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(left: ax25_uid->uid, right: 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(), uid: 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(), uid: sax->sax25_uid);
95 if (!uid_valid(uid: sax25_kuid))
96 return -EINVAL;
97 user = ax25_findbyuid(sax25_kuid);
98 if (user) {
99 ax25_uid_put(assoc: user);
100 return -EEXIST;
101 }
102 if (sax->sax25_uid == 0)
103 return -EINVAL;
104 if ((ax25_uid = kmalloc(size: sizeof(*ax25_uid), GFP_KERNEL)) == NULL)
105 return -ENOMEM;
106
107 refcount_set(r: &ax25_uid->refcount, n: 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(n: &ax25_uid->uid_node, h: &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(n: &ax25_uid->uid_node);
132 ax25_uid_put(assoc: 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(head: &ax25_uid_list, pos: *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, head: &ax25_uid_list, ppos: 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(m: seq, fmt: "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(m: seq, fmt: "%6d %s\n",
175 from_kuid_munged(to: seq_user_ns(seq), uid: 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(n: &ax25_uid->uid_node);
200 ax25_uid_put(assoc: ax25_uid);
201 goto again;
202 }
203 write_unlock(&ax25_uid_lock);
204}
205

source code of linux/net/ax25/ax25_uid.c