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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{
Lucas De Marchi93997f62013-04-30 15:28:05 -070096 struct subprocess_info *info;
97
98 info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL,
99 umh_keys_init, umh_keys_cleanup,
100 session_keyring);
101 if (!info)
102 return -ENOMEM;
103
104 key_get(session_keyring);
105 return call_usermodehelper_exec(info, wait);
Oleg Nesterov685bfd22010-05-26 14:43:00 -0700106}
107
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108/*
David Howells973c9f42011-01-20 16:38:33 +0000109 * Request userspace finish the construction of a key
David Howellsb5f545c2006-01-08 01:02:47 -0800110 * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 */
David Howells76181c12007-10-16 23:29:46 -0700112static int call_sbin_request_key(struct key_construction *cons,
David Howells4e54f082006-06-29 02:24:28 -0700113 const char *op,
114 void *aux)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115{
David Howells86a264a2008-11-14 10:39:18 +1100116 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 key_serial_t prkey, sskey;
David Howells93b4a442010-04-23 13:18:00 -0400118 struct key *key = cons->key, *authkey = cons->authkey, *keyring,
119 *session;
David Howellsb5f545c2006-01-08 01:02:47 -0800120 char *argv[9], *envp[3], uid_str[12], gid_str[12];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 char key_str[12], keyring_str[3][12];
David Howellsb5f545c2006-01-08 01:02:47 -0800122 char desc[20];
David Howells3e301482005-06-23 22:00:56 -0700123 int ret, i;
124
David Howellsb5f545c2006-01-08 01:02:47 -0800125 kenter("{%d},{%d},%s", key->serial, authkey->serial, op);
David Howells3e301482005-06-23 22:00:56 -0700126
David Howells8bbf49762008-11-14 10:39:14 +1100127 ret = install_user_keyrings();
128 if (ret < 0)
129 goto error_alloc;
130
David Howellsb5f545c2006-01-08 01:02:47 -0800131 /* allocate a new session keyring */
132 sprintf(desc, "_req.%u", key->serial);
133
David Howellsd84f4f92008-11-14 10:39:23 +1100134 cred = get_current_cred();
135 keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
David Howells96b5c8f2012-10-02 19:24:56 +0100136 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
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 */
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800150 sprintf(uid_str, "%d", from_kuid(&init_user_ns, cred->fsuid));
151 sprintf(gid_str, "%d", from_kgid(&init_user_ns, 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 Howells3a505972012-10-02 19:24:29 +0100161 if (cred->process_keyring)
162 prkey = cred->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();
David Howells3a505972012-10-02 19:24:29 +0100166 session = rcu_dereference(cred->session_keyring);
David Howells93b4a442010-04-23 13:18:00 -0400167 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 Howells3a505972012-10-02 19:24:29 +0100308 dest_keyring = key_get(cred->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 Howells3a505972012-10-02 19:24:29 +0100315 rcu_dereference(cred->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;
David Howells96b5c8f2012-10-02 19:24:56 +0100358 key_perm_t perm;
David Howells76181c12007-10-16 23:29:46 -0700359 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100360 int ret;
David Howells3e301482005-06-23 22:00:56 -0700361
David Howells76181c12007-10-16 23:29:46 -0700362 kenter("%s,%s,,,", type->name, description);
363
David Howellsf70e2e02010-04-30 14:32:39 +0100364 *_key = NULL;
David Howells76181c12007-10-16 23:29:46 -0700365 mutex_lock(&user->cons_lock);
366
David Howells96b5c8f2012-10-02 19:24:56 +0100367 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
368 perm |= KEY_USR_VIEW;
369 if (type->read)
370 perm |= KEY_POS_READ;
371 if (type == &key_type_keyring || type->update)
372 perm |= KEY_POS_WRITE;
373
David Howellsd84f4f92008-11-14 10:39:23 +1100374 key = key_alloc(type, description, cred->fsuid, cred->fsgid, cred,
David Howells96b5c8f2012-10-02 19:24:56 +0100375 perm, flags);
David Howells76181c12007-10-16 23:29:46 -0700376 if (IS_ERR(key))
377 goto alloc_failed;
378
379 set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
380
David Howellsf70e2e02010-04-30 14:32:39 +0100381 if (dest_keyring) {
382 ret = __key_link_begin(dest_keyring, type, description,
383 &prealloc);
384 if (ret < 0)
385 goto link_prealloc_failed;
386 }
David Howells76181c12007-10-16 23:29:46 -0700387
388 /* attach the key to the destination keyring under lock, but we do need
389 * to do another check just in case someone beat us to it whilst we
390 * waited for locks */
391 mutex_lock(&key_construction_mutex);
392
David Howellsd84f4f92008-11-14 10:39:23 +1100393 key_ref = search_process_keyrings(type, description, type->match, cred);
David Howells76181c12007-10-16 23:29:46 -0700394 if (!IS_ERR(key_ref))
395 goto key_already_present;
396
David Howells34574dd2009-04-09 17:14:05 +0100397 if (dest_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100398 __key_link(dest_keyring, key, &prealloc);
David Howells76181c12007-10-16 23:29:46 -0700399
400 mutex_unlock(&key_construction_mutex);
David Howells34574dd2009-04-09 17:14:05 +0100401 if (dest_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +0100402 __key_link_end(dest_keyring, type, prealloc);
David Howells76181c12007-10-16 23:29:46 -0700403 mutex_unlock(&user->cons_lock);
404 *_key = key;
405 kleave(" = 0 [%d]", key_serial(key));
406 return 0;
407
David Howells2b9e4682010-04-30 14:32:34 +0100408 /* the key is now present - we tell the caller that we found it by
409 * returning -EINPROGRESS */
David Howells76181c12007-10-16 23:29:46 -0700410key_already_present:
David Howellsf70e2e02010-04-30 14:32:39 +0100411 key_put(key);
David Howells76181c12007-10-16 23:29:46 -0700412 mutex_unlock(&key_construction_mutex);
David Howellsf70e2e02010-04-30 14:32:39 +0100413 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700414 if (dest_keyring) {
David Howellsf70e2e02010-04-30 14:32:39 +0100415 ret = __key_link_check_live_key(dest_keyring, key);
416 if (ret == 0)
417 __key_link(dest_keyring, key, &prealloc);
418 __key_link_end(dest_keyring, type, prealloc);
419 if (ret < 0)
420 goto link_check_failed;
David Howells03449cd2010-04-27 13:13:08 -0700421 }
David Howells76181c12007-10-16 23:29:46 -0700422 mutex_unlock(&user->cons_lock);
David Howellsf70e2e02010-04-30 14:32:39 +0100423 *_key = key;
David Howells76181c12007-10-16 23:29:46 -0700424 kleave(" = -EINPROGRESS [%d]", key_serial(key));
425 return -EINPROGRESS;
426
David Howellsf70e2e02010-04-30 14:32:39 +0100427link_check_failed:
428 mutex_unlock(&user->cons_lock);
429 key_put(key);
430 kleave(" = %d [linkcheck]", ret);
431 return ret;
432
433link_prealloc_failed:
David Howellsf70e2e02010-04-30 14:32:39 +0100434 mutex_unlock(&user->cons_lock);
435 kleave(" = %d [prelink]", ret);
436 return ret;
437
David Howells76181c12007-10-16 23:29:46 -0700438alloc_failed:
439 mutex_unlock(&user->cons_lock);
David Howells76181c12007-10-16 23:29:46 -0700440 kleave(" = %ld", PTR_ERR(key));
441 return PTR_ERR(key);
442}
443
444/*
David Howells973c9f42011-01-20 16:38:33 +0000445 * Commence key construction.
David Howells76181c12007-10-16 23:29:46 -0700446 */
447static struct key *construct_key_and_link(struct key_type *type,
448 const char *description,
449 const char *callout_info,
David Howells4a38e122008-04-29 01:01:24 -0700450 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700451 void *aux,
452 struct key *dest_keyring,
453 unsigned long flags)
454{
455 struct key_user *user;
456 struct key *key;
457 int ret;
458
David Howellsd84f4f92008-11-14 10:39:23 +1100459 kenter("");
460
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800461 user = key_user_lookup(current_fsuid());
David Howells76181c12007-10-16 23:29:46 -0700462 if (!user)
463 return ERR_PTR(-ENOMEM);
464
David Howells8bbf49762008-11-14 10:39:14 +1100465 construct_get_dest_keyring(&dest_keyring);
466
David Howells76181c12007-10-16 23:29:46 -0700467 ret = construct_alloc_key(type, description, dest_keyring, flags, user,
468 &key);
469 key_user_put(user);
470
471 if (ret == 0) {
David Howells8bbf49762008-11-14 10:39:14 +1100472 ret = construct_key(key, callout_info, callout_len, aux,
473 dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100474 if (ret < 0) {
475 kdebug("cons failed");
David Howells76181c12007-10-16 23:29:46 -0700476 goto construction_failed;
David Howellsd84f4f92008-11-14 10:39:23 +1100477 }
David Howells2b9e4682010-04-30 14:32:34 +0100478 } else if (ret == -EINPROGRESS) {
479 ret = 0;
480 } else {
David Howellsb1d7dd82011-06-21 14:32:05 +0100481 goto couldnt_alloc_key;
David Howells76181c12007-10-16 23:29:46 -0700482 }
483
David Howells8bbf49762008-11-14 10:39:14 +1100484 key_put(dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100485 kleave(" = key %d", key_serial(key));
David Howells76181c12007-10-16 23:29:46 -0700486 return key;
487
488construction_failed:
489 key_negate_and_link(key, key_negative_timeout, NULL, NULL);
490 key_put(key);
David Howellsb1d7dd82011-06-21 14:32:05 +0100491couldnt_alloc_key:
David Howells8bbf49762008-11-14 10:39:14 +1100492 key_put(dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100493 kleave(" = %d", ret);
David Howells76181c12007-10-16 23:29:46 -0700494 return ERR_PTR(ret);
495}
496
David Howells973c9f42011-01-20 16:38:33 +0000497/**
498 * request_key_and_link - Request a key and cache it in a keyring.
499 * @type: The type of key we want.
500 * @description: The searchable description of the key.
501 * @callout_info: The data to pass to the instantiation upcall (or NULL).
502 * @callout_len: The length of callout_info.
503 * @aux: Auxiliary data for the upcall.
504 * @dest_keyring: Where to cache the key.
505 * @flags: Flags to key_alloc().
506 *
507 * A key matching the specified criteria is searched for in the process's
508 * keyrings and returned with its usage count incremented if found. Otherwise,
509 * if callout_info is not NULL, a key will be allocated and some service
510 * (probably in userspace) will be asked to instantiate it.
511 *
512 * If successfully found or created, the key will be linked to the destination
513 * keyring if one is provided.
514 *
515 * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
516 * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
517 * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
518 * if insufficient key quota was available to create a new key; or -ENOMEM if
519 * insufficient memory was available.
520 *
521 * If the returned key was created, then it may still be under construction,
522 * and wait_for_key_construction() should be used to wait for that to complete.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 */
David Howells3e301482005-06-23 22:00:56 -0700524struct key *request_key_and_link(struct key_type *type,
525 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700526 const void *callout_info,
527 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700528 void *aux,
David Howells7e047ef2006-06-26 00:24:50 -0700529 struct key *dest_keyring,
530 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531{
David Howellsd84f4f92008-11-14 10:39:23 +1100532 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 struct key *key;
David Howells664cceb2005-09-28 17:03:15 +0100534 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100535 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536
David Howells4a38e122008-04-29 01:01:24 -0700537 kenter("%s,%s,%p,%zu,%p,%p,%lx",
538 type->name, description, callout_info, callout_len, aux,
David Howells4e54f082006-06-29 02:24:28 -0700539 dest_keyring, flags);
David Howells3e301482005-06-23 22:00:56 -0700540
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 /* search all the process keyrings for a key */
David Howells78b72802011-03-11 17:57:23 +0000542 key_ref = search_process_keyrings(type, description, type->match, cred);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
David Howells664cceb2005-09-28 17:03:15 +0100544 if (!IS_ERR(key_ref)) {
545 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700546 if (dest_keyring) {
547 construct_get_dest_keyring(&dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100548 ret = key_link(dest_keyring, key);
David Howells03449cd2010-04-27 13:13:08 -0700549 key_put(dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100550 if (ret < 0) {
551 key_put(key);
552 key = ERR_PTR(ret);
553 goto error;
554 }
David Howells03449cd2010-04-27 13:13:08 -0700555 }
David Howells76181c12007-10-16 23:29:46 -0700556 } else if (PTR_ERR(key_ref) != -EAGAIN) {
David Howellse231c2e2008-02-07 00:15:26 -0800557 key = ERR_CAST(key_ref);
David Howells76181c12007-10-16 23:29:46 -0700558 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 /* the search failed, but the keyrings were searchable, so we
560 * should consult userspace if we can */
561 key = ERR_PTR(-ENOKEY);
562 if (!callout_info)
563 goto error;
564
David Howells76181c12007-10-16 23:29:46 -0700565 key = construct_key_and_link(type, description, callout_info,
David Howells4a38e122008-04-29 01:01:24 -0700566 callout_len, aux, dest_keyring,
567 flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 }
569
David Howells3e301482005-06-23 22:00:56 -0700570error:
571 kleave(" = %p", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 return key;
David Howells76181c12007-10-16 23:29:46 -0700573}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
David Howells973c9f42011-01-20 16:38:33 +0000575/**
576 * wait_for_key_construction - Wait for construction of a key to complete
577 * @key: The key being waited for.
578 * @intr: Whether to wait interruptibly.
579 *
580 * Wait for a key to finish being constructed.
581 *
582 * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY
583 * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was
584 * revoked or expired.
David Howells76181c12007-10-16 23:29:46 -0700585 */
586int wait_for_key_construction(struct key *key, bool intr)
587{
588 int ret;
David Howells3e301482005-06-23 22:00:56 -0700589
David Howells76181c12007-10-16 23:29:46 -0700590 ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
591 intr ? key_wait_bit_intr : key_wait_bit,
592 intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
593 if (ret < 0)
594 return ret;
David Howells1e456a12010-08-06 16:08:27 +0100595 if (test_bit(KEY_FLAG_NEGATIVE, &key->flags))
David Howellsfdd1b942011-03-07 15:06:09 +0000596 return key->type_data.reject_error;
David Howells76181c12007-10-16 23:29:46 -0700597 return key_validate(key);
598}
599EXPORT_SYMBOL(wait_for_key_construction);
David Howells3e301482005-06-23 22:00:56 -0700600
David Howells973c9f42011-01-20 16:38:33 +0000601/**
602 * request_key - Request a key and wait for construction
603 * @type: Type of key.
604 * @description: The searchable description of the key.
605 * @callout_info: The data to pass to the instantiation upcall (or NULL).
606 *
607 * As for request_key_and_link() except that it does not add the returned key
608 * to a keyring if found, new keys are always allocated in the user's quota,
609 * the callout_info must be a NUL-terminated string and no auxiliary data can
610 * be passed.
611 *
612 * Furthermore, it then works as wait_for_key_construction() to wait for the
613 * completion of keys undergoing construction with a non-interruptible wait.
David Howells3e301482005-06-23 22:00:56 -0700614 */
615struct key *request_key(struct key_type *type,
616 const char *description,
617 const char *callout_info)
618{
David Howells76181c12007-10-16 23:29:46 -0700619 struct key *key;
David Howells4a38e122008-04-29 01:01:24 -0700620 size_t callout_len = 0;
David Howells76181c12007-10-16 23:29:46 -0700621 int ret;
David Howells3e301482005-06-23 22:00:56 -0700622
David Howells4a38e122008-04-29 01:01:24 -0700623 if (callout_info)
624 callout_len = strlen(callout_info);
625 key = request_key_and_link(type, description, callout_info, callout_len,
626 NULL, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700627 if (!IS_ERR(key)) {
628 ret = wait_for_key_construction(key, false);
629 if (ret < 0) {
630 key_put(key);
631 return ERR_PTR(ret);
632 }
633 }
634 return key;
635}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636EXPORT_SYMBOL(request_key);
David Howells4e54f082006-06-29 02:24:28 -0700637
David Howells973c9f42011-01-20 16:38:33 +0000638/**
639 * request_key_with_auxdata - Request a key with auxiliary data for the upcaller
640 * @type: The type of key we want.
641 * @description: The searchable description of the key.
642 * @callout_info: The data to pass to the instantiation upcall (or NULL).
643 * @callout_len: The length of callout_info.
644 * @aux: Auxiliary data for the upcall.
645 *
646 * As for request_key_and_link() except that it does not add the returned key
647 * to a keyring if found and new keys are always allocated in the user's quota.
648 *
649 * Furthermore, it then works as wait_for_key_construction() to wait for the
650 * completion of keys undergoing construction with a non-interruptible wait.
David Howells4e54f082006-06-29 02:24:28 -0700651 */
652struct key *request_key_with_auxdata(struct key_type *type,
653 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700654 const void *callout_info,
655 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700656 void *aux)
657{
David Howells76181c12007-10-16 23:29:46 -0700658 struct key *key;
659 int ret;
660
David Howells4a38e122008-04-29 01:01:24 -0700661 key = request_key_and_link(type, description, callout_info, callout_len,
662 aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700663 if (!IS_ERR(key)) {
664 ret = wait_for_key_construction(key, false);
665 if (ret < 0) {
666 key_put(key);
667 return ERR_PTR(ret);
668 }
669 }
670 return key;
671}
672EXPORT_SYMBOL(request_key_with_auxdata);
673
674/*
David Howells973c9f42011-01-20 16:38:33 +0000675 * request_key_async - Request a key (allow async construction)
676 * @type: Type of key.
677 * @description: The searchable description of the key.
678 * @callout_info: The data to pass to the instantiation upcall (or NULL).
679 * @callout_len: The length of callout_info.
680 *
681 * As for request_key_and_link() except that it does not add the returned key
682 * to a keyring if found, new keys are always allocated in the user's quota and
683 * no auxiliary data can be passed.
684 *
685 * The caller should call wait_for_key_construction() to wait for the
686 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700687 */
688struct key *request_key_async(struct key_type *type,
689 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700690 const void *callout_info,
691 size_t callout_len)
David Howells76181c12007-10-16 23:29:46 -0700692{
David Howells4a38e122008-04-29 01:01:24 -0700693 return request_key_and_link(type, description, callout_info,
694 callout_len, NULL, NULL,
695 KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700696}
697EXPORT_SYMBOL(request_key_async);
698
699/*
700 * request a key with auxiliary data for the upcaller (allow async construction)
David Howells973c9f42011-01-20 16:38:33 +0000701 * @type: Type of key.
702 * @description: The searchable description of the key.
703 * @callout_info: The data to pass to the instantiation upcall (or NULL).
704 * @callout_len: The length of callout_info.
705 * @aux: Auxiliary data for the upcall.
706 *
707 * As for request_key_and_link() except that it does not add the returned key
708 * to a keyring if found and new keys are always allocated in the user's quota.
709 *
710 * The caller should call wait_for_key_construction() to wait for the
711 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700712 */
713struct key *request_key_async_with_auxdata(struct key_type *type,
714 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700715 const void *callout_info,
716 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700717 void *aux)
718{
David Howells4a38e122008-04-29 01:01:24 -0700719 return request_key_and_link(type, description, callout_info,
720 callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700721}
722EXPORT_SYMBOL(request_key_async_with_auxdata);