net/unix/sysctl_net_unix.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * NET4:        Sysctl interface to net af_unix subsystem.
   4  *
   5  * Authors:     Mike Shaver.
   6  */
   7
   8 #include <linux/mm.h>
   9 #include <linux/slab.h>
  10 #include <linux/sysctl.h>
  11
  12 #include <net/af_unix.h>
  13
  14 static struct ctl_table unix_table[] = {
  15         {
  16                 .procname       = "max_dgram_qlen",
  17                 .data           = &init_net.unx.sysctl_max_dgram_qlen,
  18                 .maxlen         = sizeof(int),
  19                 .mode           = 0644,
  20                 .proc_handler   = proc_dointvec
  21         },
  22         { }
  23 };
  24
  25 int __net_init unix_sysctl_register(struct net *net)
  26 {
  27         struct ctl_table *table;
  28
  29         table = kmemdup(unix_table, sizeof(unix_table), GFP_KERNEL);
  30         if (table == NULL)
  31                 goto err_alloc;
  32
  33         /* Don't export sysctls to unprivileged users */
  34         if (net->user_ns != &init_user_ns)
  35                 table[0].procname = NULL;
  36
  37         table[0].data = &net->unx.sysctl_max_dgram_qlen;
  38         net->unx.ctl = register_net_sysctl(net, "net/unix", table);
  39         if (net->unx.ctl == NULL)
  40                 goto err_reg;
  41
  42         return 0;
  43
  44 err_reg:
  45         kfree(table);
  46 err_alloc:
  47         return -ENOMEM;
  48 }
  49
  50 void unix_sysctl_unregister(struct net *net)
  51 {
  52         struct ctl_table *table;
  53
  54         table = net->unx.ctl->ctl_table_arg;
  55         unregister_net_sysctl_table(net->unx.ctl);
  56         kfree(table);
  57 }