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authorEric Dumazet <eric.dumazet@gmail.com>2011-11-01 16:56:59 +0400
committerDavid S. Miller <davem@davemloft.net>2011-11-02 08:51:27 +0400
commit0ad92ad03aa444b312bd318b0341011a8be09d13 (patch)
treea6acc6651c301af1a5c7edd4258a441da091bfd3 /net/ipv4
parent501e89d3aef10f9a5b79137fbb0bcd5bf9cac2ac (diff)
downloadlinux-0ad92ad03aa444b312bd318b0341011a8be09d13.tar.xz
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: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/udp.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 131d8a720086..ab0966df1e2a 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -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,