From 9470e24f35ab81574da54e69df90c1eb4a96b43f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Dec 2015 07:25:06 -0800 Subject: [PATCH] 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(+) 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(). */ -- 2.20.1