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kernel/linux-imx6_3.14.28/net/sysctl_net.c 2.79 KB
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  /* -*- linux-c -*-
   * sysctl_net.c: sysctl interface to net subsystem.
   *
   * Begun April 1, 1996, Mike Shaver.
   * Added /proc/sys/net directories for each protocol family. [MS]
   *
   * Revision 1.2  1996/05/08  20:24:40  shaver
   * Added bits for NET_BRIDGE and the NET_IPV4_ARP stuff and
   * NET_IPV4_IP_FORWARD.
   *
   *
   */
  
  #include <linux/mm.h>
  #include <linux/export.h>
  #include <linux/sysctl.h>
  #include <linux/nsproxy.h>
  
  #include <net/sock.h>
  
  #ifdef CONFIG_INET
  #include <net/ip.h>
  #endif
  
  #ifdef CONFIG_NET
  #include <linux/if_ether.h>
  #endif
  
  static struct ctl_table_set *
  net_ctl_header_lookup(struct ctl_table_root *root, struct nsproxy *namespaces)
  {
  	return &namespaces->net_ns->sysctls;
  }
  
  static int is_seen(struct ctl_table_set *set)
  {
  	return &current->nsproxy->net_ns->sysctls == set;
  }
  
  /* Return standard mode bits for table entry. */
  static int net_ctl_permissions(struct ctl_table_header *head,
  			       struct ctl_table *table)
  {
  	struct net *net = container_of(head->set, struct net, sysctls);
  	kuid_t root_uid = make_kuid(net->user_ns, 0);
  	kgid_t root_gid = make_kgid(net->user_ns, 0);
  
  	/* Allow network administrator to have same access as root. */
  	if (ns_capable(net->user_ns, CAP_NET_ADMIN) ||
  	    uid_eq(root_uid, current_euid())) {
  		int mode = (table->mode >> 6) & 7;
  		return (mode << 6) | (mode << 3) | mode;
  	}
  	/* Allow netns root group to have the same access as the root group */
  	if (in_egroup_p(root_gid)) {
  		int mode = (table->mode >> 3) & 7;
  		return (mode << 3) | mode;
  	}
  	return table->mode;
  }
  
  static struct ctl_table_root net_sysctl_root = {
  	.lookup = net_ctl_header_lookup,
  	.permissions = net_ctl_permissions,
  };
  
  static int __net_init sysctl_net_init(struct net *net)
  {
  	setup_sysctl_set(&net->sysctls, &net_sysctl_root, is_seen);
  	return 0;
  }
  
  static void __net_exit sysctl_net_exit(struct net *net)
  {
  	retire_sysctl_set(&net->sysctls);
  }
  
  static struct pernet_operations sysctl_pernet_ops = {
  	.init = sysctl_net_init,
  	.exit = sysctl_net_exit,
  };
  
  static struct ctl_table_header *net_header;
  __init int net_sysctl_init(void)
  {
  	static struct ctl_table empty[1];
  	int ret = -ENOMEM;
  	/* Avoid limitations in the sysctl implementation by
  	 * registering "/proc/sys/net" as an empty directory not in a
  	 * network namespace.
  	 */
  	net_header = register_sysctl("net", empty);
  	if (!net_header)
  		goto out;
  	ret = register_pernet_subsys(&sysctl_pernet_ops);
  	if (ret)
  		goto out;
  	register_sysctl_root(&net_sysctl_root);
  out:
  	return ret;
  }
  
  struct ctl_table_header *register_net_sysctl(struct net *net,
  	const char *path, struct ctl_table *table)
  {
  	return __register_sysctl_table(&net->sysctls, path, table);
  }
  EXPORT_SYMBOL_GPL(register_net_sysctl);
  
  void unregister_net_sysctl_table(struct ctl_table_header *header)
  {
  	unregister_sysctl_table(header);
  }
  EXPORT_SYMBOL_GPL(unregister_net_sysctl_table);