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
  18 #ifdef CONFIG_IPC_NS
  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 #else
  27 #define get_ipc(T) ((T)->data)
  28 #endif
  29
  30 #ifdef CONFIG_PROC_FS
  31 static int proc_ipc_dointvec(ctl_table *table, int write, struct file *filp,
  32         void __user *buffer, size_t *lenp, loff_t *ppos)
  33 {
  34         struct ctl_table ipc_table;
  35         memcpy(&ipc_table, table, sizeof(ipc_table));
  36         ipc_table.data = get_ipc(table);
  37
  38         return proc_dointvec(&ipc_table, write, filp, buffer, lenp, ppos);
  39 }
  40
  41 static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
  42         struct file *filp, void __user *buffer, size_t *lenp, loff_t *ppos)
  43 {
  44         struct ctl_table ipc_table;
  45         memcpy(&ipc_table, table, sizeof(ipc_table));
  46         ipc_table.data = get_ipc(table);
  47
  48         return proc_doulongvec_minmax(&ipc_table, write, filp, buffer,
  49                                         lenp, ppos);
  50 }
  51
  52 #else
  53 #define proc_ipc_doulongvec_minmax NULL
  54 #define proc_ipc_dointvec          NULL
  55 #endif
  56
  57 #ifdef CONFIG_SYSCTL_SYSCALL
  58 /* The generic sysctl ipc data routine. */
  59 static int sysctl_ipc_data(ctl_table *table, int __user *name, int nlen,
  60                 void __user *oldval, size_t __user *oldlenp,
  61                 void __user *newval, size_t newlen)
  62 {
  63         size_t len;
  64         void *data;
  65
  66         /* Get out of I don't have a variable */
  67         if (!table->data || !table->maxlen)
  68                 return -ENOTDIR;
  69
  70         data = get_ipc(table);
  71         if (!data)
  72                 return -ENOTDIR;
  73
  74         if (oldval && oldlenp) {
  75                 if (get_user(len, oldlenp))
  76                         return -EFAULT;
  77                 if (len) {
  78                         if (len > table->maxlen)
  79                                 len = table->maxlen;
  80                         if (copy_to_user(oldval, data, len))
  81                                 return -EFAULT;
  82                         if (put_user(len, oldlenp))
  83                                 return -EFAULT;
  84                 }
  85         }
  86
  87         if (newval && newlen) {
  88                 if (newlen > table->maxlen)
  89                         newlen = table->maxlen;
  90
  91                 if (copy_from_user(data, newval, newlen))
  92                         return -EFAULT;
  93         }
  94         return 1;
  95 }
  96 #else
  97 #define sysctl_ipc_data NULL
  98 #endif
  99
 100 static struct ctl_table ipc_kern_table[] = {
 101         {
 102                 .ctl_name       = KERN_SHMMAX,
 103                 .procname       = "shmmax",
 104                 .data           = &init_ipc_ns.shm_ctlmax,
 105                 .maxlen         = sizeof (init_ipc_ns.shm_ctlmax),
 106                 .mode           = 0644,
 107                 .proc_handler   = proc_ipc_doulongvec_minmax,
 108                 .strategy       = sysctl_ipc_data,
 109         },
 110         {
 111                 .ctl_name       = KERN_SHMALL,
 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                 .strategy       = sysctl_ipc_data,
 118         },
 119         {
 120                 .ctl_name       = KERN_SHMMNI,
 121                 .procname       = "shmmni",
 122                 .data           = &init_ipc_ns.shm_ctlmni,
 123                 .maxlen         = sizeof (init_ipc_ns.shm_ctlmni),
 124                 .mode           = 0644,
 125                 .proc_handler   = proc_ipc_dointvec,
 126                 .strategy       = sysctl_ipc_data,
 127         },
 128         {
 129                 .ctl_name       = KERN_MSGMAX,
 130                 .procname       = "msgmax",
 131                 .data           = &init_ipc_ns.msg_ctlmax,
 132                 .maxlen         = sizeof (init_ipc_ns.msg_ctlmax),
 133                 .mode           = 0644,
 134                 .proc_handler   = proc_ipc_dointvec,
 135                 .strategy       = sysctl_ipc_data,
 136         },
 137         {
 138                 .ctl_name       = KERN_MSGMNI,
 139                 .procname       = "msgmni",
 140                 .data           = &init_ipc_ns.msg_ctlmni,
 141                 .maxlen         = sizeof (init_ipc_ns.msg_ctlmni),
 142                 .mode           = 0644,
 143                 .proc_handler   = proc_ipc_dointvec,
 144                 .strategy       = sysctl_ipc_data,
 145         },
 146         {
 147                 .ctl_name       = KERN_MSGMNB,
 148                 .procname       =  "msgmnb",
 149                 .data           = &init_ipc_ns.msg_ctlmnb,
 150                 .maxlen         = sizeof (init_ipc_ns.msg_ctlmnb),
 151                 .mode           = 0644,
 152                 .proc_handler   = proc_ipc_dointvec,
 153                 .strategy       = sysctl_ipc_data,
 154         },
 155         {
 156                 .ctl_name       = KERN_SEM,
 157                 .procname       = "sem",
 158                 .data           = &init_ipc_ns.sem_ctls,
 159                 .maxlen         = 4*sizeof (int),
 160                 .mode           = 0644,
 161                 .proc_handler   = proc_ipc_dointvec,
 162                 .strategy       = sysctl_ipc_data,
 163         },
 164         {}
 165 };
 166
 167 static struct ctl_table ipc_root_table[] = {
 168         {
 169                 .ctl_name       = CTL_KERN,
 170                 .procname       = "kernel",
 171                 .mode           = 0555,
 172                 .child          = ipc_kern_table,
 173         },
 174         {}
 175 };
 176
 177 static int __init ipc_sysctl_init(void)
 178 {
 179         register_sysctl_table(ipc_root_table);
 180         return 0;
 181 }
 182
 183 __initcall(ipc_sysctl_init);