sctp: ipv6: avoid touching device refcount

Avoid touching device refcount in sctp/ipv6, thanks to RCU

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 8 deletions

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index bacd6a7318be..cc50fbe99291 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -837,15 +837,16 @@ static int sctp_inet6_bind_verify(struct sctp_sock *opt, union sctp_addr *addr)
                 if (type & IPV6_ADDR_LINKLOCAL) {
                         if (!addr->v6.sin6_scope_id)
                                 return 0;
-                        dev = dev_get_by_index(&init_net, addr->v6.sin6_scope_id);
-                        if (!dev)
-                                return 0;
-                        if (!ipv6_chk_addr(&init_net, &addr->v6.sin6_addr,
+                        rcu_read_lock();
+                        dev = dev_get_by_index_rcu(&init_net,
+                                                   addr->v6.sin6_scope_id);
+                        if (!dev ||
+                            !ipv6_chk_addr(&init_net, &addr->v6.sin6_addr,
                                            dev, 0)) {
-                                dev_put(dev);
+                                rcu_read_unlock();
                                 return 0;
                         }
-                        dev_put(dev);
+                        rcu_read_unlock();
                 } else if (type == IPV6_ADDR_MAPPED) {
                         if (!opt->v4mapped)
                                 return 0;
@@ -873,10 +874,12 @@ static int sctp_inet6_send_verify(struct sctp_sock *opt, union sctp_addr *addr)
                 if (type & IPV6_ADDR_LINKLOCAL) {
                         if (!addr->v6.sin6_scope_id)
                                 return 0;
-                        dev = dev_get_by_index(&init_net, addr->v6.sin6_scope_id);
+                        rcu_read_lock();
+                        dev = dev_get_by_index_rcu(&init_net,
+                                                   addr->v6.sin6_scope_id);
+                        rcu_read_unlock();
                         if (!dev)
                                 return 0;
-                        dev_put(dev);
                 }
                 af = opt->pf->af;
         }