ipv6: sctp: add rcu protection around np->opt

This patch completes the work I did in commit 45f6fad84cc3
("ipv6: add complete rcu protection around np->opt"), as I missed
sctp part.

This simply makes sure np->opt is used with proper RCU locking
and accessors.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 3 deletions

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index e917d27328ea..acb45b8c2a9d 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -209,6 +209,7 @@ static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport)
         struct sock *sk = skb->sk;
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct flowi6 *fl6 = &transport->fl.u.ip6;
+        int res;
 
         pr_debug("%s: skb:%p, len:%d, src:%pI6 dst:%pI6\n", __func__, skb,
                  skb->len, &fl6->saddr, &fl6->daddr);
@@ -220,7 +221,10 @@ static int sctp_v6_xmit(struct sk_buff *skb, struct sctp_transport *transport)
 
         SCTP_INC_STATS(sock_net(sk), SCTP_MIB_OUTSCTPPACKS);
 
-        return ip6_xmit(sk, skb, fl6, np->opt, np->tclass);
+        rcu_read_lock();
+        res = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt), np->tclass);
+        rcu_read_unlock();
+        return res;
 }
 
 /* Returns the dst cache entry for the given source and destination ip
@@ -262,7 +266,10 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
                 pr_debug("src=%pI6 - ", &fl6->saddr);
         }
 
-        final_p = fl6_update_dst(fl6, np->opt, &final);
+        rcu_read_lock();
+        final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
+        rcu_read_unlock();
+
         dst = ip6_dst_lookup_flow(sk, fl6, final_p);
         if (!asoc || saddr)
                 goto out;
@@ -321,7 +328,7 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr,
         if (baddr) {
                 fl6->saddr = baddr->v6.sin6_addr;
                 fl6->fl6_sport = baddr->v6.sin6_port;
-                final_p = fl6_update_dst(fl6, np->opt, &final);
+                final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final);
                 dst = ip6_dst_lookup_flow(sk, fl6, final_p);
         }