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linux-next/net/ipv6/sysctl_net_ipv6.c
Eric W. Biederman 9d2a8fa96a net ipv6: Fix duplicate /proc/sys/net/ipv6/neigh directory entries.
When I was fixing issues with unregisgtering tables under /proc/sys/net/ipv6/neigh
by adding a mount point it appears I missed a critical ordering issue, in the
ipv6 initialization.  I had not realized that ipv6_sysctl_register is called
at the very end of the ipv6 initialization and in particular after we call
neigh_sysctl_register from ndisc_init.

"neigh" needs to be initialized in ipv6_static_sysctl_register which is
the first ipv6 table to initialized, and definitely before ndisc_init.
This removes the weirdness of duplicate tables while still providing a
"neigh" mount point which prevents races in sysctl unregistering.

This was initially reported at https://bugzilla.kernel.org/show_bug.cgi?id=31232
Reported-by: sunkan@zappa.cx
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-03-21 18:23:34 -07:00

177 lines
3.5 KiB
C

/*
* sysctl_net_ipv6.c: sysctl interface to net IPV6 subsystem.
*
* Changes:
* YOSHIFUJI Hideaki @USAGI: added icmp sysctl table.
*/
#include <linux/mm.h>
#include <linux/sysctl.h>
#include <linux/in6.h>
#include <linux/ipv6.h>
#include <linux/slab.h>
#include <net/ndisc.h>
#include <net/ipv6.h>
#include <net/addrconf.h>
#include <net/inet_frag.h>
static struct ctl_table empty[1];
static ctl_table ipv6_static_skeleton[] = {
{
.procname = "neigh",
.maxlen = 0,
.mode = 0555,
.child = empty,
},
{ }
};
static ctl_table ipv6_table_template[] = {
{
.procname = "route",
.maxlen = 0,
.mode = 0555,
.child = ipv6_route_table_template
},
{
.procname = "icmp",
.maxlen = 0,
.mode = 0555,
.child = ipv6_icmp_table_template
},
{
.procname = "bindv6only",
.data = &init_net.ipv6.sysctl.bindv6only,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec
},
{ }
};
static ctl_table ipv6_rotable[] = {
{
.procname = "mld_max_msf",
.data = &sysctl_mld_max_msf,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec
},
{ }
};
struct ctl_path net_ipv6_ctl_path[] = {
{ .procname = "net", },
{ .procname = "ipv6", },
{ },
};
EXPORT_SYMBOL_GPL(net_ipv6_ctl_path);
static int __net_init ipv6_sysctl_net_init(struct net *net)
{
struct ctl_table *ipv6_table;
struct ctl_table *ipv6_route_table;
struct ctl_table *ipv6_icmp_table;
int err;
err = -ENOMEM;
ipv6_table = kmemdup(ipv6_table_template, sizeof(ipv6_table_template),
GFP_KERNEL);
if (!ipv6_table)
goto out;
ipv6_route_table = ipv6_route_sysctl_init(net);
if (!ipv6_route_table)
goto out_ipv6_table;
ipv6_table[0].child = ipv6_route_table;
ipv6_icmp_table = ipv6_icmp_sysctl_init(net);
if (!ipv6_icmp_table)
goto out_ipv6_route_table;
ipv6_table[1].child = ipv6_icmp_table;
ipv6_table[2].data = &net->ipv6.sysctl.bindv6only;
net->ipv6.sysctl.table = register_net_sysctl_table(net, net_ipv6_ctl_path,
ipv6_table);
if (!net->ipv6.sysctl.table)
goto out_ipv6_icmp_table;
err = 0;
out:
return err;
out_ipv6_icmp_table:
kfree(ipv6_icmp_table);
out_ipv6_route_table:
kfree(ipv6_route_table);
out_ipv6_table:
kfree(ipv6_table);
goto out;
}
static void __net_exit ipv6_sysctl_net_exit(struct net *net)
{
struct ctl_table *ipv6_table;
struct ctl_table *ipv6_route_table;
struct ctl_table *ipv6_icmp_table;
ipv6_table = net->ipv6.sysctl.table->ctl_table_arg;
ipv6_route_table = ipv6_table[0].child;
ipv6_icmp_table = ipv6_table[1].child;
unregister_net_sysctl_table(net->ipv6.sysctl.table);
kfree(ipv6_table);
kfree(ipv6_route_table);
kfree(ipv6_icmp_table);
}
static struct pernet_operations ipv6_sysctl_net_ops = {
.init = ipv6_sysctl_net_init,
.exit = ipv6_sysctl_net_exit,
};
static struct ctl_table_header *ip6_header;
int ipv6_sysctl_register(void)
{
int err = -ENOMEM;
ip6_header = register_net_sysctl_rotable(net_ipv6_ctl_path, ipv6_rotable);
if (ip6_header == NULL)
goto out;
err = register_pernet_subsys(&ipv6_sysctl_net_ops);
if (err)
goto err_pernet;
out:
return err;
err_pernet:
unregister_net_sysctl_table(ip6_header);
goto out;
}
void ipv6_sysctl_unregister(void)
{
unregister_net_sysctl_table(ip6_header);
unregister_pernet_subsys(&ipv6_sysctl_net_ops);
}
static struct ctl_table_header *ip6_base;
int ipv6_static_sysctl_register(void)
{
ip6_base = register_sysctl_paths(net_ipv6_ctl_path, ipv6_static_skeleton);
if (ip6_base == NULL)
return -ENOMEM;
return 0;
}
void ipv6_static_sysctl_unregister(void)
{
unregister_net_sysctl_table(ip6_base);
}