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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 ([email protected])
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}