[ 3.5.y.z extended stable ] Patch "net: check net.core.somaxconn sysctl values" has been added to staging queue
Luis Henriques
luis.henriques at canonical.com
Fri Sep 20 19:33:43 UTC 2013
This is a note to let you know that I have just added a patch titled
net: check net.core.somaxconn sysctl values
to the linux-3.5.y-queue branch of the 3.5.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-3.5.y-queue
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
------
>From b2821adcfb163d7d1ea506e65a277620cd5d1018 Mon Sep 17 00:00:00 2001
From: Roman Gushchin <klamm at yandex-team.ru>
Date: Fri, 2 Aug 2013 18:36:40 +0400
Subject: [PATCH] net: check net.core.somaxconn sysctl values
commit 5f671d6b4ec3e6d66c2a868738af2cdea09e7509 upstream.
It's possible to assign an invalid value to the net.core.somaxconn
sysctl variable, because there is no checks at all.
The sk_max_ack_backlog field of the sock structure is defined as
unsigned short. Therefore, the backlog argument in inet_listen()
shouldn't exceed USHRT_MAX. The backlog argument in the listen() syscall
is truncated to the somaxconn value. So, the somaxconn value shouldn't
exceed 65535 (USHRT_MAX).
Also, negative values of somaxconn are meaningless.
before:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
net.core.somaxconn = 65536
$ sysctl -w net.core.somaxconn=-100
net.core.somaxconn = -100
after:
$ sysctl -w net.core.somaxconn=256
net.core.somaxconn = 256
$ sysctl -w net.core.somaxconn=65536
error: "Invalid argument" setting key "net.core.somaxconn"
$ sysctl -w net.core.somaxconn=-100
error: "Invalid argument" setting key "net.core.somaxconn"
Based on a prior patch from Changli Gao.
Signed-off-by: Roman Gushchin <klamm at yandex-team.ru>
Reported-by: Changli Gao <xiaosuo at gmail.com>
Suggested-by: Eric Dumazet <edumazet at google.com>
Acked-by: Eric Dumazet <edumazet at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
net/core/sysctl_net_core.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index a7c3684..df0dafe 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -20,6 +20,9 @@
#include <net/sock.h>
#include <net/net_ratelimit.h>
+static int zero = 0;
+static int ushort_max = USHRT_MAX;
+
#ifdef CONFIG_RPS
static int rps_sock_flow_sysctl(ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
@@ -198,7 +201,9 @@ static struct ctl_table netns_core_table[] = {
.data = &init_net.core.sysctl_somaxconn,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_dointvec
+ .extra1 = &zero,
+ .extra2 = &ushort_max,
+ .proc_handler = proc_dointvec_minmax
},
{ }
};
--
1.8.3.2
More information about the kernel-team
mailing list