ipc/mq_sysctl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Copyright (C) 2007 IBM Corporation
   4  *
   5  *  Author: Cedric Le Goater <clg@fr.ibm.com>
   6  */
   7
   8 #include <linux/nsproxy.h>
   9 #include <linux/ipc_namespace.h>
  10 #include <linux/sysctl.h>
  11
  12 #include <linux/stat.h>
  13 #include <linux/capability.h>
  14 #include <linux/slab.h>
  15
  16 static int msg_max_limit_min = MIN_MSGMAX;
  17 static int msg_max_limit_max = HARD_MSGMAX;
  18
  19 static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
  20 static int msg_maxsize_limit_max = HARD_MSGSIZEMAX;
  21
  22 static struct ctl_table mq_sysctls[] = {
  23         {
  24                 .procname       = "queues_max",
  25                 .data           = &init_ipc_ns.mq_queues_max,
  26                 .maxlen         = sizeof(int),
  27                 .mode           = 0644,
  28                 .proc_handler   = proc_dointvec,
  29         },
  30         {
  31                 .procname       = "msg_max",
  32                 .data           = &init_ipc_ns.mq_msg_max,
  33                 .maxlen         = sizeof(int),
  34                 .mode           = 0644,
  35                 .proc_handler   = proc_dointvec_minmax,
  36                 .extra1         = &msg_max_limit_min,
  37                 .extra2         = &msg_max_limit_max,
  38         },
  39         {
  40                 .procname       = "msgsize_max",
  41                 .data           = &init_ipc_ns.mq_msgsize_max,
  42                 .maxlen         = sizeof(int),
  43                 .mode           = 0644,
  44                 .proc_handler   = proc_dointvec_minmax,
  45                 .extra1         = &msg_maxsize_limit_min,
  46                 .extra2         = &msg_maxsize_limit_max,
  47         },
  48         {
  49                 .procname       = "msg_default",
  50                 .data           = &init_ipc_ns.mq_msg_default,
  51                 .maxlen         = sizeof(int),
  52                 .mode           = 0644,
  53                 .proc_handler   = proc_dointvec_minmax,
  54                 .extra1         = &msg_max_limit_min,
  55                 .extra2         = &msg_max_limit_max,
  56         },
  57         {
  58                 .procname       = "msgsize_default",
  59                 .data           = &init_ipc_ns.mq_msgsize_default,
  60                 .maxlen         = sizeof(int),
  61                 .mode           = 0644,
  62                 .proc_handler   = proc_dointvec_minmax,
  63                 .extra1         = &msg_maxsize_limit_min,
  64                 .extra2         = &msg_maxsize_limit_max,
  65         },
  66         {}
  67 };
  68
  69 static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
  70 {
  71         return &current->nsproxy->ipc_ns->mq_set;
  72 }
  73
  74 static int set_is_seen(struct ctl_table_set *set)
  75 {
  76         return &current->nsproxy->ipc_ns->mq_set == set;
  77 }
  78
  79 static struct ctl_table_root set_root = {
  80         .lookup = set_lookup,
  81 };
  82
  83 bool setup_mq_sysctls(struct ipc_namespace *ns)
  84 {
  85         struct ctl_table *tbl;
  86
  87         setup_sysctl_set(&ns->mq_set, &set_root, set_is_seen);
  88
  89         tbl = kmemdup(mq_sysctls, sizeof(mq_sysctls), GFP_KERNEL);
  90         if (tbl) {
  91                 int i;
  92
  93                 for (i = 0; i < ARRAY_SIZE(mq_sysctls); i++) {
  94                         if (tbl[i].data == &init_ipc_ns.mq_queues_max)
  95                                 tbl[i].data = &ns->mq_queues_max;
  96
  97                         else if (tbl[i].data == &init_ipc_ns.mq_msg_max)
  98                                 tbl[i].data = &ns->mq_msg_max;
  99
 100                         else if (tbl[i].data == &init_ipc_ns.mq_msgsize_max)
 101                                 tbl[i].data = &ns->mq_msgsize_max;
 102
 103                         else if (tbl[i].data == &init_ipc_ns.mq_msg_default)
 104                                 tbl[i].data = &ns->mq_msg_default;
 105
 106                         else if (tbl[i].data == &init_ipc_ns.mq_msgsize_default)
 107                                 tbl[i].data = &ns->mq_msgsize_default;
 108                         else
 109                                 tbl[i].data = NULL;
 110                 }
 111
 112                 ns->mq_sysctls = __register_sysctl_table(&ns->mq_set, "fs/mqueue", tbl);
 113         }
 114         if (!ns->mq_sysctls) {
 115                 kfree(tbl);
 116                 retire_sysctl_set(&ns->mq_set);
 117                 return false;
 118         }
 119
 120         return true;
 121 }
 122
 123 void retire_mq_sysctls(struct ipc_namespace *ns)
 124 {
 125         struct ctl_table *tbl;
 126
 127         tbl = ns->mq_sysctls->ctl_table_arg;
 128         unregister_sysctl_table(ns->mq_sysctls);
 129         retire_sysctl_set(&ns->mq_set);
 130         kfree(tbl);
 131 }