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
  10 #include <linux/capability.h>
  11 #include <linux/errno.h>
  12 #include <linux/types.h>
  13 #include <linux/socket.h>
  14 #include <linux/in.h>
  15 #include <linux/kernel.h>
  16 #include <linux/timer.h>
  17 #include <linux/string.h>
  18 #include <linux/sockios.h>
  19 #include <linux/net.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/slab.h>
  22 #include <net/ax25.h>
  23 #include <linux/inet.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/if_arp.h>
  26 #include <linux/skbuff.h>
  27 #include <net/sock.h>
  28 #include <asm/uaccess.h>
  29 #include <asm/system.h>
  30 #include <linux/fcntl.h>
  31 #include <linux/mm.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/list.h>
  34 #include <linux/notifier.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/seq_file.h>
  37 #include <linux/stat.h>
  38 #include <linux/netfilter.h>
  39 #include <linux/sysctl.h>
  40 #include <linux/export.h>
  41 #include <net/ip.h>
  42 #include <net/arp.h>
  43
  44 /*
  45  *      Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
  46  */
  47
  48 static HLIST_HEAD(ax25_uid_list);
  49 static DEFINE_RWLOCK(ax25_uid_lock);
  50
  51 int ax25_uid_policy;
  52
  53 EXPORT_SYMBOL(ax25_uid_policy);
  54
  55 ax25_uid_assoc *ax25_findbyuid(uid_t uid)
  56 {
  57         ax25_uid_assoc *ax25_uid, *res = NULL;
  58         struct hlist_node *node;
  59
  60         read_lock(&ax25_uid_lock);
  61         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  62                 if (ax25_uid->uid == uid) {
  63                         ax25_uid_hold(ax25_uid);
  64                         res = ax25_uid;
  65                         break;
  66                 }
  67         }
  68         read_unlock(&ax25_uid_lock);
  69
  70         return res;
  71 }
  72
  73 EXPORT_SYMBOL(ax25_findbyuid);
  74
  75 int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
  76 {
  77         ax25_uid_assoc *ax25_uid;
  78         struct hlist_node *node;
  79         ax25_uid_assoc *user;
  80         unsigned long res;
  81
  82         switch (cmd) {
  83         case SIOCAX25GETUID:
  84                 res = -ENOENT;
  85                 read_lock(&ax25_uid_lock);
  86                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  87                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
  88                                 res = ax25_uid->uid;
  89                                 break;
  90                         }
  91                 }
  92                 read_unlock(&ax25_uid_lock);
  93
  94                 return res;
  95
  96         case SIOCAX25ADDUID:
  97                 if (!capable(CAP_NET_ADMIN))
  98                         return -EPERM;
  99                 user = ax25_findbyuid(sax->sax25_uid);
 100                 if (user) {
 101                         ax25_uid_put(user);
 102                         return -EEXIST;
 103                 }
 104                 if (sax->sax25_uid == 0)
 105                         return -EINVAL;
 106                 if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
 107                         return -ENOMEM;
 108
 109                 atomic_set(&ax25_uid->refcount, 1);
 110                 ax25_uid->uid  = sax->sax25_uid;
 111                 ax25_uid->call = sax->sax25_call;
 112
 113                 write_lock(&ax25_uid_lock);
 114                 hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
 115                 write_unlock(&ax25_uid_lock);
 116
 117                 return 0;
 118
 119         case SIOCAX25DELUID:
 120                 if (!capable(CAP_NET_ADMIN))
 121                         return -EPERM;
 122
 123                 ax25_uid = NULL;
 124                 write_lock(&ax25_uid_lock);
 125                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 126                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
 127                                 break;
 128                 }
 129                 if (ax25_uid == NULL) {
 130                         write_unlock(&ax25_uid_lock);
 131                         return -ENOENT;
 132                 }
 133                 hlist_del_init(&ax25_uid->uid_node);
 134                 ax25_uid_put(ax25_uid);
 135                 write_unlock(&ax25_uid_lock);
 136
 137                 return 0;
 138
 139         default:
 140                 return -EINVAL;
 141         }
 142
 143         return -EINVAL; /*NOTREACHED */
 144 }
 145
 146 #ifdef CONFIG_PROC_FS
 147
 148 static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
 149         __acquires(ax25_uid_lock)
 150 {
 151         read_lock(&ax25_uid_lock);
 152         return seq_hlist_start_head(&ax25_uid_list, *pos);
 153 }
 154
 155 static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 156 {
 157         return seq_hlist_next(v, &ax25_uid_list, pos);
 158 }
 159
 160 static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
 161         __releases(ax25_uid_lock)
 162 {
 163         read_unlock(&ax25_uid_lock);
 164 }
 165
 166 static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 167 {
 168         char buf[11];
 169
 170         if (v == SEQ_START_TOKEN)
 171                 seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 172         else {
 173                 struct ax25_uid_assoc *pt;
 174
 175                 pt = hlist_entry(v, struct ax25_uid_assoc, uid_node);
 176                 seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(buf, &pt->call));
 177         }
 178         return 0;
 179 }
 180
 181 static const struct seq_operations ax25_uid_seqops = {
 182         .start = ax25_uid_seq_start,
 183         .next = ax25_uid_seq_next,
 184         .stop = ax25_uid_seq_stop,
 185         .show = ax25_uid_seq_show,
 186 };
 187
 188 static int ax25_uid_info_open(struct inode *inode, struct file *file)
 189 {
 190         return seq_open(file, &ax25_uid_seqops);
 191 }
 192
 193 const struct file_operations ax25_uid_fops = {
 194         .owner = THIS_MODULE,
 195         .open = ax25_uid_info_open,
 196         .read = seq_read,
 197         .llseek = seq_lseek,
 198         .release = seq_release,
 199 };
 200
 201 #endif
 202
 203 /*
 204  *      Free all memory associated with UID/Callsign structures.
 205  */
 206 void __exit ax25_uid_free(void)
 207 {
 208         ax25_uid_assoc *ax25_uid;
 209         struct hlist_node *node;
 210
 211         write_lock(&ax25_uid_lock);
 212 again:
 213         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 214                 hlist_del_init(&ax25_uid->uid_node);
 215                 ax25_uid_put(ax25_uid);
 216                 goto again;
 217         }
 218         write_unlock(&ax25_uid_lock);
 219 }