linux/ipc/mq_sysctl.c
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   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
  16static int msg_max_limit_min = MIN_MSGMAX;
  17static int msg_max_limit_max = HARD_MSGMAX;
  18
  19static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
  20static int msg_maxsize_limit_max = HARD_MSGSIZEMAX;
  21
  22static 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
  69static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
  70{
  71        return &current->nsproxy->ipc_ns->mq_set;
  72}
  73
  74static int set_is_seen(struct ctl_table_set *set)
  75{
  76        return &current->nsproxy->ipc_ns->mq_set == set;
  77}
  78
  79static struct ctl_table_root set_root = {
  80        .lookup = set_lookup,
  81};
  82
  83bool 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
 123void 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}
 132