ax25_uid.c revision 9ffc93f203c18a70623f21950f1dd473c9ec48cd 
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(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
72EXPORT_SYMBOL(ax25_findbyuid);
73
74int 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
147static 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
154static 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
159static 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
165static 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
180static 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
187static int ax25_uid_info_open(struct inode *inode, struct file *file)
188{
189	return seq_open(file, &ax25_uid_seqops);
190}
191
192const 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 */
205void __exit ax25_uid_free(void)
206{
207	ax25_uid_assoc *ax25_uid;
208	struct hlist_node *node;
209
210	write_lock(&ax25_uid_lock);
211again:
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}
219