it the
kernel crashes dereferencing table->tb6_lock.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ff5affe2636c..41c5905d3191 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1223,6 +1223,9 @@ int ip6_del_rt(struct rt6_info *rt, struct nlmsghdr *nlh, void *_rtattr, struct
         int err;
         struct fib6_table *table;
 
+        if (rt == &ip6_null_entry)
+                return -ENOENT;
+
         table = rt->rt6i_table;
         write_lock_bh(&table->tb6_lock);