linux/net/ax25/ax25_uid.c
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   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 <linux/uaccess.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/sysctl.h>
  38#include <linux/export.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
  46static HLIST_HEAD(ax25_uid_list);
  47static DEFINE_RWLOCK(ax25_uid_lock);
  48
  49int ax25_uid_policy;
  50
  51EXPORT_SYMBOL(ax25_uid_policy);
  52
  53ax25_uid_assoc *ax25_findbyuid(kuid_t uid)
  54{
  55        ax25_uid_assoc *ax25_uid, *res = NULL;
  56
  57        read_lock(&ax25_uid_lock);
  58        ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
  59                if (uid_eq(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
  70EXPORT_SYMBOL(ax25_findbyuid);
  71
  72int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
  73{
  74        ax25_uid_assoc *ax25_uid;
  75        ax25_uid_assoc *user;
  76        unsigned long res;
  77
  78        switch (cmd) {
  79        case SIOCAX25GETUID:
  80                res = -ENOENT;
  81                read_lock(&ax25_uid_lock);
  82                ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
  83                        if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
  84                                res = from_kuid_munged(current_user_ns(), ax25_uid->uid);
  85                                break;
  86                        }
  87                }
  88                read_unlock(&ax25_uid_lock);
  89
  90                return res;
  91
  92        case SIOCAX25ADDUID:
  93        {
  94                kuid_t sax25_kuid;
  95                if (!capable(CAP_NET_ADMIN))
  96                        return -EPERM;
  97                sax25_kuid = make_kuid(current_user_ns(), sax->sax25_uid);
  98                if (!uid_valid(sax25_kuid))
  99                        return -EINVAL;
 100                user = ax25_findbyuid(sax25_kuid);
 101                if (user) {
 102                        ax25_uid_put(user);
 103                        return -EEXIST;
 104                }
 105                if (sax->sax25_uid == 0)
 106                        return -EINVAL;
 107                if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
 108                        return -ENOMEM;
 109
 110                refcount_set(&ax25_uid->refcount, 1);
 111                ax25_uid->uid  = sax25_kuid;
 112                ax25_uid->call = sax->sax25_call;
 113
 114                write_lock(&ax25_uid_lock);
 115                hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
 116                write_unlock(&ax25_uid_lock);
 117
 118                return 0;
 119        }
 120        case SIOCAX25DELUID:
 121                if (!capable(CAP_NET_ADMIN))
 122                        return -EPERM;
 123
 124                ax25_uid = NULL;
 125                write_lock(&ax25_uid_lock);
 126                ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
 127                        if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
 128                                break;
 129                }
 130                if (ax25_uid == NULL) {
 131                        write_unlock(&ax25_uid_lock);
 132                        return -ENOENT;
 133                }
 134                hlist_del_init(&ax25_uid->uid_node);
 135                ax25_uid_put(ax25_uid);
 136                write_unlock(&ax25_uid_lock);
 137
 138                return 0;
 139
 140        default:
 141                return -EINVAL;
 142        }
 143
 144        return -EINVAL; /*NOTREACHED */
 145}
 146
 147#ifdef CONFIG_PROC_FS
 148
 149static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
 150        __acquires(ax25_uid_lock)
 151{
 152        read_lock(&ax25_uid_lock);
 153        return seq_hlist_start_head(&ax25_uid_list, *pos);
 154}
 155
 156static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 157{
 158        return seq_hlist_next(v, &ax25_uid_list, pos);
 159}
 160
 161static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
 162        __releases(ax25_uid_lock)
 163{
 164        read_unlock(&ax25_uid_lock);
 165}
 166
 167static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 168{
 169        char buf[11];
 170
 171        if (v == SEQ_START_TOKEN)
 172                seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 173        else {
 174                struct ax25_uid_assoc *pt;
 175
 176                pt = hlist_entry(v, struct ax25_uid_assoc, uid_node);
 177                seq_printf(seq, "%6d %s\n",
 178                        from_kuid_munged(seq_user_ns(seq), pt->uid),
 179                        ax2asc(buf, &pt->call));
 180        }
 181        return 0;
 182}
 183
 184static const struct seq_operations ax25_uid_seqops = {
 185        .start = ax25_uid_seq_start,
 186        .next = ax25_uid_seq_next,
 187        .stop = ax25_uid_seq_stop,
 188        .show = ax25_uid_seq_show,
 189};
 190
 191static int ax25_uid_info_open(struct inode *inode, struct file *file)
 192{
 193        return seq_open(file, &ax25_uid_seqops);
 194}
 195
 196const struct file_operations ax25_uid_fops = {
 197        .open = ax25_uid_info_open,
 198        .read = seq_read,
 199        .llseek = seq_lseek,
 200        .release = seq_release,
 201};
 202
 203#endif
 204
 205/*
 206 *      Free all memory associated with UID/Callsign structures.
 207 */
 208void __exit ax25_uid_free(void)
 209{
 210        ax25_uid_assoc *ax25_uid;
 211
 212        write_lock(&ax25_uid_lock);
 213again:
 214        ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
 215                hlist_del_init(&ax25_uid->uid_node);
 216                ax25_uid_put(ax25_uid);
 217                goto again;
 218        }
 219        write_unlock(&ax25_uid_lock);
 220}
 221