net/ax25/ax25_uid.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   8  */
   9 #include <linux/errno.h>
  10 #include <linux/types.h>
  11 #include <linux/socket.h>
  12 #include <linux/in.h>
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/timer.h>
  16 #include <linux/string.h>
  17 #include <linux/sockios.h>
  18 #include <linux/net.h>
  19 #include <linux/spinlock.h>
  20 #include <net/ax25.h>
  21 #include <linux/inet.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/if_arp.h>
  24 #include <linux/skbuff.h>
  25 #include <net/sock.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/system.h>
  28 #include <linux/fcntl.h>
  29 #include <linux/mm.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/notifier.h>
  32 #include <linux/proc_fs.h>
  33 #include <linux/seq_file.h>
  34 #include <linux/stat.h>
  35 #include <linux/netfilter.h>
  36 #include <linux/sysctl.h>
  37 #include <net/ip.h>
  38 #include <net/arp.h>
  39
  40 /*
  41  *      Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
  42  */
  43
  44 static ax25_uid_assoc *ax25_uid_list;
  45 static DEFINE_RWLOCK(ax25_uid_lock);
  46
  47 int ax25_uid_policy = 0;
  48
  49 ax25_address *ax25_findbyuid(uid_t uid)
  50 {
  51         ax25_uid_assoc *ax25_uid;
  52         ax25_address *res = NULL;
  53
  54         read_lock(&ax25_uid_lock);
  55         for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
  56                 if (ax25_uid->uid == uid) {
  57                         res = &ax25_uid->call;
  58                         break;
  59                 }
  60         }
  61         read_unlock(&ax25_uid_lock);
  62
  63         return NULL;
  64 }
  65
  66 int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
  67 {
  68         ax25_uid_assoc *s, *ax25_uid;
  69         unsigned long res;
  70
  71         switch (cmd) {
  72         case SIOCAX25GETUID:
  73                 res = -ENOENT;
  74                 read_lock(&ax25_uid_lock);
  75                 for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
  76                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
  77                                 res = ax25_uid->uid;
  78                                 break;
  79                         }
  80                 }
  81                 read_unlock(&ax25_uid_lock);
  82
  83                 return res;
  84
  85         case SIOCAX25ADDUID:
  86                 if (!capable(CAP_NET_ADMIN))
  87                         return -EPERM;
  88                 if (ax25_findbyuid(sax->sax25_uid))
  89                         return -EEXIST;
  90                 if (sax->sax25_uid == 0)
  91                         return -EINVAL;
  92                 if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
  93                         return -ENOMEM;
  94
  95                 ax25_uid->uid  = sax->sax25_uid;
  96                 ax25_uid->call = sax->sax25_call;
  97
  98                 write_lock(&ax25_uid_lock);
  99                 ax25_uid->next = ax25_uid_list;
 100                 ax25_uid_list  = ax25_uid;
 101                 write_unlock(&ax25_uid_lock);
 102
 103                 return 0;
 104
 105         case SIOCAX25DELUID:
 106                 if (!capable(CAP_NET_ADMIN))
 107                         return -EPERM;
 108
 109                 write_lock(&ax25_uid_lock);
 110                 for (ax25_uid = ax25_uid_list; ax25_uid != NULL; ax25_uid = ax25_uid->next) {
 111                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
 112                                 break;
 113                         }
 114                 }
 115                 if (ax25_uid == NULL) {
 116                         write_unlock(&ax25_uid_lock);
 117                         return -ENOENT;
 118                 }
 119                 if ((s = ax25_uid_list) == ax25_uid) {
 120                         ax25_uid_list = s->next;
 121                         write_unlock(&ax25_uid_lock);
 122                         kfree(ax25_uid);
 123                         return 0;
 124                 }
 125                 while (s != NULL && s->next != NULL) {
 126                         if (s->next == ax25_uid) {
 127                                 s->next = ax25_uid->next;
 128                                 write_unlock(&ax25_uid_lock);
 129                                 kfree(ax25_uid);
 130                                 return 0;
 131                         }
 132                         s = s->next;
 133                 }
 134                 write_unlock(&ax25_uid_lock);
 135
 136                 return -ENOENT;
 137
 138         default:
 139                 return -EINVAL;
 140         }
 141
 142         return -EINVAL; /*NOTREACHED */
 143 }
 144
 145 #ifdef CONFIG_PROC_FS
 146
 147 static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
 148 {
 149         struct ax25_uid_assoc *pt;
 150         int i = 1;
 151
 152         read_lock(&ax25_uid_lock);
 153         if (*pos == 0)
 154                 return SEQ_START_TOKEN;
 155
 156         for (pt = ax25_uid_list; pt != NULL; pt = pt->next) {
 157                 if (i == *pos)
 158                         return pt;
 159                 ++i;
 160         }
 161         return NULL;
 162 }
 163
 164 static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 165 {
 166         ++*pos;
 167         return (v == SEQ_START_TOKEN) ? ax25_uid_list :
 168                 ((struct ax25_uid_assoc *) v)->next;
 169 }
 170
 171 static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
 172 {
 173         read_unlock(&ax25_uid_lock);
 174 }
 175
 176 static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 177 {
 178         if (v == SEQ_START_TOKEN)
 179                 seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 180         else {
 181                 struct ax25_uid_assoc *pt = v;
 182
 183
 184                 seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(&pt->call));
 185         }
 186         return 0;
 187 }
 188
 189 static struct seq_operations ax25_uid_seqops = {
 190         .start = ax25_uid_seq_start,
 191         .next = ax25_uid_seq_next,
 192         .stop = ax25_uid_seq_stop,
 193         .show = ax25_uid_seq_show,
 194 };
 195
 196 static int ax25_uid_info_open(struct inode *inode, struct file *file)
 197 {
 198         return seq_open(file, &ax25_uid_seqops);
 199 }
 200
 201 struct file_operations ax25_uid_fops = {
 202         .owner = THIS_MODULE,
 203         .open = ax25_uid_info_open,
 204         .read = seq_read,
 205         .llseek = seq_lseek,
 206         .release = seq_release,
 207 };
 208
 209 #endif
 210
 211 /*
 212  *      Free all memory associated with UID/Callsign structures.
 213  */
 214 void __exit ax25_uid_free(void)
 215 {
 216         ax25_uid_assoc *s, *ax25_uid;
 217
 218         write_lock(&ax25_uid_lock);
 219         ax25_uid = ax25_uid_list;
 220         while (ax25_uid != NULL) {
 221                 s        = ax25_uid;
 222                 ax25_uid = ax25_uid->next;
 223
 224                 kfree(s);
 225         }
 226         ax25_uid_list = NULL;
 227         write_unlock(&ax25_uid_lock);
 228 }