ipc/ipc_sysctl.c

   1 /*
   2  *  Copyright (C) 2007
   3  *
   4  *  Author: Eric Biederman <ebiederm@xmision.com>
   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 as
   8  *  published by the Free Software Foundation, version 2 of the
   9  *  License.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/ipc.h>
  14 #include <linux/nsproxy.h>
  15 #include <linux/sysctl.h>
  16 #include <linux/uaccess.h>
  17 #include <linux/ipc_namespace.h>
  18 #include <linux/msg.h>
  19 #include "util.h"
  20
  21 static void *get_ipc(struct ctl_table *table)
  22 {
  23         char *which = table->data;
  24         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
  25         which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
  26         return which;
  27 }
  28
  29 #ifdef CONFIG_PROC_SYSCTL
  30 static int proc_ipc_dointvec(struct ctl_table *table, int write,
  31         void __user *buffer, size_t *lenp, loff_t *ppos)
  32 {
  33         struct ctl_table ipc_table;
  34
  35         memcpy(&ipc_table, table, sizeof(ipc_table));
  36         ipc_table.data = get_ipc(table);
  37
  38         return proc_dointvec(&ipc_table, write, buffer, lenp, ppos);
  39 }
  40
  41 static int proc_ipc_dointvec_minmax(struct ctl_table *table, int write,
  42         void __user *buffer, size_t *lenp, loff_t *ppos)
  43 {
  44         struct ctl_table ipc_table;
  45
  46         memcpy(&ipc_table, table, sizeof(ipc_table));
  47         ipc_table.data = get_ipc(table);
  48
  49         return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
  50 }
  51
  52 static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
  53         void __user *buffer, size_t *lenp, loff_t *ppos)
  54 {
  55         struct ipc_namespace *ns = current->nsproxy->ipc_ns;
  56         int err = proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos);
  57
  58         if (err < 0)
  59                 return err;
  60         if (ns->shm_rmid_forced)
  61                 shm_destroy_orphaned(ns);
  62         return err;
  63 }
  64
  65 static int proc_ipc_doulongvec_minmax(struct ctl_table *table, int write,
  66         void __user *buffer, size_t *lenp, loff_t *ppos)
  67 {
  68         struct ctl_table ipc_table;
  69         memcpy(&ipc_table, table, sizeof(ipc_table));
  70         ipc_table.data = get_ipc(table);
  71
  72         return proc_doulongvec_minmax(&ipc_table, write, buffer,
  73                                         lenp, ppos);
  74 }
  75
  76 static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
  77         void __user *buffer, size_t *lenp, loff_t *ppos)
  78 {
  79         struct ctl_table ipc_table;
  80         int dummy = 0;
  81
  82         memcpy(&ipc_table, table, sizeof(ipc_table));
  83         ipc_table.data = &dummy;
  84
  85         if (write)
  86                 pr_info_once("writing to auto_msgmni has no effect");
  87
  88         return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
  89 }
  90
  91 #else
  92 #define proc_ipc_doulongvec_minmax NULL
  93 #define proc_ipc_dointvec          NULL
  94 #define proc_ipc_dointvec_minmax   NULL
  95 #define proc_ipc_dointvec_minmax_orphans   NULL
  96 #define proc_ipc_auto_msgmni       NULL
  97 #endif
  98
  99 static int zero;
 100 static int one = 1;
 101 static int int_max = INT_MAX;
 102
 103 static struct ctl_table ipc_kern_table[] = {
 104         {
 105                 .procname       = "shmmax",
 106                 .data           = &init_ipc_ns.shm_ctlmax,
 107                 .maxlen         = sizeof(init_ipc_ns.shm_ctlmax),
 108                 .mode           = 0644,
 109                 .proc_handler   = proc_ipc_doulongvec_minmax,
 110         },
 111         {
 112                 .procname       = "shmall",
 113                 .data           = &init_ipc_ns.shm_ctlall,
 114                 .maxlen         = sizeof(init_ipc_ns.shm_ctlall),
 115                 .mode           = 0644,
 116                 .proc_handler   = proc_ipc_doulongvec_minmax,
 117         },
 118         {
 119                 .procname       = "shmmni",
 120                 .data           = &init_ipc_ns.shm_ctlmni,
 121                 .maxlen         = sizeof(init_ipc_ns.shm_ctlmni),
 122                 .mode           = 0644,
 123                 .proc_handler   = proc_ipc_dointvec,
 124         },
 125         {
 126                 .procname       = "shm_rmid_forced",
 127                 .data           = &init_ipc_ns.shm_rmid_forced,
 128                 .maxlen         = sizeof(init_ipc_ns.shm_rmid_forced),
 129                 .mode           = 0644,
 130                 .proc_handler   = proc_ipc_dointvec_minmax_orphans,
 131                 .extra1         = &zero,
 132                 .extra2         = &one,
 133         },
 134         {
 135                 .procname       = "msgmax",
 136                 .data           = &init_ipc_ns.msg_ctlmax,
 137                 .maxlen         = sizeof(init_ipc_ns.msg_ctlmax),
 138                 .mode           = 0644,
 139                 .proc_handler   = proc_ipc_dointvec_minmax,
 140                 .extra1         = &zero,
 141                 .extra2         = &int_max,
 142         },
 143         {
 144                 .procname       = "msgmni",
 145                 .data           = &init_ipc_ns.msg_ctlmni,
 146                 .maxlen         = sizeof(init_ipc_ns.msg_ctlmni),
 147                 .mode           = 0644,
 148                 .proc_handler   = proc_ipc_dointvec_minmax,
 149                 .extra1         = &zero,
 150                 .extra2         = &int_max,
 151         },
 152         {
 153                 .procname       = "auto_msgmni",
 154                 .data           = NULL,
 155                 .maxlen         = sizeof(int),
 156                 .mode           = 0644,
 157                 .proc_handler   = proc_ipc_auto_msgmni,
 158                 .extra1         = &zero,
 159                 .extra2         = &one,
 160         },
 161         {
 162                 .procname       =  "msgmnb",
 163                 .data           = &init_ipc_ns.msg_ctlmnb,
 164                 .maxlen         = sizeof(init_ipc_ns.msg_ctlmnb),
 165                 .mode           = 0644,
 166                 .proc_handler   = proc_ipc_dointvec_minmax,
 167                 .extra1         = &zero,
 168                 .extra2         = &int_max,
 169         },
 170         {
 171                 .procname       = "sem",
 172                 .data           = &init_ipc_ns.sem_ctls,
 173                 .maxlen         = 4*sizeof(int),
 174                 .mode           = 0644,
 175                 .proc_handler   = proc_ipc_dointvec,
 176         },
 177 #ifdef CONFIG_CHECKPOINT_RESTORE
 178         {
 179                 .procname       = "sem_next_id",
 180                 .data           = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
 181                 .maxlen         = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
 182                 .mode           = 0644,
 183                 .proc_handler   = proc_ipc_dointvec_minmax,
 184                 .extra1         = &zero,
 185                 .extra2         = &int_max,
 186         },
 187         {
 188                 .procname       = "msg_next_id",
 189                 .data           = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
 190                 .maxlen         = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
 191                 .mode           = 0644,
 192                 .proc_handler   = proc_ipc_dointvec_minmax,
 193                 .extra1         = &zero,
 194                 .extra2         = &int_max,
 195         },
 196         {
 197                 .procname       = "shm_next_id",
 198                 .data           = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
 199                 .maxlen         = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
 200                 .mode           = 0644,
 201                 .proc_handler   = proc_ipc_dointvec_minmax,
 202                 .extra1         = &zero,
 203                 .extra2         = &int_max,
 204         },
 205 #endif
 206         {}
 207 };
 208
 209 static struct ctl_table ipc_root_table[] = {
 210         {
 211                 .procname       = "kernel",
 212                 .mode           = 0555,
 213                 .child          = ipc_kern_table,
 214         },
 215         {}
 216 };
 217
 218 static int __init ipc_sysctl_init(void)
 219 {
 220         register_sysctl_table(ipc_root_table);
 221         return 0;
 222 }
 223
 224 device_initcall(ipc_sysctl_init);