[Patch net v2] ipv6: check for ip6_null_entry in __ip6_del_rt_siblings()
From: Cong Wang <hidden>
Date: 2017-02-27 21:34:55
Andrey reported a NULL pointer deref bug in ipv6_route_ioctl()
-> ip6_route_del() -> __ip6_del_rt_siblings() code path. This is
because ip6_null_entry is returned in this path since ip6_null_entry
is kinda default for a ipv6 route table root node. Quote from
David Ahern:
ip6_null_entry is the root of all ipv6 fib tables making it integrated
into the table ...
We should ignore any attempt of trying to delete it, like we do in
__ip6_del_rt() path and several others.
Reported-by: Andrey Konovalov <redacted>
Fixes: 0ae8133586ad ("net: ipv6: Allow shorthand delete of all nexthops in multipath route")
Cc: David Ahern <redacted>
Cc: Eric Dumazet <redacted>
Signed-off-by: Cong Wang <redacted>
---
net/ipv6/route.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index f54f426..78be2cb 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c@@ -2169,10 +2169,13 @@ int ip6_del_rt(struct rt6_info *rt) static int __ip6_del_rt_siblings(struct rt6_info *rt, struct fib6_config *cfg) { struct nl_info *info = &cfg->fc_nlinfo; + struct net *net = info->nl_net; struct sk_buff *skb = NULL; struct fib6_table *table; int err; + if (rt == net->ipv6.ip6_null_entry) + goto out_put; table = rt->rt6i_table; write_lock_bh(&table->tb6_lock);
@@ -2184,7 +2187,7 @@ static int __ip6_del_rt_siblings(struct rt6_info *rt, struct fib6_config *cfg) if (skb) { u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0; - if (rt6_fill_node(info->nl_net, skb, rt, + if (rt6_fill_node(net, skb, rt, NULL, NULL, 0, RTM_DELROUTE, info->portid, seq, 0) < 0) { kfree_skb(skb);
@@ -2205,10 +2208,11 @@ static int __ip6_del_rt_siblings(struct rt6_info *rt, struct fib6_config *cfg) err = fib6_del(rt, info); out: write_unlock_bh(&table->tb6_lock); +out_put: ip6_rt_put(rt); if (skb) { - rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV6_ROUTE, + rtnl_notify(skb, net, info->portid, RTNLGRP_IPV6_ROUTE, info->nlh, gfp_any()); } return err;
--
2.5.5