ipv6: fix rtnl locking in setsockopt for anycast and multicast

Calling setsockopt with IPV6_JOIN_ANYCAST or IPV6_LEAVE_ANYCAST
triggers the assertion in addrconf_join_solict()/addrconf_leave_solict()

ipv6_sock_ac_join(), ipv6_sock_ac_drop(), ipv6_sock_ac_close() need to
take RTNL before calling ipv6_dev_ac_inc/dec. Same thing with
ipv6_sock_mc_join(), ipv6_sock_mc_drop(), ipv6_sock_mc_close() before
calling ipv6_dev_mc_inc/dec.

This patch moves ASSERT_RTNL() up a level in the call stack.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reported-by: Tommi Rantala <tt.rantala@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 0 deletions

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index 210183244689..45b9d81d91e8 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -77,6 +77,7 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
         pac->acl_next = NULL;
         pac->acl_addr = *addr;
 
+        rtnl_lock();
         rcu_read_lock();
         if (ifindex == 0) {
                 struct rt6_info *rt;
@@ -137,6 +138,7 @@ int ipv6_sock_ac_join(struct sock *sk, int ifindex, const struct in6_addr *addr)
 
 error:
         rcu_read_unlock();
+        rtnl_unlock();
         if (pac)
                 sock_kfree_s(sk, pac, sizeof(*pac));
         return err;
@@ -171,13 +173,17 @@ int ipv6_sock_ac_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
 
         spin_unlock_bh(&ipv6_sk_ac_lock);
 
+        rtnl_lock();
         rcu_read_lock();
         dev = dev_get_by_index_rcu(net, pac->acl_ifindex);
         if (dev)
                 ipv6_dev_ac_dec(dev, &pac->acl_addr);
         rcu_read_unlock();
+        rtnl_unlock();
 
         sock_kfree_s(sk, pac, sizeof(*pac));
+        if (!dev)
+                return -ENODEV;
         return 0;
 }
 
@@ -198,6 +204,7 @@ void ipv6_sock_ac_close(struct sock *sk)
         spin_unlock_bh(&ipv6_sk_ac_lock);
 
         prev_index = 0;
+        rtnl_lock();
         rcu_read_lock();
         while (pac) {
                 struct ipv6_ac_socklist *next = pac->acl_next;
@@ -212,6 +219,7 @@ void ipv6_sock_ac_close(struct sock *sk)
                 pac = next;
         }
         rcu_read_unlock();
+        rtnl_unlock();
 }
 
 static void aca_put(struct ifacaddr6 *ac)
@@ -233,6 +241,8 @@ int ipv6_dev_ac_inc(struct net_device *dev, const struct in6_addr *addr)
         struct rt6_info *rt;
         int err;
 
+        ASSERT_RTNL();
+
         idev = in6_dev_get(dev);
 
         if (idev == NULL)
@@ -302,6 +312,8 @@ int __ipv6_dev_ac_dec(struct inet6_dev *idev, const struct in6_addr *addr)
 {
         struct ifacaddr6 *aca, *prev_aca;
 
+        ASSERT_RTNL();
+
         write_lock_bh(&idev->lock);
         prev_aca = NULL;
         for (aca = idev->ac_list; aca; aca = aca->aca_next) {