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 ax25_uid_assoc *ax25_findbyuid(uid_t uid)
  53 {
  54         ax25_uid_assoc *ax25_uid, *res = NULL;
  55         struct hlist_node *node;
  56
  57         read_lock(&ax25_uid_lock);
  58         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  59                 if (ax25_uid->uid == uid) {
  60                         ax25_uid_hold(ax25_uid);
  61                         res = ax25_uid;
  62                         break;
  63                 }
  64         }
  65         read_unlock(&ax25_uid_lock);
  66
  67         return res;
  68 }
  69
  70 int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
  71 {
  72         ax25_uid_assoc *ax25_uid;
  73         struct hlist_node *node;
  74         ax25_uid_assoc *user;
  75         unsigned long res;
  76
  77         switch (cmd) {
  78         case SIOCAX25GETUID:
  79                 res = -ENOENT;
  80                 read_lock(&ax25_uid_lock);
  81                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
  82                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
  83                                 res = ax25_uid->uid;
  84                                 break;
  85                         }
  86                 }
  87                 read_unlock(&ax25_uid_lock);
  88
  89                 return res;
  90
  91         case SIOCAX25ADDUID:
  92                 if (!capable(CAP_NET_ADMIN))
  93                         return -EPERM;
  94                 user = ax25_findbyuid(sax->sax25_uid);
  95                 if (user) {
  96                         ax25_uid_put(user);
  97                         return -EEXIST;
  98                 }
  99                 if (sax->sax25_uid == 0)
 100                         return -EINVAL;
 101                 if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
 102                         return -ENOMEM;
 103
 104                 atomic_set(&ax25_uid->refcount, 1);
 105                 ax25_uid->uid  = sax->sax25_uid;
 106                 ax25_uid->call = sax->sax25_call;
 107
 108                 write_lock(&ax25_uid_lock);
 109                 hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
 110                 write_unlock(&ax25_uid_lock);
 111
 112                 return 0;
 113
 114         case SIOCAX25DELUID:
 115                 if (!capable(CAP_NET_ADMIN))
 116                         return -EPERM;
 117
 118                 ax25_uid = NULL;
 119                 write_lock(&ax25_uid_lock);
 120                 ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 121                         if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
 122                                 break;
 123                 }
 124                 if (ax25_uid == NULL) {
 125                         write_unlock(&ax25_uid_lock);
 126                         return -ENOENT;
 127                 }
 128                 hlist_del_init(&ax25_uid->uid_node);
 129                 ax25_uid_put(ax25_uid);
 130                 write_unlock(&ax25_uid_lock);
 131
 132                 return 0;
 133
 134         default:
 135                 return -EINVAL;
 136         }
 137
 138         return -EINVAL; /*NOTREACHED */
 139 }
 140
 141 #ifdef CONFIG_PROC_FS
 142
 143 static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
 144 {
 145         struct ax25_uid_assoc *pt;
 146         struct hlist_node *node;
 147         int i = 0;
 148
 149         read_lock(&ax25_uid_lock);
 150         ax25_uid_for_each(pt, node, &ax25_uid_list) {
 151                 if (i == *pos)
 152                         return pt;
 153                 ++i;
 154         }
 155         return NULL;
 156 }
 157
 158 static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 159 {
 160         ++*pos;
 161
 162         return hlist_entry(((ax25_uid_assoc *)v)->uid_node.next,
 163                            ax25_uid_assoc, uid_node);
 164 }
 165
 166 static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
 167 {
 168         read_unlock(&ax25_uid_lock);
 169 }
 170
 171 static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 172 {
 173         char buf[11];
 174
 175         if (v == SEQ_START_TOKEN)
 176                 seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 177         else {
 178                 struct ax25_uid_assoc *pt = v;
 179
 180                 seq_printf(seq, "%6d %s\n", pt->uid, ax2asc(buf, &pt->call));
 181         }
 182         return 0;
 183 }
 184
 185 static struct seq_operations ax25_uid_seqops = {
 186         .start = ax25_uid_seq_start,
 187         .next = ax25_uid_seq_next,
 188         .stop = ax25_uid_seq_stop,
 189         .show = ax25_uid_seq_show,
 190 };
 191
 192 static int ax25_uid_info_open(struct inode *inode, struct file *file)
 193 {
 194         return seq_open(file, &ax25_uid_seqops);
 195 }
 196
 197 struct file_operations ax25_uid_fops = {
 198         .owner = THIS_MODULE,
 199         .open = ax25_uid_info_open,
 200         .read = seq_read,
 201         .llseek = seq_lseek,
 202         .release = seq_release,
 203 };
 204
 205 #endif
 206
 207 /*
 208  *      Free all memory associated with UID/Callsign structures.
 209  */
 210 void __exit ax25_uid_free(void)
 211 {
 212         ax25_uid_assoc *ax25_uid;
 213         struct hlist_node *node;
 214
 215         write_lock(&ax25_uid_lock);
 216         ax25_uid_for_each(ax25_uid, node, &ax25_uid_list) {
 217                 hlist_del_init(&ax25_uid->uid_node);
 218                 ax25_uid_put(ax25_uid);
 219         }
 220         write_unlock(&ax25_uid_lock);
 221 }