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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 Howells973c9f42011-01-20 16:38:33 +000024/**
25 * complete_request_key - Complete the construction of a key.
26 * @cons: The key construction record.
27 * @error: The success or failute of the construction.
28 *
29 * Complete the attempt to construct a key. The key will be negated
30 * if an error is indicated. The authorisation key will be revoked
31 * unconditionally.
David Howells76181c12007-10-16 23:29:46 -070032 */
33void complete_request_key(struct key_construction *cons, int error)
34{
35 kenter("{%d,%d},%d", cons->key->serial, cons->authkey->serial, error);
36
37 if (error < 0)
38 key_negate_and_link(cons->key, key_negative_timeout, NULL,
39 cons->authkey);
40 else
41 key_revoke(cons->authkey);
42
43 key_put(cons->key);
44 key_put(cons->authkey);
45 kfree(cons);
46}
47EXPORT_SYMBOL(complete_request_key);
48
David Howells973c9f42011-01-20 16:38:33 +000049/*
50 * Initialise a usermode helper that is going to have a specific session
51 * keyring.
52 *
53 * This is called in context of freshly forked kthread before kernel_execve(),
54 * so we can simply install the desired session_keyring at this point.
55 */
David Howells87966992011-06-17 11:25:59 +010056static int umh_keys_init(struct subprocess_info *info, struct cred *cred)
Oleg Nesterov685bfd22010-05-26 14:43:00 -070057{
Oleg Nesterov685bfd22010-05-26 14:43:00 -070058 struct key *keyring = info->data;
David Howells973c9f42011-01-20 16:38:33 +000059
Oleg Nesterov685bfd22010-05-26 14:43:00 -070060 return install_session_keyring_to_cred(cred, keyring);
61}
62
David Howells973c9f42011-01-20 16:38:33 +000063/*
64 * Clean up a usermode helper with session keyring.
65 */
Oleg Nesterov685bfd22010-05-26 14:43:00 -070066static void umh_keys_cleanup(struct subprocess_info *info)
67{
68 struct key *keyring = info->data;
69 key_put(keyring);
70}
71
David Howells973c9f42011-01-20 16:38:33 +000072/*
73 * Call a usermode helper with a specific session keyring.
74 */
Oleg Nesterov685bfd22010-05-26 14:43:00 -070075static int call_usermodehelper_keys(char *path, char **argv, char **envp,
Oleg Nesterov9d944ef2012-03-23 15:02:48 -070076 struct key *session_keyring, int wait)
Oleg Nesterov685bfd22010-05-26 14:43:00 -070077{
Lucas De Marchi93997f62013-04-30 15:28:05 -070078 struct subprocess_info *info;
79
80 info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL,
81 umh_keys_init, umh_keys_cleanup,
82 session_keyring);
83 if (!info)
84 return -ENOMEM;
85
86 key_get(session_keyring);
87 return call_usermodehelper_exec(info, wait);
Oleg Nesterov685bfd22010-05-26 14:43:00 -070088}
89
Linus Torvalds1da177e2005-04-16 15:20:36 -070090/*
David Howells973c9f42011-01-20 16:38:33 +000091 * Request userspace finish the construction of a key
David Howellsb5f545c2006-01-08 01:02:47 -080092 * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>"
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 */
David Howells76181c12007-10-16 23:29:46 -070094static int call_sbin_request_key(struct key_construction *cons,
David Howells4e54f082006-06-29 02:24:28 -070095 const char *op,
96 void *aux)
Linus Torvalds1da177e2005-04-16 15:20:36 -070097{
David Howells86a264a2008-11-14 10:39:18 +110098 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 key_serial_t prkey, sskey;
David Howells93b4a442010-04-23 13:18:00 -0400100 struct key *key = cons->key, *authkey = cons->authkey, *keyring,
101 *session;
David Howellsb5f545c2006-01-08 01:02:47 -0800102 char *argv[9], *envp[3], uid_str[12], gid_str[12];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 char key_str[12], keyring_str[3][12];
David Howellsb5f545c2006-01-08 01:02:47 -0800104 char desc[20];
David Howells3e301482005-06-23 22:00:56 -0700105 int ret, i;
106
David Howellsb5f545c2006-01-08 01:02:47 -0800107 kenter("{%d},{%d},%s", key->serial, authkey->serial, op);
David Howells3e301482005-06-23 22:00:56 -0700108
David Howells8bbf49762008-11-14 10:39:14 +1100109 ret = install_user_keyrings();
110 if (ret < 0)
111 goto error_alloc;
112
David Howellsb5f545c2006-01-08 01:02:47 -0800113 /* allocate a new session keyring */
114 sprintf(desc, "_req.%u", key->serial);
115
David Howellsd84f4f92008-11-14 10:39:23 +1100116 cred = get_current_cred();
117 keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred,
David Howells96b5c8f2012-10-02 19:24:56 +0100118 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
David Howells5ac7eac2016-04-06 16:14:24 +0100119 KEY_ALLOC_QUOTA_OVERRUN, NULL, NULL);
David Howellsd84f4f92008-11-14 10:39:23 +1100120 put_cred(cred);
David Howellsb5f545c2006-01-08 01:02:47 -0800121 if (IS_ERR(keyring)) {
122 ret = PTR_ERR(keyring);
123 goto error_alloc;
David Howells3e301482005-06-23 22:00:56 -0700124 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125
David Howellsb5f545c2006-01-08 01:02:47 -0800126 /* attach the auth key to the session keyring */
David Howells896903c2010-04-30 14:32:23 +0100127 ret = key_link(keyring, authkey);
David Howellsb5f545c2006-01-08 01:02:47 -0800128 if (ret < 0)
129 goto error_link;
130
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 /* record the UID and GID */
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800132 sprintf(uid_str, "%d", from_kuid(&init_user_ns, cred->fsuid));
133 sprintf(gid_str, "%d", from_kgid(&init_user_ns, cred->fsgid));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134
135 /* we say which key is under construction */
136 sprintf(key_str, "%d", key->serial);
137
138 /* we specify the process's default keyrings */
139 sprintf(keyring_str[0], "%d",
David Howellsd84f4f92008-11-14 10:39:23 +1100140 cred->thread_keyring ? cred->thread_keyring->serial : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
142 prkey = 0;
David Howells3a505972012-10-02 19:24:29 +0100143 if (cred->process_keyring)
144 prkey = cred->process_keyring->serial;
Justin P. Mattock5ad18a02010-06-30 10:39:11 +0100145 sprintf(keyring_str[1], "%d", prkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146
David Howells93b4a442010-04-23 13:18:00 -0400147 rcu_read_lock();
David Howells3a505972012-10-02 19:24:29 +0100148 session = rcu_dereference(cred->session_keyring);
David Howells93b4a442010-04-23 13:18:00 -0400149 if (!session)
150 session = cred->user->session_keyring;
151 sskey = session->serial;
152 rcu_read_unlock();
David Howells3e301482005-06-23 22:00:56 -0700153
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 sprintf(keyring_str[2], "%d", sskey);
155
156 /* set up a minimal environment */
157 i = 0;
158 envp[i++] = "HOME=/";
159 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
160 envp[i] = NULL;
161
162 /* set up the argument list */
163 i = 0;
164 argv[i++] = "/sbin/request-key";
165 argv[i++] = (char *) op;
166 argv[i++] = key_str;
167 argv[i++] = uid_str;
168 argv[i++] = gid_str;
169 argv[i++] = keyring_str[0];
170 argv[i++] = keyring_str[1];
171 argv[i++] = keyring_str[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 argv[i] = NULL;
173
174 /* do it */
Jeremy Fitzhardinge86313c42007-07-17 18:37:03 -0700175 ret = call_usermodehelper_keys(argv[0], argv, envp, keyring,
176 UMH_WAIT_PROC);
David Howells76181c12007-10-16 23:29:46 -0700177 kdebug("usermode -> 0x%x", ret);
178 if (ret >= 0) {
179 /* ret is the exit/wait code */
180 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) ||
181 key_validate(key) < 0)
182 ret = -ENOKEY;
183 else
184 /* ignore any errors from userspace if the key was
185 * instantiated */
186 ret = 0;
187 }
David Howells3e301482005-06-23 22:00:56 -0700188
David Howellsb5f545c2006-01-08 01:02:47 -0800189error_link:
190 key_put(keyring);
David Howells3e301482005-06-23 22:00:56 -0700191
David Howellsb5f545c2006-01-08 01:02:47 -0800192error_alloc:
David Howells76181c12007-10-16 23:29:46 -0700193 complete_request_key(cons, ret);
David Howellsd84f4f92008-11-14 10:39:23 +1100194 kleave(" = %d", ret);
David Howells3e301482005-06-23 22:00:56 -0700195 return ret;
David Howells76181c12007-10-16 23:29:46 -0700196}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198/*
David Howells973c9f42011-01-20 16:38:33 +0000199 * Call out to userspace for key construction.
200 *
201 * Program failure is ignored in favour of key status.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 */
David Howells4a38e122008-04-29 01:01:24 -0700203static int construct_key(struct key *key, const void *callout_info,
David Howells8bbf49762008-11-14 10:39:14 +1100204 size_t callout_len, void *aux,
205 struct key *dest_keyring)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206{
David Howells76181c12007-10-16 23:29:46 -0700207 struct key_construction *cons;
David Howellsb5f545c2006-01-08 01:02:47 -0800208 request_key_actor_t actor;
David Howells76181c12007-10-16 23:29:46 -0700209 struct key *authkey;
210 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211
David Howells4a38e122008-04-29 01:01:24 -0700212 kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux);
David Howells3e301482005-06-23 22:00:56 -0700213
David Howells76181c12007-10-16 23:29:46 -0700214 cons = kmalloc(sizeof(*cons), GFP_KERNEL);
215 if (!cons)
216 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217
David Howellsb5f545c2006-01-08 01:02:47 -0800218 /* allocate an authorisation key */
David Howells8bbf49762008-11-14 10:39:14 +1100219 authkey = request_key_auth_new(key, callout_info, callout_len,
220 dest_keyring);
David Howellsb5f545c2006-01-08 01:02:47 -0800221 if (IS_ERR(authkey)) {
David Howells76181c12007-10-16 23:29:46 -0700222 kfree(cons);
David Howellsb5f545c2006-01-08 01:02:47 -0800223 ret = PTR_ERR(authkey);
224 authkey = NULL;
David Howells76181c12007-10-16 23:29:46 -0700225 } else {
226 cons->authkey = key_get(authkey);
227 cons->key = key_get(key);
228
229 /* make the call */
230 actor = call_sbin_request_key;
231 if (key->type->request_key)
232 actor = key->type->request_key;
233
234 ret = actor(cons, "create", aux);
235
236 /* check that the actor called complete_request_key() prior to
237 * returning an error */
238 WARN_ON(ret < 0 &&
239 !test_bit(KEY_FLAG_REVOKED, &authkey->flags));
240 key_put(authkey);
David Howellsb5f545c2006-01-08 01:02:47 -0800241 }
242
David Howells76181c12007-10-16 23:29:46 -0700243 kleave(" = %d", ret);
244 return ret;
245}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247/*
David Howells973c9f42011-01-20 16:38:33 +0000248 * Get the appropriate destination keyring for the request.
249 *
250 * The keyring selected is returned with an extra reference upon it which the
251 * caller must release.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 */
Eric Biggers982707e2017-12-08 15:13:27 +0000253static int construct_get_dest_keyring(struct key **_dest_keyring)
David Howells3e301482005-06-23 22:00:56 -0700254{
David Howells8bbf49762008-11-14 10:39:14 +1100255 struct request_key_auth *rka;
David Howellsbb952bb2008-11-14 10:39:20 +1100256 const struct cred *cred = current_cred();
David Howells8bbf49762008-11-14 10:39:14 +1100257 struct key *dest_keyring = *_dest_keyring, *authkey;
Eric Biggers982707e2017-12-08 15:13:27 +0000258 int ret;
David Howells3e301482005-06-23 22:00:56 -0700259
David Howells8bbf49762008-11-14 10:39:14 +1100260 kenter("%p", dest_keyring);
David Howells3e301482005-06-23 22:00:56 -0700261
262 /* find the appropriate keyring */
David Howells8bbf49762008-11-14 10:39:14 +1100263 if (dest_keyring) {
264 /* the caller supplied one */
265 key_get(dest_keyring);
266 } else {
Eric Biggers982707e2017-12-08 15:13:27 +0000267 bool do_perm_check = true;
268
David Howells8bbf49762008-11-14 10:39:14 +1100269 /* use a default keyring; falling through the cases until we
270 * find one that we actually have */
David Howellsbb952bb2008-11-14 10:39:20 +1100271 switch (cred->jit_keyring) {
David Howells3e301482005-06-23 22:00:56 -0700272 case KEY_REQKEY_DEFL_DEFAULT:
David Howells8bbf49762008-11-14 10:39:14 +1100273 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100274 if (cred->request_key_auth) {
275 authkey = cred->request_key_auth;
David Howells8bbf49762008-11-14 10:39:14 +1100276 down_read(&authkey->sem);
David Howells146aa8b2015-10-21 14:04:48 +0100277 rka = authkey->payload.data[0];
David Howells8bbf49762008-11-14 10:39:14 +1100278 if (!test_bit(KEY_FLAG_REVOKED,
279 &authkey->flags))
280 dest_keyring =
281 key_get(rka->dest_keyring);
282 up_read(&authkey->sem);
Eric Biggers982707e2017-12-08 15:13:27 +0000283 if (dest_keyring) {
284 do_perm_check = false;
David Howells8bbf49762008-11-14 10:39:14 +1100285 break;
Eric Biggers982707e2017-12-08 15:13:27 +0000286 }
David Howells8bbf49762008-11-14 10:39:14 +1100287 }
288
David Howells3e301482005-06-23 22:00:56 -0700289 case KEY_REQKEY_DEFL_THREAD_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100290 dest_keyring = key_get(cred->thread_keyring);
David Howells3e301482005-06-23 22:00:56 -0700291 if (dest_keyring)
292 break;
293
294 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
David Howells3a505972012-10-02 19:24:29 +0100295 dest_keyring = key_get(cred->process_keyring);
David Howells3e301482005-06-23 22:00:56 -0700296 if (dest_keyring)
297 break;
298
299 case KEY_REQKEY_DEFL_SESSION_KEYRING:
300 rcu_read_lock();
301 dest_keyring = key_get(
David Howells3a505972012-10-02 19:24:29 +0100302 rcu_dereference(cred->session_keyring));
David Howells3e301482005-06-23 22:00:56 -0700303 rcu_read_unlock();
David Howells3e301482005-06-23 22:00:56 -0700304
305 if (dest_keyring)
306 break;
307
308 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
David Howellsb6dff3e2008-11-14 10:39:16 +1100309 dest_keyring =
David Howellsbb952bb2008-11-14 10:39:20 +1100310 key_get(cred->user->session_keyring);
David Howells3e301482005-06-23 22:00:56 -0700311 break;
312
313 case KEY_REQKEY_DEFL_USER_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100314 dest_keyring = key_get(cred->user->uid_keyring);
David Howells3e301482005-06-23 22:00:56 -0700315 break;
316
317 case KEY_REQKEY_DEFL_GROUP_KEYRING:
318 default:
319 BUG();
320 }
Eric Biggers982707e2017-12-08 15:13:27 +0000321
322 /*
323 * Require Write permission on the keyring. This is essential
324 * because the default keyring may be the session keyring, and
325 * joining a keyring only requires Search permission.
326 *
327 * However, this check is skipped for the "requestor keyring" so
328 * that /sbin/request-key can itself use request_key() to add
329 * keys to the original requestor's destination keyring.
330 */
331 if (dest_keyring && do_perm_check) {
332 ret = key_permission(make_key_ref(dest_keyring, 1),
333 KEY_NEED_WRITE);
334 if (ret) {
335 key_put(dest_keyring);
336 return ret;
337 }
338 }
David Howells3e301482005-06-23 22:00:56 -0700339 }
340
David Howells8bbf49762008-11-14 10:39:14 +1100341 *_dest_keyring = dest_keyring;
342 kleave(" [dk %d]", key_serial(dest_keyring));
Eric Biggers982707e2017-12-08 15:13:27 +0000343 return 0;
David Howells76181c12007-10-16 23:29:46 -0700344}
David Howells3e301482005-06-23 22:00:56 -0700345
David Howells76181c12007-10-16 23:29:46 -0700346/*
David Howells973c9f42011-01-20 16:38:33 +0000347 * Allocate a new key in under-construction state and attempt to link it in to
348 * the requested keyring.
349 *
350 * May return a key that's already under construction instead if there was a
351 * race between two thread calling request_key().
David Howells76181c12007-10-16 23:29:46 -0700352 */
David Howells4bdf0bc2013-09-24 10:35:15 +0100353static int construct_alloc_key(struct keyring_search_context *ctx,
David Howells76181c12007-10-16 23:29:46 -0700354 struct key *dest_keyring,
355 unsigned long flags,
356 struct key_user *user,
357 struct key **_key)
358{
David Howellsb2a4df22013-09-24 10:35:18 +0100359 struct assoc_array_edit *edit;
David Howells76181c12007-10-16 23:29:46 -0700360 struct key *key;
David Howells96b5c8f2012-10-02 19:24:56 +0100361 key_perm_t perm;
David Howells76181c12007-10-16 23:29:46 -0700362 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100363 int ret;
David Howells3e301482005-06-23 22:00:56 -0700364
David Howells4bdf0bc2013-09-24 10:35:15 +0100365 kenter("%s,%s,,,",
366 ctx->index_key.type->name, ctx->index_key.description);
David Howells76181c12007-10-16 23:29:46 -0700367
David Howellsf70e2e02010-04-30 14:32:39 +0100368 *_key = NULL;
David Howells76181c12007-10-16 23:29:46 -0700369 mutex_lock(&user->cons_lock);
370
David Howells96b5c8f2012-10-02 19:24:56 +0100371 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
372 perm |= KEY_USR_VIEW;
David Howells4bdf0bc2013-09-24 10:35:15 +0100373 if (ctx->index_key.type->read)
David Howells96b5c8f2012-10-02 19:24:56 +0100374 perm |= KEY_POS_READ;
David Howells4bdf0bc2013-09-24 10:35:15 +0100375 if (ctx->index_key.type == &key_type_keyring ||
376 ctx->index_key.type->update)
David Howells96b5c8f2012-10-02 19:24:56 +0100377 perm |= KEY_POS_WRITE;
378
David Howells4bdf0bc2013-09-24 10:35:15 +0100379 key = key_alloc(ctx->index_key.type, ctx->index_key.description,
380 ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred,
David Howells5ac7eac2016-04-06 16:14:24 +0100381 perm, flags, NULL);
David Howells76181c12007-10-16 23:29:46 -0700382 if (IS_ERR(key))
383 goto alloc_failed;
384
385 set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
386
David Howellsf70e2e02010-04-30 14:32:39 +0100387 if (dest_keyring) {
David Howellsb2a4df22013-09-24 10:35:18 +0100388 ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit);
David Howellsf70e2e02010-04-30 14:32:39 +0100389 if (ret < 0)
390 goto link_prealloc_failed;
391 }
David Howells76181c12007-10-16 23:29:46 -0700392
393 /* attach the key to the destination keyring under lock, but we do need
394 * to do another check just in case someone beat us to it whilst we
395 * waited for locks */
396 mutex_lock(&key_construction_mutex);
397
David Howells4bdf0bc2013-09-24 10:35:15 +0100398 key_ref = search_process_keyrings(ctx);
David Howells76181c12007-10-16 23:29:46 -0700399 if (!IS_ERR(key_ref))
400 goto key_already_present;
401
David Howells34574dd2009-04-09 17:14:05 +0100402 if (dest_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +0100403 __key_link(key, &edit);
David Howells76181c12007-10-16 23:29:46 -0700404
405 mutex_unlock(&key_construction_mutex);
David Howells34574dd2009-04-09 17:14:05 +0100406 if (dest_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +0100407 __key_link_end(dest_keyring, &ctx->index_key, edit);
David Howells76181c12007-10-16 23:29:46 -0700408 mutex_unlock(&user->cons_lock);
409 *_key = key;
410 kleave(" = 0 [%d]", key_serial(key));
411 return 0;
412
David Howells2b9e4682010-04-30 14:32:34 +0100413 /* the key is now present - we tell the caller that we found it by
414 * returning -EINPROGRESS */
David Howells76181c12007-10-16 23:29:46 -0700415key_already_present:
David Howellsf70e2e02010-04-30 14:32:39 +0100416 key_put(key);
David Howells76181c12007-10-16 23:29:46 -0700417 mutex_unlock(&key_construction_mutex);
David Howellsf70e2e02010-04-30 14:32:39 +0100418 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700419 if (dest_keyring) {
David Howellsf70e2e02010-04-30 14:32:39 +0100420 ret = __key_link_check_live_key(dest_keyring, key);
421 if (ret == 0)
David Howellsb2a4df22013-09-24 10:35:18 +0100422 __key_link(key, &edit);
423 __key_link_end(dest_keyring, &ctx->index_key, edit);
David Howellsf70e2e02010-04-30 14:32:39 +0100424 if (ret < 0)
425 goto link_check_failed;
David Howells03449cd2010-04-27 13:13:08 -0700426 }
David Howells76181c12007-10-16 23:29:46 -0700427 mutex_unlock(&user->cons_lock);
David Howellsf70e2e02010-04-30 14:32:39 +0100428 *_key = key;
David Howells76181c12007-10-16 23:29:46 -0700429 kleave(" = -EINPROGRESS [%d]", key_serial(key));
430 return -EINPROGRESS;
431
David Howellsf70e2e02010-04-30 14:32:39 +0100432link_check_failed:
433 mutex_unlock(&user->cons_lock);
434 key_put(key);
435 kleave(" = %d [linkcheck]", ret);
436 return ret;
437
438link_prealloc_failed:
David Howellsf70e2e02010-04-30 14:32:39 +0100439 mutex_unlock(&user->cons_lock);
David Jefferyd0709f12015-02-12 16:45:31 +0000440 key_put(key);
David Howellsf70e2e02010-04-30 14:32:39 +0100441 kleave(" = %d [prelink]", ret);
442 return ret;
443
David Howells76181c12007-10-16 23:29:46 -0700444alloc_failed:
445 mutex_unlock(&user->cons_lock);
David Howells76181c12007-10-16 23:29:46 -0700446 kleave(" = %ld", PTR_ERR(key));
447 return PTR_ERR(key);
448}
449
450/*
David Howells973c9f42011-01-20 16:38:33 +0000451 * Commence key construction.
David Howells76181c12007-10-16 23:29:46 -0700452 */
David Howells4bdf0bc2013-09-24 10:35:15 +0100453static struct key *construct_key_and_link(struct keyring_search_context *ctx,
David Howells76181c12007-10-16 23:29:46 -0700454 const char *callout_info,
David Howells4a38e122008-04-29 01:01:24 -0700455 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700456 void *aux,
457 struct key *dest_keyring,
458 unsigned long flags)
459{
460 struct key_user *user;
461 struct key *key;
462 int ret;
463
David Howellsd84f4f92008-11-14 10:39:23 +1100464 kenter("");
465
David Howells911b79c2015-10-19 11:20:28 +0100466 if (ctx->index_key.type == &key_type_keyring)
467 return ERR_PTR(-EPERM);
David Howells965475a2016-06-14 10:29:44 +0100468
Eric Biggers982707e2017-12-08 15:13:27 +0000469 ret = construct_get_dest_keyring(&dest_keyring);
470 if (ret)
471 goto error;
David Howells76181c12007-10-16 23:29:46 -0700472
Eric Biggers982707e2017-12-08 15:13:27 +0000473 user = key_user_lookup(current_fsuid());
474 if (!user) {
475 ret = -ENOMEM;
476 goto error_put_dest_keyring;
477 }
David Howells8bbf49762008-11-14 10:39:14 +1100478
David Howells4bdf0bc2013-09-24 10:35:15 +0100479 ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key);
David Howells76181c12007-10-16 23:29:46 -0700480 key_user_put(user);
481
482 if (ret == 0) {
David Howells8bbf49762008-11-14 10:39:14 +1100483 ret = construct_key(key, callout_info, callout_len, aux,
484 dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100485 if (ret < 0) {
486 kdebug("cons failed");
David Howells76181c12007-10-16 23:29:46 -0700487 goto construction_failed;
David Howellsd84f4f92008-11-14 10:39:23 +1100488 }
David Howells2b9e4682010-04-30 14:32:34 +0100489 } else if (ret == -EINPROGRESS) {
490 ret = 0;
491 } else {
Eric Biggers982707e2017-12-08 15:13:27 +0000492 goto error_put_dest_keyring;
David Howells76181c12007-10-16 23:29:46 -0700493 }
494
David Howells8bbf49762008-11-14 10:39:14 +1100495 key_put(dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100496 kleave(" = key %d", key_serial(key));
David Howells76181c12007-10-16 23:29:46 -0700497 return key;
498
499construction_failed:
500 key_negate_and_link(key, key_negative_timeout, NULL, NULL);
501 key_put(key);
Eric Biggers982707e2017-12-08 15:13:27 +0000502error_put_dest_keyring:
David Howells8bbf49762008-11-14 10:39:14 +1100503 key_put(dest_keyring);
Eric Biggers982707e2017-12-08 15:13:27 +0000504error:
David Howellsd84f4f92008-11-14 10:39:23 +1100505 kleave(" = %d", ret);
David Howells76181c12007-10-16 23:29:46 -0700506 return ERR_PTR(ret);
507}
508
David Howells973c9f42011-01-20 16:38:33 +0000509/**
510 * request_key_and_link - Request a key and cache it in a keyring.
511 * @type: The type of key we want.
512 * @description: The searchable description of the key.
513 * @callout_info: The data to pass to the instantiation upcall (or NULL).
514 * @callout_len: The length of callout_info.
515 * @aux: Auxiliary data for the upcall.
516 * @dest_keyring: Where to cache the key.
517 * @flags: Flags to key_alloc().
518 *
519 * A key matching the specified criteria is searched for in the process's
520 * keyrings and returned with its usage count incremented if found. Otherwise,
521 * if callout_info is not NULL, a key will be allocated and some service
522 * (probably in userspace) will be asked to instantiate it.
523 *
524 * If successfully found or created, the key will be linked to the destination
525 * keyring if one is provided.
526 *
527 * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
528 * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
529 * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
530 * if insufficient key quota was available to create a new key; or -ENOMEM if
531 * insufficient memory was available.
532 *
533 * If the returned key was created, then it may still be under construction,
534 * and wait_for_key_construction() should be used to wait for that to complete.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 */
David Howells3e301482005-06-23 22:00:56 -0700536struct key *request_key_and_link(struct key_type *type,
537 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700538 const void *callout_info,
539 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700540 void *aux,
David Howells7e047ef2006-06-26 00:24:50 -0700541 struct key *dest_keyring,
542 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543{
David Howells4bdf0bc2013-09-24 10:35:15 +0100544 struct keyring_search_context ctx = {
545 .index_key.type = type,
546 .index_key.description = description,
547 .cred = current_cred(),
David Howellsc06cfb02014-09-16 17:36:06 +0100548 .match_data.cmp = key_default_cmp,
David Howells46291952014-09-16 17:36:02 +0100549 .match_data.raw_data = description,
550 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
David Howells0b0a8412014-12-01 22:52:53 +0000551 .flags = (KEYRING_SEARCH_DO_STATE_CHECK |
552 KEYRING_SEARCH_SKIP_EXPIRED),
David Howells4bdf0bc2013-09-24 10:35:15 +0100553 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 struct key *key;
David Howells664cceb2005-09-28 17:03:15 +0100555 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100556 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557
David Howells4a38e122008-04-29 01:01:24 -0700558 kenter("%s,%s,%p,%zu,%p,%p,%lx",
David Howells4bdf0bc2013-09-24 10:35:15 +0100559 ctx.index_key.type->name, ctx.index_key.description,
560 callout_info, callout_len, aux, dest_keyring, flags);
David Howells3e301482005-06-23 22:00:56 -0700561
David Howells46291952014-09-16 17:36:02 +0100562 if (type->match_preparse) {
563 ret = type->match_preparse(&ctx.match_data);
564 if (ret < 0) {
565 key = ERR_PTR(ret);
566 goto error;
567 }
568 }
569
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 /* search all the process keyrings for a key */
David Howells4bdf0bc2013-09-24 10:35:15 +0100571 key_ref = search_process_keyrings(&ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572
David Howells664cceb2005-09-28 17:03:15 +0100573 if (!IS_ERR(key_ref)) {
574 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700575 if (dest_keyring) {
576 construct_get_dest_keyring(&dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100577 ret = key_link(dest_keyring, key);
David Howells03449cd2010-04-27 13:13:08 -0700578 key_put(dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100579 if (ret < 0) {
580 key_put(key);
581 key = ERR_PTR(ret);
David Howells46291952014-09-16 17:36:02 +0100582 goto error_free;
David Howells2b9e4682010-04-30 14:32:34 +0100583 }
David Howells03449cd2010-04-27 13:13:08 -0700584 }
David Howells76181c12007-10-16 23:29:46 -0700585 } else if (PTR_ERR(key_ref) != -EAGAIN) {
David Howellse231c2e2008-02-07 00:15:26 -0800586 key = ERR_CAST(key_ref);
David Howells76181c12007-10-16 23:29:46 -0700587 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 /* the search failed, but the keyrings were searchable, so we
589 * should consult userspace if we can */
590 key = ERR_PTR(-ENOKEY);
591 if (!callout_info)
David Howells46291952014-09-16 17:36:02 +0100592 goto error_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
David Howells4bdf0bc2013-09-24 10:35:15 +0100594 key = construct_key_and_link(&ctx, callout_info, callout_len,
595 aux, dest_keyring, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 }
597
David Howells46291952014-09-16 17:36:02 +0100598error_free:
599 if (type->match_free)
600 type->match_free(&ctx.match_data);
David Howells3e301482005-06-23 22:00:56 -0700601error:
602 kleave(" = %p", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700603 return key;
David Howells76181c12007-10-16 23:29:46 -0700604}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605
David Howells973c9f42011-01-20 16:38:33 +0000606/**
607 * wait_for_key_construction - Wait for construction of a key to complete
608 * @key: The key being waited for.
609 * @intr: Whether to wait interruptibly.
610 *
611 * Wait for a key to finish being constructed.
612 *
613 * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY
614 * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was
615 * revoked or expired.
David Howells76181c12007-10-16 23:29:46 -0700616 */
617int wait_for_key_construction(struct key *key, bool intr)
618{
619 int ret;
David Howells3e301482005-06-23 22:00:56 -0700620
David Howells76181c12007-10-16 23:29:46 -0700621 ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT,
David Howells76181c12007-10-16 23:29:46 -0700622 intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
NeilBrown74316202014-07-07 15:16:04 +1000623 if (ret)
624 return -ERESTARTSYS;
David Howells63c8e452017-10-04 16:43:25 +0100625 ret = key_read_state(key);
626 if (ret < 0)
627 return ret;
David Howells76181c12007-10-16 23:29:46 -0700628 return key_validate(key);
629}
630EXPORT_SYMBOL(wait_for_key_construction);
David Howells3e301482005-06-23 22:00:56 -0700631
David Howells973c9f42011-01-20 16:38:33 +0000632/**
633 * request_key - Request a key and wait for construction
634 * @type: Type of key.
635 * @description: The searchable description of the key.
636 * @callout_info: The data to pass to the instantiation upcall (or NULL).
637 *
638 * As for request_key_and_link() except that it does not add the returned key
639 * to a keyring if found, new keys are always allocated in the user's quota,
640 * the callout_info must be a NUL-terminated string and no auxiliary data can
641 * be passed.
642 *
643 * Furthermore, it then works as wait_for_key_construction() to wait for the
644 * completion of keys undergoing construction with a non-interruptible wait.
David Howells3e301482005-06-23 22:00:56 -0700645 */
646struct key *request_key(struct key_type *type,
647 const char *description,
648 const char *callout_info)
649{
David Howells76181c12007-10-16 23:29:46 -0700650 struct key *key;
David Howells4a38e122008-04-29 01:01:24 -0700651 size_t callout_len = 0;
David Howells76181c12007-10-16 23:29:46 -0700652 int ret;
David Howells3e301482005-06-23 22:00:56 -0700653
David Howells4a38e122008-04-29 01:01:24 -0700654 if (callout_info)
655 callout_len = strlen(callout_info);
656 key = request_key_and_link(type, description, callout_info, callout_len,
657 NULL, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700658 if (!IS_ERR(key)) {
659 ret = wait_for_key_construction(key, false);
660 if (ret < 0) {
661 key_put(key);
662 return ERR_PTR(ret);
663 }
664 }
665 return key;
666}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667EXPORT_SYMBOL(request_key);
David Howells4e54f082006-06-29 02:24:28 -0700668
David Howells973c9f42011-01-20 16:38:33 +0000669/**
670 * request_key_with_auxdata - Request a key with auxiliary data for the upcaller
671 * @type: The type of key we want.
672 * @description: The searchable description of the key.
673 * @callout_info: The data to pass to the instantiation upcall (or NULL).
674 * @callout_len: The length of callout_info.
675 * @aux: Auxiliary data for the upcall.
676 *
677 * As for request_key_and_link() except that it does not add the returned key
678 * to a keyring if found and new keys are always allocated in the user's quota.
679 *
680 * Furthermore, it then works as wait_for_key_construction() to wait for the
681 * completion of keys undergoing construction with a non-interruptible wait.
David Howells4e54f082006-06-29 02:24:28 -0700682 */
683struct key *request_key_with_auxdata(struct key_type *type,
684 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700685 const void *callout_info,
686 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700687 void *aux)
688{
David Howells76181c12007-10-16 23:29:46 -0700689 struct key *key;
690 int ret;
691
David Howells4a38e122008-04-29 01:01:24 -0700692 key = request_key_and_link(type, description, callout_info, callout_len,
693 aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700694 if (!IS_ERR(key)) {
695 ret = wait_for_key_construction(key, false);
696 if (ret < 0) {
697 key_put(key);
698 return ERR_PTR(ret);
699 }
700 }
701 return key;
702}
703EXPORT_SYMBOL(request_key_with_auxdata);
704
705/*
David Howells973c9f42011-01-20 16:38:33 +0000706 * request_key_async - Request a key (allow async construction)
707 * @type: Type of key.
708 * @description: The searchable description of the key.
709 * @callout_info: The data to pass to the instantiation upcall (or NULL).
710 * @callout_len: The length of callout_info.
711 *
712 * As for request_key_and_link() except that it does not add the returned key
713 * to a keyring if found, new keys are always allocated in the user's quota and
714 * no auxiliary data can be passed.
715 *
716 * The caller should call wait_for_key_construction() to wait for the
717 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700718 */
719struct key *request_key_async(struct key_type *type,
720 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700721 const void *callout_info,
722 size_t callout_len)
David Howells76181c12007-10-16 23:29:46 -0700723{
David Howells4a38e122008-04-29 01:01:24 -0700724 return request_key_and_link(type, description, callout_info,
725 callout_len, NULL, NULL,
726 KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700727}
728EXPORT_SYMBOL(request_key_async);
729
730/*
731 * request a key with auxiliary data for the upcaller (allow async construction)
David Howells973c9f42011-01-20 16:38:33 +0000732 * @type: Type of key.
733 * @description: The searchable description of the key.
734 * @callout_info: The data to pass to the instantiation upcall (or NULL).
735 * @callout_len: The length of callout_info.
736 * @aux: Auxiliary data for the upcall.
737 *
738 * As for request_key_and_link() except that it does not add the returned key
739 * to a keyring if found and new keys are always allocated in the user's quota.
740 *
741 * The caller should call wait_for_key_construction() to wait for the
742 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700743 */
744struct key *request_key_async_with_auxdata(struct key_type *type,
745 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700746 const void *callout_info,
747 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700748 void *aux)
749{
David Howells4a38e122008-04-29 01:01:24 -0700750 return request_key_and_link(type, description, callout_info,
751 callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700752}
753EXPORT_SYMBOL(request_key_async_with_auxdata);