net/ax25/ax25_uid.c

   1 /*
   2  *      AX.25 release 037
   3  *
   4  *      This code REQUIRES 2.1.15 or higher/ NET3.038
   5  *
   6  *      This module:
   7  *              This module is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              as published by the Free Software Foundation; either version
  10  *              2 of the License, or (at your option) any later version.
  11  *
  12  *      History
  13  *      AX.25 036       Jonathan(G4KLX) Split from af_ax25.c.
  14  */
  15
  16 #include <linux/errno.h>
  17 #include <linux/types.h>
  18 #include <linux/socket.h>
  19 #include <linux/in.h>
  20 #include <linux/kernel.h>
  21 #include <linux/sched.h>
  22 #include <linux/timer.h>
  23 #include <linux/string.h>
  24 #include <linux/sockios.h>
  25 #include <linux/net.h>
  26 #include <net/ax25.h>
  27 #include <linux/inet.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/if_arp.h>
  30 #include <linux/skbuff.h>
  31 #include <net/sock.h>
  32 #include <asm/uaccess.h>
  33 #include <asm/system.h>
  34 #include <linux/fcntl.h>
  35 #include <linux/mm.h>
  36 #include <linux/interrupt.h>
  37 #include <linux/notifier.h>
  38 #include <linux/proc_fs.h>
  39 #include <linux/stat.h>
  40 #include <linux/netfilter.h>
  41 #include <linux/sysctl.h>
  42 #include <net/ip.h>
  43 #include <net/arp.h>
  44
  45 /*
  46  *      Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
  47  */
  48
  49 static ax25_uid_assoc *ax25_uid_list;
  50
  51 int ax25_uid_policy = 0;
  52
  53 ax25_address *ax25_findbyuid(uid_t uid)
  54 {
  55         ax25_uid_assoc *ax25_uid;
  56
  57         for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
  58                 if (ax25_uid->uid == uid)
  59                         return &ax25_uid->call;
  60         }
  61
  62         return NULL;
  63 }
  64
  65 int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
  66 {
  67         ax25_uid_assoc *s, *ax25_uid;
  68         unsigned long flags;
  69
  70         switch (cmd) {
  71                 case SIOCAX25GETUID:
  72                         for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
  73                                 if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
  74                                         return ax25_uid->uid;
  75                         }
  76                         return -ENOENT;
  77
  78                 case SIOCAX25ADDUID:
  79                         if (!capable(CAP_NET_ADMIN))
  80                                 return -EPERM;
  81                         if (ax25_findbyuid(sax->sax25_uid))
  82                                 return -EEXIST;
  83                         if (sax->sax25_uid == 0)
  84                                 return -EINVAL;
  85                         if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
  86                                 return -ENOMEM;
  87                         ax25_uid->uid  = sax->sax25_uid;
  88                         ax25_uid->call = sax->sax25_call;
  89                         save_flags(flags); cli();
  90                         ax25_uid->next = ax25_uid_list;
  91                         ax25_uid_list  = ax25_uid;
  92                         restore_flags(flags);
  93                         return 0;
  94
  95                 case SIOCAX25DELUID:
  96                         if (!capable(CAP_NET_ADMIN))
  97                                 return -EPERM;
  98                         for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
  99                                 if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
 100                                         break;
 101                         }
 102                         if (ax25_uid == NULL)
 103                                 return -ENOENT;
 104                         save_flags(flags); cli();
 105                         if ((s = ax25_uid_list) == ax25_uid) {
 106                                 ax25_uid_list = s->next;
 107                                 restore_flags(flags);
 108                                 kfree(ax25_uid);
 109                                 return 0;
 110                         }
 111                         while (s != NULL && s->next != NULL) {
 112                                 if (s->next == ax25_uid) {
 113                                         s->next = ax25_uid->next;
 114                                         restore_flags(flags);
 115                                         kfree(ax25_uid);
 116                                         return 0;
 117                                 }
 118                                 s = s->next;
 119                         }
 120                         restore_flags(flags);
 121                         return -ENOENT;
 122
 123                 default:
 124                         return -EINVAL;
 125         }
 126
 127         return -EINVAL; /*NOTREACHED */
 128 }
 129
 130 int ax25_uid_get_info(char *buffer, char **start, off_t offset, int length)
 131 {
 132         ax25_uid_assoc *pt;
 133         int len     = 0;
 134         off_t pos   = 0;
 135         off_t begin = 0;
 136
 137         cli();
 138
 139         len += sprintf(buffer, "Policy: %d\n", ax25_uid_policy);
 140
 141         for (pt = ax25_uid_list; pt != NULL; pt = pt->next) {
 142                 len += sprintf(buffer + len, "%6d %s\n", pt->uid, ax2asc(&pt->call));
 143
 144                 pos = begin + len;
 145
 146                 if (pos < offset) {
 147                         len = 0;
 148                         begin = pos;
 149                 }
 150
 151                 if (pos > offset + length)
 152                         break;
 153         }
 154
 155         sti();
 156
 157         *start = buffer + (offset - begin);
 158         len   -= offset - begin;
 159
 160         if (len > length) len = length;
 161
 162         return len;
 163 }
 164
 165 /*
 166  *      Free all memory associated with UID/Callsign structures.
 167  */
 168 void __exit ax25_uid_free(void)
 169 {
 170         ax25_uid_assoc *s, *ax25_uid = ax25_uid_list;
 171
 172         while (ax25_uid != NULL) {
 173                 s        = ax25_uid;
 174                 ax25_uid = ax25_uid->next;
 175
 176                 kfree(s);
 177         }
 178 }