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 <asm/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/netfilter.h>
  38#include <linux/sysctl.h>
  39#include <linux/export.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
  47static HLIST_HEAD(ax25_uid_list);
  48static DEFINE_RWLOCK(ax25_uid_lock);
  49
  50int ax25_uid_policy;
  51
  52EXPORT_SYMBOL(ax25_uid_policy);
  53
  54ax25_uid_assoc *ax25_findbyuid(kuid_t uid)
  55{
  56        ax25_uid_assoc *ax25_uid, *res = NULL;
  57
  58        read_lock(&ax25_uid_lock);
  59        ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
  60                if (uid_eq(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
  71EXPORT_SYMBOL(ax25_findbyuid);
  72
  73int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
  74{
  75        ax25_uid_assoc *ax25_uid;
  76        ax25_uid_assoc *user;
  77        unsigned long res;
  78
  79        switch (cmd) {
  80        case SIOCAX25GETUID:
  81                res = -ENOENT;
  82                read_lock(&ax25_uid_lock);
  83                ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
  84                        if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
  85                                res = from_kuid_munged(current_user_ns(), ax25_uid->uid);
  86                                break;
  87                        }
  88                }
  89                read_unlock(&ax25_uid_lock);
  90
  91                return res;
  92
  93        case SIOCAX25ADDUID:
  94        {
  95                kuid_t sax25_kuid;
  96                if (!capable(CAP_NET_ADMIN))
  97                        return -EPERM;
  98                sax25_kuid = make_kuid(current_user_ns(), sax->sax25_uid);
  99                if (!uid_valid(sax25_kuid))
 100                        return -EINVAL;
 101                user = ax25_findbyuid(sax25_kuid);
 102                if (user) {
 103                        ax25_uid_put(user);
 104                        return -EEXIST;
 105                }
 106                if (sax->sax25_uid == 0)
 107                        return -EINVAL;
 108                if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
 109                        return -ENOMEM;
 110
 111                atomic_set(&ax25_uid->refcount, 1);
 112                ax25_uid->uid  = sax25_kuid;
 113                ax25_uid->call = sax->sax25_call;
 114
 115                write_lock(&ax25_uid_lock);
 116                hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
 117                write_unlock(&ax25_uid_lock);
 118
 119                return 0;
 120        }
 121        case SIOCAX25DELUID:
 122                if (!capable(CAP_NET_ADMIN))
 123                        return -EPERM;
 124
 125                ax25_uid = NULL;
 126                write_lock(&ax25_uid_lock);
 127                ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
 128                        if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
 129                                break;
 130                }
 131                if (ax25_uid == NULL) {
 132                        write_unlock(&ax25_uid_lock);
 133                        return -ENOENT;
 134                }
 135                hlist_del_init(&ax25_uid->uid_node);
 136                ax25_uid_put(ax25_uid);
 137                write_unlock(&ax25_uid_lock);
 138
 139                return 0;
 140
 141        default:
 142                return -EINVAL;
 143        }
 144
 145        return -EINVAL; /*NOTREACHED */
 146}
 147
 148#ifdef CONFIG_PROC_FS
 149
 150static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
 151        __acquires(ax25_uid_lock)
 152{
 153        read_lock(&ax25_uid_lock);
 154        return seq_hlist_start_head(&ax25_uid_list, *pos);
 155}
 156
 157static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 158{
 159        return seq_hlist_next(v, &ax25_uid_list, pos);
 160}
 161
 162static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
 163        __releases(ax25_uid_lock)
 164{
 165        read_unlock(&ax25_uid_lock);
 166}
 167
 168static int ax25_uid_seq_show(struct seq_file *seq, void *v)
 169{
 170        char buf[11];
 171
 172        if (v == SEQ_START_TOKEN)
 173                seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
 174        else {
 175                struct ax25_uid_assoc *pt;
 176
 177                pt = hlist_entry(v, struct ax25_uid_assoc, uid_node);
 178                seq_printf(seq, "%6d %s\n",
 179                        from_kuid_munged(seq_user_ns(seq), pt->uid),
 180                        ax2asc(buf, &pt->call));
 181        }
 182        return 0;
 183}
 184
 185static const 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
 192static int ax25_uid_info_open(struct inode *inode, struct file *file)
 193{
 194        return seq_open(file, &ax25_uid_seqops);
 195}
 196
 197const 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 */
 210void __exit ax25_uid_free(void)
 211{
 212        ax25_uid_assoc *ax25_uid;
 213
 214        write_lock(&ax25_uid_lock);
 215again:
 216        ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
 217                hlist_del_init(&ax25_uid->uid_node);
 218                ax25_uid_put(ax25_uid);
 219                goto again;
 220        }
 221        write_unlock(&ax25_uid_lock);
 222}
 223