From c836a8ba93869d6a0290a6ae0047fbef09066871 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 2 Dec 2015 21:48:14 -0800 Subject: 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 Signed-off-by: David S. Miller --- net/sctp/ipv6.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'net/sctp/ipv6.c') 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); } -- cgit v1.2.1 From 69ce6487dcd364245a3d26322fc8f4ffd1e8d947 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 7 Dec 2015 08:25:21 -0800 Subject: ipv6: sctp: fix lockdep splat in sctp_v6_get_dst() While cooking the sctp np->opt rcu fixes, I forgot to move one rcu_read_unlock() after the added rcu_dereference() in sctp_v6_get_dst() This gave lockdep warnings reported by Dave Jones. Fixes: c836a8ba9386 ("ipv6: sctp: add rcu protection around np->opt") Reported-by: Dave Jones Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sctp/ipv6.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'net/sctp/ipv6.c') diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c index acb45b8c2a9d..d28c0b4c9128 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -323,14 +323,13 @@ static void sctp_v6_get_dst(struct sctp_transport *t, union sctp_addr *saddr, } } } - rcu_read_unlock(); - if (baddr) { fl6->saddr = baddr->v6.sin6_addr; fl6->fl6_sport = baddr->v6.sin6_port; final_p = fl6_update_dst(fl6, rcu_dereference(np->opt), &final); dst = ip6_dst_lookup_flow(sk, fl6, final_p); } + rcu_read_unlock(); out: if (!IS_ERR_OR_NULL(dst)) { -- cgit v1.2.1 From 9470e24f35ab81574da54e69df90c1eb4a96b43f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Dec 2015 07:25:06 -0800 Subject: ipv6: sctp: clone options to avoid use after free SCTP is lacking proper np->opt cloning at accept() time. TCP and DCCP use ipv6_dup_options() helper, do the same in SCTP. We might later factorize this code in a common helper to avoid future mistakes. Reported-by: Dmitry Vyukov Signed-off-by: Eric Dumazet Acked-by: Vlad Yasevich Signed-off-by: David S. Miller --- net/sctp/ipv6.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'net/sctp/ipv6.c') diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c index d28c0b4c9128..ec529121f38a 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -641,6 +641,7 @@ static struct sock *sctp_v6_create_accept_sk(struct sock *sk, struct sock *newsk; struct ipv6_pinfo *newnp, *np = inet6_sk(sk); struct sctp6_sock *newsctp6sk; + struct ipv6_txoptions *opt; newsk = sk_alloc(sock_net(sk), PF_INET6, GFP_KERNEL, sk->sk_prot, 0); if (!newsk) @@ -660,6 +661,13 @@ static struct sock *sctp_v6_create_accept_sk(struct sock *sk, memcpy(newnp, np, sizeof(struct ipv6_pinfo)); + rcu_read_lock(); + opt = rcu_dereference(np->opt); + if (opt) + opt = ipv6_dup_options(newsk, opt); + RCU_INIT_POINTER(newnp->opt, opt); + rcu_read_unlock(); + /* Initialize sk's sport, dport, rcv_saddr and daddr for getsockname() * and getpeername(). */ -- cgit v1.2.1