From 646697b9e3fef913bb6393ebfb6115c442a96be7 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 30 Oct 2014 02:55:38 +0100 Subject: [PATCH] syncookies: only increment SYNCOOKIESFAILED on validation error Only count packets that failed cookie-authentication. We can get SYNCOOKIESFAILED > 0 while we never even sent a single cookie. Signed-off-by: Florian Westphal Signed-off-by: David S. Miller --- net/ipv4/syncookies.c | 7 +++++-- net/ipv6/syncookies.c | 7 +++++-- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 32b98d0207b4..4ac7bcaf2f46 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -275,8 +275,11 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb) if (!sysctl_tcp_syncookies || !th->ack || th->rst) goto out; - if (tcp_synq_no_recent_overflow(sk) || - (mss = __cookie_v4_check(ip_hdr(skb), th, cookie)) == 0) { + if (tcp_synq_no_recent_overflow(sk)) + goto out; + + mss = __cookie_v4_check(ip_hdr(skb), th, cookie); + if (mss == 0) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED); goto out; } diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c index 0e26e795b703..be291baa2ec2 100644 --- a/net/ipv6/syncookies.c +++ b/net/ipv6/syncookies.c @@ -171,8 +171,11 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) if (!sysctl_tcp_syncookies || !th->ack || th->rst) goto out; - if (tcp_synq_no_recent_overflow(sk) || - (mss = __cookie_v6_check(ipv6_hdr(skb), th, cookie)) == 0) { + if (tcp_synq_no_recent_overflow(sk)) + goto out; + + mss = __cookie_v6_check(ipv6_hdr(skb), th, cookie); + if (mss == 0) { NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_SYNCOOKIESFAILED); goto out; } -- 2.20.1