Commit 0ad92ad0 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

udp: fix a race in encap_rcv handling

udp_queue_rcv_skb() has a possible race in encap_rcv handling, since
this pointer can be changed anytime.

We should use ACCESS_ONCE() to close the race.
Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 501e89d3
......@@ -1397,6 +1397,8 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
nf_reset(skb);
if (up->encap_type) {
int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
/*
* This is an encapsulation socket so pass the skb to
* the socket's udp_encap_rcv() hook. Otherwise, just
......@@ -1409,11 +1411,11 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
*/
/* if we're overly short, let UDP handle it */
if (skb->len > sizeof(struct udphdr) &&
up->encap_rcv != NULL) {
encap_rcv = ACCESS_ONCE(up->encap_rcv);
if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
int ret;
ret = (*up->encap_rcv)(sk, skb);
ret = encap_rcv(sk, skb);
if (ret <= 0) {
UDP_INC_STATS_BH(sock_net(sk),
UDP_MIB_INDATAGRAMS,
......
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