Commit 7a1abd08 authored by David S. Miller's avatar David S. Miller

tcp: Increase TCP_MAXSEG socket option minimum.

As noted by Steve Chen, since commit
f5fff5dc ("tcp: advertise MSS
requested by user") we can end up with a situation where
tcp_select_initial_window() does a divide by a zero (or
even negative) mss value.

The problem is that sometimes we effectively subtract
TCPOLEN_TSTAMP_ALIGNED and/or TCPOLEN_MD5SIG_ALIGNED from the mss.

Fix this by increasing the minimum from 8 to 64.
Reported-by: default avatarSteve Chen <schen@mvista.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8d987e5c
......@@ -2246,7 +2246,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
/* Values greater than interface MTU won't take effect. However
* at the point when this call is done we typically don't yet
* know which interface is going to be used */
if (val < 8 || val > MAX_TCP_WINDOW) {
if (val < 64 || val > MAX_TCP_WINDOW) {
err = -EINVAL;
break;
}
......
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