linux-kernel - [PATCH] [46/139] tcp: Increase TCP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue,  1 Feb 2011 16:44:01 -0800 (PST)
From:	Andi Kleen <andi@...stfloor.org>
To:	davem@...emloft.net, gregkh@...e.de, ak@...ux.intel.com,
	linux-kernel@...r.kernel.org, stable@...nel.org
Subject: [PATCH] [46/139] tcp: Increase TCP_MAXSEG socket option minimum.

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------

From: David S. Miller <davem@...emloft.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@...sta.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
Signed-off-by: Andi Kleen <ak@...ux.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;
 		}
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/