net/unix/sysctl_net_unix.c

   1 /*
   2  * NET4:        Sysctl interface to net af_unix subsystem.
   3  *
   4  * Authors:     Mike Shaver.
   5  *
   6  *              This program is free software; you can redistribute it and/or
   7  *              modify it under the terms of the GNU General Public License
   8  *              as published by the Free Software Foundation; either version
   9  *              2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/mm.h>
  13 #include <linux/slab.h>
  14 #include <linux/sysctl.h>
  15
  16 #include <net/af_unix.h>
  17
  18 static struct ctl_table unix_table[] = {
  19         {
  20                 .procname       = "max_dgram_qlen",
  21                 .data           = &init_net.unx.sysctl_max_dgram_qlen,
  22                 .maxlen         = sizeof(int),
  23                 .mode           = 0644,
  24                 .proc_handler   = proc_dointvec
  25         },
  26         { }
  27 };
  28
  29 int __net_init unix_sysctl_register(struct net *net)
  30 {
  31         struct ctl_table *table;
  32
  33         table = kmemdup(unix_table, sizeof(unix_table), GFP_KERNEL);
  34         if (table == NULL)
  35                 goto err_alloc;
  36
  37         /* Don't export sysctls to unprivileged users */
  38         if (net->user_ns != &init_user_ns)
  39                 table[0].procname = NULL;
  40
  41         table[0].data = &net->unx.sysctl_max_dgram_qlen;
  42         net->unx.ctl = register_net_sysctl(net, "net/unix", table);
  43         if (net->unx.ctl == NULL)
  44                 goto err_reg;
  45
  46         return 0;
  47
  48 err_reg:
  49         kfree(table);
  50 err_alloc:
  51         return -ENOMEM;
  52 }
  53
  54 void unix_sysctl_unregister(struct net *net)
  55 {
  56         struct ctl_table *table;
  57
  58         table = net->unx.ctl->ctl_table_arg;
  59         unregister_net_sysctl_table(net->unx.ctl);
  60         kfree(table);
  61 }