From a20ea298071f46effa3aaf965bf9bb34c901db3f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 13 May 2022 11:55:42 -0700 Subject: sctp: read sk->sk_bound_dev_if once in sctp_rcv() sctp_rcv() reads sk->sk_bound_dev_if twice while the socket is not locked. Another cpu could change this field under us. Fixes: 0fd9a65a76e8 ("[SCTP] Support SO_BINDTODEVICE socket option on incoming packets.") Signed-off-by: Eric Dumazet Cc: Neil Horman Cc: Vlad Yasevich Cc: Marcelo Ricardo Leitner Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller --- net/sctp/input.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/sctp') diff --git a/net/sctp/input.c b/net/sctp/input.c index 90e12bafdd48..4f43afa8678f 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -92,6 +92,7 @@ int sctp_rcv(struct sk_buff *skb) struct sctp_chunk *chunk; union sctp_addr src; union sctp_addr dest; + int bound_dev_if; int family; struct sctp_af *af; struct net *net = dev_net(skb->dev); @@ -169,7 +170,8 @@ int sctp_rcv(struct sk_buff *skb) * If a frame arrives on an interface and the receiving socket is * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB */ - if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) { + bound_dev_if = READ_ONCE(sk->sk_bound_dev_if); + if (bound_dev_if && (bound_dev_if != af->skb_iif(skb))) { if (transport) { sctp_transport_put(transport); asoc = NULL; -- cgit v1.2.3