blob: d41cc153a31373a33580f69d53ba21455d187d4e [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 */
Oleg Nesterov685bfd22010-05-26 14:43:00 -070074static int umh_keys_init(struct subprocess_info *info)
75{
76 struct cred *cred = (struct cred*)current_cred();
77 struct key *keyring = info->data;
David Howells973c9f42011-01-20 16:38:33 +000078
Oleg Nesterov685bfd22010-05-26 14:43:00 -070079 return install_session_keyring_to_cred(cred, keyring);
80}
81
David Howells973c9f42011-01-20 16:38:33 +000082/*
83 * Clean up a usermode helper with session keyring.
84 */
Oleg Nesterov685bfd22010-05-26 14:43:00 -070085static void umh_keys_cleanup(struct subprocess_info *info)
86{
87 struct key *keyring = info->data;
88 key_put(keyring);
89}
90
David Howells973c9f42011-01-20 16:38:33 +000091/*
92 * Call a usermode helper with a specific session keyring.
93 */
Oleg Nesterov685bfd22010-05-26 14:43:00 -070094static int call_usermodehelper_keys(char *path, char **argv, char **envp,
95 struct key *session_keyring, enum umh_wait wait)
96{
97 gfp_t gfp_mask = (wait == UMH_NO_WAIT) ? GFP_ATOMIC : GFP_KERNEL;
98 struct subprocess_info *info =
99 call_usermodehelper_setup(path, argv, envp, gfp_mask);
100
101 if (!info)
102 return -ENOMEM;
103
104 call_usermodehelper_setfns(info, umh_keys_init, umh_keys_cleanup,
105 key_get(session_keyring));
106 return call_usermodehelper_exec(info, wait);
107}
108
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109/*
David Howells973c9f42011-01-20 16:38:33 +0000110 * Request userspace finish the construction of a key
David Howellsb5f545c2006-01-08 01:02:47 -0800111 * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 */
David Howells76181c12007-10-16 23:29:46 -0700113static int call_sbin_request_key(struct key_construction *cons,
David Howells4e54f082006-06-29 02:24:28 -0700114 const char *op,
115 void *aux)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116{
David Howells86a264a2008-11-14 10:39:18 +1100117 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 key_serial_t prkey, sskey;
David Howells93b4a442010-04-23 13:18:00 -0400119 struct key *key = cons->key, *authkey = cons->authkey, *keyring,
120 *session;
David Howellsb5f545c2006-01-08 01:02:47 -0800121 char *argv[9], *envp[3], uid_str[12], gid_str[12];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 char key_str[12], keyring_str[3][12];
David Howellsb5f545c2006-01-08 01:02:47 -0800123 char desc[20];
David Howells3e301482005-06-23 22:00:56 -0700124 int ret, i;
125
David Howellsb5f545c2006-01-08 01:02:47 -0800126 kenter("{%d},{%d},%s", key->serial, authkey->serial, op);
David Howells3e301482005-06-23 22:00:56 -0700127
David Howells8bbf49762008-11-14 10:39:14 +1100128 ret = install_user_keyrings();
129 if (ret < 0)
130 goto error_alloc;
131
David Howellsb5f545c2006-01-08 01:02:47 -0800132 /* allocate a new session keyring */
133 sprintf(desc, "_req.%u", key->serial);
134
David Howellsd84f4f92008-11-14 10:39:23 +1100135 cred = get_current_cred();
136 keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
David Howells7e047ef2006-06-26 00:24:50 -0700137 KEY_ALLOC_QUOTA_OVERRUN, NULL);
David Howellsd84f4f92008-11-14 10:39:23 +1100138 put_cred(cred);
David Howellsb5f545c2006-01-08 01:02:47 -0800139 if (IS_ERR(keyring)) {
140 ret = PTR_ERR(keyring);
141 goto error_alloc;
David Howells3e301482005-06-23 22:00:56 -0700142 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
David Howellsb5f545c2006-01-08 01:02:47 -0800144 /* attach the auth key to the session keyring */
David Howells896903c2010-04-30 14:32:23 +0100145 ret = key_link(keyring, authkey);
David Howellsb5f545c2006-01-08 01:02:47 -0800146 if (ret < 0)
147 goto error_link;
148
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 /* record the UID and GID */
David Howells86a264a2008-11-14 10:39:18 +1100150 sprintf(uid_str, "%d", cred->fsuid);
151 sprintf(gid_str, "%d", cred->fsgid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
153 /* we say which key is under construction */
154 sprintf(key_str, "%d", key->serial);
155
156 /* we specify the process's default keyrings */
157 sprintf(keyring_str[0], "%d",
David Howellsd84f4f92008-11-14 10:39:23 +1100158 cred->thread_keyring ? cred->thread_keyring->serial : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159
160 prkey = 0;
David Howellsbb952bb2008-11-14 10:39:20 +1100161 if (cred->tgcred->process_keyring)
162 prkey = cred->tgcred->process_keyring->serial;
Justin P. Mattock5ad18a02010-06-30 10:39:11 +0100163 sprintf(keyring_str[1], "%d", prkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
David Howells93b4a442010-04-23 13:18:00 -0400165 rcu_read_lock();
166 session = rcu_dereference(cred->tgcred->session_keyring);
167 if (!session)
168 session = cred->user->session_keyring;
169 sskey = session->serial;
170 rcu_read_unlock();
David Howells3e301482005-06-23 22:00:56 -0700171
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 sprintf(keyring_str[2], "%d", sskey);
173
174 /* set up a minimal environment */
175 i = 0;
176 envp[i++] = "HOME=/";
177 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
178 envp[i] = NULL;
179
180 /* set up the argument list */
181 i = 0;
182 argv[i++] = "/sbin/request-key";
183 argv[i++] = (char *) op;
184 argv[i++] = key_str;
185 argv[i++] = uid_str;
186 argv[i++] = gid_str;
187 argv[i++] = keyring_str[0];
188 argv[i++] = keyring_str[1];
189 argv[i++] = keyring_str[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 argv[i] = NULL;
191
192 /* do it */
Jeremy Fitzhardinge86313c42007-07-17 18:37:03 -0700193 ret = call_usermodehelper_keys(argv[0], argv, envp, keyring,
194 UMH_WAIT_PROC);
David Howells76181c12007-10-16 23:29:46 -0700195 kdebug("usermode -> 0x%x", ret);
196 if (ret >= 0) {
197 /* ret is the exit/wait code */
198 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) ||
199 key_validate(key) < 0)
200 ret = -ENOKEY;
201 else
202 /* ignore any errors from userspace if the key was
203 * instantiated */
204 ret = 0;
205 }
David Howells3e301482005-06-23 22:00:56 -0700206
David Howellsb5f545c2006-01-08 01:02:47 -0800207error_link:
208 key_put(keyring);
David Howells3e301482005-06-23 22:00:56 -0700209
David Howellsb5f545c2006-01-08 01:02:47 -0800210error_alloc:
David Howells76181c12007-10-16 23:29:46 -0700211 complete_request_key(cons, ret);
David Howellsd84f4f92008-11-14 10:39:23 +1100212 kleave(" = %d", ret);
David Howells3e301482005-06-23 22:00:56 -0700213 return ret;
David Howells76181c12007-10-16 23:29:46 -0700214}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216/*
David Howells973c9f42011-01-20 16:38:33 +0000217 * Call out to userspace for key construction.
218 *
219 * Program failure is ignored in favour of key status.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220 */
David Howells4a38e122008-04-29 01:01:24 -0700221static int construct_key(struct key *key, const void *callout_info,
David Howells8bbf49762008-11-14 10:39:14 +1100222 size_t callout_len, void *aux,
223 struct key *dest_keyring)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224{
David Howells76181c12007-10-16 23:29:46 -0700225 struct key_construction *cons;
David Howellsb5f545c2006-01-08 01:02:47 -0800226 request_key_actor_t actor;
David Howells76181c12007-10-16 23:29:46 -0700227 struct key *authkey;
228 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
David Howells4a38e122008-04-29 01:01:24 -0700230 kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux);
David Howells3e301482005-06-23 22:00:56 -0700231
David Howells76181c12007-10-16 23:29:46 -0700232 cons = kmalloc(sizeof(*cons), GFP_KERNEL);
233 if (!cons)
234 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
David Howellsb5f545c2006-01-08 01:02:47 -0800236 /* allocate an authorisation key */
David Howells8bbf49762008-11-14 10:39:14 +1100237 authkey = request_key_auth_new(key, callout_info, callout_len,
238 dest_keyring);
David Howellsb5f545c2006-01-08 01:02:47 -0800239 if (IS_ERR(authkey)) {
David Howells76181c12007-10-16 23:29:46 -0700240 kfree(cons);
David Howellsb5f545c2006-01-08 01:02:47 -0800241 ret = PTR_ERR(authkey);
242 authkey = NULL;
David Howells76181c12007-10-16 23:29:46 -0700243 } else {
244 cons->authkey = key_get(authkey);
245 cons->key = key_get(key);
246
247 /* make the call */
248 actor = call_sbin_request_key;
249 if (key->type->request_key)
250 actor = key->type->request_key;
251
252 ret = actor(cons, "create", aux);
253
254 /* check that the actor called complete_request_key() prior to
255 * returning an error */
256 WARN_ON(ret < 0 &&
257 !test_bit(KEY_FLAG_REVOKED, &authkey->flags));
258 key_put(authkey);
David Howellsb5f545c2006-01-08 01:02:47 -0800259 }
260
David Howells76181c12007-10-16 23:29:46 -0700261 kleave(" = %d", ret);
262 return ret;
263}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265/*
David Howells973c9f42011-01-20 16:38:33 +0000266 * Get the appropriate destination keyring for the request.
267 *
268 * The keyring selected is returned with an extra reference upon it which the
269 * caller must release.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 */
David Howells8bbf49762008-11-14 10:39:14 +1100271static void construct_get_dest_keyring(struct key **_dest_keyring)
David Howells3e301482005-06-23 22:00:56 -0700272{
David Howells8bbf49762008-11-14 10:39:14 +1100273 struct request_key_auth *rka;
David Howellsbb952bb2008-11-14 10:39:20 +1100274 const struct cred *cred = current_cred();
David Howells8bbf49762008-11-14 10:39:14 +1100275 struct key *dest_keyring = *_dest_keyring, *authkey;
David Howells3e301482005-06-23 22:00:56 -0700276
David Howells8bbf49762008-11-14 10:39:14 +1100277 kenter("%p", dest_keyring);
David Howells3e301482005-06-23 22:00:56 -0700278
279 /* find the appropriate keyring */
David Howells8bbf49762008-11-14 10:39:14 +1100280 if (dest_keyring) {
281 /* the caller supplied one */
282 key_get(dest_keyring);
283 } else {
284 /* use a default keyring; falling through the cases until we
285 * find one that we actually have */
David Howellsbb952bb2008-11-14 10:39:20 +1100286 switch (cred->jit_keyring) {
David Howells3e301482005-06-23 22:00:56 -0700287 case KEY_REQKEY_DEFL_DEFAULT:
David Howells8bbf49762008-11-14 10:39:14 +1100288 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100289 if (cred->request_key_auth) {
290 authkey = cred->request_key_auth;
David Howells8bbf49762008-11-14 10:39:14 +1100291 down_read(&authkey->sem);
292 rka = authkey->payload.data;
293 if (!test_bit(KEY_FLAG_REVOKED,
294 &authkey->flags))
295 dest_keyring =
296 key_get(rka->dest_keyring);
297 up_read(&authkey->sem);
298 if (dest_keyring)
299 break;
300 }
301
David Howells3e301482005-06-23 22:00:56 -0700302 case KEY_REQKEY_DEFL_THREAD_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100303 dest_keyring = key_get(cred->thread_keyring);
David Howells3e301482005-06-23 22:00:56 -0700304 if (dest_keyring)
305 break;
306
307 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100308 dest_keyring = key_get(cred->tgcred->process_keyring);
David Howells3e301482005-06-23 22:00:56 -0700309 if (dest_keyring)
310 break;
311
312 case KEY_REQKEY_DEFL_SESSION_KEYRING:
313 rcu_read_lock();
314 dest_keyring = key_get(
David Howellsbb952bb2008-11-14 10:39:20 +1100315 rcu_dereference(cred->tgcred->session_keyring));
David Howells3e301482005-06-23 22:00:56 -0700316 rcu_read_unlock();
David Howells3e301482005-06-23 22:00:56 -0700317
318 if (dest_keyring)
319 break;
320
321 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
David Howellsb6dff3e2008-11-14 10:39:16 +1100322 dest_keyring =
David Howellsbb952bb2008-11-14 10:39:20 +1100323 key_get(cred->user->session_keyring);
David Howells3e301482005-06-23 22:00:56 -0700324 break;
325
326 case KEY_REQKEY_DEFL_USER_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100327 dest_keyring = key_get(cred->user->uid_keyring);
David Howells3e301482005-06-23 22:00:56 -0700328 break;
329
330 case KEY_REQKEY_DEFL_GROUP_KEYRING:
331 default:
332 BUG();
333 }
334 }
335
David Howells8bbf49762008-11-14 10:39:14 +1100336 *_dest_keyring = dest_keyring;
337 kleave(" [dk %d]", key_serial(dest_keyring));
338 return;
David Howells76181c12007-10-16 23:29:46 -0700339}
David Howells3e301482005-06-23 22:00:56 -0700340
David Howells76181c12007-10-16 23:29:46 -0700341/*
David Howells973c9f42011-01-20 16:38:33 +0000342 * Allocate a new key in under-construction state and attempt to link it in to
343 * the requested keyring.
344 *
345 * May return a key that's already under construction instead if there was a
346 * race between two thread calling request_key().
David Howells76181c12007-10-16 23:29:46 -0700347 */
348static int construct_alloc_key(struct key_type *type,
349 const char *description,
350 struct key *dest_keyring,
351 unsigned long flags,
352 struct key_user *user,
353 struct key **_key)
354{
David Howellsd84f4f92008-11-14 10:39:23 +1100355 const struct cred *cred = current_cred();
David Howellsceb73c12011-01-25 16:34:28 +0000356 unsigned long prealloc;
David Howells76181c12007-10-16 23:29:46 -0700357 struct key *key;
358 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100359 int ret;
David Howells3e301482005-06-23 22:00:56 -0700360
David Howells76181c12007-10-16 23:29:46 -0700361 kenter("%s,%s,,,", type->name, description);
362
David Howellsf70e2e02010-04-30 14:32:39 +0100363 *_key = NULL;
David Howells76181c12007-10-16 23:29:46 -0700364 mutex_lock(&user->cons_lock);
365
David Howellsd84f4f92008-11-14 10:39:23 +1100366 key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
367 KEY_POS_ALL, flags);
David Howells76181c12007-10-16 23:29:46 -0700368 if (IS_ERR(key))
369 goto alloc_failed;
370
371 set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
372
David Howellsf70e2e02010-04-30 14:32:39 +0100373 if (dest_keyring) {
374 ret = __key_link_begin(dest_keyring, type, description,
375 &prealloc);
376 if (ret < 0)
377 goto link_prealloc_failed;
378 }
David Howells76181c12007-10-16 23:29:46 -0700379
380 /* attach the key to the destination keyring under lock, but we do need
381 * to do another check just in case someone beat us to it whilst we
382 * waited for locks */
383 mutex_lock(&key_construction_mutex);
384
David Howellsd84f4f92008-11-14 10:39:23 +1100385 key_ref = search_process_keyrings(type, description, type->match, cred);
David Howells76181c12007-10-16 23:29:46 -0700386 if (!IS_ERR(key_ref))
387 goto key_already_present;
388
David Howells34574dd2009-04-09 17:14:05 +0100389 if (dest_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100390 __key_link(dest_keyring, key, &prealloc);
David Howells76181c12007-10-16 23:29:46 -0700391
392 mutex_unlock(&key_construction_mutex);
David Howells34574dd2009-04-09 17:14:05 +0100393 if (dest_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100394 __key_link_end(dest_keyring, type, prealloc);
David Howells76181c12007-10-16 23:29:46 -0700395 mutex_unlock(&user->cons_lock);
396 *_key = key;
397 kleave(" = 0 [%d]", key_serial(key));
398 return 0;
399
David Howells2b9e4682010-04-30 14:32:34 +0100400 /* the key is now present - we tell the caller that we found it by
401 * returning -EINPROGRESS */
David Howells76181c12007-10-16 23:29:46 -0700402key_already_present:
David Howellsf70e2e02010-04-30 14:32:39 +0100403 key_put(key);
David Howells76181c12007-10-16 23:29:46 -0700404 mutex_unlock(&key_construction_mutex);
David Howellsf70e2e02010-04-30 14:32:39 +0100405 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700406 if (dest_keyring) {
David Howellsf70e2e02010-04-30 14:32:39 +0100407 ret = __key_link_check_live_key(dest_keyring, key);
408 if (ret == 0)
409 __key_link(dest_keyring, key, &prealloc);
410 __key_link_end(dest_keyring, type, prealloc);
411 if (ret < 0)
412 goto link_check_failed;
David Howells03449cd2010-04-27 13:13:08 -0700413 }
David Howells76181c12007-10-16 23:29:46 -0700414 mutex_unlock(&user->cons_lock);
David Howellsf70e2e02010-04-30 14:32:39 +0100415 *_key = key;
David Howells76181c12007-10-16 23:29:46 -0700416 kleave(" = -EINPROGRESS [%d]", key_serial(key));
417 return -EINPROGRESS;
418
David Howellsf70e2e02010-04-30 14:32:39 +0100419link_check_failed:
420 mutex_unlock(&user->cons_lock);
421 key_put(key);
422 kleave(" = %d [linkcheck]", ret);
423 return ret;
424
425link_prealloc_failed:
David Howellsf70e2e02010-04-30 14:32:39 +0100426 mutex_unlock(&user->cons_lock);
427 kleave(" = %d [prelink]", ret);
428 return ret;
429
David Howells76181c12007-10-16 23:29:46 -0700430alloc_failed:
431 mutex_unlock(&user->cons_lock);
David Howells76181c12007-10-16 23:29:46 -0700432 kleave(" = %ld", PTR_ERR(key));
433 return PTR_ERR(key);
434}
435
436/*
David Howells973c9f42011-01-20 16:38:33 +0000437 * Commence key construction.
David Howells76181c12007-10-16 23:29:46 -0700438 */
439static struct key *construct_key_and_link(struct key_type *type,
440 const char *description,
441 const char *callout_info,
David Howells4a38e122008-04-29 01:01:24 -0700442 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700443 void *aux,
444 struct key *dest_keyring,
445 unsigned long flags)
446{
447 struct key_user *user;
448 struct key *key;
449 int ret;
450
David Howellsd84f4f92008-11-14 10:39:23 +1100451 kenter("");
452
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -0600453 user = key_user_lookup(current_fsuid(), current_user_ns());
David Howells76181c12007-10-16 23:29:46 -0700454 if (!user)
455 return ERR_PTR(-ENOMEM);
456
David Howells8bbf49762008-11-14 10:39:14 +1100457 construct_get_dest_keyring(&dest_keyring);
458
David Howells76181c12007-10-16 23:29:46 -0700459 ret = construct_alloc_key(type, description, dest_keyring, flags, user,
460 &key);
461 key_user_put(user);
462
463 if (ret == 0) {
David Howells8bbf49762008-11-14 10:39:14 +1100464 ret = construct_key(key, callout_info, callout_len, aux,
465 dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100466 if (ret < 0) {
467 kdebug("cons failed");
David Howells76181c12007-10-16 23:29:46 -0700468 goto construction_failed;
David Howellsd84f4f92008-11-14 10:39:23 +1100469 }
David Howells2b9e4682010-04-30 14:32:34 +0100470 } else if (ret == -EINPROGRESS) {
471 ret = 0;
472 } else {
473 key = ERR_PTR(ret);
David Howells76181c12007-10-16 23:29:46 -0700474 }
475
David Howells8bbf49762008-11-14 10:39:14 +1100476 key_put(dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100477 kleave(" = key %d", key_serial(key));
David Howells76181c12007-10-16 23:29:46 -0700478 return key;
479
480construction_failed:
481 key_negate_and_link(key, key_negative_timeout, NULL, NULL);
482 key_put(key);
David Howells8bbf49762008-11-14 10:39:14 +1100483 key_put(dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100484 kleave(" = %d", ret);
David Howells76181c12007-10-16 23:29:46 -0700485 return ERR_PTR(ret);
486}
487
David Howells973c9f42011-01-20 16:38:33 +0000488/**
489 * request_key_and_link - Request a key and cache it in a keyring.
490 * @type: The type of key we want.
491 * @description: The searchable description of the key.
492 * @callout_info: The data to pass to the instantiation upcall (or NULL).
493 * @callout_len: The length of callout_info.
494 * @aux: Auxiliary data for the upcall.
495 * @dest_keyring: Where to cache the key.
496 * @flags: Flags to key_alloc().
497 *
498 * A key matching the specified criteria is searched for in the process's
499 * keyrings and returned with its usage count incremented if found. Otherwise,
500 * if callout_info is not NULL, a key will be allocated and some service
501 * (probably in userspace) will be asked to instantiate it.
502 *
503 * If successfully found or created, the key will be linked to the destination
504 * keyring if one is provided.
505 *
506 * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
507 * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
508 * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
509 * if insufficient key quota was available to create a new key; or -ENOMEM if
510 * insufficient memory was available.
511 *
512 * If the returned key was created, then it may still be under construction,
513 * and wait_for_key_construction() should be used to wait for that to complete.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 */
David Howells3e301482005-06-23 22:00:56 -0700515struct key *request_key_and_link(struct key_type *type,
516 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700517 const void *callout_info,
518 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700519 void *aux,
David Howells7e047ef2006-06-26 00:24:50 -0700520 struct key *dest_keyring,
521 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522{
David Howellsd84f4f92008-11-14 10:39:23 +1100523 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 struct key *key;
David Howells664cceb2005-09-28 17:03:15 +0100525 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100526 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
David Howells4a38e122008-04-29 01:01:24 -0700528 kenter("%s,%s,%p,%zu,%p,%p,%lx",
529 type->name, description, callout_info, callout_len, aux,
David Howells4e54f082006-06-29 02:24:28 -0700530 dest_keyring, flags);
David Howells3e301482005-06-23 22:00:56 -0700531
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 /* search all the process keyrings for a key */
David Howells664cceb2005-09-28 17:03:15 +0100533 key_ref = search_process_keyrings(type, description, type->match,
David Howellsd84f4f92008-11-14 10:39:23 +1100534 cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535
David Howells664cceb2005-09-28 17:03:15 +0100536 if (!IS_ERR(key_ref)) {
537 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700538 if (dest_keyring) {
539 construct_get_dest_keyring(&dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100540 ret = key_link(dest_keyring, key);
David Howells03449cd2010-04-27 13:13:08 -0700541 key_put(dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100542 if (ret < 0) {
543 key_put(key);
544 key = ERR_PTR(ret);
545 goto error;
546 }
David Howells03449cd2010-04-27 13:13:08 -0700547 }
David Howells76181c12007-10-16 23:29:46 -0700548 } else if (PTR_ERR(key_ref) != -EAGAIN) {
David Howellse231c2e2008-02-07 00:15:26 -0800549 key = ERR_CAST(key_ref);
David Howells76181c12007-10-16 23:29:46 -0700550 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 /* the search failed, but the keyrings were searchable, so we
552 * should consult userspace if we can */
553 key = ERR_PTR(-ENOKEY);
554 if (!callout_info)
555 goto error;
556
David Howells76181c12007-10-16 23:29:46 -0700557 key = construct_key_and_link(type, description, callout_info,
David Howells4a38e122008-04-29 01:01:24 -0700558 callout_len, aux, dest_keyring,
559 flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 }
561
David Howells3e301482005-06-23 22:00:56 -0700562error:
563 kleave(" = %p", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564 return key;
David Howells76181c12007-10-16 23:29:46 -0700565}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566
David Howells973c9f42011-01-20 16:38:33 +0000567/**
568 * wait_for_key_construction - Wait for construction of a key to complete
569 * @key: The key being waited for.
570 * @intr: Whether to wait interruptibly.
571 *
572 * Wait for a key to finish being constructed.
573 *
574 * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY
575 * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was
576 * revoked or expired.
David Howells76181c12007-10-16 23:29:46 -0700577 */
578int wait_for_key_construction(struct key *key, bool intr)
579{
580 int ret;
David Howells3e301482005-06-23 22:00:56 -0700581
David Howells76181c12007-10-16 23:29:46 -0700582 ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
583 intr ? key_wait_bit_intr : key_wait_bit,
584 intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
585 if (ret < 0)
586 return ret;
David Howells1e456a12010-08-06 16:08:27 +0100587 if (test_bit(KEY_FLAG_NEGATIVE, &key->flags))
David Howellsfdd1b942011-03-07 15:06:09 +0000588 return key->type_data.reject_error;
David Howells76181c12007-10-16 23:29:46 -0700589 return key_validate(key);
590}
591EXPORT_SYMBOL(wait_for_key_construction);
David Howells3e301482005-06-23 22:00:56 -0700592
David Howells973c9f42011-01-20 16:38:33 +0000593/**
594 * request_key - Request a key and wait for construction
595 * @type: Type of key.
596 * @description: The searchable description of the key.
597 * @callout_info: The data to pass to the instantiation upcall (or NULL).
598 *
599 * As for request_key_and_link() except that it does not add the returned key
600 * to a keyring if found, new keys are always allocated in the user's quota,
601 * the callout_info must be a NUL-terminated string and no auxiliary data can
602 * be passed.
603 *
604 * Furthermore, it then works as wait_for_key_construction() to wait for the
605 * completion of keys undergoing construction with a non-interruptible wait.
David Howells3e301482005-06-23 22:00:56 -0700606 */
607struct key *request_key(struct key_type *type,
608 const char *description,
609 const char *callout_info)
610{
David Howells76181c12007-10-16 23:29:46 -0700611 struct key *key;
David Howells4a38e122008-04-29 01:01:24 -0700612 size_t callout_len = 0;
David Howells76181c12007-10-16 23:29:46 -0700613 int ret;
David Howells3e301482005-06-23 22:00:56 -0700614
David Howells4a38e122008-04-29 01:01:24 -0700615 if (callout_info)
616 callout_len = strlen(callout_info);
617 key = request_key_and_link(type, description, callout_info, callout_len,
618 NULL, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700619 if (!IS_ERR(key)) {
620 ret = wait_for_key_construction(key, false);
621 if (ret < 0) {
622 key_put(key);
623 return ERR_PTR(ret);
624 }
625 }
626 return key;
627}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628EXPORT_SYMBOL(request_key);
David Howells4e54f082006-06-29 02:24:28 -0700629
David Howells973c9f42011-01-20 16:38:33 +0000630/**
631 * request_key_with_auxdata - Request a key with auxiliary data for the upcaller
632 * @type: The type of key we want.
633 * @description: The searchable description of the key.
634 * @callout_info: The data to pass to the instantiation upcall (or NULL).
635 * @callout_len: The length of callout_info.
636 * @aux: Auxiliary data for the upcall.
637 *
638 * As for request_key_and_link() except that it does not add the returned key
639 * to a keyring if found and new keys are always allocated in the user's quota.
640 *
641 * Furthermore, it then works as wait_for_key_construction() to wait for the
642 * completion of keys undergoing construction with a non-interruptible wait.
David Howells4e54f082006-06-29 02:24:28 -0700643 */
644struct key *request_key_with_auxdata(struct key_type *type,
645 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700646 const void *callout_info,
647 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700648 void *aux)
649{
David Howells76181c12007-10-16 23:29:46 -0700650 struct key *key;
651 int ret;
652
David Howells4a38e122008-04-29 01:01:24 -0700653 key = request_key_and_link(type, description, callout_info, callout_len,
654 aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700655 if (!IS_ERR(key)) {
656 ret = wait_for_key_construction(key, false);
657 if (ret < 0) {
658 key_put(key);
659 return ERR_PTR(ret);
660 }
661 }
662 return key;
663}
664EXPORT_SYMBOL(request_key_with_auxdata);
665
666/*
David Howells973c9f42011-01-20 16:38:33 +0000667 * request_key_async - Request a key (allow async construction)
668 * @type: Type of key.
669 * @description: The searchable description of the key.
670 * @callout_info: The data to pass to the instantiation upcall (or NULL).
671 * @callout_len: The length of callout_info.
672 *
673 * As for request_key_and_link() except that it does not add the returned key
674 * to a keyring if found, new keys are always allocated in the user's quota and
675 * no auxiliary data can be passed.
676 *
677 * The caller should call wait_for_key_construction() to wait for the
678 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700679 */
680struct key *request_key_async(struct key_type *type,
681 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700682 const void *callout_info,
683 size_t callout_len)
David Howells76181c12007-10-16 23:29:46 -0700684{
David Howells4a38e122008-04-29 01:01:24 -0700685 return request_key_and_link(type, description, callout_info,
686 callout_len, NULL, NULL,
687 KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700688}
689EXPORT_SYMBOL(request_key_async);
690
691/*
692 * request a key with auxiliary data for the upcaller (allow async construction)
David Howells973c9f42011-01-20 16:38:33 +0000693 * @type: Type of key.
694 * @description: The searchable description of the key.
695 * @callout_info: The data to pass to the instantiation upcall (or NULL).
696 * @callout_len: The length of callout_info.
697 * @aux: Auxiliary data for the upcall.
698 *
699 * As for request_key_and_link() except that it does not add the returned key
700 * to a keyring if found and new keys are always allocated in the user's quota.
701 *
702 * The caller should call wait_for_key_construction() to wait for the
703 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700704 */
705struct key *request_key_async_with_auxdata(struct key_type *type,
706 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700707 const void *callout_info,
708 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700709 void *aux)
710{
David Howells4a38e122008-04-29 01:01:24 -0700711 return request_key_and_link(type, description, callout_info,
712 callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700713}
714EXPORT_SYMBOL(request_key_async_with_auxdata);