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