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 <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 static HLIST_HEAD(ax25_uid_list);
  48 static DEFINE_RWLOCK(ax25_uid_lock);
  49
  50 int ax25_uid_policy;
  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         __acquires(ax25_uid_lock)
 149 {
 150         read_lock(&ax25_uid_lock);
 151         return seq_hlist_start_head(&ax25_uid_list, *pos);
 152 }
 153
 154 static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 155 {
 156         return seq_hlist_next(v, &ax25_uid_list, pos);
 157 }
 158
 159 static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
 160         __releases(ax25_uid_lock)
 161 {
 162         read_unlock(&ax25_uid_lock);
 163 }
 164
 165 static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 166 {
 167         char buf[11];
 168
 169         if (v == SEQ_START_TOKEN)
 170                 seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 171         else {
 172                 struct ax25_uid_assoc *pt;
 173
 174                 pt = hlist_entry(v, struct ax25_uid_assoc, uid_node);
 175                 seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(buf, &pt->call));
 176         }
 177         return 0;
 178 }
 179
 180 static const struct seq_operations ax25_uid_seqops = {
 181         .start = ax25_uid_seq_start,
 182         .next = ax25_uid_seq_next,
 183         .stop = ax25_uid_seq_stop,
 184         .show = ax25_uid_seq_show,
 185 };
 186
 187 static int ax25_uid_info_open(struct inode *inode, struct file *file)
 188 {
 189         return seq_open(file, &ax25_uid_seqops);
 190 }
 191
 192 const struct file_operations ax25_uid_fops = {
 193         .owner = THIS_MODULE,
 194         .open = ax25_uid_info_open,
 195         .read = seq_read,
 196         .llseek = seq_lseek,
 197         .release = seq_release,
 198 };
 199
 200 #endif
 201
 202 /*
 203  *      Free all memory associated with UID/Callsign structures.
 204  */
 205 void __exit ax25_uid_free(void)
 206 {
 207         ax25_uid_assoc *ax25_uid;
 208         struct hlist_node *node;
 209
 210         write_lock(&ax25_uid_lock);
 211 again:
 212         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 213                 hlist_del_init(&ax25_uid->uid_node);
 214                 ax25_uid_put(ax25_uid);
 215                 goto again;
 216         }
 217         write_unlock(&ax25_uid_lock);
 218 }