1 /* procfs 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 static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
22 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
23 static void proc_keys_stop(struct seq_file *p, void *v);
24 static int proc_keys_show(struct seq_file *m, void *v);
25
26 static const struct seq_operations proc_keys_ops = {
27 .start = proc_keys_start,
28 .next = proc_keys_next,
29 .stop = proc_keys_stop,
30 .show = proc_keys_show,
31 };
32
33 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
34 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
35 static void proc_key_users_stop(struct seq_file *p, void *v);
36 static int proc_key_users_show(struct seq_file *m, void *v);
37
38 static const struct seq_operations proc_key_users_ops = {
39 .start = proc_key_users_start,
40 .next = proc_key_users_next,
41 .stop = proc_key_users_stop,
42 .show = proc_key_users_show,
43 };
44
45 /*
46 * Declare the /proc files.
47 */
key_proc_init(void)48 static int __init key_proc_init(void)
49 {
50 struct proc_dir_entry *p;
51
52 p = proc_create_seq("keys", 0, NULL, &proc_keys_ops);
53 if (!p)
54 panic("Cannot create /proc/keys\n");
55
56 p = proc_create_seq("key-users", 0, NULL, &proc_key_users_ops);
57 if (!p)
58 panic("Cannot create /proc/key-users\n");
59
60 return 0;
61 }
62
63 __initcall(key_proc_init);
64
65 /*
66 * Implement "/proc/keys" to provide a list of the keys on the system that
67 * grant View permission to the caller.
68 */
key_serial_next(struct seq_file * p,struct rb_node * n)69 static struct rb_node *key_serial_next(struct seq_file *p, struct rb_node *n)
70 {
71 struct user_namespace *user_ns = seq_user_ns(p);
72
73 n = rb_next(n);
74 while (n) {
75 struct key *key = rb_entry(n, struct key, serial_node);
76 if (kuid_has_mapping(user_ns, key->user->uid))
77 break;
78 n = rb_next(n);
79 }
80 return n;
81 }
82
find_ge_key(struct seq_file * p,key_serial_t id)83 static struct key *find_ge_key(struct seq_file *p, key_serial_t id)
84 {
85 struct user_namespace *user_ns = seq_user_ns(p);
86 struct rb_node *n = key_serial_tree.rb_node;
87 struct key *minkey = NULL;
88
89 while (n) {
90 struct key *key = rb_entry(n, struct key, serial_node);
91 if (id < key->serial) {
92 if (!minkey || minkey->serial > key->serial)
93 minkey = key;
94 n = n->rb_left;
95 } else if (id > key->serial) {
96 n = n->rb_right;
97 } else {
98 minkey = key;
99 break;
100 }
101 key = NULL;
102 }
103
104 if (!minkey)
105 return NULL;
106
107 for (;;) {
108 if (kuid_has_mapping(user_ns, minkey->user->uid))
109 return minkey;
110 n = rb_next(&minkey->serial_node);
111 if (!n)
112 return NULL;
113 minkey = rb_entry(n, struct key, serial_node);
114 }
115 }
116
proc_keys_start(struct seq_file * p,loff_t * _pos)117 static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
118 __acquires(key_serial_lock)
119 {
120 key_serial_t pos = *_pos;
121 struct key *key;
122
123 spin_lock(&key_serial_lock);
124
125 if (*_pos > INT_MAX)
126 return NULL;
127 key = find_ge_key(p, pos);
128 if (!key)
129 return NULL;
130 *_pos = key->serial;
131 return &key->serial_node;
132 }
133
key_node_serial(struct rb_node * n)134 static inline key_serial_t key_node_serial(struct rb_node *n)
135 {
136 struct key *key = rb_entry(n, struct key, serial_node);
137 return key->serial;
138 }
139
proc_keys_next(struct seq_file * p,void * v,loff_t * _pos)140 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
141 {
142 struct rb_node *n;
143
144 n = key_serial_next(p, v);
145 if (n)
146 *_pos = key_node_serial(n);
147 else
148 (*_pos)++;
149 return n;
150 }
151
proc_keys_stop(struct seq_file * p,void * v)152 static void proc_keys_stop(struct seq_file *p, void *v)
153 __releases(key_serial_lock)
154 {
155 spin_unlock(&key_serial_lock);
156 }
157
proc_keys_show(struct seq_file * m,void * v)158 static int proc_keys_show(struct seq_file *m, void *v)
159 {
160 struct rb_node *_p = v;
161 struct key *key = rb_entry(_p, struct key, serial_node);
162 unsigned long flags;
163 key_ref_t key_ref, skey_ref;
164 time64_t now, expiry;
165 char xbuf[16];
166 short state;
167 u64 timo;
168 int rc;
169
170 struct keyring_search_context ctx = {
171 .index_key = key->index_key,
172 .cred = m->file->f_cred,
173 .match_data.cmp = lookup_user_key_possessed,
174 .match_data.raw_data = key,
175 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
176 .flags = KEYRING_SEARCH_NO_STATE_CHECK,
177 };
178
179 key_ref = make_key_ref(key, 0);
180
181 /* determine if the key is possessed by this process (a test we can
182 * skip if the key does not indicate the possessor can view it
183 */
184 if (key->perm & KEY_POS_VIEW) {
185 skey_ref = search_my_process_keyrings(&ctx);
186 if (!IS_ERR(skey_ref)) {
187 key_ref_put(skey_ref);
188 key_ref = make_key_ref(key, 1);
189 }
190 }
191
192 /* check whether the current task is allowed to view the key */
193 rc = key_task_permission(key_ref, ctx.cred, KEY_NEED_VIEW);
194 if (rc < 0)
195 return 0;
196
197 now = ktime_get_real_seconds();
198
199 rcu_read_lock();
200
201 /* come up with a suitable timeout value */
202 expiry = READ_ONCE(key->expiry);
203 if (expiry == 0) {
204 memcpy(xbuf, "perm", 5);
205 } else if (now >= expiry) {
206 memcpy(xbuf, "expd", 5);
207 } else {
208 timo = expiry - now;
209
210 if (timo < 60)
211 sprintf(xbuf, "%llus", timo);
212 else if (timo < 60*60)
213 sprintf(xbuf, "%llum", div_u64(timo, 60));
214 else if (timo < 60*60*24)
215 sprintf(xbuf, "%lluh", div_u64(timo, 60 * 60));
216 else if (timo < 60*60*24*7)
217 sprintf(xbuf, "%llud", div_u64(timo, 60 * 60 * 24));
218 else
219 sprintf(xbuf, "%lluw", div_u64(timo, 60 * 60 * 24 * 7));
220 }
221
222 state = key_read_state(key);
223
224 #define showflag(FLAGS, LETTER, FLAG) \
225 ((FLAGS & (1 << FLAG)) ? LETTER : '-')
226
227 flags = READ_ONCE(key->flags);
228 seq_printf(m, "%08x %c%c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
229 key->serial,
230 state != KEY_IS_UNINSTANTIATED ? 'I' : '-',
231 showflag(flags, 'R', KEY_FLAG_REVOKED),
232 showflag(flags, 'D', KEY_FLAG_DEAD),
233 showflag(flags, 'Q', KEY_FLAG_IN_QUOTA),
234 showflag(flags, 'U', KEY_FLAG_USER_CONSTRUCT),
235 state < 0 ? 'N' : '-',
236 showflag(flags, 'i', KEY_FLAG_INVALIDATED),
237 refcount_read(&key->usage),
238 xbuf,
239 key->perm,
240 from_kuid_munged(seq_user_ns(m), key->uid),
241 from_kgid_munged(seq_user_ns(m), key->gid),
242 key->type->name);
243
244 #undef showflag
245
246 if (key->type->describe)
247 key->type->describe(key, m);
248 seq_putc(m, '\n');
249
250 rcu_read_unlock();
251 return 0;
252 }
253
__key_user_next(struct user_namespace * user_ns,struct rb_node * n)254 static struct rb_node *__key_user_next(struct user_namespace *user_ns, struct rb_node *n)
255 {
256 while (n) {
257 struct key_user *user = rb_entry(n, struct key_user, node);
258 if (kuid_has_mapping(user_ns, user->uid))
259 break;
260 n = rb_next(n);
261 }
262 return n;
263 }
264
key_user_next(struct user_namespace * user_ns,struct rb_node * n)265 static struct rb_node *key_user_next(struct user_namespace *user_ns, struct rb_node *n)
266 {
267 return __key_user_next(user_ns, rb_next(n));
268 }
269
key_user_first(struct user_namespace * user_ns,struct rb_root * r)270 static struct rb_node *key_user_first(struct user_namespace *user_ns, struct rb_root *r)
271 {
272 struct rb_node *n = rb_first(r);
273 return __key_user_next(user_ns, n);
274 }
275
proc_key_users_start(struct seq_file * p,loff_t * _pos)276 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
277 __acquires(key_user_lock)
278 {
279 struct rb_node *_p;
280 loff_t pos = *_pos;
281
282 spin_lock(&key_user_lock);
283
284 _p = key_user_first(seq_user_ns(p), &key_user_tree);
285 while (pos > 0 && _p) {
286 pos--;
287 _p = key_user_next(seq_user_ns(p), _p);
288 }
289
290 return _p;
291 }
292
proc_key_users_next(struct seq_file * p,void * v,loff_t * _pos)293 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
294 {
295 (*_pos)++;
296 return key_user_next(seq_user_ns(p), (struct rb_node *)v);
297 }
298
proc_key_users_stop(struct seq_file * p,void * v)299 static void proc_key_users_stop(struct seq_file *p, void *v)
300 __releases(key_user_lock)
301 {
302 spin_unlock(&key_user_lock);
303 }
304
proc_key_users_show(struct seq_file * m,void * v)305 static int proc_key_users_show(struct seq_file *m, void *v)
306 {
307 struct rb_node *_p = v;
308 struct key_user *user = rb_entry(_p, struct key_user, node);
309 unsigned maxkeys = uid_eq(user->uid, GLOBAL_ROOT_UID) ?
310 key_quota_root_maxkeys : key_quota_maxkeys;
311 unsigned maxbytes = uid_eq(user->uid, GLOBAL_ROOT_UID) ?
312 key_quota_root_maxbytes : key_quota_maxbytes;
313
314 seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
315 from_kuid_munged(seq_user_ns(m), user->uid),
316 refcount_read(&user->usage),
317 atomic_read(&user->nkeys),
318 atomic_read(&user->nikeys),
319 user->qnkeys,
320 maxkeys,
321 user->qnbytes,
322 maxbytes);
323
324 return 0;
325 }
326