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/list.h>
  32 #include <linux/notifier.h>
  33 #include <linux/proc_fs.h>
  34 #include <linux/seq_file.h>
  35 #include <linux/stat.h>
  36 #include <linux/netfilter.h>
  37 #include <linux/sysctl.h>
  38 #include <net/ip.h>
  39 #include <net/arp.h>
  40
  41 /*
  42  *      Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
  43  */
  44
  45 HLIST_HEAD(ax25_uid_list);
  46 static DEFINE_RWLOCK(ax25_uid_lock);
  47
  48 int ax25_uid_policy = 0;
  49
  50 ax25_uid_assoc *ax25_findbyuid(uid_t uid)
  51 {
  52         ax25_uid_assoc *ax25_uid, *res = NULL;
  53         struct hlist_node *node;
  54
  55         read_lock(&ax25_uid_lock);
  56         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  57                 if (ax25_uid->uid == uid) {
  58                         ax25_uid_hold(ax25_uid);
  59                         res = ax25_uid;
  60                         break;
  61                 }
  62         }
  63         read_unlock(&ax25_uid_lock);
  64
  65         return res;
  66 }
  67
  68 int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
  69 {
  70         ax25_uid_assoc *ax25_uid;
  71         struct hlist_node *node;
  72         ax25_uid_assoc *user;
  73         unsigned long res;
  74
  75         switch (cmd) {
  76         case SIOCAX25GETUID:
  77                 res = -ENOENT;
  78                 read_lock(&ax25_uid_lock);
  79                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  80                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
  81                                 res = ax25_uid->uid;
  82                                 break;
  83                         }
  84                 }
  85                 read_unlock(&ax25_uid_lock);
  86
  87                 return res;
  88
  89         case SIOCAX25ADDUID:
  90                 if (!capable(CAP_NET_ADMIN))
  91                         return -EPERM;
  92                 user = ax25_findbyuid(sax->sax25_uid);
  93                 if (user) {
  94                         ax25_uid_put(user);
  95                         return -EEXIST;
  96                 }
  97                 if (sax->sax25_uid == 0)
  98                         return -EINVAL;
  99                 if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
 100                         return -ENOMEM;
 101
 102                 atomic_set(&ax25_uid->refcount, 1);
 103                 ax25_uid->uid  = sax->sax25_uid;
 104                 ax25_uid->call = sax->sax25_call;
 105
 106                 write_lock(&ax25_uid_lock);
 107                 hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
 108                 write_unlock(&ax25_uid_lock);
 109
 110                 return 0;
 111
 112         case SIOCAX25DELUID:
 113                 if (!capable(CAP_NET_ADMIN))
 114                         return -EPERM;
 115
 116                 ax25_uid = NULL;
 117                 write_lock(&ax25_uid_lock);
 118                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 119                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
 120                                 break;
 121                 }
 122                 if (ax25_uid == NULL) {
 123                         write_unlock(&ax25_uid_lock);
 124                         return -ENOENT;
 125                 }
 126                 hlist_del_init(&ax25_uid->uid_node);
 127                 ax25_uid_put(ax25_uid);
 128                 write_unlock(&ax25_uid_lock);
 129
 130                 return 0;
 131
 132         default:
 133                 return -EINVAL;
 134         }
 135
 136         return -EINVAL; /*NOTREACHED */
 137 }
 138
 139 #ifdef CONFIG_PROC_FS
 140
 141 static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
 142 {
 143         struct ax25_uid_assoc *pt;
 144         struct hlist_node *node;
 145         int i = 0;
 146
 147         read_lock(&ax25_uid_lock);
 148         ax25_uid_for_each(pt, node, &ax25_uid_list) {
 149                 if (i == *pos)
 150                         return pt;
 151                 ++i;
 152         }
 153         return NULL;
 154 }
 155
 156 static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 157 {
 158         ++*pos;
 159
 160         return hlist_entry(((ax25_uid_assoc *)v)->uid_node.next,
 161                            ax25_uid_assoc, uid_node);
 162 }
 163
 164 static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
 165 {
 166         read_unlock(&ax25_uid_lock);
 167 }
 168
 169 static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 170 {
 171         char buf[11];
 172
 173         if (v == SEQ_START_TOKEN)
 174                 seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 175         else {
 176                 struct ax25_uid_assoc *pt = v;
 177
 178                 seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(buf, &pt->call));
 179         }
 180         return 0;
 181 }
 182
 183 static struct seq_operations ax25_uid_seqops = {
 184         .start = ax25_uid_seq_start,
 185         .next = ax25_uid_seq_next,
 186         .stop = ax25_uid_seq_stop,
 187         .show = ax25_uid_seq_show,
 188 };
 189
 190 static int ax25_uid_info_open(struct inode *inode, struct file *file)
 191 {
 192         return seq_open(file, &ax25_uid_seqops);
 193 }
 194
 195 struct file_operations ax25_uid_fops = {
 196         .owner = THIS_MODULE,
 197         .open = ax25_uid_info_open,
 198         .read = seq_read,
 199         .llseek = seq_lseek,
 200         .release = seq_release,
 201 };
 202
 203 #endif
 204
 205 /*
 206  *      Free all memory associated with UID/Callsign structures.
 207  */
 208 void __exit ax25_uid_free(void)
 209 {
 210         ax25_uid_assoc *ax25_uid;
 211         struct hlist_node *node;
 212
 213         write_lock(&ax25_uid_lock);
 214         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 215                 hlist_del_init(&ax25_uid->uid_node);
 216                 ax25_uid_put(ax25_uid);
 217         }
 218         write_unlock(&ax25_uid_lock);
 219 }