1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *
4 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
5 */
6
7#include <linux/capability.h>
8#include <linux/errno.h>
9#include <linux/types.h>
10#include <linux/socket.h>
11#include <linux/in.h>
12#include <linux/kernel.h>
13#include <linux/timer.h>
14#include <linux/string.h>
15#include <linux/sockios.h>
16#include <linux/net.h>
17#include <linux/spinlock.h>
18#include <linux/slab.h>
19#include <net/ax25.h>
20#include <linux/inet.h>
21#include <linux/netdevice.h>
22#include <linux/if_arp.h>
23#include <linux/skbuff.h>
24#include <net/sock.h>
25#include <linux/uaccess.h>
26#include <linux/fcntl.h>
27#include <linux/mm.h>
28#include <linux/interrupt.h>
29#include <linux/list.h>
30#include <linux/notifier.h>
31#include <linux/proc_fs.h>
32#include <linux/seq_file.h>
33#include <linux/stat.h>
34#include <linux/sysctl.h>
35#include <linux/export.h>
36#include <net/ip.h>
37#include <net/arp.h>
38
39/*
40 *	Callsign/UID mapper. This is in kernel space for security on multi-amateur machines.
41 */
42
43static HLIST_HEAD(ax25_uid_list);
44static DEFINE_RWLOCK(ax25_uid_lock);
45
46int ax25_uid_policy;
47
48EXPORT_SYMBOL(ax25_uid_policy);
49
50ax25_uid_assoc *ax25_findbyuid(kuid_t uid)
51{
52	ax25_uid_assoc *ax25_uid, *res = NULL;
53
54	read_lock(&ax25_uid_lock);
55	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
56		if (uid_eq(ax25_uid->uid, uid)) {
57			ax25_uid_hold(ax25_uid);
58			res = ax25_uid;
59			break;
60		}
61	}
62	read_unlock(&ax25_uid_lock);
63
64	return res;
65}
66
67EXPORT_SYMBOL(ax25_findbyuid);
68
69int ax25_uid_ioctl(int cmd, struct sockaddr_ax25 *sax)
70{
71	ax25_uid_assoc *ax25_uid;
72	ax25_uid_assoc *user;
73	unsigned long res;
74
75	switch (cmd) {
76	case SIOCAX25GETUID:
77		res = -ENOENT;
78		read_lock(&ax25_uid_lock);
79		ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
80			if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0) {
81				res = from_kuid_munged(current_user_ns(), ax25_uid->uid);
82				break;
83			}
84		}
85		read_unlock(&ax25_uid_lock);
86
87		return res;
88
89	case SIOCAX25ADDUID:
90	{
91		kuid_t sax25_kuid;
92		if (!capable(CAP_NET_ADMIN))
93			return -EPERM;
94		sax25_kuid = make_kuid(current_user_ns(), sax->sax25_uid);
95		if (!uid_valid(sax25_kuid))
96			return -EINVAL;
97		user = ax25_findbyuid(sax25_kuid);
98		if (user) {
99			ax25_uid_put(user);
100			return -EEXIST;
101		}
102		if (sax->sax25_uid == 0)
103			return -EINVAL;
104		if ((ax25_uid = kmalloc(sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
105			return -ENOMEM;
106
107		refcount_set(&ax25_uid->refcount, 1);
108		ax25_uid->uid  = sax25_kuid;
109		ax25_uid->call = sax->sax25_call;
110
111		write_lock(&ax25_uid_lock);
112		hlist_add_head(&ax25_uid->uid_node, &ax25_uid_list);
113		write_unlock(&ax25_uid_lock);
114
115		return 0;
116	}
117	case SIOCAX25DELUID:
118		if (!capable(CAP_NET_ADMIN))
119			return -EPERM;
120
121		ax25_uid = NULL;
122		write_lock(&ax25_uid_lock);
123		ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
124			if (ax25cmp(&sax->sax25_call, &ax25_uid->call) == 0)
125				break;
126		}
127		if (ax25_uid == NULL) {
128			write_unlock(&ax25_uid_lock);
129			return -ENOENT;
130		}
131		hlist_del_init(&ax25_uid->uid_node);
132		ax25_uid_put(ax25_uid);
133		write_unlock(&ax25_uid_lock);
134
135		return 0;
136
137	default:
138		return -EINVAL;
139	}
140
141	return -EINVAL;	/*NOTREACHED */
142}
143
144#ifdef CONFIG_PROC_FS
145
146static void *ax25_uid_seq_start(struct seq_file *seq, loff_t *pos)
147	__acquires(ax25_uid_lock)
148{
149	read_lock(&ax25_uid_lock);
150	return seq_hlist_start_head(&ax25_uid_list, *pos);
151}
152
153static void *ax25_uid_seq_next(struct seq_file *seq, void *v, loff_t *pos)
154{
155	return seq_hlist_next(v, &ax25_uid_list, pos);
156}
157
158static void ax25_uid_seq_stop(struct seq_file *seq, void *v)
159	__releases(ax25_uid_lock)
160{
161	read_unlock(&ax25_uid_lock);
162}
163
164static int ax25_uid_seq_show(struct seq_file *seq, void *v)
165{
166	char buf[11];
167
168	if (v == SEQ_START_TOKEN)
169		seq_printf(seq, "Policy: %d\n", ax25_uid_policy);
170	else {
171		struct ax25_uid_assoc *pt;
172
173		pt = hlist_entry(v, struct ax25_uid_assoc, uid_node);
174		seq_printf(seq, "%6d %s\n",
175			from_kuid_munged(seq_user_ns(seq), pt->uid),
176			ax2asc(buf, &pt->call));
177	}
178	return 0;
179}
180
181const struct seq_operations ax25_uid_seqops = {
182	.start = ax25_uid_seq_start,
183	.next = ax25_uid_seq_next,
184	.stop = ax25_uid_seq_stop,
185	.show = ax25_uid_seq_show,
186};
187#endif
188
189/*
190 *	Free all memory associated with UID/Callsign structures.
191 */
192void __exit ax25_uid_free(void)
193{
194	ax25_uid_assoc *ax25_uid;
195
196	write_lock(&ax25_uid_lock);
197again:
198	ax25_uid_for_each(ax25_uid, &ax25_uid_list) {
199		hlist_del_init(&ax25_uid->uid_node);
200		ax25_uid_put(ax25_uid);
201		goto again;
202	}
203	write_unlock(&ax25_uid_lock);
204}
205