ipc/ipc_sysctl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Copyright (C) 2007
   4  *
   5  *  Author: Eric Biederman <ebiederm@xmision.com>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/ipc.h>
  10 #include <linux/nsproxy.h>
  11 #include <linux/sysctl.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/ipc_namespace.h>
  14 #include <linux/msg.h>
  15 #include "util.h"
  16
  17 static void *get_ipc(struct ctl_table *table)
  18 {
  19         char *which = table->data;
  20         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
  21         which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
  22         return which;
  23 }
  24
  25 #ifdef CONFIG_PROC_SYSCTL
  26 static int proc_ipc_dointvec(struct ctl_table *table, int write,
  27         void __user *buffer, size_t *lenp, loff_t *ppos)
  28 {
  29         struct ctl_table ipc_table;
  30
  31         memcpy(&ipc_table, table, sizeof(ipc_table));
  32         ipc_table.data = get_ipc(table);
  33
  34         return proc_dointvec(&ipc_table, write, buffer, lenp, ppos);
  35 }
  36
  37 static int proc_ipc_dointvec_minmax(struct ctl_table *table, int write,
  38         void __user *buffer, size_t *lenp, loff_t *ppos)
  39 {
  40         struct ctl_table ipc_table;
  41
  42         memcpy(&ipc_table, table, sizeof(ipc_table));
  43         ipc_table.data = get_ipc(table);
  44
  45         return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
  46 }
  47
  48 static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
  49         void __user *buffer, size_t *lenp, loff_t *ppos)
  50 {
  51         struct ipc_namespace *ns = current->nsproxy->ipc_ns;
  52         int err = proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos);
  53
  54         if (err < 0)
  55                 return err;
  56         if (ns->shm_rmid_forced)
  57                 shm_destroy_orphaned(ns);
  58         return err;
  59 }
  60
  61 static int proc_ipc_doulongvec_minmax(struct ctl_table *table, int write,
  62         void __user *buffer, size_t *lenp, loff_t *ppos)
  63 {
  64         struct ctl_table ipc_table;
  65         memcpy(&ipc_table, table, sizeof(ipc_table));
  66         ipc_table.data = get_ipc(table);
  67
  68         return proc_doulongvec_minmax(&ipc_table, write, buffer,
  69                                         lenp, ppos);
  70 }
  71
  72 static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
  73         void __user *buffer, size_t *lenp, loff_t *ppos)
  74 {
  75         struct ctl_table ipc_table;
  76         int dummy = 0;
  77
  78         memcpy(&ipc_table, table, sizeof(ipc_table));
  79         ipc_table.data = &dummy;
  80
  81         if (write)
  82                 pr_info_once("writing to auto_msgmni has no effect");
  83
  84         return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
  85 }
  86
  87 static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
  88         void __user *buffer, size_t *lenp, loff_t *ppos)
  89 {
  90         int ret, semmni;
  91         struct ipc_namespace *ns = current->nsproxy->ipc_ns;
  92
  93         semmni = ns->sem_ctls[3];
  94         ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos);
  95
  96         if (!ret)
  97                 ret = sem_check_semmni(current->nsproxy->ipc_ns);
  98
  99         /*
 100          * Reset the semmni value if an error happens.
 101          */
 102         if (ret)
 103                 ns->sem_ctls[3] = semmni;
 104         return ret;
 105 }
 106
 107 #else
 108 #define proc_ipc_doulongvec_minmax NULL
 109 #define proc_ipc_dointvec          NULL
 110 #define proc_ipc_dointvec_minmax   NULL
 111 #define proc_ipc_dointvec_minmax_orphans   NULL
 112 #define proc_ipc_auto_msgmni       NULL
 113 #define proc_ipc_sem_dointvec      NULL
 114 #endif
 115
 116 static int zero;
 117 static int one = 1;
 118 static int int_max = INT_MAX;
 119 int ipc_mni = IPCMNI;
 120 int ipc_mni_shift = IPCMNI_SHIFT;
 121 int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
 122
 123 static struct ctl_table ipc_kern_table[] = {
 124         {
 125                 .procname       = "shmmax",
 126                 .data           = &init_ipc_ns.shm_ctlmax,
 127                 .maxlen         = sizeof(init_ipc_ns.shm_ctlmax),
 128                 .mode           = 0644,
 129                 .proc_handler   = proc_ipc_doulongvec_minmax,
 130         },
 131         {
 132                 .procname       = "shmall",
 133                 .data           = &init_ipc_ns.shm_ctlall,
 134                 .maxlen         = sizeof(init_ipc_ns.shm_ctlall),
 135                 .mode           = 0644,
 136                 .proc_handler   = proc_ipc_doulongvec_minmax,
 137         },
 138         {
 139                 .procname       = "shmmni",
 140                 .data           = &init_ipc_ns.shm_ctlmni,
 141                 .maxlen         = sizeof(init_ipc_ns.shm_ctlmni),
 142                 .mode           = 0644,
 143                 .proc_handler   = proc_ipc_dointvec_minmax,
 144                 .extra1         = &zero,
 145                 .extra2         = &ipc_mni,
 146         },
 147         {
 148                 .procname       = "shm_rmid_forced",
 149                 .data           = &init_ipc_ns.shm_rmid_forced,
 150                 .maxlen         = sizeof(init_ipc_ns.shm_rmid_forced),
 151                 .mode           = 0644,
 152                 .proc_handler   = proc_ipc_dointvec_minmax_orphans,
 153                 .extra1         = &zero,
 154                 .extra2         = &one,
 155         },
 156         {
 157                 .procname       = "msgmax",
 158                 .data           = &init_ipc_ns.msg_ctlmax,
 159                 .maxlen         = sizeof(init_ipc_ns.msg_ctlmax),
 160                 .mode           = 0644,
 161                 .proc_handler   = proc_ipc_dointvec_minmax,
 162                 .extra1         = &zero,
 163                 .extra2         = &int_max,
 164         },
 165         {
 166                 .procname       = "msgmni",
 167                 .data           = &init_ipc_ns.msg_ctlmni,
 168                 .maxlen         = sizeof(init_ipc_ns.msg_ctlmni),
 169                 .mode           = 0644,
 170                 .proc_handler   = proc_ipc_dointvec_minmax,
 171                 .extra1         = &zero,
 172                 .extra2         = &ipc_mni,
 173         },
 174         {
 175                 .procname       = "auto_msgmni",
 176                 .data           = NULL,
 177                 .maxlen         = sizeof(int),
 178                 .mode           = 0644,
 179                 .proc_handler   = proc_ipc_auto_msgmni,
 180                 .extra1         = &zero,
 181                 .extra2         = &one,
 182         },
 183         {
 184                 .procname       =  "msgmnb",
 185                 .data           = &init_ipc_ns.msg_ctlmnb,
 186                 .maxlen         = sizeof(init_ipc_ns.msg_ctlmnb),
 187                 .mode           = 0644,
 188                 .proc_handler   = proc_ipc_dointvec_minmax,
 189                 .extra1         = &zero,
 190                 .extra2         = &int_max,
 191         },
 192         {
 193                 .procname       = "sem",
 194                 .data           = &init_ipc_ns.sem_ctls,
 195                 .maxlen         = 4*sizeof(int),
 196                 .mode           = 0644,
 197                 .proc_handler   = proc_ipc_sem_dointvec,
 198         },
 199 #ifdef CONFIG_CHECKPOINT_RESTORE
 200         {
 201                 .procname       = "sem_next_id",
 202                 .data           = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
 203                 .maxlen         = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
 204                 .mode           = 0644,
 205                 .proc_handler   = proc_ipc_dointvec_minmax,
 206                 .extra1         = &zero,
 207                 .extra2         = &int_max,
 208         },
 209         {
 210                 .procname       = "msg_next_id",
 211                 .data           = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
 212                 .maxlen         = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
 213                 .mode           = 0644,
 214                 .proc_handler   = proc_ipc_dointvec_minmax,
 215                 .extra1         = &zero,
 216                 .extra2         = &int_max,
 217         },
 218         {
 219                 .procname       = "shm_next_id",
 220                 .data           = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
 221                 .maxlen         = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
 222                 .mode           = 0644,
 223                 .proc_handler   = proc_ipc_dointvec_minmax,
 224                 .extra1         = &zero,
 225                 .extra2         = &int_max,
 226         },
 227 #endif
 228         {}
 229 };
 230
 231 static struct ctl_table ipc_root_table[] = {
 232         {
 233                 .procname       = "kernel",
 234                 .mode           = 0555,
 235                 .child          = ipc_kern_table,
 236         },
 237         {}
 238 };
 239
 240 static int __init ipc_sysctl_init(void)
 241 {
 242         register_sysctl_table(ipc_root_table);
 243         return 0;
 244 }
 245
 246 device_initcall(ipc_sysctl_init);
 247
 248 static int __init ipc_mni_extend(char *str)
 249 {
 250         ipc_mni = IPCMNI_EXTEND;
 251         ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
 252         ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
 253         pr_info("IPCMNI extended to %d.\n", ipc_mni);
 254         return 0;
 255 }
 256 early_param("ipcmni_extend", ipc_mni_extend);