1// SPDX-License-Identifier: GPL-2.0-or-later
2/* procfs files for key database enumeration
3 *
4 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/init.h>
9#include <linux/sched.h>
10#include <linux/fs.h>
11#include <linux/proc_fs.h>
12#include <linux/seq_file.h>
13#include <asm/errno.h>
14#include "internal.h"
15
16static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
17static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
18static void proc_keys_stop(struct seq_file *p, void *v);
19static int proc_keys_show(struct seq_file *m, void *v);
20
21static const struct seq_operations proc_keys_ops = {
22	.start	= proc_keys_start,
23	.next	= proc_keys_next,
24	.stop	= proc_keys_stop,
25	.show	= proc_keys_show,
26};
27
28static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
29static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
30static void proc_key_users_stop(struct seq_file *p, void *v);
31static int proc_key_users_show(struct seq_file *m, void *v);
32
33static const struct seq_operations proc_key_users_ops = {
34	.start	= proc_key_users_start,
35	.next	= proc_key_users_next,
36	.stop	= proc_key_users_stop,
37	.show	= proc_key_users_show,
38};
39
40/*
41 * Declare the /proc files.
42 */
43static int __init key_proc_init(void)
44{
45	struct proc_dir_entry *p;
46
47	p = proc_create_seq("keys", 0, NULL, &proc_keys_ops);
48	if (!p)
49		panic("Cannot create /proc/keys\n");
50
51	p = proc_create_seq("key-users", 0, NULL, &proc_key_users_ops);
52	if (!p)
53		panic("Cannot create /proc/key-users\n");
54
55	return 0;
56}
57
58__initcall(key_proc_init);
59
60/*
61 * Implement "/proc/keys" to provide a list of the keys on the system that
62 * grant View permission to the caller.
63 */
64static struct rb_node *key_serial_next(struct seq_file *p, struct rb_node *n)
65{
66	struct user_namespace *user_ns = seq_user_ns(p);
67
68	n = rb_next(n);
69	while (n) {
70		struct key *key = rb_entry(n, struct key, serial_node);
71		if (kuid_has_mapping(user_ns, key->user->uid))
72			break;
73		n = rb_next(n);
74	}
75	return n;
76}
77
78static struct key *find_ge_key(struct seq_file *p, key_serial_t id)
79{
80	struct user_namespace *user_ns = seq_user_ns(p);
81	struct rb_node *n = key_serial_tree.rb_node;
82	struct key *minkey = NULL;
83
84	while (n) {
85		struct key *key = rb_entry(n, struct key, serial_node);
86		if (id < key->serial) {
87			if (!minkey || minkey->serial > key->serial)
88				minkey = key;
89			n = n->rb_left;
90		} else if (id > key->serial) {
91			n = n->rb_right;
92		} else {
93			minkey = key;
94			break;
95		}
96		key = NULL;
97	}
98
99	if (!minkey)
100		return NULL;
101
102	for (;;) {
103		if (kuid_has_mapping(user_ns, minkey->user->uid))
104			return minkey;
105		n = rb_next(&minkey->serial_node);
106		if (!n)
107			return NULL;
108		minkey = rb_entry(n, struct key, serial_node);
109	}
110}
111
112static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
113	__acquires(key_serial_lock)
114{
115	key_serial_t pos = *_pos;
116	struct key *key;
117
118	spin_lock(&key_serial_lock);
119
120	if (*_pos > INT_MAX)
121		return NULL;
122	key = find_ge_key(p, pos);
123	if (!key)
124		return NULL;
125	*_pos = key->serial;
126	return &key->serial_node;
127}
128
129static inline key_serial_t key_node_serial(struct rb_node *n)
130{
131	struct key *key = rb_entry(n, struct key, serial_node);
132	return key->serial;
133}
134
135static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
136{
137	struct rb_node *n;
138
139	n = key_serial_next(p, v);
140	if (n)
141		*_pos = key_node_serial(n);
142	else
143		(*_pos)++;
144	return n;
145}
146
147static void proc_keys_stop(struct seq_file *p, void *v)
148	__releases(key_serial_lock)
149{
150	spin_unlock(&key_serial_lock);
151}
152
153static int proc_keys_show(struct seq_file *m, void *v)
154{
155	struct rb_node *_p = v;
156	struct key *key = rb_entry(_p, struct key, serial_node);
157	unsigned long flags;
158	key_ref_t key_ref, skey_ref;
159	time64_t now, expiry;
160	char xbuf[16];
161	short state;
162	u64 timo;
163	int rc;
164
165	struct keyring_search_context ctx = {
166		.index_key		= key->index_key,
167		.cred			= m->file->f_cred,
168		.match_data.cmp		= lookup_user_key_possessed,
169		.match_data.raw_data	= key,
170		.match_data.lookup_type	= KEYRING_SEARCH_LOOKUP_DIRECT,
171		.flags			= (KEYRING_SEARCH_NO_STATE_CHECK |
172					   KEYRING_SEARCH_RECURSE),
173	};
174
175	key_ref = make_key_ref(key, 0);
176
177	/* determine if the key is possessed by this process (a test we can
178	 * skip if the key does not indicate the possessor can view it
179	 */
180	if (key->perm & KEY_POS_VIEW) {
181		rcu_read_lock();
182		skey_ref = search_cred_keyrings_rcu(&ctx);
183		rcu_read_unlock();
184		if (!IS_ERR(skey_ref)) {
185			key_ref_put(skey_ref);
186			key_ref = make_key_ref(key, 1);
187		}
188	}
189
190	/* check whether the current task is allowed to view the key */
191	rc = key_task_permission(key_ref, ctx.cred, KEY_NEED_VIEW);
192	if (rc < 0)
193		return 0;
194
195	now = ktime_get_real_seconds();
196
197	rcu_read_lock();
198
199	/* come up with a suitable timeout value */
200	expiry = READ_ONCE(key->expiry);
201	if (expiry == TIME64_MAX) {
202		memcpy(xbuf, "perm", 5);
203	} else if (now >= expiry) {
204		memcpy(xbuf, "expd", 5);
205	} else {
206		timo = expiry - now;
207
208		if (timo < 60)
209			sprintf(xbuf, "%llus", timo);
210		else if (timo < 60*60)
211			sprintf(xbuf, "%llum", div_u64(timo, 60));
212		else if (timo < 60*60*24)
213			sprintf(xbuf, "%lluh", div_u64(timo, 60 * 60));
214		else if (timo < 60*60*24*7)
215			sprintf(xbuf, "%llud", div_u64(timo, 60 * 60 * 24));
216		else
217			sprintf(xbuf, "%lluw", div_u64(timo, 60 * 60 * 24 * 7));
218	}
219
220	state = key_read_state(key);
221
222#define showflag(FLAGS, LETTER, FLAG) \
223	((FLAGS & (1 << FLAG)) ? LETTER : '-')
224
225	flags = READ_ONCE(key->flags);
226	seq_printf(m, "%08x %c%c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
227		   key->serial,
228		   state != KEY_IS_UNINSTANTIATED ? 'I' : '-',
229		   showflag(flags, 'R', KEY_FLAG_REVOKED),
230		   showflag(flags, 'D', KEY_FLAG_DEAD),
231		   showflag(flags, 'Q', KEY_FLAG_IN_QUOTA),
232		   showflag(flags, 'U', KEY_FLAG_USER_CONSTRUCT),
233		   state < 0 ? 'N' : '-',
234		   showflag(flags, 'i', KEY_FLAG_INVALIDATED),
235		   refcount_read(&key->usage),
236		   xbuf,
237		   key->perm,
238		   from_kuid_munged(seq_user_ns(m), key->uid),
239		   from_kgid_munged(seq_user_ns(m), key->gid),
240		   key->type->name);
241
242#undef showflag
243
244	if (key->type->describe)
245		key->type->describe(key, m);
246	seq_putc(m, '\n');
247
248	rcu_read_unlock();
249	return 0;
250}
251
252static struct rb_node *__key_user_next(struct user_namespace *user_ns, struct rb_node *n)
253{
254	while (n) {
255		struct key_user *user = rb_entry(n, struct key_user, node);
256		if (kuid_has_mapping(user_ns, user->uid))
257			break;
258		n = rb_next(n);
259	}
260	return n;
261}
262
263static struct rb_node *key_user_next(struct user_namespace *user_ns, struct rb_node *n)
264{
265	return __key_user_next(user_ns, rb_next(n));
266}
267
268static struct rb_node *key_user_first(struct user_namespace *user_ns, struct rb_root *r)
269{
270	struct rb_node *n = rb_first(r);
271	return __key_user_next(user_ns, n);
272}
273
274static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
275	__acquires(key_user_lock)
276{
277	struct rb_node *_p;
278	loff_t pos = *_pos;
279
280	spin_lock(&key_user_lock);
281
282	_p = key_user_first(seq_user_ns(p), &key_user_tree);
283	while (pos > 0 && _p) {
284		pos--;
285		_p = key_user_next(seq_user_ns(p), _p);
286	}
287
288	return _p;
289}
290
291static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
292{
293	(*_pos)++;
294	return key_user_next(seq_user_ns(p), (struct rb_node *)v);
295}
296
297static void proc_key_users_stop(struct seq_file *p, void *v)
298	__releases(key_user_lock)
299{
300	spin_unlock(&key_user_lock);
301}
302
303static int proc_key_users_show(struct seq_file *m, void *v)
304{
305	struct rb_node *_p = v;
306	struct key_user *user = rb_entry(_p, struct key_user, node);
307	unsigned maxkeys = uid_eq(user->uid, GLOBAL_ROOT_UID) ?
308		key_quota_root_maxkeys : key_quota_maxkeys;
309	unsigned maxbytes = uid_eq(user->uid, GLOBAL_ROOT_UID) ?
310		key_quota_root_maxbytes : key_quota_maxbytes;
311
312	seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
313		   from_kuid_munged(seq_user_ns(m), user->uid),
314		   refcount_read(&user->usage),
315		   atomic_read(&user->nkeys),
316		   atomic_read(&user->nikeys),
317		   user->qnkeys,
318		   maxkeys,
319		   user->qnbytes,
320		   maxbytes);
321
322	return 0;
323}
324