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authorEric Dumazet <edumazet@google.com>2022-05-13 20:55:42 +0200
committerDavid S. Miller <davem@davemloft.net>2022-05-16 11:31:06 +0200
commita20ea298071f46effa3aaf965bf9bb34c901db3f (patch)
tree7a871cb0b15e5e73b3a77b794e29380f3290cb39
parentnet: annotate races around sk->sk_bound_dev_if (diff)
downloadlinux-a20ea298071f46effa3aaf965bf9bb34c901db3f.tar.xz
linux-a20ea298071f46effa3aaf965bf9bb34c901db3f.zip
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 <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>
-rw-r--r--net/sctp/input.c4
1 files changed, 3 insertions, 1 deletions
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;