xref: /openbmc/linux/security/keys/proc.c (revision 4bdf0bb7) 
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/slab.h>
16 #include <linux/fs.h>
17 #include <linux/proc_fs.h>
18 #include <linux/seq_file.h>
19 #include <asm/errno.h>
20 #include "internal.h"
21 
22 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
23 static int proc_keys_open(struct inode *inode, struct file *file);
24 static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
25 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
26 static void proc_keys_stop(struct seq_file *p, void *v);
27 static int proc_keys_show(struct seq_file *m, void *v);
28 
29 static const struct seq_operations proc_keys_ops = {
30 	.start	= proc_keys_start,
31 	.next	= proc_keys_next,
32 	.stop	= proc_keys_stop,
33 	.show	= proc_keys_show,
34 };
35 
36 static const struct file_operations proc_keys_fops = {
37 	.open		= proc_keys_open,
38 	.read		= seq_read,
39 	.llseek		= seq_lseek,
40 	.release	= seq_release,
41 };
42 #endif
43 
44 static int proc_key_users_open(struct inode *inode, struct file *file);
45 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
46 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
47 static void proc_key_users_stop(struct seq_file *p, void *v);
48 static int proc_key_users_show(struct seq_file *m, void *v);
49 
50 static const struct seq_operations proc_key_users_ops = {
51 	.start	= proc_key_users_start,
52 	.next	= proc_key_users_next,
53 	.stop	= proc_key_users_stop,
54 	.show	= proc_key_users_show,
55 };
56 
57 static const struct file_operations proc_key_users_fops = {
58 	.open		= proc_key_users_open,
59 	.read		= seq_read,
60 	.llseek		= seq_lseek,
61 	.release	= seq_release,
62 };
63 
64 /*****************************************************************************/
65 /*
66  * declare the /proc files
67  */
68 static int __init key_proc_init(void)
69 {
70 	struct proc_dir_entry *p;
71 
72 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
73 	p = proc_create("keys", 0, NULL, &proc_keys_fops);
74 	if (!p)
75 		panic("Cannot create /proc/keys\n");
76 #endif
77 
78 	p = proc_create("key-users", 0, NULL, &proc_key_users_fops);
79 	if (!p)
80 		panic("Cannot create /proc/key-users\n");
81 
82 	return 0;
83 
84 } /* end key_proc_init() */
85 
86 __initcall(key_proc_init);
87 
88 /*****************************************************************************/
89 /*
90  * implement "/proc/keys" to provides a list of the keys on the system
91  */
92 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
93 
94 static struct rb_node *key_serial_next(struct rb_node *n)
95 {
96 	struct user_namespace *user_ns = current_user_ns();
97 
98 	n = rb_next(n);
99 	while (n) {
100 		struct key *key = rb_entry(n, struct key, serial_node);
101 		if (key->user->user_ns == user_ns)
102 			break;
103 		n = rb_next(n);
104 	}
105 	return n;
106 }
107 
108 static int proc_keys_open(struct inode *inode, struct file *file)
109 {
110 	return seq_open(file, &proc_keys_ops);
111 }
112 
113 static struct key *find_ge_key(key_serial_t id)
114 {
115 	struct user_namespace *user_ns = current_user_ns();
116 	struct rb_node *n = key_serial_tree.rb_node;
117 	struct key *minkey = NULL;
118 
119 	while (n) {
120 		struct key *key = rb_entry(n, struct key, serial_node);
121 		if (id < key->serial) {
122 			if (!minkey || minkey->serial > key->serial)
123 				minkey = key;
124 			n = n->rb_left;
125 		} else if (id > key->serial) {
126 			n = n->rb_right;
127 		} else {
128 			minkey = key;
129 			break;
130 		}
131 		key = NULL;
132 	}
133 
134 	if (!minkey)
135 		return NULL;
136 
137 	for (;;) {
138 		if (minkey->user->user_ns == user_ns)
139 			return minkey;
140 		n = rb_next(&minkey->serial_node);
141 		if (!n)
142 			return NULL;
143 		minkey = rb_entry(n, struct key, serial_node);
144 	}
145 }
146 
147 static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
148 	__acquires(key_serial_lock)
149 {
150 	key_serial_t pos = *_pos;
151 	struct key *key;
152 
153 	spin_lock(&key_serial_lock);
154 
155 	if (*_pos > INT_MAX)
156 		return NULL;
157 	key = find_ge_key(pos);
158 	if (!key)
159 		return NULL;
160 	*_pos = key->serial;
161 	return &key->serial_node;
162 }
163 
164 static inline key_serial_t key_node_serial(struct rb_node *n)
165 {
166 	struct key *key = rb_entry(n, struct key, serial_node);
167 	return key->serial;
168 }
169 
170 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
171 {
172 	struct rb_node *n;
173 
174 	n = key_serial_next(v);
175 	if (n)
176 		*_pos = key_node_serial(n);
177 	return n;
178 }
179 
180 static void proc_keys_stop(struct seq_file *p, void *v)
181 	__releases(key_serial_lock)
182 {
183 	spin_unlock(&key_serial_lock);
184 }
185 
186 static int proc_keys_show(struct seq_file *m, void *v)
187 {
188 	struct rb_node *_p = v;
189 	struct key *key = rb_entry(_p, struct key, serial_node);
190 	struct timespec now;
191 	unsigned long timo;
192 	char xbuf[12];
193 	int rc;
194 
195 	/* check whether the current task is allowed to view the key (assuming
196 	 * non-possession)
197 	 * - the caller holds a spinlock, and thus the RCU read lock, making our
198 	 *   access to __current_cred() safe
199 	 */
200 	rc = key_task_permission(make_key_ref(key, 0), current_cred(),
201 				 KEY_VIEW);
202 	if (rc < 0)
203 		return 0;
204 
205 	now = current_kernel_time();
206 
207 	rcu_read_lock();
208 
209 	/* come up with a suitable timeout value */
210 	if (key->expiry == 0) {
211 		memcpy(xbuf, "perm", 5);
212 	} else if (now.tv_sec >= key->expiry) {
213 		memcpy(xbuf, "expd", 5);
214 	} else {
215 		timo = key->expiry - now.tv_sec;
216 
217 		if (timo < 60)
218 			sprintf(xbuf, "%lus", timo);
219 		else if (timo < 60*60)
220 			sprintf(xbuf, "%lum", timo / 60);
221 		else if (timo < 60*60*24)
222 			sprintf(xbuf, "%luh", timo / (60*60));
223 		else if (timo < 60*60*24*7)
224 			sprintf(xbuf, "%lud", timo / (60*60*24));
225 		else
226 			sprintf(xbuf, "%luw", timo / (60*60*24*7));
227 	}
228 
229 #define showflag(KEY, LETTER, FLAG) \
230 	(test_bit(FLAG,	&(KEY)->flags) ? LETTER : '-')
231 
232 	seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
233 		   key->serial,
234 		   showflag(key, 'I', KEY_FLAG_INSTANTIATED),
235 		   showflag(key, 'R', KEY_FLAG_REVOKED),
236 		   showflag(key, 'D', KEY_FLAG_DEAD),
237 		   showflag(key, 'Q', KEY_FLAG_IN_QUOTA),
238 		   showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
239 		   showflag(key, 'N', KEY_FLAG_NEGATIVE),
240 		   atomic_read(&key->usage),
241 		   xbuf,
242 		   key->perm,
243 		   key->uid,
244 		   key->gid,
245 		   key->type->name);
246 
247 #undef showflag
248 
249 	if (key->type->describe)
250 		key->type->describe(key, m);
251 	seq_putc(m, '\n');
252 
253 	rcu_read_unlock();
254 	return 0;
255 }
256 
257 #endif /* CONFIG_KEYS_DEBUG_PROC_KEYS */
258 
259 static struct rb_node *__key_user_next(struct rb_node *n)
260 {
261 	while (n) {
262 		struct key_user *user = rb_entry(n, struct key_user, node);
263 		if (user->user_ns == current_user_ns())
264 			break;
265 		n = rb_next(n);
266 	}
267 	return n;
268 }
269 
270 static struct rb_node *key_user_next(struct rb_node *n)
271 {
272 	return __key_user_next(rb_next(n));
273 }
274 
275 static struct rb_node *key_user_first(struct rb_root *r)
276 {
277 	struct rb_node *n = rb_first(r);
278 	return __key_user_next(n);
279 }
280 
281 /*****************************************************************************/
282 /*
283  * implement "/proc/key-users" to provides a list of the key users
284  */
285 static int proc_key_users_open(struct inode *inode, struct file *file)
286 {
287 	return seq_open(file, &proc_key_users_ops);
288 }
289 
290 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
291 	__acquires(key_user_lock)
292 {
293 	struct rb_node *_p;
294 	loff_t pos = *_pos;
295 
296 	spin_lock(&key_user_lock);
297 
298 	_p = key_user_first(&key_user_tree);
299 	while (pos > 0 && _p) {
300 		pos--;
301 		_p = key_user_next(_p);
302 	}
303 
304 	return _p;
305 }
306 
307 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
308 {
309 	(*_pos)++;
310 	return key_user_next((struct rb_node *) v);
311 }
312 
313 static void proc_key_users_stop(struct seq_file *p, void *v)
314 	__releases(key_user_lock)
315 {
316 	spin_unlock(&key_user_lock);
317 }
318 
319 static int proc_key_users_show(struct seq_file *m, void *v)
320 {
321 	struct rb_node *_p = v;
322 	struct key_user *user = rb_entry(_p, struct key_user, node);
323 	unsigned maxkeys = (user->uid == 0) ?
324 		key_quota_root_maxkeys : key_quota_maxkeys;
325 	unsigned maxbytes = (user->uid == 0) ?
326 		key_quota_root_maxbytes : key_quota_maxbytes;
327 
328 	seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
329 		   user->uid,
330 		   atomic_read(&user->usage),
331 		   atomic_read(&user->nkeys),
332 		   atomic_read(&user->nikeys),
333 		   user->qnkeys,
334 		   maxkeys,
335 		   user->qnbytes,
336 		   maxbytes);
337 
338 	return 0;
339 
340 }
341