Commit 79539f34 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by David S. Miller

tcp: Fix data-races around sysctl_max_syn_backlog.

While reading sysctl_max_syn_backlog, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cbfc6495
......@@ -6956,10 +6956,12 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops,
tcp_rsk(req)->ts_off = af_ops->init_ts_off(net, skb);
if (!want_cookie && !isn) {
int max_syn_backlog = READ_ONCE(net->ipv4.sysctl_max_syn_backlog);
/* Kill the following clause, if you dislike this way. */
if (!syncookies &&
(net->ipv4.sysctl_max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
(net->ipv4.sysctl_max_syn_backlog >> 2)) &&
(max_syn_backlog - inet_csk_reqsk_queue_len(sk) <
(max_syn_backlog >> 2)) &&
!tcp_peer_is_proven(req, dst)) {
/* Without syncookies last quarter of
* backlog is filled with destinations,
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment