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 static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
  92         void __user *buffer, size_t *lenp, loff_t *ppos)
  93 {
  94         int ret, semmni;
  95         struct ipc_namespace *ns = current->nsproxy->ipc_ns;
  96
  97         semmni = ns->sem_ctls[3];
  98         ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos);
  99
 100         if (!ret)
 101                 ret = sem_check_semmni(current->nsproxy->ipc_ns);
 102
 103         /*
 104          * Reset the semmni value if an error happens.
 105          */
 106         if (ret)
 107                 ns->sem_ctls[3] = semmni;
 108         return ret;
 109 }
 110
 111 #else
 112 #define proc_ipc_doulongvec_minmax NULL
 113 #define proc_ipc_dointvec          NULL
 114 #define proc_ipc_dointvec_minmax   NULL
 115 #define proc_ipc_dointvec_minmax_orphans   NULL
 116 #define proc_ipc_auto_msgmni       NULL
 117 #define proc_ipc_sem_dointvec      NULL
 118 #endif
 119
 120 static int zero;
 121 static int one = 1;
 122 static int int_max = INT_MAX;
 123 static int ipc_mni = IPCMNI;
 124
 125 static struct ctl_table ipc_kern_table[] = {
 126         {
 127                 .procname       = "shmmax",
 128                 .data           = &init_ipc_ns.shm_ctlmax,
 129                 .maxlen         = sizeof(init_ipc_ns.shm_ctlmax),
 130                 .mode           = 0644,
 131                 .proc_handler   = proc_ipc_doulongvec_minmax,
 132         },
 133         {
 134                 .procname       = "shmall",
 135                 .data           = &init_ipc_ns.shm_ctlall,
 136                 .maxlen         = sizeof(init_ipc_ns.shm_ctlall),
 137                 .mode           = 0644,
 138                 .proc_handler   = proc_ipc_doulongvec_minmax,
 139         },
 140         {
 141                 .procname       = "shmmni",
 142                 .data           = &init_ipc_ns.shm_ctlmni,
 143                 .maxlen         = sizeof(init_ipc_ns.shm_ctlmni),
 144                 .mode           = 0644,
 145                 .proc_handler   = proc_ipc_dointvec_minmax,
 146                 .extra1         = &zero,
 147                 .extra2         = &ipc_mni,
 148         },
 149         {
 150                 .procname       = "shm_rmid_forced",
 151                 .data           = &init_ipc_ns.shm_rmid_forced,
 152                 .maxlen         = sizeof(init_ipc_ns.shm_rmid_forced),
 153                 .mode           = 0644,
 154                 .proc_handler   = proc_ipc_dointvec_minmax_orphans,
 155                 .extra1         = &zero,
 156                 .extra2         = &one,
 157         },
 158         {
 159                 .procname       = "msgmax",
 160                 .data           = &init_ipc_ns.msg_ctlmax,
 161                 .maxlen         = sizeof(init_ipc_ns.msg_ctlmax),
 162                 .mode           = 0644,
 163                 .proc_handler   = proc_ipc_dointvec_minmax,
 164                 .extra1         = &zero,
 165                 .extra2         = &int_max,
 166         },
 167         {
 168                 .procname       = "msgmni",
 169                 .data           = &init_ipc_ns.msg_ctlmni,
 170                 .maxlen         = sizeof(init_ipc_ns.msg_ctlmni),
 171                 .mode           = 0644,
 172                 .proc_handler   = proc_ipc_dointvec_minmax,
 173                 .extra1         = &zero,
 174                 .extra2         = &ipc_mni,
 175         },
 176         {
 177                 .procname       = "auto_msgmni",
 178                 .data           = NULL,
 179                 .maxlen         = sizeof(int),
 180                 .mode           = 0644,
 181                 .proc_handler   = proc_ipc_auto_msgmni,
 182                 .extra1         = &zero,
 183                 .extra2         = &one,
 184         },
 185         {
 186                 .procname       =  "msgmnb",
 187                 .data           = &init_ipc_ns.msg_ctlmnb,
 188                 .maxlen         = sizeof(init_ipc_ns.msg_ctlmnb),
 189                 .mode           = 0644,
 190                 .proc_handler   = proc_ipc_dointvec_minmax,
 191                 .extra1         = &zero,
 192                 .extra2         = &int_max,
 193         },
 194         {
 195                 .procname       = "sem",
 196                 .data           = &init_ipc_ns.sem_ctls,
 197                 .maxlen         = 4*sizeof(int),
 198                 .mode           = 0644,
 199                 .proc_handler   = proc_ipc_sem_dointvec,
 200         },
 201 #ifdef CONFIG_CHECKPOINT_RESTORE
 202         {
 203                 .procname       = "sem_next_id",
 204                 .data           = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
 205                 .maxlen         = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
 206                 .mode           = 0644,
 207                 .proc_handler   = proc_ipc_dointvec_minmax,
 208                 .extra1         = &zero,
 209                 .extra2         = &int_max,
 210         },
 211         {
 212                 .procname       = "msg_next_id",
 213                 .data           = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
 214                 .maxlen         = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
 215                 .mode           = 0644,
 216                 .proc_handler   = proc_ipc_dointvec_minmax,
 217                 .extra1         = &zero,
 218                 .extra2         = &int_max,
 219         },
 220         {
 221                 .procname       = "shm_next_id",
 222                 .data           = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
 223                 .maxlen         = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
 224                 .mode           = 0644,
 225                 .proc_handler   = proc_ipc_dointvec_minmax,
 226                 .extra1         = &zero,
 227                 .extra2         = &int_max,
 228         },
 229 #endif
 230         {}
 231 };
 232
 233 static struct ctl_table ipc_root_table[] = {
 234         {
 235                 .procname       = "kernel",
 236                 .mode           = 0555,
 237                 .child          = ipc_kern_table,
 238         },
 239         {}
 240 };
 241
 242 static int __init ipc_sysctl_init(void)
 243 {
 244         register_sysctl_table(ipc_root_table);
 245         return 0;
 246 }
 247
 248 device_initcall(ipc_sysctl_init);