xref: /openbmc/linux/security/keys/proc.c (revision e190bfe5) 
1 /* proc.c: proc files for key database enumeration
2  *
3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/fs.h>
16 #include <linux/proc_fs.h>
17 #include <linux/seq_file.h>
18 #include <asm/errno.h>
19 #include "internal.h"
20 
21 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
22 static int proc_keys_open(struct inode *inode, struct file *file);
23 static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
24 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
25 static void proc_keys_stop(struct seq_file *p, void *v);
26 static int proc_keys_show(struct seq_file *m, void *v);
27 
28 static const struct seq_operations proc_keys_ops = {
29 	.start	= proc_keys_start,
30 	.next	= proc_keys_next,
31 	.stop	= proc_keys_stop,
32 	.show	= proc_keys_show,
33 };
34 
35 static const struct file_operations proc_keys_fops = {
36 	.open		= proc_keys_open,
37 	.read		= seq_read,
38 	.llseek		= seq_lseek,
39 	.release	= seq_release,
40 };
41 #endif
42 
43 static int proc_key_users_open(struct inode *inode, struct file *file);
44 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
45 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
46 static void proc_key_users_stop(struct seq_file *p, void *v);
47 static int proc_key_users_show(struct seq_file *m, void *v);
48 
49 static const struct seq_operations proc_key_users_ops = {
50 	.start	= proc_key_users_start,
51 	.next	= proc_key_users_next,
52 	.stop	= proc_key_users_stop,
53 	.show	= proc_key_users_show,
54 };
55 
56 static const struct file_operations proc_key_users_fops = {
57 	.open		= proc_key_users_open,
58 	.read		= seq_read,
59 	.llseek		= seq_lseek,
60 	.release	= seq_release,
61 };
62 
63 /*****************************************************************************/
64 /*
65  * declare the /proc files
66  */
67 static int __init key_proc_init(void)
68 {
69 	struct proc_dir_entry *p;
70 
71 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
72 	p = proc_create("keys", 0, NULL, &proc_keys_fops);
73 	if (!p)
74 		panic("Cannot create /proc/keys\n");
75 #endif
76 
77 	p = proc_create("key-users", 0, NULL, &proc_key_users_fops);
78 	if (!p)
79 		panic("Cannot create /proc/key-users\n");
80 
81 	return 0;
82 
83 } /* end key_proc_init() */
84 
85 __initcall(key_proc_init);
86 
87 /*****************************************************************************/
88 /*
89  * implement "/proc/keys" to provides a list of the keys on the system
90  */
91 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
92 
93 static struct rb_node *key_serial_next(struct rb_node *n)
94 {
95 	struct user_namespace *user_ns = current_user_ns();
96 
97 	n = rb_next(n);
98 	while (n) {
99 		struct key *key = rb_entry(n, struct key, serial_node);
100 		if (key->user->user_ns == user_ns)
101 			break;
102 		n = rb_next(n);
103 	}
104 	return n;
105 }
106 
107 static int proc_keys_open(struct inode *inode, struct file *file)
108 {
109 	return seq_open(file, &proc_keys_ops);
110 }
111 
112 static struct key *find_ge_key(key_serial_t id)
113 {
114 	struct user_namespace *user_ns = current_user_ns();
115 	struct rb_node *n = key_serial_tree.rb_node;
116 	struct key *minkey = NULL;
117 
118 	while (n) {
119 		struct key *key = rb_entry(n, struct key, serial_node);
120 		if (id < key->serial) {
121 			if (!minkey || minkey->serial > key->serial)
122 				minkey = key;
123 			n = n->rb_left;
124 		} else if (id > key->serial) {
125 			n = n->rb_right;
126 		} else {
127 			minkey = key;
128 			break;
129 		}
130 		key = NULL;
131 	}
132 
133 	if (!minkey)
134 		return NULL;
135 
136 	for (;;) {
137 		if (minkey->user->user_ns == user_ns)
138 			return minkey;
139 		n = rb_next(&minkey->serial_node);
140 		if (!n)
141 			return NULL;
142 		minkey = rb_entry(n, struct key, serial_node);
143 	}
144 }
145 
146 static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
147 	__acquires(key_serial_lock)
148 {
149 	key_serial_t pos = *_pos;
150 	struct key *key;
151 
152 	spin_lock(&key_serial_lock);
153 
154 	if (*_pos > INT_MAX)
155 		return NULL;
156 	key = find_ge_key(pos);
157 	if (!key)
158 		return NULL;
159 	*_pos = key->serial;
160 	return &key->serial_node;
161 }
162 
163 static inline key_serial_t key_node_serial(struct rb_node *n)
164 {
165 	struct key *key = rb_entry(n, struct key, serial_node);
166 	return key->serial;
167 }
168 
169 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
170 {
171 	struct rb_node *n;
172 
173 	n = key_serial_next(v);
174 	if (n)
175 		*_pos = key_node_serial(n);
176 	return n;
177 }
178 
179 static void proc_keys_stop(struct seq_file *p, void *v)
180 	__releases(key_serial_lock)
181 {
182 	spin_unlock(&key_serial_lock);
183 }
184 
185 static int proc_keys_show(struct seq_file *m, void *v)
186 {
187 	struct rb_node *_p = v;
188 	struct key *key = rb_entry(_p, struct key, serial_node);
189 	struct timespec now;
190 	unsigned long timo;
191 	char xbuf[12];
192 	int rc;
193 
194 	/* check whether the current task is allowed to view the key (assuming
195 	 * non-possession)
196 	 * - the caller holds a spinlock, and thus the RCU read lock, making our
197 	 *   access to __current_cred() safe
198 	 */
199 	rc = key_task_permission(make_key_ref(key, 0), current_cred(),
200 				 KEY_VIEW);
201 	if (rc < 0)
202 		return 0;
203 
204 	now = current_kernel_time();
205 
206 	rcu_read_lock();
207 
208 	/* come up with a suitable timeout value */
209 	if (key->expiry == 0) {
210 		memcpy(xbuf, "perm", 5);
211 	} else if (now.tv_sec >= key->expiry) {
212 		memcpy(xbuf, "expd", 5);
213 	} else {
214 		timo = key->expiry - now.tv_sec;
215 
216 		if (timo < 60)
217 			sprintf(xbuf, "%lus", timo);
218 		else if (timo < 60*60)
219 			sprintf(xbuf, "%lum", timo / 60);
220 		else if (timo < 60*60*24)
221 			sprintf(xbuf, "%luh", timo / (60*60));
222 		else if (timo < 60*60*24*7)
223 			sprintf(xbuf, "%lud", timo / (60*60*24));
224 		else
225 			sprintf(xbuf, "%luw", timo / (60*60*24*7));
226 	}
227 
228 #define showflag(KEY, LETTER, FLAG) \
229 	(test_bit(FLAG,	&(KEY)->flags) ? LETTER : '-')
230 
231 	seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
232 		   key->serial,
233 		   showflag(key, 'I', KEY_FLAG_INSTANTIATED),
234 		   showflag(key, 'R', KEY_FLAG_REVOKED),
235 		   showflag(key, 'D', KEY_FLAG_DEAD),
236 		   showflag(key, 'Q', KEY_FLAG_IN_QUOTA),
237 		   showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
238 		   showflag(key, 'N', KEY_FLAG_NEGATIVE),
239 		   atomic_read(&key->usage),
240 		   xbuf,
241 		   key->perm,
242 		   key->uid,
243 		   key->gid,
244 		   key->type->name);
245 
246 #undef showflag
247 
248 	if (key->type->describe)
249 		key->type->describe(key, m);
250 	seq_putc(m, '\n');
251 
252 	rcu_read_unlock();
253 	return 0;
254 }
255 
256 #endif /* CONFIG_KEYS_DEBUG_PROC_KEYS */
257 
258 static struct rb_node *__key_user_next(struct rb_node *n)
259 {
260 	while (n) {
261 		struct key_user *user = rb_entry(n, struct key_user, node);
262 		if (user->user_ns == current_user_ns())
263 			break;
264 		n = rb_next(n);
265 	}
266 	return n;
267 }
268 
269 static struct rb_node *key_user_next(struct rb_node *n)
270 {
271 	return __key_user_next(rb_next(n));
272 }
273 
274 static struct rb_node *key_user_first(struct rb_root *r)
275 {
276 	struct rb_node *n = rb_first(r);
277 	return __key_user_next(n);
278 }
279 
280 /*****************************************************************************/
281 /*
282  * implement "/proc/key-users" to provides a list of the key users
283  */
284 static int proc_key_users_open(struct inode *inode, struct file *file)
285 {
286 	return seq_open(file, &proc_key_users_ops);
287 }
288 
289 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
290 	__acquires(key_user_lock)
291 {
292 	struct rb_node *_p;
293 	loff_t pos = *_pos;
294 
295 	spin_lock(&key_user_lock);
296 
297 	_p = key_user_first(&key_user_tree);
298 	while (pos > 0 && _p) {
299 		pos--;
300 		_p = key_user_next(_p);
301 	}
302 
303 	return _p;
304 }
305 
306 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
307 {
308 	(*_pos)++;
309 	return key_user_next((struct rb_node *)v);
310 }
311 
312 static void proc_key_users_stop(struct seq_file *p, void *v)
313 	__releases(key_user_lock)
314 {
315 	spin_unlock(&key_user_lock);
316 }
317 
318 static int proc_key_users_show(struct seq_file *m, void *v)
319 {
320 	struct rb_node *_p = v;
321 	struct key_user *user = rb_entry(_p, struct key_user, node);
322 	unsigned maxkeys = (user->uid == 0) ?
323 		key_quota_root_maxkeys : key_quota_maxkeys;
324 	unsigned maxbytes = (user->uid == 0) ?
325 		key_quota_root_maxbytes : key_quota_maxbytes;
326 
327 	seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
328 		   user->uid,
329 		   atomic_read(&user->usage),
330 		   atomic_read(&user->nkeys),
331 		   atomic_read(&user->nikeys),
332 		   user->qnkeys,
333 		   maxkeys,
334 		   user->qnbytes,
335 		   maxbytes);
336 
337 	return 0;
338 
339 }
340