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authorEric Dumazet <edumazet@google.com>2015-12-09 16:25:06 +0100
committerDavid S. Miller <davem@davemloft.net>2015-12-12 02:18:40 +0100
commit9470e24f35ab81574da54e69df90c1eb4a96b43f (patch)
treef1ddb2ca0d9eb735f1fb9dbafc238b0d8f83b543 /net/sctp/ipv6.c
parentxfrm: add rcu protection to sk->sk_policy[] (diff)
downloadlinux-9470e24f35ab81574da54e69df90c1eb4a96b43f.tar.xz
linux-9470e24f35ab81574da54e69df90c1eb4a96b43f.zip
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 <dvyukov@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp/ipv6.c')
-rw-r--r--net/sctp/ipv6.c8
1 files changed, 8 insertions, 0 deletions
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().
*/