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ipv6: sctp: clone options to avoid use after free

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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>
This commit is contained in:
Eric Dumazet 2015-12-09 07:25:06 -08:00 committed by David S. Miller
parent d188ba86dd
commit 9470e24f35
1 changed files with 8 additions and 0 deletions
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8
net/sctp/ipv6.c
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@ -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().
*/