From 8c76368174ed2359739f1b7b8a9c042b1ef839c4 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 16 Jun 2010 14:42:15 -0700 Subject: syncookies: check decoded options against sysctl settings Discard the ACK if we find options that do not match current sysctl settings. Previously it was possible to create a connection with sack, wscale, etc. enabled even if the feature was disabled via sysctl. Also remove an unneeded call to tcp_sack_reset() in cookie_check_timestamp: Both call sites (cookie_v4_check, cookie_v6_check) zero "struct tcp_options_received", hand it to tcp_parse_options() (which does not change tcp_opt->num_sacks/dsack) and then call cookie_check_timestamp(). Even if num_sacks/dsacks were changed, the structure is allocated on the stack and after cookie_check_timestamp returns only a few selected members are copied to the inet_request_sock. Signed-off-by: Florian Westphal Signed-off-by: David S. Miller --- net/ipv6/syncookies.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/ipv6') diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c index 70d330f..c7ee574 100644 --- a/net/ipv6/syncookies.c +++ b/net/ipv6/syncookies.c @@ -180,8 +180,8 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) memset(&tcp_opt, 0, sizeof(tcp_opt)); tcp_parse_options(skb, &tcp_opt, &hash_location, 0); - if (tcp_opt.saw_tstamp) - cookie_check_timestamp(&tcp_opt); + if (!cookie_check_timestamp(&tcp_opt)) + goto out; ret = NULL; req = inet6_reqsk_alloc(&tcp6_request_sock_ops); -- cgit v1.1