blob: 486ef6fa393b2cc9d8ceb8cb11f187f97730bd90 [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 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 Howells7e047ef2006-06-26 00:24:50 -0700119 KEY_ALLOC_QUOTA_OVERRUN, 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 */
David Howells8bbf49762008-11-14 10:39:14 +1100253static void 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;
David Howells3e301482005-06-23 22:00:56 -0700258
David Howells8bbf49762008-11-14 10:39:14 +1100259 kenter("%p", dest_keyring);
David Howells3e301482005-06-23 22:00:56 -0700260
261 /* find the appropriate keyring */
David Howells8bbf49762008-11-14 10:39:14 +1100262 if (dest_keyring) {
263 /* the caller supplied one */
264 key_get(dest_keyring);
265 } else {
266 /* use a default keyring; falling through the cases until we
267 * find one that we actually have */
David Howellsbb952bb2008-11-14 10:39:20 +1100268 switch (cred->jit_keyring) {
David Howells3e301482005-06-23 22:00:56 -0700269 case KEY_REQKEY_DEFL_DEFAULT:
David Howells8bbf49762008-11-14 10:39:14 +1100270 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100271 if (cred->request_key_auth) {
272 authkey = cred->request_key_auth;
David Howells8bbf49762008-11-14 10:39:14 +1100273 down_read(&authkey->sem);
274 rka = authkey->payload.data;
275 if (!test_bit(KEY_FLAG_REVOKED,
276 &authkey->flags))
277 dest_keyring =
278 key_get(rka->dest_keyring);
279 up_read(&authkey->sem);
280 if (dest_keyring)
281 break;
282 }
283
David Howells3e301482005-06-23 22:00:56 -0700284 case KEY_REQKEY_DEFL_THREAD_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100285 dest_keyring = key_get(cred->thread_keyring);
David Howells3e301482005-06-23 22:00:56 -0700286 if (dest_keyring)
287 break;
288
289 case KEY_REQKEY_DEFL_PROCESS_KEYRING:
David Howells3a505972012-10-02 19:24:29 +0100290 dest_keyring = key_get(cred->process_keyring);
David Howells3e301482005-06-23 22:00:56 -0700291 if (dest_keyring)
292 break;
293
294 case KEY_REQKEY_DEFL_SESSION_KEYRING:
295 rcu_read_lock();
296 dest_keyring = key_get(
David Howells3a505972012-10-02 19:24:29 +0100297 rcu_dereference(cred->session_keyring));
David Howells3e301482005-06-23 22:00:56 -0700298 rcu_read_unlock();
David Howells3e301482005-06-23 22:00:56 -0700299
300 if (dest_keyring)
301 break;
302
303 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
David Howellsb6dff3e2008-11-14 10:39:16 +1100304 dest_keyring =
David Howellsbb952bb2008-11-14 10:39:20 +1100305 key_get(cred->user->session_keyring);
David Howells3e301482005-06-23 22:00:56 -0700306 break;
307
308 case KEY_REQKEY_DEFL_USER_KEYRING:
David Howellsbb952bb2008-11-14 10:39:20 +1100309 dest_keyring = key_get(cred->user->uid_keyring);
David Howells3e301482005-06-23 22:00:56 -0700310 break;
311
312 case KEY_REQKEY_DEFL_GROUP_KEYRING:
313 default:
314 BUG();
315 }
316 }
317
David Howells8bbf49762008-11-14 10:39:14 +1100318 *_dest_keyring = dest_keyring;
319 kleave(" [dk %d]", key_serial(dest_keyring));
320 return;
David Howells76181c12007-10-16 23:29:46 -0700321}
David Howells3e301482005-06-23 22:00:56 -0700322
David Howells76181c12007-10-16 23:29:46 -0700323/*
David Howells973c9f42011-01-20 16:38:33 +0000324 * Allocate a new key in under-construction state and attempt to link it in to
325 * the requested keyring.
326 *
327 * May return a key that's already under construction instead if there was a
328 * race between two thread calling request_key().
David Howells76181c12007-10-16 23:29:46 -0700329 */
David Howells4bdf0bc2013-09-24 10:35:15 +0100330static int construct_alloc_key(struct keyring_search_context *ctx,
David Howells76181c12007-10-16 23:29:46 -0700331 struct key *dest_keyring,
332 unsigned long flags,
333 struct key_user *user,
334 struct key **_key)
335{
David Howellsb2a4df22013-09-24 10:35:18 +0100336 struct assoc_array_edit *edit;
David Howells76181c12007-10-16 23:29:46 -0700337 struct key *key;
David Howells96b5c8f2012-10-02 19:24:56 +0100338 key_perm_t perm;
David Howells76181c12007-10-16 23:29:46 -0700339 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100340 int ret;
David Howells3e301482005-06-23 22:00:56 -0700341
David Howells4bdf0bc2013-09-24 10:35:15 +0100342 kenter("%s,%s,,,",
343 ctx->index_key.type->name, ctx->index_key.description);
David Howells76181c12007-10-16 23:29:46 -0700344
David Howellsf70e2e02010-04-30 14:32:39 +0100345 *_key = NULL;
David Howells76181c12007-10-16 23:29:46 -0700346 mutex_lock(&user->cons_lock);
347
David Howells96b5c8f2012-10-02 19:24:56 +0100348 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR;
349 perm |= KEY_USR_VIEW;
David Howells4bdf0bc2013-09-24 10:35:15 +0100350 if (ctx->index_key.type->read)
David Howells96b5c8f2012-10-02 19:24:56 +0100351 perm |= KEY_POS_READ;
David Howells4bdf0bc2013-09-24 10:35:15 +0100352 if (ctx->index_key.type == &key_type_keyring ||
353 ctx->index_key.type->update)
David Howells96b5c8f2012-10-02 19:24:56 +0100354 perm |= KEY_POS_WRITE;
355
David Howells4bdf0bc2013-09-24 10:35:15 +0100356 key = key_alloc(ctx->index_key.type, ctx->index_key.description,
357 ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred,
David Howells96b5c8f2012-10-02 19:24:56 +0100358 perm, flags);
David Howells76181c12007-10-16 23:29:46 -0700359 if (IS_ERR(key))
360 goto alloc_failed;
361
362 set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags);
363
David Howellsf70e2e02010-04-30 14:32:39 +0100364 if (dest_keyring) {
David Howellsb2a4df22013-09-24 10:35:18 +0100365 ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit);
David Howellsf70e2e02010-04-30 14:32:39 +0100366 if (ret < 0)
367 goto link_prealloc_failed;
368 }
David Howells76181c12007-10-16 23:29:46 -0700369
370 /* attach the key to the destination keyring under lock, but we do need
371 * to do another check just in case someone beat us to it whilst we
372 * waited for locks */
373 mutex_lock(&key_construction_mutex);
374
David Howells4bdf0bc2013-09-24 10:35:15 +0100375 key_ref = search_process_keyrings(ctx);
David Howells76181c12007-10-16 23:29:46 -0700376 if (!IS_ERR(key_ref))
377 goto key_already_present;
378
David Howells34574dd2009-04-09 17:14:05 +0100379 if (dest_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +0100380 __key_link(key, &edit);
David Howells76181c12007-10-16 23:29:46 -0700381
382 mutex_unlock(&key_construction_mutex);
David Howells34574dd2009-04-09 17:14:05 +0100383 if (dest_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +0100384 __key_link_end(dest_keyring, &ctx->index_key, edit);
David Howells76181c12007-10-16 23:29:46 -0700385 mutex_unlock(&user->cons_lock);
386 *_key = key;
387 kleave(" = 0 [%d]", key_serial(key));
388 return 0;
389
David Howells2b9e4682010-04-30 14:32:34 +0100390 /* the key is now present - we tell the caller that we found it by
391 * returning -EINPROGRESS */
David Howells76181c12007-10-16 23:29:46 -0700392key_already_present:
David Howellsf70e2e02010-04-30 14:32:39 +0100393 key_put(key);
David Howells76181c12007-10-16 23:29:46 -0700394 mutex_unlock(&key_construction_mutex);
David Howellsf70e2e02010-04-30 14:32:39 +0100395 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700396 if (dest_keyring) {
David Howellsf70e2e02010-04-30 14:32:39 +0100397 ret = __key_link_check_live_key(dest_keyring, key);
398 if (ret == 0)
David Howellsb2a4df22013-09-24 10:35:18 +0100399 __key_link(key, &edit);
400 __key_link_end(dest_keyring, &ctx->index_key, edit);
David Howellsf70e2e02010-04-30 14:32:39 +0100401 if (ret < 0)
402 goto link_check_failed;
David Howells03449cd2010-04-27 13:13:08 -0700403 }
David Howells76181c12007-10-16 23:29:46 -0700404 mutex_unlock(&user->cons_lock);
David Howellsf70e2e02010-04-30 14:32:39 +0100405 *_key = key;
David Howells76181c12007-10-16 23:29:46 -0700406 kleave(" = -EINPROGRESS [%d]", key_serial(key));
407 return -EINPROGRESS;
408
David Howellsf70e2e02010-04-30 14:32:39 +0100409link_check_failed:
410 mutex_unlock(&user->cons_lock);
411 key_put(key);
412 kleave(" = %d [linkcheck]", ret);
413 return ret;
414
415link_prealloc_failed:
David Howellsf70e2e02010-04-30 14:32:39 +0100416 mutex_unlock(&user->cons_lock);
David Jefferyd0709f12015-02-12 16:45:31 +0000417 key_put(key);
David Howellsf70e2e02010-04-30 14:32:39 +0100418 kleave(" = %d [prelink]", ret);
419 return ret;
420
David Howells76181c12007-10-16 23:29:46 -0700421alloc_failed:
422 mutex_unlock(&user->cons_lock);
David Howells76181c12007-10-16 23:29:46 -0700423 kleave(" = %ld", PTR_ERR(key));
424 return PTR_ERR(key);
425}
426
427/*
David Howells973c9f42011-01-20 16:38:33 +0000428 * Commence key construction.
David Howells76181c12007-10-16 23:29:46 -0700429 */
David Howells4bdf0bc2013-09-24 10:35:15 +0100430static struct key *construct_key_and_link(struct keyring_search_context *ctx,
David Howells76181c12007-10-16 23:29:46 -0700431 const char *callout_info,
David Howells4a38e122008-04-29 01:01:24 -0700432 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700433 void *aux,
434 struct key *dest_keyring,
435 unsigned long flags)
436{
437 struct key_user *user;
438 struct key *key;
439 int ret;
440
David Howellsd84f4f92008-11-14 10:39:23 +1100441 kenter("");
442
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800443 user = key_user_lookup(current_fsuid());
David Howells76181c12007-10-16 23:29:46 -0700444 if (!user)
445 return ERR_PTR(-ENOMEM);
446
David Howells8bbf49762008-11-14 10:39:14 +1100447 construct_get_dest_keyring(&dest_keyring);
448
David Howells4bdf0bc2013-09-24 10:35:15 +0100449 ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key);
David Howells76181c12007-10-16 23:29:46 -0700450 key_user_put(user);
451
452 if (ret == 0) {
David Howells8bbf49762008-11-14 10:39:14 +1100453 ret = construct_key(key, callout_info, callout_len, aux,
454 dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100455 if (ret < 0) {
456 kdebug("cons failed");
David Howells76181c12007-10-16 23:29:46 -0700457 goto construction_failed;
David Howellsd84f4f92008-11-14 10:39:23 +1100458 }
David Howells2b9e4682010-04-30 14:32:34 +0100459 } else if (ret == -EINPROGRESS) {
460 ret = 0;
461 } else {
David Howellsb1d7dd82011-06-21 14:32:05 +0100462 goto couldnt_alloc_key;
David Howells76181c12007-10-16 23:29:46 -0700463 }
464
David Howells8bbf49762008-11-14 10:39:14 +1100465 key_put(dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100466 kleave(" = key %d", key_serial(key));
David Howells76181c12007-10-16 23:29:46 -0700467 return key;
468
469construction_failed:
470 key_negate_and_link(key, key_negative_timeout, NULL, NULL);
471 key_put(key);
David Howellsb1d7dd82011-06-21 14:32:05 +0100472couldnt_alloc_key:
David Howells8bbf49762008-11-14 10:39:14 +1100473 key_put(dest_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100474 kleave(" = %d", ret);
David Howells76181c12007-10-16 23:29:46 -0700475 return ERR_PTR(ret);
476}
477
David Howells973c9f42011-01-20 16:38:33 +0000478/**
479 * request_key_and_link - Request a key and cache it in a keyring.
480 * @type: The type of key we want.
481 * @description: The searchable description of the key.
482 * @callout_info: The data to pass to the instantiation upcall (or NULL).
483 * @callout_len: The length of callout_info.
484 * @aux: Auxiliary data for the upcall.
485 * @dest_keyring: Where to cache the key.
486 * @flags: Flags to key_alloc().
487 *
488 * A key matching the specified criteria is searched for in the process's
489 * keyrings and returned with its usage count incremented if found. Otherwise,
490 * if callout_info is not NULL, a key will be allocated and some service
491 * (probably in userspace) will be asked to instantiate it.
492 *
493 * If successfully found or created, the key will be linked to the destination
494 * keyring if one is provided.
495 *
496 * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED
497 * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was
498 * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT
499 * if insufficient key quota was available to create a new key; or -ENOMEM if
500 * insufficient memory was available.
501 *
502 * If the returned key was created, then it may still be under construction,
503 * and wait_for_key_construction() should be used to wait for that to complete.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 */
David Howells3e301482005-06-23 22:00:56 -0700505struct key *request_key_and_link(struct key_type *type,
506 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700507 const void *callout_info,
508 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700509 void *aux,
David Howells7e047ef2006-06-26 00:24:50 -0700510 struct key *dest_keyring,
511 unsigned long flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512{
David Howells4bdf0bc2013-09-24 10:35:15 +0100513 struct keyring_search_context ctx = {
514 .index_key.type = type,
515 .index_key.description = description,
516 .cred = current_cred(),
David Howellsc06cfb02014-09-16 17:36:06 +0100517 .match_data.cmp = key_default_cmp,
David Howells46291952014-09-16 17:36:02 +0100518 .match_data.raw_data = description,
519 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
David Howells0b0a8412014-12-01 22:52:53 +0000520 .flags = (KEYRING_SEARCH_DO_STATE_CHECK |
521 KEYRING_SEARCH_SKIP_EXPIRED),
David Howells4bdf0bc2013-09-24 10:35:15 +0100522 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 struct key *key;
David Howells664cceb2005-09-28 17:03:15 +0100524 key_ref_t key_ref;
David Howells2b9e4682010-04-30 14:32:34 +0100525 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526
David Howells4a38e122008-04-29 01:01:24 -0700527 kenter("%s,%s,%p,%zu,%p,%p,%lx",
David Howells4bdf0bc2013-09-24 10:35:15 +0100528 ctx.index_key.type->name, ctx.index_key.description,
529 callout_info, callout_len, aux, dest_keyring, flags);
David Howells3e301482005-06-23 22:00:56 -0700530
David Howells46291952014-09-16 17:36:02 +0100531 if (type->match_preparse) {
532 ret = type->match_preparse(&ctx.match_data);
533 if (ret < 0) {
534 key = ERR_PTR(ret);
535 goto error;
536 }
537 }
538
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 /* search all the process keyrings for a key */
David Howells4bdf0bc2013-09-24 10:35:15 +0100540 key_ref = search_process_keyrings(&ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541
David Howells664cceb2005-09-28 17:03:15 +0100542 if (!IS_ERR(key_ref)) {
543 key = key_ref_to_ptr(key_ref);
David Howells03449cd2010-04-27 13:13:08 -0700544 if (dest_keyring) {
545 construct_get_dest_keyring(&dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100546 ret = key_link(dest_keyring, key);
David Howells03449cd2010-04-27 13:13:08 -0700547 key_put(dest_keyring);
David Howells2b9e4682010-04-30 14:32:34 +0100548 if (ret < 0) {
549 key_put(key);
550 key = ERR_PTR(ret);
David Howells46291952014-09-16 17:36:02 +0100551 goto error_free;
David Howells2b9e4682010-04-30 14:32:34 +0100552 }
David Howells03449cd2010-04-27 13:13:08 -0700553 }
David Howells76181c12007-10-16 23:29:46 -0700554 } else if (PTR_ERR(key_ref) != -EAGAIN) {
David Howellse231c2e2008-02-07 00:15:26 -0800555 key = ERR_CAST(key_ref);
David Howells76181c12007-10-16 23:29:46 -0700556 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 /* the search failed, but the keyrings were searchable, so we
558 * should consult userspace if we can */
559 key = ERR_PTR(-ENOKEY);
560 if (!callout_info)
David Howells46291952014-09-16 17:36:02 +0100561 goto error_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562
David Howells4bdf0bc2013-09-24 10:35:15 +0100563 key = construct_key_and_link(&ctx, callout_info, callout_len,
564 aux, dest_keyring, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 }
566
David Howells46291952014-09-16 17:36:02 +0100567error_free:
568 if (type->match_free)
569 type->match_free(&ctx.match_data);
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,
David Howells76181c12007-10-16 23:29:46 -0700591 intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
NeilBrown74316202014-07-07 15:16:04 +1000592 if (ret)
593 return -ERESTARTSYS;
David Howells74792b02013-10-30 11:15:24 +0000594 if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
595 smp_rmb();
David Howellsfdd1b942011-03-07 15:06:09 +0000596 return key->type_data.reject_error;
David Howells74792b02013-10-30 11:15:24 +0000597 }
David Howells76181c12007-10-16 23:29:46 -0700598 return key_validate(key);
599}
600EXPORT_SYMBOL(wait_for_key_construction);
David Howells3e301482005-06-23 22:00:56 -0700601
David Howells973c9f42011-01-20 16:38:33 +0000602/**
603 * request_key - Request a key and wait for construction
604 * @type: Type of key.
605 * @description: The searchable description of the key.
606 * @callout_info: The data to pass to the instantiation upcall (or NULL).
607 *
608 * As for request_key_and_link() except that it does not add the returned key
609 * to a keyring if found, new keys are always allocated in the user's quota,
610 * the callout_info must be a NUL-terminated string and no auxiliary data can
611 * be passed.
612 *
613 * Furthermore, it then works as wait_for_key_construction() to wait for the
614 * completion of keys undergoing construction with a non-interruptible wait.
David Howells3e301482005-06-23 22:00:56 -0700615 */
616struct key *request_key(struct key_type *type,
617 const char *description,
618 const char *callout_info)
619{
David Howells76181c12007-10-16 23:29:46 -0700620 struct key *key;
David Howells4a38e122008-04-29 01:01:24 -0700621 size_t callout_len = 0;
David Howells76181c12007-10-16 23:29:46 -0700622 int ret;
David Howells3e301482005-06-23 22:00:56 -0700623
David Howells4a38e122008-04-29 01:01:24 -0700624 if (callout_info)
625 callout_len = strlen(callout_info);
626 key = request_key_and_link(type, description, callout_info, callout_len,
627 NULL, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700628 if (!IS_ERR(key)) {
629 ret = wait_for_key_construction(key, false);
630 if (ret < 0) {
631 key_put(key);
632 return ERR_PTR(ret);
633 }
634 }
635 return key;
636}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637EXPORT_SYMBOL(request_key);
David Howells4e54f082006-06-29 02:24:28 -0700638
David Howells973c9f42011-01-20 16:38:33 +0000639/**
640 * request_key_with_auxdata - Request a key with auxiliary data for the upcaller
641 * @type: The type of key we want.
642 * @description: The searchable description of the key.
643 * @callout_info: The data to pass to the instantiation upcall (or NULL).
644 * @callout_len: The length of callout_info.
645 * @aux: Auxiliary data for the upcall.
646 *
647 * As for request_key_and_link() except that it does not add the returned key
648 * to a keyring if found and new keys are always allocated in the user's quota.
649 *
650 * Furthermore, it then works as wait_for_key_construction() to wait for the
651 * completion of keys undergoing construction with a non-interruptible wait.
David Howells4e54f082006-06-29 02:24:28 -0700652 */
653struct key *request_key_with_auxdata(struct key_type *type,
654 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700655 const void *callout_info,
656 size_t callout_len,
David Howells4e54f082006-06-29 02:24:28 -0700657 void *aux)
658{
David Howells76181c12007-10-16 23:29:46 -0700659 struct key *key;
660 int ret;
661
David Howells4a38e122008-04-29 01:01:24 -0700662 key = request_key_and_link(type, description, callout_info, callout_len,
663 aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700664 if (!IS_ERR(key)) {
665 ret = wait_for_key_construction(key, false);
666 if (ret < 0) {
667 key_put(key);
668 return ERR_PTR(ret);
669 }
670 }
671 return key;
672}
673EXPORT_SYMBOL(request_key_with_auxdata);
674
675/*
David Howells973c9f42011-01-20 16:38:33 +0000676 * request_key_async - Request a key (allow async construction)
677 * @type: Type of key.
678 * @description: The searchable description of the key.
679 * @callout_info: The data to pass to the instantiation upcall (or NULL).
680 * @callout_len: The length of callout_info.
681 *
682 * As for request_key_and_link() except that it does not add the returned key
683 * to a keyring if found, new keys are always allocated in the user's quota and
684 * no auxiliary data can be passed.
685 *
686 * The caller should call wait_for_key_construction() to wait for the
687 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700688 */
689struct key *request_key_async(struct key_type *type,
690 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700691 const void *callout_info,
692 size_t callout_len)
David Howells76181c12007-10-16 23:29:46 -0700693{
David Howells4a38e122008-04-29 01:01:24 -0700694 return request_key_and_link(type, description, callout_info,
695 callout_len, NULL, NULL,
696 KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700697}
698EXPORT_SYMBOL(request_key_async);
699
700/*
701 * request a key with auxiliary data for the upcaller (allow async construction)
David Howells973c9f42011-01-20 16:38:33 +0000702 * @type: Type of key.
703 * @description: The searchable description of the key.
704 * @callout_info: The data to pass to the instantiation upcall (or NULL).
705 * @callout_len: The length of callout_info.
706 * @aux: Auxiliary data for the upcall.
707 *
708 * As for request_key_and_link() except that it does not add the returned key
709 * to a keyring if found and new keys are always allocated in the user's quota.
710 *
711 * The caller should call wait_for_key_construction() to wait for the
712 * completion of the returned key if it is still undergoing construction.
David Howells76181c12007-10-16 23:29:46 -0700713 */
714struct key *request_key_async_with_auxdata(struct key_type *type,
715 const char *description,
David Howells4a38e122008-04-29 01:01:24 -0700716 const void *callout_info,
717 size_t callout_len,
David Howells76181c12007-10-16 23:29:46 -0700718 void *aux)
719{
David Howells4a38e122008-04-29 01:01:24 -0700720 return request_key_and_link(type, description, callout_info,
721 callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA);
David Howells76181c12007-10-16 23:29:46 -0700722}
723EXPORT_SYMBOL(request_key_async_with_auxdata);