[ 3.8.y.z extended stable ] Patch "net: avoid to hang up on sending due to sysctl configuration" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    net: avoid to hang up on sending due to sysctl configuration

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 0c94ffe0d312c885c15442a103ea26a8d941d34d Mon Sep 17 00:00:00 2001
From: "bingtian.ly at taobao.com" <bingtian.ly at taobao.com>
Date: Wed, 23 Jan 2013 20:35:28 +0000
Subject: net: avoid to hang up on sending due to sysctl configuration
 overflow.

commit cdda88912d62f9603d27433338a18be83ef23ac1 upstream.

    I found if we write a larger than 4GB value to some sysctl
variables, the sending syscall will hang up forever, because these
variables are 32 bits, such large values make them overflow to 0 or
negative.

    This patch try to fix overflow or prevent from zero value setup
of below sysctl variables:

net.core.wmem_default
net.core.rmem_default

net.core.rmem_max
net.core.wmem_max

net.ipv4.udp_rmem_min
net.ipv4.udp_wmem_min

net.ipv4.tcp_wmem
net.ipv4.tcp_rmem

Signed-off-by: Eric Dumazet <eric.dumazet at gmail.com>
Signed-off-by: Li Yu <raise.sail at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/core/sysctl_net_core.c | 14 ++++++++++----
 net/ipv4/sysctl_net_ipv4.c | 11 +++++++----
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index d1b0804..cfdb46a 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -20,6 +20,8 @@
 #include <net/sock.h>
 #include <net/net_ratelimit.h>

+static int one = 1;
+
 #ifdef CONFIG_RPS
 static int rps_sock_flow_sysctl(ctl_table *table, int write,
 				void __user *buffer, size_t *lenp, loff_t *ppos)
@@ -92,28 +94,32 @@ static struct ctl_table net_core_table[] = {
 		.data		= &sysctl_wmem_max,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
 	},
 	{
 		.procname	= "rmem_max",
 		.data		= &sysctl_rmem_max,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
 	},
 	{
 		.procname	= "wmem_default",
 		.data		= &sysctl_wmem_default,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
 	},
 	{
 		.procname	= "rmem_default",
 		.data		= &sysctl_rmem_default,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
 	},
 	{
 		.procname	= "dev_weight",
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 63632ea..d22765d 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -27,6 +27,7 @@
 #include <net/tcp_memcontrol.h>

 static int zero;
+static int one = 1;
 static int two = 2;
 static int tcp_retr1_max = 255;
 static int ip_local_port_range_min[] = { 1, 1 };
@@ -560,14 +561,16 @@ static struct ctl_table ipv4_table[] = {
 		.data		= &sysctl_tcp_wmem,
 		.maxlen		= sizeof(sysctl_tcp_wmem),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
 	},
 	{
 		.procname	= "tcp_rmem",
 		.data		= &sysctl_tcp_rmem,
 		.maxlen		= sizeof(sysctl_tcp_rmem),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &one,
 	},
 	{
 		.procname	= "tcp_app_win",
@@ -790,7 +793,7 @@ static struct ctl_table ipv4_table[] = {
 		.maxlen		= sizeof(sysctl_udp_rmem_min),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero
+		.extra1		= &one
 	},
 	{
 		.procname	= "udp_wmem_min",
@@ -798,7 +801,7 @@ static struct ctl_table ipv4_table[] = {
 		.maxlen		= sizeof(sysctl_udp_wmem_min),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero
+		.extra1		= &one
 	},
 	{ }
 };
--
1.8.1.2