tcp: fix tcp header size miscalculation when window scale is unused
authorPhilip Love <love_phil@emc.com>
Wed, 27 Aug 2008 09:33:50 +0000 (02:33 -0700)
committerDavid S. Miller <davem@davemloft.net>
Wed, 27 Aug 2008 09:33:50 +0000 (02:33 -0700)
The size of the TCP header is miscalculated when the window scale ends
up being 0. Additionally, this can be induced by sending a SYN to a
passive open port with a window scale option with value 0.

Signed-off-by: Philip Love <love_phil@emc.com>
Signed-off-by: Adam Langley <agl@imperialviolet.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/tcp_output.c

index a00532de2a8c17ce19238681764b518c268c0400..8165f5aa8c71b68f5d01dee2abb8dad5c7449c44 100644 (file)
@@ -468,7 +468,8 @@ static unsigned tcp_syn_options(struct sock *sk, struct sk_buff *skb,
        }
        if (likely(sysctl_tcp_window_scaling)) {
                opts->ws = tp->rx_opt.rcv_wscale;
-               size += TCPOLEN_WSCALE_ALIGNED;
+               if(likely(opts->ws))
+                       size += TCPOLEN_WSCALE_ALIGNED;
        }
        if (likely(sysctl_tcp_sack)) {
                opts->options |= OPTION_SACK_ADVERTISE;
@@ -509,7 +510,8 @@ static unsigned tcp_synack_options(struct sock *sk,
 
        if (likely(ireq->wscale_ok)) {
                opts->ws = ireq->rcv_wscale;
-               size += TCPOLEN_WSCALE_ALIGNED;
+               if(likely(opts->ws))
+                       size += TCPOLEN_WSCALE_ALIGNED;
        }
        if (likely(doing_ts)) {
                opts->options |= OPTION_TS;