blob: 66e21184b559e2f0097fe73c970a7da17e2b951d [file] [log] [blame]
David Howells76181c12007-10-16 23:29:46 -07001/* Request a key from userspace
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
David Howells76181c12007-10-16 23:29:46 -07003 * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * 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.
David Howellsf1a9bad2005-10-07 15:04:52 +010010 *
Randy Dunlapd410fa42011-05-19 15:59:38 -070011 * See Documentation/security/keys-request-key.txt
Linus Torvalds1da177e2005-04-16 15:20:36 -070012 */
13
14#include <linux/module.h>
15#include <linux/sched.h>
16#include <linux/kmod.h>
17#include <linux/err.h>
David Howells3e301482005-06-23 22:00:56 -070018#include <linux/keyctl.h>
Robert P. J. Dayfdb89bc2008-04-29 01:01:32 -070019#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include "internal.h"
21
David Howellse9e349b2008-11-14 10:39:13 +110022#define key_negative_timeout 60 /* default timeout on a negative key's existence */
23
David Howells76181c12007-10-16 23:29:46 -070024/*
25 * wait_on_bit() sleep function for uninterruptible waiting
26 */
27static int key_wait_bit(void *flags)
28{
29 schedule();
30 return 0;
31}
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
David Howells76181c12007-10-16 23:29:46 -070033/*
34 * wait_on_bit() sleep function for interruptible waiting
35 */
36static int key_wait_bit_intr(void *flags)
37{
38 schedule();
39 return signal_pending(current) ? -ERESTARTSYS : 0;
40}
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
David Howells973c9f42011-01-20 16:38:33 +000042/**
43 * complete_request_key - Complete the construction of a key.
44 * @cons: The key construction record.
45 * @error: The success or failute of the construction.
46 *
47 * Complete the attempt to construct a key. The key will be negated
48 * if an error is indicated. The authorisation key will be revoked
49 * unconditionally.
David Howells76181c12007-10-16 23:29:46 -070050 */
51void complete_request_key(struct key_construction *cons, int error)
52{
53 kenter("{%d,%d},%d", cons->key->serial, cons->authkey->serial, error);
54
55 if (error < 0)
56 key_negate_and_link(cons->key, key_negative_timeout, NULL,
57 cons->authkey);
58 else
59 key_revoke(cons->authkey);
60
61 key_put(cons->key);
62 key_put(cons->authkey);
63 kfree(cons);
64}
65EXPORT_SYMBOL(complete_request_key);
66
David Howells973c9f42011-01-20 16:38:33 +000067/*
68 * Initialise a usermode helper that is going to have a specific session
69 * keyring.
70 *
71 * This is called in context of freshly forked kthread before kernel_execve(),
72 * so we can simply install the desired session_keyring at this point.
73 */
David Howells87966992011-06-17 11:25:59 +010074static int umh_keys_init(struct subprocess_info *info, struct cred *cred)
Oleg Nesterov685bfd22010-05-26 14:43:00 -070075{
Oleg Nesterov685bfd22010-05-26 14:43:00 -070076 struct key *keyring = info->data;
David Howells973c9f42011-01-20 16:38:33 +000077
Oleg Nesterov685bfd22010-05-26 14:43:00 -070078 return install_session_keyring_to_cred(cred, keyring);
79}
80
David Howells973c9f42011-01-20 16:38:33 +000081/*
82 * Clean up a usermode helper with session keyring.
83 */
Oleg Nesterov685bfd22010-05-26 14:43:00 -070084static void umh_keys_cleanup(struct subprocess_info *info)
85{
86 struct key *keyring = info->data;
87 key_put(keyring);
88}
89
David Howells973c9f42011-01-20 16:38:33 +000090/*
91 * Call a usermode helper with a specific session keyring.
92 */
Oleg Nesterov685bfd22010-05-26 14:43:00 -070093static int call_usermodehelper_keys(char *path, char **argv, char **envp,
Oleg Nesterov9d944ef2012-03-23 15:02:48 -070094 struct key *session_keyring, int wait)
Oleg Nesterov685bfd22010-05-26 14:43:00 -070095{
Boaz Harrosh81ab6e72012-05-31 16:26:15 -070096 return call_usermodehelper_fns(path, argv, envp, wait,
97 umh_keys_init, umh_keys_cleanup,
98 key_get(session_keyring));
Oleg Nesterov685bfd22010-05-26 14:43:00 -070099}
100
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101/*
David Howells973c9f42011-01-20 16:38:33 +0000102 * Request userspace finish the construction of a key
David Howellsb5f545c2006-01-08 01:02:47 -0800103 * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 */
David Howells76181c12007-10-16 23:29:46 -0700105static int call_sbin_request_key(struct key_construction *cons,
David Howells4e54f082006-06-29 02:24:28 -0700106 const char *op,
107 void *aux)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108{
David Howells86a264a2008-11-14 10:39:18 +1100109 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 key_serial_t prkey, sskey;
David Howells93b4a442010-04-23 13:18:00 -0400111 struct key *key = cons->key, *authkey = cons->authkey, *keyring,
112 *session;
David Howellsb5f545c2006-01-08 01:02:47 -0800113 char *argv[9], *envp[3], uid_str[12], gid_str[12];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 char key_str[12], keyring_str[3][12];
David Howellsb5f545c2006-01-08 01:02:47 -0800115 char desc[20];
David Howells3e301482005-06-23 22:00:56 -0700116 int ret, i;
117
David Howellsb5f545c2006-01-08 01:02:47 -0800118 kenter("{%d},{%d},%s", key->serial, authkey->serial, op);
David Howells3e301482005-06-23 22:00:56 -0700119
David Howells8bbf49762008-11-14 10:39:14 +1100120 ret = install_user_keyrings();
121 if (ret < 0)
122 goto error_alloc;
123
David Howellsb5f545c2006-01-08 01:02:47 -0800124 /* allocate a new session keyring */
125 sprintf(desc, "_req.%u", key->serial);
126
David Howellsd84f4f92008-11-14 10:39:23 +1100127 cred = get_current_cred();
128 keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
David Howells7e047ef2006-06-26 00:24:50 -0700129 KEY_ALLOC_QUOTA_OVERRUN, NULL);
David Howellsd84f4f92008-11-14 10:39:23 +1100130 put_cred(cred);
David Howellsb5f545c2006-01-08 01:02:47 -0800131 if (IS_ERR(keyring)) {
132 ret = PTR_ERR(keyring);
133 goto error_alloc;
David Howells3e301482005-06-23 22:00:56 -0700134 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135
David Howellsb5f545c2006-01-08 01:02:47 -0800136 /* attach the auth key to the session keyring */
David Howells896903c2010-04-30 14:32:23 +0100137 ret = key_link(keyring, authkey);
David Howellsb5f545c2006-01-08 01:02:47 -0800138 if (ret < 0)
139 goto error_link;
140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 /* record the UID and GID */
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800142 sprintf(uid_str, "%d", from_kuid(&init_user_ns, cred->fsuid));
143 sprintf(gid_str, "%d", from_kgid(&init_user_ns, cred->fsgid));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
145 /* we say which key is under construction */
146 sprintf(key_str, "%d", key->serial);
147
148 /* we specify the process's default keyrings */
149 sprintf(keyring_str[0], "%d",
David Howellsd84f4f92008-11-14 10:39:23 +1100150 cred->thread_keyring ? cred->thread_keyring->serial : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151
152 prkey = 0;
David Howellsbb952bb2008-11-14 10:39:20 +1100153 if (cred->tgcred->process_keyring)
154 prkey = cred->tgcred->process_keyring->serial;
Justin P. Mattock5ad18a02010-06-30 10:39:11 +0100155 sprintf(keyring_str[1], "%d", prkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156
David Howells93b4a442010-04-23 13:18:00 -0400157 rcu_read_lock();
158 session = rcu_dereference(cred->tgcred->session_keyring);
159 if (!session)
160 session = cred->user->session_keyring;
161 sskey = session->serial;
162 rcu_read_unlock();
David Howells3e301482005-06-23 22:00:56 -0700163
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 sprintf(keyring_str[2], "%d", sskey);
165
166 /* set up a minimal environment */
167 i = 0;
168 envp[i++] = "HOME=/";
169 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
170 envp[i] = NULL;
171
172 /* set up the argument list */
173 i = 0;
174 argv[i++] = "/sbin/request-key";
175 argv[i++] = (char *) op;
176 argv[i++] = key_str;
177 argv[i++] = uid_str;
178 argv[i++] = gid_str;
179 argv[i++] = keyring_str[0];
180 argv[i++] = keyring_str[1];
181 argv[i++] = keyring_str[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 argv[i] = NULL;
183
184 /* do it */
Jeremy Fitzhardinge86313c42007-07-17 18:37:03 -0700185 ret = call_usermodehelper_keys(argv[0], argv, envp, keyring,
186 UMH_WAIT_PROC);
David Howells76181c12007-10-16 23:29:46 -0700187 kdebug("usermode -> 0x%x", ret);
188 if (ret >= 0) {
189 /* ret is the exit/wait code */
190 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) ||
191 key_validate(key) < 0)
192 ret = -ENOKEY;
193 else
194 /* ignore any errors from userspace if the key was
195 * instantiated */
196 ret = 0;
197 }
David Howells3e301482005-06-23 22:00:56 -0700198
David Howellsb5f545c2006-01-08 01:02:47 -0800199error_link:
200 key_put(keyring);
David Howells3e301482005-06-23 22:00:56 -0700201
David Howellsb5f545c2006-01-08 01:02:47 -0800202error_alloc:
David Howells76181c12007-10-16 23:29:46 -0700203 complete_request_key(cons, ret);
David Howellsd84f4f92008-11-14 10:39:23 +1100204 kleave(" = %d", ret);
David Howells3e301482005-06-23 22:00:56 -0700205 return ret;
David Howells76181c12007-10-16 23:29:46 -0700206}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208/*
David Howells973c9f42011-01-20 16:38:33 +0000209 * Call out to userspace for key construction.
210 *
211 * Program failure is ignored in favour of key status.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 */
David Howells4a38e122008-04-29 01:01:24 -0700213static int construct_key(struct key *key, const void *callout_info,
David Howells8bbf49762008-11-14 10:39:14 +1100214 size_t callout_len, void *aux,
215 struct key *dest_keyring)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216{
David Howells76181c12007-10-16 23:29:46 -0700217 struct key_construction *cons;
David Howellsb5f545c2006-01-08 01:02:47 -0800218 request_key_actor_t actor;
David Howells76181c12007-10-16 23:29:46 -0700219 struct key *authkey;
220 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221
David Howells4a38e122008-04-29 01:01:24 -0700222 kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux);
David Howells3e301482005-06-23 22:00:56 -0700223
David Howells76181c12007-10-16 23:29:46 -0700224 cons = kmalloc(sizeof(*cons), GFP_KERNEL);
225 if (!cons)
226 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
David Howellsb5f545c2006-01-08 01:02:47 -0800228 /* allocate an authorisation key */
David Howells8bbf49762008-11-14 10:39:14 +1100229 authkey = request_key_auth_new(key, callout_info, callout_len,
230 dest_keyring);
David Howellsb5f545c2006-01-08 01:02:47 -0800231 if (IS_ERR(authkey)) {
David Howells76181c12007-10-16 23:29:46 -0700232 kfree(cons);
David Howellsb5f545c2006-01-08 01:02:47 -0800233 ret = PTR_ERR(authkey);
234 authkey = NULL;
David Howells76181c12007-10-16 23:29:46 -0700235 } else {
236 cons->authkey = key_get(authkey);
237 cons->key = key_get(key);
238
239 /* make the call */
240 actor = call_sbin_request_key;
241 if (key->type->request_key)
242 actor = key->type->request_key;
243
244 ret = actor(cons, "create", aux);
245
246 /* check that the actor called complete_request_key() prior to
247 * returning an error */
248 WARN_ON(ret < 0 &&
249 !test_bit(KEY_FLAG_REVOKED, &authkey->flags));
250 key_put(authkey);
David Howellsb5f545c2006-01-08 01:02:47 -0800251 }
252
David Howells76181c12007-10-16 23:29:46 -0700253 kleave(" = %d", ret);
254 return ret;
255}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257/*
David Howells973c9f42011-01-20 16:38:33 +0000258 * Get the appropriate destination keyring for the request.
259 *
260 * The keyring selected is returned with an extra reference upon it which the
261 * caller must release.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 */
David Howells8bbf49762008-11-14 10:39:14 +1100263static void construct_get_dest_keyring(struct key **_dest_keyring)
David Howells3e301482005-06-23 22:00:56 -0700264{
David Howells8bbf49762008-11-14 10:39:14 +1100265 struct request_key_auth *rka;
David Howellsbb952bb2008-11-14 10:39:20 +1100266 const struct cred *cred = current_cred();
David Howells8bbf49762008-11-14 10:39:14 +1100267 struct key *dest_keyring = *_dest_keyring, *authkey;
David Howells3e301482005-06-23 22:00:56 -0700268
David Howells8bbf49762008-11-14 10:39:14 +1100269 kenter("%p", dest_keyring);
David Howells3e301482005-06-23 22:00:56 -0700270
271 /* find the appropriate keyring */
David Howells8bbf49762008-11-14 10:39:14 +1100272 if (dest_keyring) {
273 /* the caller supplied one */
274 key_get(dest_keyring);
275 } else {
276 /* use a default keyring; falling through the cases until we
277 * find one that we actually have */
David Howellsbb952bb2008-11-14 10:39:20 +1100278 switch (cred->jit_keyring) {
David Howells3e301482005-06-23 22:00:56 -0700279 case KEY_REQKEY_DEFL_DEFAULT:
David Howells8bbf49762008-11-14 10:39:14 +1100280 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100281 if (cred->request_key_auth) {
282 authkey = cred->request_key_auth;
David Howells8bbf49762008-11-14 10:39:14 +1100283 down_read(&authkey->sem);
284 rka = authkey->payload.data;
285 if (!test_bit(KEY_FLAG_REVOKED,
286 &authkey->flags))
287 dest_keyring =
288 key_get(rka->dest_keyring);
289 up_read(&authkey->sem);
290 if (dest_keyring)
291 break;
292 }
293
David Howells3e301482005-06-23 22:00:56 -0700294 case KEY_REQKEY_DEFL_THREAD_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100295 dest_keyring = key_get(cred->thread_keyring);
David Howells3e301482005-06-23 22:00:56 -0700296 if (dest_keyring)
297 break;
298
299 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100300 dest_keyring = key_get(cred->tgcred->process_keyring);
David Howells3e301482005-06-23 22:00:56 -0700301 if (dest_keyring)
302 break;
303
304 case KEY_REQKEY_DEFL_SESSION_KEYRING:
305 rcu_read_lock();
306 dest_keyring = key_get(
David Howellsbb952bb2008-11-14 10:39:20 +1100307 rcu_dereference(cred->tgcred->session_keyring));
David Howells3e301482005-06-23 22:00:56 -0700308 rcu_read_unlock();
David Howells3e301482005-06-23 22:00:56 -0700309
310 if (dest_keyring)
311 break;
312
313 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
David Howellsb6dff3e2008-11-14 10:39:16 +1100314 dest_keyring =
David Howellsbb952bb2008-11-14 10:39:20 +1100315 key_get(cred->user->session_keyring);
David Howells3e301482005-06-23 22:00:56 -0700316 break;
317
318 case KEY_REQKEY_DEFL_USER_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100319 dest_keyring = key_get(cred->user->uid_keyring);
David Howells3e301482005-06-23 22:00:56 -0700320 break;
321
322 case KEY_REQKEY_DEFL_GROUP_KEYRING:
323 default:
324 BUG();
325 }
326 }
327
David Howells8bbf49762008-11-14 10:39:14 +1100328 *_dest_keyring = dest_keyring;
329 kleave(" [dk %d]", key_serial(dest_keyring));
330 return;
David Howells76181c12007-10-16 23:29:46 -0700331}
David Howells3e301482005-06-23 22:00:56 -0700332
David Howells76181c12007-10-16 23:29:46 -0700333/*
David Howells973c9f42011-01-20 16:38:33 +0000334 * Allocate a new key in under-construction state and attempt to link it in to
335 * the requested keyring.
336 *
337 * May return a key that's already under construction instead if there was a
338 * race between two thread calling request_key().
David Howells76181c12007-10-16 23:29:46 -0700339 */
340static int construct_alloc_key(struct key_type *type,
341 const char *description,
342 struct key *dest_keyring,
343 unsigned long flags,
344 struct key_user *user,
345 struct key **_key)
346{
David Howellsd84f4f92008-11-14 10:39:23 +1100347 const struct cred *cred = current_cred();
David Howellsceb73c12011-01-25 16:34:28 +0000348 unsigned long prealloc;
David Howells76181c12007-10-16 23:29:46 -0700349 struct key *key;
350 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100351 int ret;
David Howells3e301482005-06-23 22:00:56 -0700352
David Howells76181c12007-10-16 23:29:46 -0700353 kenter("%s,%s,,,", type->name, description);
354
David Howellsf70e2e02010-04-30 14:32:39 +0100355 *_key = NULL;
David Howells76181c12007-10-16 23:29:46 -0700356 mutex_lock(&user->cons_lock);
357
David Howellsd84f4f92008-11-14 10:39:23 +1100358 key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
359 KEY_POS_ALL, flags);
David Howells76181c12007-10-16 23:29:46 -0700360 if (IS_ERR(key))
361 goto alloc_failed;
362
363 set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
364
David Howellsf70e2e02010-04-30 14:32:39 +0100365 if (dest_keyring) {
366 ret = __key_link_begin(dest_keyring, type, description,
367 &prealloc);
368 if (ret < 0)
369 goto link_prealloc_failed;
370 }
David Howells76181c12007-10-16 23:29:46 -0700371
372 /* attach the key to the destination keyring under lock, but we do need
373 * to do another check just in case someone beat us to it whilst we
374 * waited for locks */
375 mutex_lock(&key_construction_mutex);
376
David Howellsd84f4f92008-11-14 10:39:23 +1100377 key_ref = search_process_keyrings(type, description, type->match, cred);
David Howells76181c12007-10-16 23:29:46 -0700378 if (!IS_ERR(key_ref))
379 goto key_already_present;
380
David Howells34574dd2009-04-09 17:14:05 +0100381 if (dest_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100382 __key_link(dest_keyring, key, &prealloc);
David Howells76181c12007-10-16 23:29:46 -0700383
384 mutex_unlock(&key_construction_mutex);
David Howells34574dd2009-04-09 17:14:05 +0100385 if (dest_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100386 __key_link_end(dest_keyring, type, prealloc);
David Howells76181c12007-10-16 23:29:46 -0700387 mutex_unlock(&user->cons_lock);
388 *_key = key;
389 kleave(" = 0 [%d]", key_serial(key));
390 return 0;
391
David Howells2b9e4682010-04-30 14:32:34 +0100392 /* the key is now present - we tell the caller that we found it by
393 * returning -EINPROGRESS */
David Howells76181c12007-10-16 23:29:46 -0700394key_already_present:
David Howellsf70e2e02010-04-30 14:32:39 +0100395 key_put(key);
David Howells76181c12007-10-16 23:29:46 -0700396 mutex_unlock(&key_construction_mutex);
David Howellsf70e2e02010-04-30 14:32:39 +0100397 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700398 if (dest_keyring) {
David Howellsf70e2e02010-04-30 14:32:39 +0100399 ret = __key_link_check_live_key(dest_keyring, key);
400 if (ret == 0)
401 __key_link(dest_keyring, key, &prealloc);
402 __key_link_end(dest_keyring, type, prealloc);
403 if (ret < 0)
404 goto link_check_failed;
David Howells03449cd2010-04-27 13:13:08 -0700405 }
David Howells76181c12007-10-16 23:29:46 -0700406 mutex_unlock(&user->cons_lock);
David Howellsf70e2e02010-04-30 14:32:39 +0100407 *_key = key;
David Howells76181c12007-10-16 23:29:46 -0700408 kleave(" = -EINPROGRESS [%d]", key_serial(key));
409 return -EINPROGRESS;
410
David Howellsf70e2e02010-04-30 14:32:39 +0100411link_check_failed:
412 mutex_unlock(&user->cons_lock);
413 key_put(key);
414 kleave(" = %d [linkcheck]", ret);
415 return ret;
416
417link_prealloc_failed:
David Howellsf70e2e02010-04-30 14:32:39 +0100418 mutex_unlock(&user->cons_lock);
419 kleave(" = %d [prelink]", ret);
420 return ret;
421
David Howells76181c12007-10-16 23:29:46 -0700422alloc_failed:
423 mutex_unlock(&user->cons_lock);
David Howells76181c12007-10-16 23:29:46 -0700424 kleave(" = %ld", PTR_ERR(key));
425 return PTR_ERR(key);
426}
427
428/*
David Howells973c9f42011-01-20 16:38:33 +0000429 * Commence key construction.
David Howells76181c12007-10-16 23:29:46 -0700430 */
431static struct key *construct_key_and_link(struct key_type *type,
432 const char *description,
433 const char *callout_info,
David Howells4a38e122008-04-29 01:01:24 -0700434 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700435 void *aux,
436 struct key *dest_keyring,
437 unsigned long flags)
438{
439 struct key_user *user;
440 struct key *key;
441 int ret;
442
David Howellsd84f4f92008-11-14 10:39:23 +1100443 kenter("");
444
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800445 user = key_user_lookup(current_fsuid());
David Howells76181c12007-10-16 23:29:46 -0700446 if (!user)
447 return ERR_PTR(-ENOMEM);
448
David Howells8bbf49762008-11-14 10:39:14 +1100449 construct_get_dest_keyring(&dest_keyring);
450
David Howells76181c12007-10-16 23:29:46 -0700451 ret = construct_alloc_key(type, description, dest_keyring, flags, user,
452 &key);
453 key_user_put(user);
454
455 if (ret == 0) {
David Howells8bbf49762008-11-14 10:39:14 +1100456 ret = construct_key(key, callout_info, callout_len, aux,
457 dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100458 if (ret < 0) {
459 kdebug("cons failed");
David Howells76181c12007-10-16 23:29:46 -0700460 goto construction_failed;
David Howellsd84f4f92008-11-14 10:39:23 +1100461 }
David Howells2b9e4682010-04-30 14:32:34 +0100462 } else if (ret == -EINPROGRESS) {
463 ret = 0;
464 } else {
David Howellsb1d7dd82011-06-21 14:32:05 +0100465 goto couldnt_alloc_key;
David Howells76181c12007-10-16 23:29:46 -0700466 }
467
David Howells8bbf49762008-11-14 10:39:14 +1100468 key_put(dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100469 kleave(" = key %d", key_serial(key));
David Howells76181c12007-10-16 23:29:46 -0700470 return key;
471
472construction_failed:
473 key_negate_and_link(key, key_negative_timeout, NULL, NULL);
474 key_put(key);
David Howellsb1d7dd82011-06-21 14:32:05 +0100475couldnt_alloc_key:
David Howells8bbf49762008-11-14 10:39:14 +1100476 key_put(dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100477 kleave(" = %d", ret);
David Howells76181c12007-10-16 23:29:46 -0700478 return ERR_PTR(ret);
479}
480
David Howells973c9f42011-01-20 16:38:33 +0000481/**
482 * request_key_and_link - Request a key and cache it in a keyring.
483 * @type: The type of key we want.
484 * @description: The searchable description of the key.
485 * @callout_info: The data to pass to the instantiation upcall (or NULL).
486 * @callout_len: The length of callout_info.
487 * @aux: Auxiliary data for the upcall.
488 * @dest_keyring: Where to cache the key.
489 * @flags: Flags to key_alloc().
490 *
491 * A key matching the specified criteria is searched for in the process's
492 * keyrings and returned with its usage count incremented if found. Otherwise,
493 * if callout_info is not NULL, a key will be allocated and some service
494 * (probably in userspace) will be asked to instantiate it.
495 *
496 * If successfully found or created, the key will be linked to the destination
497 * keyring if one is provided.
498 *
499 * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
500 * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
501 * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
502 * if insufficient key quota was available to create a new key; or -ENOMEM if
503 * insufficient memory was available.
504 *
505 * If the returned key was created, then it may still be under construction,
506 * and wait_for_key_construction() should be used to wait for that to complete.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 */
David Howells3e301482005-06-23 22:00:56 -0700508struct key *request_key_and_link(struct key_type *type,
509 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700510 const void *callout_info,
511 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700512 void *aux,
David Howells7e047ef2006-06-26 00:24:50 -0700513 struct key *dest_keyring,
514 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515{
David Howellsd84f4f92008-11-14 10:39:23 +1100516 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 struct key *key;
David Howells664cceb2005-09-28 17:03:15 +0100518 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100519 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
David Howells4a38e122008-04-29 01:01:24 -0700521 kenter("%s,%s,%p,%zu,%p,%p,%lx",
522 type->name, description, callout_info, callout_len, aux,
David Howells4e54f082006-06-29 02:24:28 -0700523 dest_keyring, flags);
David Howells3e301482005-06-23 22:00:56 -0700524
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 /* search all the process keyrings for a key */
David Howells78b72802011-03-11 17:57:23 +0000526 key_ref = search_process_keyrings(type, description, type->match, cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
David Howells664cceb2005-09-28 17:03:15 +0100528 if (!IS_ERR(key_ref)) {
529 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700530 if (dest_keyring) {
531 construct_get_dest_keyring(&dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100532 ret = key_link(dest_keyring, key);
David Howells03449cd2010-04-27 13:13:08 -0700533 key_put(dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100534 if (ret < 0) {
535 key_put(key);
536 key = ERR_PTR(ret);
537 goto error;
538 }
David Howells03449cd2010-04-27 13:13:08 -0700539 }
David Howells76181c12007-10-16 23:29:46 -0700540 } else if (PTR_ERR(key_ref) != -EAGAIN) {
David Howellse231c2e2008-02-07 00:15:26 -0800541 key = ERR_CAST(key_ref);
David Howells76181c12007-10-16 23:29:46 -0700542 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 /* the search failed, but the keyrings were searchable, so we
544 * should consult userspace if we can */
545 key = ERR_PTR(-ENOKEY);
546 if (!callout_info)
547 goto error;
548
David Howells76181c12007-10-16 23:29:46 -0700549 key = construct_key_and_link(type, description, callout_info,
David Howells4a38e122008-04-29 01:01:24 -0700550 callout_len, aux, dest_keyring,
551 flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 }
553
David Howells3e301482005-06-23 22:00:56 -0700554error:
555 kleave(" = %p", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 return key;
David Howells76181c12007-10-16 23:29:46 -0700557}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558
David Howells973c9f42011-01-20 16:38:33 +0000559/**
560 * wait_for_key_construction - Wait for construction of a key to complete
561 * @key: The key being waited for.
562 * @intr: Whether to wait interruptibly.
563 *
564 * Wait for a key to finish being constructed.
565 *
566 * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY
567 * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was
568 * revoked or expired.
David Howells76181c12007-10-16 23:29:46 -0700569 */
570int wait_for_key_construction(struct key *key, bool intr)
571{
572 int ret;
David Howells3e301482005-06-23 22:00:56 -0700573
David Howells76181c12007-10-16 23:29:46 -0700574 ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
575 intr ? key_wait_bit_intr : key_wait_bit,
576 intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
577 if (ret < 0)
578 return ret;
David Howells1e456a12010-08-06 16:08:27 +0100579 if (test_bit(KEY_FLAG_NEGATIVE, &key->flags))
David Howellsfdd1b942011-03-07 15:06:09 +0000580 return key->type_data.reject_error;
David Howells76181c12007-10-16 23:29:46 -0700581 return key_validate(key);
582}
583EXPORT_SYMBOL(wait_for_key_construction);
David Howells3e301482005-06-23 22:00:56 -0700584
David Howells973c9f42011-01-20 16:38:33 +0000585/**
586 * request_key - Request a key and wait for construction
587 * @type: Type of key.
588 * @description: The searchable description of the key.
589 * @callout_info: The data to pass to the instantiation upcall (or NULL).
590 *
591 * As for request_key_and_link() except that it does not add the returned key
592 * to a keyring if found, new keys are always allocated in the user's quota,
593 * the callout_info must be a NUL-terminated string and no auxiliary data can
594 * be passed.
595 *
596 * Furthermore, it then works as wait_for_key_construction() to wait for the
597 * completion of keys undergoing construction with a non-interruptible wait.
David Howells3e301482005-06-23 22:00:56 -0700598 */
599struct key *request_key(struct key_type *type,
600 const char *description,
601 const char *callout_info)
602{
David Howells76181c12007-10-16 23:29:46 -0700603 struct key *key;
David Howells4a38e122008-04-29 01:01:24 -0700604 size_t callout_len = 0;
David Howells76181c12007-10-16 23:29:46 -0700605 int ret;
David Howells3e301482005-06-23 22:00:56 -0700606
David Howells4a38e122008-04-29 01:01:24 -0700607 if (callout_info)
608 callout_len = strlen(callout_info);
609 key = request_key_and_link(type, description, callout_info, callout_len,
610 NULL, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700611 if (!IS_ERR(key)) {
612 ret = wait_for_key_construction(key, false);
613 if (ret < 0) {
614 key_put(key);
615 return ERR_PTR(ret);
616 }
617 }
618 return key;
619}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620EXPORT_SYMBOL(request_key);
David Howells4e54f082006-06-29 02:24:28 -0700621
David Howells973c9f42011-01-20 16:38:33 +0000622/**
623 * request_key_with_auxdata - Request a key with auxiliary data for the upcaller
624 * @type: The type of key we want.
625 * @description: The searchable description of the key.
626 * @callout_info: The data to pass to the instantiation upcall (or NULL).
627 * @callout_len: The length of callout_info.
628 * @aux: Auxiliary data for the upcall.
629 *
630 * As for request_key_and_link() except that it does not add the returned key
631 * to a keyring if found and new keys are always allocated in the user's quota.
632 *
633 * Furthermore, it then works as wait_for_key_construction() to wait for the
634 * completion of keys undergoing construction with a non-interruptible wait.
David Howells4e54f082006-06-29 02:24:28 -0700635 */
636struct key *request_key_with_auxdata(struct key_type *type,
637 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700638 const void *callout_info,
639 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700640 void *aux)
641{
David Howells76181c12007-10-16 23:29:46 -0700642 struct key *key;
643 int ret;
644
David Howells4a38e122008-04-29 01:01:24 -0700645 key = request_key_and_link(type, description, callout_info, callout_len,
646 aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700647 if (!IS_ERR(key)) {
648 ret = wait_for_key_construction(key, false);
649 if (ret < 0) {
650 key_put(key);
651 return ERR_PTR(ret);
652 }
653 }
654 return key;
655}
656EXPORT_SYMBOL(request_key_with_auxdata);
657
658/*
David Howells973c9f42011-01-20 16:38:33 +0000659 * request_key_async - Request a key (allow async construction)
660 * @type: Type of key.
661 * @description: The searchable description of the key.
662 * @callout_info: The data to pass to the instantiation upcall (or NULL).
663 * @callout_len: The length of callout_info.
664 *
665 * As for request_key_and_link() except that it does not add the returned key
666 * to a keyring if found, new keys are always allocated in the user's quota and
667 * no auxiliary data can be passed.
668 *
669 * The caller should call wait_for_key_construction() to wait for the
670 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700671 */
672struct key *request_key_async(struct key_type *type,
673 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700674 const void *callout_info,
675 size_t callout_len)
David Howells76181c12007-10-16 23:29:46 -0700676{
David Howells4a38e122008-04-29 01:01:24 -0700677 return request_key_and_link(type, description, callout_info,
678 callout_len, NULL, NULL,
679 KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700680}
681EXPORT_SYMBOL(request_key_async);
682
683/*
684 * request a key with auxiliary data for the upcaller (allow async construction)
David Howells973c9f42011-01-20 16:38:33 +0000685 * @type: Type of key.
686 * @description: The searchable description of the key.
687 * @callout_info: The data to pass to the instantiation upcall (or NULL).
688 * @callout_len: The length of callout_info.
689 * @aux: Auxiliary data for the upcall.
690 *
691 * As for request_key_and_link() except that it does not add the returned key
692 * to a keyring if found and new keys are always allocated in the user's quota.
693 *
694 * The caller should call wait_for_key_construction() to wait for the
695 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700696 */
697struct key *request_key_async_with_auxdata(struct key_type *type,
698 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700699 const void *callout_info,
700 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700701 void *aux)
702{
David Howells4a38e122008-04-29 01:01:24 -0700703 return request_key_and_link(type, description, callout_info,
704 callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700705}
706EXPORT_SYMBOL(request_key_async_with_auxdata);