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
  19 static void *get_ipc(ctl_table *table)
  20 {
  21         char *which = table->data;
  22         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
  23         which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
  24         return which;
  25 }
  26
  27 #ifdef CONFIG_PROC_FS
  28 static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
  29         void __user *buffer, size_t *lenp, loff_t *ppos)
  30 {
  31         struct ctl_table ipc_table;
  32         memcpy(&ipc_table, table, sizeof(ipc_table));
  33         ipc_table.data = get_ipc(table);
  34
  35         return proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos);
  36 }
  37
  38 static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
  39         struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
  40 {
  41         struct ctl_table ipc_table;
  42         memcpy(&ipc_table, table, sizeof(ipc_table));
  43         ipc_table.data = get_ipc(table);
  44
  45         return proc_doulongvec_minmax(&ipc_table, write, filp, buffer,
  46                                         lenp, ppos);
  47 }
  48
  49 #else
  50 #define proc_ipc_doulongvec_minmax NULL
  51 #define proc_ipc_dointvec          NULL
  52 #endif
  53
  54 #ifdef CONFIG_SYSCTL_SYSCALL
  55 /* The generic sysctl ipc data routine. */
  56 static int sysctl_ipc_data(ctl_table *table, int __user *name, int nlen,
  57                 void __user *oldval, size_t __user *oldlenp,
  58                 void __user *newval, size_t newlen)
  59 {
  60         size_t len;
  61         void *data;
  62
  63         /* Get out of I don't have a variable */
  64         if (!table->data || !table->maxlen)
  65                 return -ENOTDIR;
  66
  67         data = get_ipc(table);
  68         if (!data)
  69                 return -ENOTDIR;
  70
  71         if (oldval && oldlenp) {
  72                 if (get_user(len, oldlenp))
  73                         return -EFAULT;
  74                 if (len) {
  75                         if (len > table->maxlen)
  76                                 len = table->maxlen;
  77                         if (copy_to_user(oldval, data, len))
  78                                 return -EFAULT;
  79                         if (put_user(len, oldlenp))
  80                                 return -EFAULT;
  81                 }
  82         }
  83
  84         if (newval && newlen) {
  85                 if (newlen > table->maxlen)
  86                         newlen = table->maxlen;
  87
  88                 if (copy_from_user(data, newval, newlen))
  89                         return -EFAULT;
  90         }
  91         return 1;
  92 }
  93 #else
  94 #define sysctl_ipc_data NULL
  95 #endif
  96
  97 static struct ctl_table ipc_kern_table[] = {
  98         {
  99                 .ctl_name       = KERN_SHMMAX,
 100                 .procname       = "shmmax",
 101                 .data           = &init_ipc_ns.shm_ctlmax,
 102                 .maxlen         = sizeof (init_ipc_ns.shm_ctlmax),
 103                 .mode           = 0644,
 104                 .proc_handler   = proc_ipc_doulongvec_minmax,
 105                 .strategy       = sysctl_ipc_data,
 106         },
 107         {
 108                 .ctl_name       = KERN_SHMALL,
 109                 .procname       = "shmall",
 110                 .data           = &init_ipc_ns.shm_ctlall,
 111                 .maxlen         = sizeof (init_ipc_ns.shm_ctlall),
 112                 .mode           = 0644,
 113                 .proc_handler   = proc_ipc_doulongvec_minmax,
 114                 .strategy       = sysctl_ipc_data,
 115         },
 116         {
 117                 .ctl_name       = KERN_SHMMNI,
 118                 .procname       = "shmmni",
 119                 .data           = &init_ipc_ns.shm_ctlmni,
 120                 .maxlen         = sizeof (init_ipc_ns.shm_ctlmni),
 121                 .mode           = 0644,
 122                 .proc_handler   = proc_ipc_dointvec,
 123                 .strategy       = sysctl_ipc_data,
 124         },
 125         {
 126                 .ctl_name       = KERN_MSGMAX,
 127                 .procname       = "msgmax",
 128                 .data           = &init_ipc_ns.msg_ctlmax,
 129                 .maxlen         = sizeof (init_ipc_ns.msg_ctlmax),
 130                 .mode           = 0644,
 131                 .proc_handler   = proc_ipc_dointvec,
 132                 .strategy       = sysctl_ipc_data,
 133         },
 134         {
 135                 .ctl_name       = KERN_MSGMNI,
 136                 .procname       = "msgmni",
 137                 .data           = &init_ipc_ns.msg_ctlmni,
 138                 .maxlen         = sizeof (init_ipc_ns.msg_ctlmni),
 139                 .mode           = 0644,
 140                 .proc_handler   = proc_ipc_dointvec,
 141                 .strategy       = sysctl_ipc_data,
 142         },
 143         {
 144                 .ctl_name       = KERN_MSGMNB,
 145                 .procname       =  "msgmnb",
 146                 .data           = &init_ipc_ns.msg_ctlmnb,
 147                 .maxlen         = sizeof (init_ipc_ns.msg_ctlmnb),
 148                 .mode           = 0644,
 149                 .proc_handler   = proc_ipc_dointvec,
 150                 .strategy       = sysctl_ipc_data,
 151         },
 152         {
 153                 .ctl_name       = KERN_SEM,
 154                 .procname       = "sem",
 155                 .data           = &init_ipc_ns.sem_ctls,
 156                 .maxlen         = 4*sizeof (int),
 157                 .mode           = 0644,
 158                 .proc_handler   = proc_ipc_dointvec,
 159                 .strategy       = sysctl_ipc_data,
 160         },
 161         {}
 162 };
 163
 164 static struct ctl_table ipc_root_table[] = {
 165         {
 166                 .ctl_name       = CTL_KERN,
 167                 .procname       = "kernel",
 168                 .mode           = 0555,
 169                 .child          = ipc_kern_table,
 170         },
 171         {}
 172 };
 173
 174 static int __init ipc_sysctl_init(void)
 175 {
 176         register_sysctl_table(ipc_root_table);
 177         return 0;
 178 }
 179
 180 __initcall(ipc_sysctl_init);