/security/keys/proc.c

  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
 22static int proc_keys_open(struct inode *inode, struct file *file);
 23static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
 24static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
 25static void proc_keys_stop(struct seq_file *p, void *v);
 26static int proc_keys_show(struct seq_file *m, void *v);
 27
 28static 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
 35static 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
 43static int proc_key_users_open(struct inode *inode, struct file *file);
 44static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
 45static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
 46static void proc_key_users_stop(struct seq_file *p, void *v);
 47static int proc_key_users_show(struct seq_file *m, void *v);
 48
 49static 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
 56static 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 */
 67static 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
 93static 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
107static int proc_keys_open(struct inode *inode, struct file *file)
108{
109	return seq_open(file, &proc_keys_ops);
110}
111
112static 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
146static 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
163static 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
169static 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
179static void proc_keys_stop(struct seq_file *p, void *v)
180	__releases(key_serial_lock)
181{
182	spin_unlock(&key_serial_lock);
183}
184
185static 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
258static 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
269static struct rb_node *key_user_next(struct rb_node *n)
270{
271	return __key_user_next(rb_next(n));
272}
273
274static 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 */
284static int proc_key_users_open(struct inode *inode, struct file *file)
285{
286	return seq_open(file, &proc_key_users_ops);
287}
288
289static 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
306static 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
312static 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
318static 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}