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/sched.h>
  17 #include <linux/timer.h>
  18 #include <linux/string.h>
  19 #include <linux/sockios.h>
  20 #include <linux/net.h>
  21 #include <linux/spinlock.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 <net/ip.h>
  41 #include <net/arp.h>
  42
  43 /*
  44  *      Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
  45  */
  46
  47 HLIST_HEAD(ax25_uid_list);
  48 static DEFINE_RWLOCK(ax25_uid_lock);
  49
  50 int ax25_uid_policy = 0;
  51
  52 EXPORT_SYMBOL(ax25_uid_policy);
  53
  54 ax25_uid_assoc *ax25_findbyuid(uid_t uid)
  55 {
  56         ax25_uid_assoc *ax25_uid, *res = NULL;
  57         struct hlist_node *node;
  58
  59         read_lock(&ax25_uid_lock);
  60         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  61                 if (ax25_uid->uid == uid) {
  62                         ax25_uid_hold(ax25_uid);
  63                         res = ax25_uid;
  64                         break;
  65                 }
  66         }
  67         read_unlock(&ax25_uid_lock);
  68
  69         return res;
  70 }
  71
  72 EXPORT_SYMBOL(ax25_findbyuid);
  73
  74 int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
  75 {
  76         ax25_uid_assoc *ax25_uid;
  77         struct hlist_node *node;
  78         ax25_uid_assoc *user;
  79         unsigned long res;
  80
  81         switch (cmd) {
  82         case SIOCAX25GETUID:
  83                 res = -ENOENT;
  84                 read_lock(&ax25_uid_lock);
  85                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  86                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
  87                                 res = ax25_uid->uid;
  88                                 break;
  89                         }
  90                 }
  91                 read_unlock(&ax25_uid_lock);
  92
  93                 return res;
  94
  95         case SIOCAX25ADDUID:
  96                 if (!capable(CAP_NET_ADMIN))
  97                         return -EPERM;
  98                 user = ax25_findbyuid(sax->sax25_uid);
  99                 if (user) {
 100                         ax25_uid_put(user);
 101                         return -EEXIST;
 102                 }
 103                 if (sax->sax25_uid == 0)
 104                         return -EINVAL;
 105                 if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
 106                         return -ENOMEM;
 107
 108                 atomic_set(&ax25_uid->refcount, 1);
 109                 ax25_uid->uid  = sax->sax25_uid;
 110                 ax25_uid->call = sax->sax25_call;
 111
 112                 write_lock(&ax25_uid_lock);
 113                 hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
 114                 write_unlock(&ax25_uid_lock);
 115
 116                 return 0;
 117
 118         case SIOCAX25DELUID:
 119                 if (!capable(CAP_NET_ADMIN))
 120                         return -EPERM;
 121
 122                 ax25_uid = NULL;
 123                 write_lock(&ax25_uid_lock);
 124                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 125                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
 126                                 break;
 127                 }
 128                 if (ax25_uid == NULL) {
 129                         write_unlock(&ax25_uid_lock);
 130                         return -ENOENT;
 131                 }
 132                 hlist_del_init(&ax25_uid->uid_node);
 133                 ax25_uid_put(ax25_uid);
 134                 write_unlock(&ax25_uid_lock);
 135
 136                 return 0;
 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         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 {
 172         read_unlock(&ax25_uid_lock);
 173 }
 174
 175 static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 176 {
 177         char buf[11];
 178
 179         if (v == SEQ_START_TOKEN)
 180                 seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 181         else {
 182                 struct ax25_uid_assoc *pt = v;
 183
 184                 seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(buf, &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 *ax25_uid;
 217         struct hlist_node *node;
 218
 219         write_lock(&ax25_uid_lock);
 220         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 221                 hlist_del_init(&ax25_uid->uid_node);
 222                 ax25_uid_put(ax25_uid);
 223         }
 224         write_unlock(&ax25_uid_lock);
 225 }