From 4308fc58dceda40fac8a8d9c05b7cfba0a6bbed3 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Wed, 19 Sep 2012 15:46:06 +0100 Subject: [PATCH] tcp: Document use of undefined variable. Both tcp_timewait_state_process and tcp_check_req use the same basic construct of struct tcp_options received tmp_opt; tmp_opt.saw_tstamp = 0; then call tcp_parse_options However if they are fed a frame containing a TCP_SACK then tbe code behaviour is undefined because opt_rx->sack_ok is undefined data. This ought to be documented if it is intentional. Signed-off-by: Alan Cox Signed-off-by: David S. Miller --- net/ipv4/tcp_minisocks.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index e965319..5792577 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -85,6 +85,8 @@ static bool tcp_in_window(u32 seq, u32 end_seq, u32 s_win, u32 e_win) * spinlock it. I do not want! Well, probability of misbehaviour * is ridiculously low and, seems, we could use some mb() tricks * to avoid misread sequence numbers, states etc. --ANK + * + * We don't need to initialize tmp_out.sack_ok as we don't use the results */ enum tcp_tw_status tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, @@ -522,6 +524,8 @@ EXPORT_SYMBOL(tcp_create_openreq_child); * * XXX (TFO) - The current impl contains a special check for ack * validation and inside tcp_v4_reqsk_send_ack(). Can we do better? + * + * We don't need to initialize tmp_opt.sack_ok as we don't use the results */ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, -- 2.7.4