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 <net/ax25.h>
  22 #include <linux/inet.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/if_arp.h>
  25 #include <linux/skbuff.h>
  26 #include <net/sock.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/system.h>
  29 #include <linux/fcntl.h>
  30 #include <linux/mm.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/list.h>
  33 #include <linux/notifier.h>
  34 #include <linux/proc_fs.h>
  35 #include <linux/seq_file.h>
  36 #include <linux/stat.h>
  37 #include <linux/netfilter.h>
  38 #include <linux/sysctl.h>
  39 #include <net/ip.h>
  40 #include <net/arp.h>
  41
  42 /*
  43  *      Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
  44  */
  45
  46 static HLIST_HEAD(ax25_uid_list);
  47 static DEFINE_RWLOCK(ax25_uid_lock);
  48
  49 int ax25_uid_policy;
  50
  51 EXPORT_SYMBOL(ax25_uid_policy);
  52
  53 ax25_uid_assoc *ax25_findbyuid(uid_t uid)
  54 {
  55         ax25_uid_assoc *ax25_uid, *res = NULL;
  56         struct hlist_node *node;
  57
  58         read_lock(&ax25_uid_lock);
  59         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  60                 if (ax25_uid->uid == uid) {
  61                         ax25_uid_hold(ax25_uid);
  62                         res = ax25_uid;
  63                         break;
  64                 }
  65         }
  66         read_unlock(&ax25_uid_lock);
  67
  68         return res;
  69 }
  70
  71 EXPORT_SYMBOL(ax25_findbyuid);
  72
  73 int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
  74 {
  75         ax25_uid_assoc *ax25_uid;
  76         struct hlist_node *node;
  77         ax25_uid_assoc *user;
  78         unsigned long res;
  79
  80         switch (cmd) {
  81         case SIOCAX25GETUID:
  82                 res = -ENOENT;
  83                 read_lock(&ax25_uid_lock);
  84                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  85                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
  86                                 res = ax25_uid->uid;
  87                                 break;
  88                         }
  89                 }
  90                 read_unlock(&ax25_uid_lock);
  91
  92                 return res;
  93
  94         case SIOCAX25ADDUID:
  95                 if (!capable(CAP_NET_ADMIN))
  96                         return -EPERM;
  97                 user = ax25_findbyuid(sax->sax25_uid);
  98                 if (user) {
  99                         ax25_uid_put(user);
 100                         return -EEXIST;
 101                 }
 102                 if (sax->sax25_uid == 0)
 103                         return -EINVAL;
 104                 if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
 105                         return -ENOMEM;
 106
 107                 atomic_set(&ax25_uid->refcount, 1);
 108                 ax25_uid->uid  = sax->sax25_uid;
 109                 ax25_uid->call = sax->sax25_call;
 110
 111                 write_lock(&ax25_uid_lock);
 112                 hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
 113                 write_unlock(&ax25_uid_lock);
 114
 115                 return 0;
 116
 117         case SIOCAX25DELUID:
 118                 if (!capable(CAP_NET_ADMIN))
 119                         return -EPERM;
 120
 121                 ax25_uid = NULL;
 122                 write_lock(&ax25_uid_lock);
 123                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 124                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
 125                                 break;
 126                 }
 127                 if (ax25_uid == NULL) {
 128                         write_unlock(&ax25_uid_lock);
 129                         return -ENOENT;
 130                 }
 131                 hlist_del_init(&ax25_uid->uid_node);
 132                 ax25_uid_put(ax25_uid);
 133                 write_unlock(&ax25_uid_lock);
 134
 135                 return 0;
 136
 137         default:
 138                 return -EINVAL;
 139         }
 140
 141         return -EINVAL; /*NOTREACHED */
 142 }
 143
 144 #ifdef CONFIG_PROC_FS
 145
 146 static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
 147         __acquires(ax25_uid_lock)
 148 {
 149         struct ax25_uid_assoc *pt;
 150         struct hlist_node *node;
 151         int i = 0;
 152
 153         read_lock(&ax25_uid_lock);
 154         ax25_uid_for_each(pt, node, &ax25_uid_list) {
 155                 if (i == *pos)
 156                         return pt;
 157                 ++i;
 158         }
 159         return NULL;
 160 }
 161
 162 static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 163 {
 164         ++*pos;
 165
 166         return hlist_entry(((ax25_uid_assoc *)v)->uid_node.next,
 167                            ax25_uid_assoc, uid_node);
 168 }
 169
 170 static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
 171         __releases(ax25_uid_lock)
 172 {
 173         read_unlock(&ax25_uid_lock);
 174 }
 175
 176 static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 177 {
 178         char buf[11];
 179
 180         if (v == SEQ_START_TOKEN)
 181                 seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 182         else {
 183                 struct ax25_uid_assoc *pt = v;
 184
 185                 seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(buf, &pt->call));
 186         }
 187         return 0;
 188 }
 189
 190 static const struct seq_operations ax25_uid_seqops = {
 191         .start = ax25_uid_seq_start,
 192         .next = ax25_uid_seq_next,
 193         .stop = ax25_uid_seq_stop,
 194         .show = ax25_uid_seq_show,
 195 };
 196
 197 static int ax25_uid_info_open(struct inode *inode, struct file *file)
 198 {
 199         return seq_open(file, &ax25_uid_seqops);
 200 }
 201
 202 const struct file_operations ax25_uid_fops = {
 203         .owner = THIS_MODULE,
 204         .open = ax25_uid_info_open,
 205         .read = seq_read,
 206         .llseek = seq_lseek,
 207         .release = seq_release,
 208 };
 209
 210 #endif
 211
 212 /*
 213  *      Free all memory associated with UID/Callsign structures.
 214  */
 215 void __exit ax25_uid_free(void)
 216 {
 217         ax25_uid_assoc *ax25_uid;
 218         struct hlist_node *node;
 219
 220         write_lock(&ax25_uid_lock);
 221 again:
 222         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 223                 hlist_del_init(&ax25_uid->uid_node);
 224                 ax25_uid_put(ax25_uid);
 225                 goto again;
 226         }
 227         write_unlock(&ax25_uid_lock);
 228 }