| From | Andi Kleen <> | Subject | [PATCH] [46/139] tcp: Increase TCP_MAXSEG socket option minimum. | Date | Tue, 1 Feb 2011 16:44:01 -0800 (PST) |
| |
2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------
From: David S. Miller <davem@davemloft.net>
[ Upstream commit 7a1abd08d52fdeddb3e9a5a33f2f15cc6a5674d2 ]
As noted by Steve Chen, since commit f5fff5dc8a7a3f395b0525c02ba92c95d42b7390 ("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: Steve Chen <schen@mvista.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- net/ipv4/tcp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.35.y/net/ipv4/tcp.c =================================================================== --- linux-2.6.35.y.orig/net/ipv4/tcp.c +++ linux-2.6.35.y/net/ipv4/tcp.c @@ -2235,7 +2235,7 @@ static int do_tcp_setsockopt(struct sock /* 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; }
|