 9d2a8fa96a
			
		
	
	
	9d2a8fa96a
	
	
	
		
			
			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>
		
			
				
	
	
		
			176 lines
		
	
	
	
		
			3.5 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			176 lines
		
	
	
	
		
			3.5 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * sysctl_net_ipv6.c: sysctl interface to net IPV6 subsystem.
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|  *
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|  * Changes:
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|  * YOSHIFUJI Hideaki @USAGI:	added icmp sysctl table.
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|  */
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| 
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| #include <linux/mm.h>
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| #include <linux/sysctl.h>
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| #include <linux/in6.h>
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| #include <linux/ipv6.h>
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| #include <linux/slab.h>
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| #include <net/ndisc.h>
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| #include <net/ipv6.h>
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| #include <net/addrconf.h>
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| #include <net/inet_frag.h>
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| 
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| static struct ctl_table empty[1];
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| 
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| static ctl_table ipv6_static_skeleton[] = {
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| 	{
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| 		.procname	= "neigh",
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| 		.maxlen		= 0,
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| 		.mode		= 0555,
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| 		.child		= empty,
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| 	},
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| 	{ }
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| };
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| 
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| static ctl_table ipv6_table_template[] = {
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| 	{
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| 		.procname	= "route",
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| 		.maxlen		= 0,
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| 		.mode		= 0555,
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| 		.child		= ipv6_route_table_template
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| 	},
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| 	{
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| 		.procname	= "icmp",
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| 		.maxlen		= 0,
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| 		.mode		= 0555,
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| 		.child		= ipv6_icmp_table_template
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| 	},
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| 	{
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| 		.procname	= "bindv6only",
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| 		.data		= &init_net.ipv6.sysctl.bindv6only,
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| 		.maxlen		= sizeof(int),
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| 		.mode		= 0644,
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| 		.proc_handler	= proc_dointvec
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| 	},
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| 	{ }
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| };
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| 
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| static ctl_table ipv6_rotable[] = {
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| 	{
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| 		.procname	= "mld_max_msf",
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| 		.data		= &sysctl_mld_max_msf,
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| 		.maxlen		= sizeof(int),
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| 		.mode		= 0644,
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| 		.proc_handler	= proc_dointvec
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| 	},
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| 	{ }
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| };
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| 
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| struct ctl_path net_ipv6_ctl_path[] = {
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| 	{ .procname = "net", },
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| 	{ .procname = "ipv6", },
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| 	{ },
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| };
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| EXPORT_SYMBOL_GPL(net_ipv6_ctl_path);
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| 
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| static int __net_init ipv6_sysctl_net_init(struct net *net)
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| {
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| 	struct ctl_table *ipv6_table;
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| 	struct ctl_table *ipv6_route_table;
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| 	struct ctl_table *ipv6_icmp_table;
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| 	int err;
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| 
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| 	err = -ENOMEM;
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| 	ipv6_table = kmemdup(ipv6_table_template, sizeof(ipv6_table_template),
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| 			     GFP_KERNEL);
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| 	if (!ipv6_table)
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| 		goto out;
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| 
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| 	ipv6_route_table = ipv6_route_sysctl_init(net);
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| 	if (!ipv6_route_table)
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| 		goto out_ipv6_table;
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| 	ipv6_table[0].child = ipv6_route_table;
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| 
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| 	ipv6_icmp_table = ipv6_icmp_sysctl_init(net);
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| 	if (!ipv6_icmp_table)
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| 		goto out_ipv6_route_table;
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| 	ipv6_table[1].child = ipv6_icmp_table;
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| 
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| 	ipv6_table[2].data = &net->ipv6.sysctl.bindv6only;
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| 
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| 	net->ipv6.sysctl.table = register_net_sysctl_table(net, net_ipv6_ctl_path,
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| 							   ipv6_table);
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| 	if (!net->ipv6.sysctl.table)
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| 		goto out_ipv6_icmp_table;
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| 
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| 	err = 0;
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| out:
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| 	return err;
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| 
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| out_ipv6_icmp_table:
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| 	kfree(ipv6_icmp_table);
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| out_ipv6_route_table:
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| 	kfree(ipv6_route_table);
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| out_ipv6_table:
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| 	kfree(ipv6_table);
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| 	goto out;
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| }
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| 
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| static void __net_exit ipv6_sysctl_net_exit(struct net *net)
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| {
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| 	struct ctl_table *ipv6_table;
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| 	struct ctl_table *ipv6_route_table;
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| 	struct ctl_table *ipv6_icmp_table;
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| 
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| 	ipv6_table = net->ipv6.sysctl.table->ctl_table_arg;
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| 	ipv6_route_table = ipv6_table[0].child;
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| 	ipv6_icmp_table = ipv6_table[1].child;
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| 
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| 	unregister_net_sysctl_table(net->ipv6.sysctl.table);
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| 
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| 	kfree(ipv6_table);
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| 	kfree(ipv6_route_table);
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| 	kfree(ipv6_icmp_table);
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| }
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| 
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| static struct pernet_operations ipv6_sysctl_net_ops = {
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| 	.init = ipv6_sysctl_net_init,
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| 	.exit = ipv6_sysctl_net_exit,
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| };
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| 
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| static struct ctl_table_header *ip6_header;
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| 
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| int ipv6_sysctl_register(void)
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| {
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| 	int err = -ENOMEM;
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| 
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| 	ip6_header = register_net_sysctl_rotable(net_ipv6_ctl_path, ipv6_rotable);
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| 	if (ip6_header == NULL)
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| 		goto out;
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| 
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| 	err = register_pernet_subsys(&ipv6_sysctl_net_ops);
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| 	if (err)
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| 		goto err_pernet;
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| out:
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| 	return err;
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| 
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| err_pernet:
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| 	unregister_net_sysctl_table(ip6_header);
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| 	goto out;
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| }
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| 
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| void ipv6_sysctl_unregister(void)
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| {
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| 	unregister_net_sysctl_table(ip6_header);
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| 	unregister_pernet_subsys(&ipv6_sysctl_net_ops);
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| }
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| 
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| static struct ctl_table_header *ip6_base;
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| 
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| int ipv6_static_sysctl_register(void)
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| {
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| 	ip6_base = register_sysctl_paths(net_ipv6_ctl_path, ipv6_static_skeleton);
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| 	if (ip6_base == NULL)
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| 		return -ENOMEM;
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| 	return 0;
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| }
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| 
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| void ipv6_static_sysctl_unregister(void)
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| {
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| 	unregister_net_sysctl_table(ip6_base);
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| }
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