netdev - [PATCH net-next] ipv4: fix kfree static array pointer in ipv4_sysctl_exit

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Message-ID: <536B34FD.8030601@huawei.com>
Date:	Thu, 8 May 2014 15:40:45 +0800
From:	Wang Weidong <wangweidong1@...wei.com>
To:	David Miller <davem@...emloft.net>, <kuznet@....inr.ac.ru>,
	<jmorris@...ei.org>, <yoshfuji@...ux-ipv6.org>, <kaber@...sh.net>
CC:	<netdev@...r.kernel.org>
Subject: [PATCH net-next] ipv4: fix kfree static array pointer in ipv4_sysctl_exit_net

In ipv4_sysctl_init_net, we don't kmemdup a sysctl_table for init_net,
so init_net->ipv4.ipv4_hdr->ctl_table_arg points to ipv4_net_table which
is a static array pointer. So when do ipv4_sysctl_exit_net, it will
free the ipv4_net_table for init_net.

So add a check net_namespace init_net before kfree the sysctl_table.

Signed-off-by: Wang Weidong <wangweidong1@...wei.com>
---
 net/ipv4/sysctl_net_ipv4.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 44eba05..2825577 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -891,7 +891,8 @@ static __net_exit void ipv4_sysctl_exit_net(struct net *net)
 
 	table = net->ipv4.ipv4_hdr->ctl_table_arg;
 	unregister_net_sysctl_table(net->ipv4.ipv4_hdr);
-	kfree(table);
+	if (!net_eq(net, &init_net))
+		kfree(table);
 }
 
 static __net_initdata struct pernet_operations ipv4_sysctl_ops = {
-- 
1.7.12


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