| From ae216d4249310227d56f53f4274f8683e4087638 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Fri, 13 May 2022 11:55:42 -0700 |
| Subject: sctp: read sk->sk_bound_dev_if once in sctp_rcv() |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| [ Upstream commit a20ea298071f46effa3aaf965bf9bb34c901db3f ] |
| |
| 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 <edumazet@google.com> |
| Cc: Neil Horman <nhorman@tuxdriver.com> |
| Cc: Vlad Yasevich <vyasevich@gmail.com> |
| Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> |
| Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/sctp/input.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| diff --git a/net/sctp/input.c b/net/sctp/input.c |
| index 9c1670b4a687..ed3a8a66a00b 100644 |
| --- a/net/sctp/input.c |
| +++ b/net/sctp/input.c |
| @@ -103,6 +103,7 @@ 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); |
| @@ -180,7 +181,8 @@ 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; |
| -- |
| 2.35.1 |
| |
