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David Howells973c9f42011-01-20 16:38:33 +00001/* Manage a process's keyrings
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
David Howells69664cf2008-04-29 01:01:31 -07003 * Copyright (C) 2004-2005, 2008 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.
10 */
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/sched.h>
Ingo Molnar8703e8a2017-02-08 18:51:30 +010015#include <linux/sched/user.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/keyctl.h>
17#include <linux/fs.h>
18#include <linux/err.h>
Ingo Molnarbb0030792006-03-22 00:09:14 -080019#include <linux/mutex.h>
David Howellsee18d642009-09-02 09:14:21 +010020#include <linux/security.h>
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -060021#include <linux/user_namespace.h>
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080022#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include "internal.h"
24
David Howells973c9f42011-01-20 16:38:33 +000025/* Session keyring create vs join semaphore */
Ingo Molnarbb0030792006-03-22 00:09:14 -080026static DEFINE_MUTEX(key_session_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070027
David Howells973c9f42011-01-20 16:38:33 +000028/* User keyring creation semaphore */
David Howells69664cf2008-04-29 01:01:31 -070029static DEFINE_MUTEX(key_user_keyring_mutex);
30
David Howells973c9f42011-01-20 16:38:33 +000031/* The root user's tracking struct */
Linus Torvalds1da177e2005-04-16 15:20:36 -070032struct key_user root_key_user = {
Elena Reshetovaddb99e12017-03-31 15:20:49 +030033 .usage = REFCOUNT_INIT(3),
David Howells76181c12007-10-16 23:29:46 -070034 .cons_lock = __MUTEX_INITIALIZER(root_key_user.cons_lock),
Peter Zijlstra6cfd76a2006-12-06 20:37:22 -080035 .lock = __SPIN_LOCK_UNLOCKED(root_key_user.lock),
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 .nkeys = ATOMIC_INIT(2),
37 .nikeys = ATOMIC_INIT(2),
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -080038 .uid = GLOBAL_ROOT_UID,
Linus Torvalds1da177e2005-04-16 15:20:36 -070039};
40
Linus Torvalds1da177e2005-04-16 15:20:36 -070041/*
David Howells973c9f42011-01-20 16:38:33 +000042 * Install the user and user session keyrings for the current process's UID.
Linus Torvalds1da177e2005-04-16 15:20:36 -070043 */
David Howells8bbf49762008-11-14 10:39:14 +110044int install_user_keyrings(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070045{
David Howellsd84f4f92008-11-14 10:39:23 +110046 struct user_struct *user;
47 const struct cred *cred;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 struct key *uid_keyring, *session_keyring;
David Howells96b5c8f2012-10-02 19:24:56 +010049 key_perm_t user_keyring_perm;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 char buf[20];
51 int ret;
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -080052 uid_t uid;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
David Howells96b5c8f2012-10-02 19:24:56 +010054 user_keyring_perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_ALL;
David Howellsd84f4f92008-11-14 10:39:23 +110055 cred = current_cred();
56 user = cred->user;
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -080057 uid = from_kuid(cred->user_ns, user->uid);
David Howellsd84f4f92008-11-14 10:39:23 +110058
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -080059 kenter("%p{%u}", user, uid);
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
David Howells0da9dfd2013-03-12 16:44:31 +110061 if (user->uid_keyring && user->session_keyring) {
David Howells69664cf2008-04-29 01:01:31 -070062 kleave(" = 0 [exist]");
63 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 }
65
David Howells69664cf2008-04-29 01:01:31 -070066 mutex_lock(&key_user_keyring_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 ret = 0;
68
David Howells69664cf2008-04-29 01:01:31 -070069 if (!user->uid_keyring) {
70 /* get the UID-specific keyring
71 * - there may be one in existence already as it may have been
72 * pinned by a session, but the user_struct pointing to it
73 * may have been destroyed by setuid */
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -080074 sprintf(buf, "_uid.%u", uid);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
David Howells69664cf2008-04-29 01:01:31 -070076 uid_keyring = find_keyring_by_name(buf, true);
77 if (IS_ERR(uid_keyring)) {
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -080078 uid_keyring = keyring_alloc(buf, user->uid, INVALID_GID,
David Howells96b5c8f2012-10-02 19:24:56 +010079 cred, user_keyring_perm,
Eric Biggers237bbd22017-09-18 11:37:03 -070080 KEY_ALLOC_UID_KEYRING |
81 KEY_ALLOC_IN_QUOTA,
David Howells5ac7eac2016-04-06 16:14:24 +010082 NULL, NULL);
David Howells69664cf2008-04-29 01:01:31 -070083 if (IS_ERR(uid_keyring)) {
84 ret = PTR_ERR(uid_keyring);
85 goto error;
86 }
87 }
88
89 /* get a default session keyring (which might also exist
90 * already) */
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -080091 sprintf(buf, "_uid_ses.%u", uid);
David Howells69664cf2008-04-29 01:01:31 -070092
93 session_keyring = find_keyring_by_name(buf, true);
94 if (IS_ERR(session_keyring)) {
95 session_keyring =
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -080096 keyring_alloc(buf, user->uid, INVALID_GID,
David Howells96b5c8f2012-10-02 19:24:56 +010097 cred, user_keyring_perm,
Eric Biggers237bbd22017-09-18 11:37:03 -070098 KEY_ALLOC_UID_KEYRING |
99 KEY_ALLOC_IN_QUOTA,
David Howells5ac7eac2016-04-06 16:14:24 +0100100 NULL, NULL);
David Howells69664cf2008-04-29 01:01:31 -0700101 if (IS_ERR(session_keyring)) {
102 ret = PTR_ERR(session_keyring);
103 goto error_release;
104 }
105
106 /* we install a link from the user session keyring to
107 * the user keyring */
108 ret = key_link(session_keyring, uid_keyring);
109 if (ret < 0)
110 goto error_release_both;
111 }
112
113 /* install the keyrings */
114 user->uid_keyring = uid_keyring;
115 user->session_keyring = session_keyring;
116 }
117
118 mutex_unlock(&key_user_keyring_mutex);
119 kleave(" = 0");
120 return 0;
121
122error_release_both:
123 key_put(session_keyring);
124error_release:
125 key_put(uid_keyring);
126error:
127 mutex_unlock(&key_user_keyring_mutex);
128 kleave(" = %d", ret);
129 return ret;
130}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100133 * Install a thread keyring to the given credentials struct if it didn't have
134 * one already. This is allowed to overrun the quota.
135 *
136 * Return: 0 if a thread keyring is now present; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 */
David Howellsd84f4f92008-11-14 10:39:23 +1100138int install_thread_keyring_to_cred(struct cred *new)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
David Howellsd84f4f92008-11-14 10:39:23 +1100140 struct key *keyring;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
Eric Biggersc9f838d2017-04-18 15:31:09 +0100142 if (new->thread_keyring)
143 return 0;
144
David Howellsd84f4f92008-11-14 10:39:23 +1100145 keyring = keyring_alloc("_tid", new->uid, new->gid, new,
David Howells96b5c8f2012-10-02 19:24:56 +0100146 KEY_POS_ALL | KEY_USR_VIEW,
David Howells5ac7eac2016-04-06 16:14:24 +0100147 KEY_ALLOC_QUOTA_OVERRUN,
148 NULL, NULL);
David Howellsd84f4f92008-11-14 10:39:23 +1100149 if (IS_ERR(keyring))
150 return PTR_ERR(keyring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151
David Howellsd84f4f92008-11-14 10:39:23 +1100152 new->thread_keyring = keyring;
153 return 0;
154}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100157 * Install a thread keyring to the current task if it didn't have one already.
158 *
159 * Return: 0 if a thread keyring is now present; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 */
David Howellsd84f4f92008-11-14 10:39:23 +1100161static int install_thread_keyring(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162{
David Howellsd84f4f92008-11-14 10:39:23 +1100163 struct cred *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 int ret;
165
David Howellsd84f4f92008-11-14 10:39:23 +1100166 new = prepare_creds();
167 if (!new)
168 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169
David Howellsd84f4f92008-11-14 10:39:23 +1100170 ret = install_thread_keyring_to_cred(new);
171 if (ret < 0) {
172 abort_creds(new);
173 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 }
175
David Howellsd84f4f92008-11-14 10:39:23 +1100176 return commit_creds(new);
177}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
David Howellsd84f4f92008-11-14 10:39:23 +1100179/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100180 * Install a process keyring to the given credentials struct if it didn't have
181 * one already. This is allowed to overrun the quota.
David Howells973c9f42011-01-20 16:38:33 +0000182 *
Eric Biggersc9f838d2017-04-18 15:31:09 +0100183 * Return: 0 if a process keyring is now present; -errno on failure.
David Howellsd84f4f92008-11-14 10:39:23 +1100184 */
185int install_process_keyring_to_cred(struct cred *new)
186{
187 struct key *keyring;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188
David Howells3a505972012-10-02 19:24:29 +0100189 if (new->process_keyring)
Eric Biggersc9f838d2017-04-18 15:31:09 +0100190 return 0;
David Howellsd84f4f92008-11-14 10:39:23 +1100191
David Howells96b5c8f2012-10-02 19:24:56 +0100192 keyring = keyring_alloc("_pid", new->uid, new->gid, new,
193 KEY_POS_ALL | KEY_USR_VIEW,
David Howells5ac7eac2016-04-06 16:14:24 +0100194 KEY_ALLOC_QUOTA_OVERRUN,
195 NULL, NULL);
David Howellsd84f4f92008-11-14 10:39:23 +1100196 if (IS_ERR(keyring))
197 return PTR_ERR(keyring);
198
David Howells3a505972012-10-02 19:24:29 +0100199 new->process_keyring = keyring;
200 return 0;
David Howellsd84f4f92008-11-14 10:39:23 +1100201}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100204 * Install a process keyring to the current task if it didn't have one already.
David Howells973c9f42011-01-20 16:38:33 +0000205 *
Eric Biggersc9f838d2017-04-18 15:31:09 +0100206 * Return: 0 if a process keyring is now present; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 */
David Howellsd84f4f92008-11-14 10:39:23 +1100208static int install_process_keyring(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209{
David Howellsd84f4f92008-11-14 10:39:23 +1100210 struct cred *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 int ret;
212
David Howellsd84f4f92008-11-14 10:39:23 +1100213 new = prepare_creds();
214 if (!new)
215 return -ENOMEM;
David Howells1a26feb2006-04-10 22:54:26 -0700216
David Howellsd84f4f92008-11-14 10:39:23 +1100217 ret = install_process_keyring_to_cred(new);
218 if (ret < 0) {
219 abort_creds(new);
Eric Biggersc9f838d2017-04-18 15:31:09 +0100220 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 }
222
David Howellsd84f4f92008-11-14 10:39:23 +1100223 return commit_creds(new);
224}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100227 * Install the given keyring as the session keyring of the given credentials
228 * struct, replacing the existing one if any. If the given keyring is NULL,
229 * then install a new anonymous session keyring.
230 *
231 * Return: 0 on success; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 */
Oleg Nesterov685bfd22010-05-26 14:43:00 -0700233int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234{
David Howells7e047ef2006-06-26 00:24:50 -0700235 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 struct key *old;
David Howells1a26feb2006-04-10 22:54:26 -0700237
238 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
240 /* create an empty session keyring */
241 if (!keyring) {
David Howells7e047ef2006-06-26 00:24:50 -0700242 flags = KEY_ALLOC_QUOTA_OVERRUN;
David Howells3a505972012-10-02 19:24:29 +0100243 if (cred->session_keyring)
David Howells7e047ef2006-06-26 00:24:50 -0700244 flags = KEY_ALLOC_IN_QUOTA;
245
David Howells96b5c8f2012-10-02 19:24:56 +0100246 keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
247 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
David Howells5ac7eac2016-04-06 16:14:24 +0100248 flags, NULL, NULL);
David Howells1a26feb2006-04-10 22:54:26 -0700249 if (IS_ERR(keyring))
250 return PTR_ERR(keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100251 } else {
David Howellsccc3e6d2013-09-24 10:35:16 +0100252 __key_get(keyring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253 }
254
255 /* install the keyring */
David Howells3a505972012-10-02 19:24:29 +0100256 old = cred->session_keyring;
257 rcu_assign_pointer(cred->session_keyring, keyring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
David Howells3a505972012-10-02 19:24:29 +0100259 if (old)
David Howells1a26feb2006-04-10 22:54:26 -0700260 key_put(old);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
David Howells1a26feb2006-04-10 22:54:26 -0700262 return 0;
David Howellsd84f4f92008-11-14 10:39:23 +1100263}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100266 * Install the given keyring as the session keyring of the current task,
267 * replacing the existing one if any. If the given keyring is NULL, then
268 * install a new anonymous session keyring.
269 *
270 * Return: 0 on success; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 */
David Howellsd84f4f92008-11-14 10:39:23 +1100272static int install_session_keyring(struct key *keyring)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273{
David Howellsd84f4f92008-11-14 10:39:23 +1100274 struct cred *new;
275 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276
David Howellsd84f4f92008-11-14 10:39:23 +1100277 new = prepare_creds();
278 if (!new)
279 return -ENOMEM;
David Howellsb5f545c2006-01-08 01:02:47 -0800280
David Howells995995372011-08-22 14:08:33 +0100281 ret = install_session_keyring_to_cred(new, keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100282 if (ret < 0) {
283 abort_creds(new);
284 return ret;
285 }
David Howellsb5f545c2006-01-08 01:02:47 -0800286
David Howellsd84f4f92008-11-14 10:39:23 +1100287 return commit_creds(new);
288}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290/*
David Howells973c9f42011-01-20 16:38:33 +0000291 * Handle the fsuid changing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 */
293void key_fsuid_changed(struct task_struct *tsk)
294{
295 /* update the ownership of the thread keyring */
David Howellsb6dff3e2008-11-14 10:39:16 +1100296 BUG_ON(!tsk->cred);
297 if (tsk->cred->thread_keyring) {
298 down_write(&tsk->cred->thread_keyring->sem);
299 tsk->cred->thread_keyring->uid = tsk->cred->fsuid;
300 up_write(&tsk->cred->thread_keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000302}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304/*
David Howells973c9f42011-01-20 16:38:33 +0000305 * Handle the fsgid changing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 */
307void key_fsgid_changed(struct task_struct *tsk)
308{
309 /* update the ownership of the thread keyring */
David Howellsb6dff3e2008-11-14 10:39:16 +1100310 BUG_ON(!tsk->cred);
311 if (tsk->cred->thread_keyring) {
312 down_write(&tsk->cred->thread_keyring->sem);
313 tsk->cred->thread_keyring->gid = tsk->cred->fsgid;
314 up_write(&tsk->cred->thread_keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000316}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318/*
David Howells973c9f42011-01-20 16:38:33 +0000319 * Search the process keyrings attached to the supplied cred for the first
320 * matching key.
321 *
322 * The search criteria are the type and the match function. The description is
323 * given to the match function as a parameter, but doesn't otherwise influence
324 * the search. Typically the match function will compare the description
325 * parameter to the key's description.
326 *
327 * This can only search keyrings that grant Search permission to the supplied
328 * credentials. Keyrings linked to searched keyrings will also be searched if
329 * they grant Search permission too. Keys can only be found if they grant
330 * Search permission to the credentials.
331 *
332 * Returns a pointer to the key with the key usage count incremented if
333 * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
334 * matched negative keys.
335 *
336 * In the case of a successful return, the possession attribute is set on the
337 * returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 */
David Howells4bdf0bc2013-09-24 10:35:15 +0100339key_ref_t search_my_process_keyrings(struct keyring_search_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340{
David Howellsb5f545c2006-01-08 01:02:47 -0800341 key_ref_t key_ref, ret, err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342
343 /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
344 * searchable, but we failed to find a key or we found a negative key;
345 * otherwise we want to return a sample error (probably -EACCES) if
346 * none of the keyrings were searchable
347 *
348 * in terms of priority: success > -ENOKEY > -EAGAIN > other error
349 */
David Howells664cceb2005-09-28 17:03:15 +0100350 key_ref = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 ret = NULL;
352 err = ERR_PTR(-EAGAIN);
353
354 /* search the thread keyring first */
David Howells4bdf0bc2013-09-24 10:35:15 +0100355 if (ctx->cred->thread_keyring) {
David Howells664cceb2005-09-28 17:03:15 +0100356 key_ref = keyring_search_aux(
David Howells4bdf0bc2013-09-24 10:35:15 +0100357 make_key_ref(ctx->cred->thread_keyring, 1), ctx);
David Howells664cceb2005-09-28 17:03:15 +0100358 if (!IS_ERR(key_ref))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 goto found;
360
David Howells664cceb2005-09-28 17:03:15 +0100361 switch (PTR_ERR(key_ref)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 case -EAGAIN: /* no key */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 case -ENOKEY: /* negative key */
David Howells664cceb2005-09-28 17:03:15 +0100364 ret = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 break;
366 default:
David Howells664cceb2005-09-28 17:03:15 +0100367 err = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 break;
369 }
370 }
371
372 /* search the process keyring second */
David Howells4bdf0bc2013-09-24 10:35:15 +0100373 if (ctx->cred->process_keyring) {
David Howells664cceb2005-09-28 17:03:15 +0100374 key_ref = keyring_search_aux(
David Howells4bdf0bc2013-09-24 10:35:15 +0100375 make_key_ref(ctx->cred->process_keyring, 1), ctx);
David Howells664cceb2005-09-28 17:03:15 +0100376 if (!IS_ERR(key_ref))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 goto found;
378
David Howells664cceb2005-09-28 17:03:15 +0100379 switch (PTR_ERR(key_ref)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 case -EAGAIN: /* no key */
David Howellsfe9453a2013-02-21 12:00:25 +0000381 if (ret)
382 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 case -ENOKEY: /* negative key */
David Howells664cceb2005-09-28 17:03:15 +0100384 ret = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 break;
386 default:
David Howells664cceb2005-09-28 17:03:15 +0100387 err = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 break;
389 }
390 }
391
David Howells3e301482005-06-23 22:00:56 -0700392 /* search the session keyring */
David Howells4bdf0bc2013-09-24 10:35:15 +0100393 if (ctx->cred->session_keyring) {
David Howells8589b4e2005-06-23 22:00:53 -0700394 rcu_read_lock();
David Howells664cceb2005-09-28 17:03:15 +0100395 key_ref = keyring_search_aux(
David Howells4bdf0bc2013-09-24 10:35:15 +0100396 make_key_ref(rcu_dereference(ctx->cred->session_keyring), 1),
397 ctx);
David Howells8589b4e2005-06-23 22:00:53 -0700398 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399
David Howells664cceb2005-09-28 17:03:15 +0100400 if (!IS_ERR(key_ref))
David Howells3e301482005-06-23 22:00:56 -0700401 goto found;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402
David Howells664cceb2005-09-28 17:03:15 +0100403 switch (PTR_ERR(key_ref)) {
David Howells3e301482005-06-23 22:00:56 -0700404 case -EAGAIN: /* no key */
405 if (ret)
406 break;
407 case -ENOKEY: /* negative key */
David Howells664cceb2005-09-28 17:03:15 +0100408 ret = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 break;
David Howells3e301482005-06-23 22:00:56 -0700410 default:
David Howells664cceb2005-09-28 17:03:15 +0100411 err = key_ref;
David Howells3e301482005-06-23 22:00:56 -0700412 break;
413 }
David Howells3e301482005-06-23 22:00:56 -0700414 }
415 /* or search the user-session keyring */
David Howells4bdf0bc2013-09-24 10:35:15 +0100416 else if (ctx->cred->user->session_keyring) {
David Howells664cceb2005-09-28 17:03:15 +0100417 key_ref = keyring_search_aux(
David Howells4bdf0bc2013-09-24 10:35:15 +0100418 make_key_ref(ctx->cred->user->session_keyring, 1),
419 ctx);
David Howells664cceb2005-09-28 17:03:15 +0100420 if (!IS_ERR(key_ref))
David Howells3e301482005-06-23 22:00:56 -0700421 goto found;
422
David Howells664cceb2005-09-28 17:03:15 +0100423 switch (PTR_ERR(key_ref)) {
David Howells3e301482005-06-23 22:00:56 -0700424 case -EAGAIN: /* no key */
425 if (ret)
426 break;
427 case -ENOKEY: /* negative key */
David Howells664cceb2005-09-28 17:03:15 +0100428 ret = key_ref;
David Howells3e301482005-06-23 22:00:56 -0700429 break;
430 default:
David Howells664cceb2005-09-28 17:03:15 +0100431 err = key_ref;
David Howells3e301482005-06-23 22:00:56 -0700432 break;
433 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 }
435
David Howells927942a2010-06-11 17:31:10 +0100436 /* no key - decide on the error we're going to go for */
437 key_ref = ret ? ret : err;
438
439found:
440 return key_ref;
441}
442
David Howells927942a2010-06-11 17:31:10 +0100443/*
David Howells973c9f42011-01-20 16:38:33 +0000444 * Search the process keyrings attached to the supplied cred for the first
445 * matching key in the manner of search_my_process_keyrings(), but also search
446 * the keys attached to the assumed authorisation key using its credentials if
447 * one is available.
448 *
449 * Return same as search_my_process_keyrings().
David Howells927942a2010-06-11 17:31:10 +0100450 */
David Howells4bdf0bc2013-09-24 10:35:15 +0100451key_ref_t search_process_keyrings(struct keyring_search_context *ctx)
David Howells927942a2010-06-11 17:31:10 +0100452{
453 struct request_key_auth *rka;
454 key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
455
456 might_sleep();
457
David Howells4bdf0bc2013-09-24 10:35:15 +0100458 key_ref = search_my_process_keyrings(ctx);
David Howells927942a2010-06-11 17:31:10 +0100459 if (!IS_ERR(key_ref))
460 goto found;
461 err = key_ref;
462
David Howellsb5f545c2006-01-08 01:02:47 -0800463 /* if this process has an instantiation authorisation key, then we also
464 * search the keyrings of the process mentioned there
465 * - we don't permit access to request_key auth keys via this method
466 */
David Howells4bdf0bc2013-09-24 10:35:15 +0100467 if (ctx->cred->request_key_auth &&
468 ctx->cred == current_cred() &&
469 ctx->index_key.type != &key_type_request_key_auth
David Howellsb5f545c2006-01-08 01:02:47 -0800470 ) {
David Howells4bdf0bc2013-09-24 10:35:15 +0100471 const struct cred *cred = ctx->cred;
472
David Howells04c567d2006-06-22 14:47:18 -0700473 /* defend against the auth key being revoked */
David Howellsc69e8d92008-11-14 10:39:19 +1100474 down_read(&cred->request_key_auth->sem);
David Howells3e301482005-06-23 22:00:56 -0700475
David Howells4bdf0bc2013-09-24 10:35:15 +0100476 if (key_validate(ctx->cred->request_key_auth) == 0) {
David Howells146aa8b2015-10-21 14:04:48 +0100477 rka = ctx->cred->request_key_auth->payload.data[0];
David Howellsb5f545c2006-01-08 01:02:47 -0800478
David Howells4bdf0bc2013-09-24 10:35:15 +0100479 ctx->cred = rka->cred;
480 key_ref = search_process_keyrings(ctx);
481 ctx->cred = cred;
David Howellsb5f545c2006-01-08 01:02:47 -0800482
David Howellsc69e8d92008-11-14 10:39:19 +1100483 up_read(&cred->request_key_auth->sem);
David Howells04c567d2006-06-22 14:47:18 -0700484
485 if (!IS_ERR(key_ref))
486 goto found;
487
David Howells927942a2010-06-11 17:31:10 +0100488 ret = key_ref;
David Howells04c567d2006-06-22 14:47:18 -0700489 } else {
David Howellsc69e8d92008-11-14 10:39:19 +1100490 up_read(&cred->request_key_auth->sem);
David Howellsb5f545c2006-01-08 01:02:47 -0800491 }
492 }
493
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 /* no key - decide on the error we're going to go for */
David Howells927942a2010-06-11 17:31:10 +0100495 if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY))
496 key_ref = ERR_PTR(-ENOKEY);
497 else if (err == ERR_PTR(-EACCES))
498 key_ref = ret;
499 else
500 key_ref = err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501
David Howells3e301482005-06-23 22:00:56 -0700502found:
David Howells664cceb2005-09-28 17:03:15 +0100503 return key_ref;
David Howellsa8b17ed2011-01-20 16:38:27 +0000504}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506/*
David Howells973c9f42011-01-20 16:38:33 +0000507 * See if the key we're looking at is the target key.
David Howells664cceb2005-09-28 17:03:15 +0100508 */
David Howells0c903ab2014-09-16 17:36:08 +0100509bool lookup_user_key_possessed(const struct key *key,
510 const struct key_match_data *match_data)
David Howells664cceb2005-09-28 17:03:15 +0100511{
David Howells46291952014-09-16 17:36:02 +0100512 return key == match_data->raw_data;
David Howellsa8b17ed2011-01-20 16:38:27 +0000513}
David Howells664cceb2005-09-28 17:03:15 +0100514
David Howells664cceb2005-09-28 17:03:15 +0100515/*
David Howells973c9f42011-01-20 16:38:33 +0000516 * Look up a key ID given us by userspace with a given permissions mask to get
517 * the key it refers to.
518 *
519 * Flags can be passed to request that special keyrings be created if referred
520 * to directly, to permit partially constructed keys to be found and to skip
521 * validity and permission checks on the found key.
522 *
523 * Returns a pointer to the key with an incremented usage count if successful;
524 * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond
525 * to a key or the best found key was a negative key; -EKEYREVOKED or
526 * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the
527 * found key doesn't grant the requested permit or the LSM denied access to it;
528 * or -ENOMEM if a special keyring couldn't be created.
529 *
530 * In the case of a successful return, the possession attribute is set on the
531 * returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 */
David Howells55931222009-09-02 09:13:45 +0100533key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
David Howells8bbf49762008-11-14 10:39:14 +1100534 key_perm_t perm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535{
David Howells4bdf0bc2013-09-24 10:35:15 +0100536 struct keyring_search_context ctx = {
David Howells46291952014-09-16 17:36:02 +0100537 .match_data.cmp = lookup_user_key_possessed,
538 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
539 .flags = KEYRING_SEARCH_NO_STATE_CHECK,
David Howells4bdf0bc2013-09-24 10:35:15 +0100540 };
David Howells8bbf49762008-11-14 10:39:14 +1100541 struct request_key_auth *rka;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 struct key *key;
David Howellsb6dff3e2008-11-14 10:39:16 +1100543 key_ref_t key_ref, skey_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 int ret;
545
David Howellsbb952bb2008-11-14 10:39:20 +1100546try_again:
David Howells4bdf0bc2013-09-24 10:35:15 +0100547 ctx.cred = get_current_cred();
David Howells664cceb2005-09-28 17:03:15 +0100548 key_ref = ERR_PTR(-ENOKEY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549
550 switch (id) {
551 case KEY_SPEC_THREAD_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100552 if (!ctx.cred->thread_keyring) {
David Howells55931222009-09-02 09:13:45 +0100553 if (!(lflags & KEY_LOOKUP_CREATE))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 goto error;
555
David Howells8bbf49762008-11-14 10:39:14 +1100556 ret = install_thread_keyring();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 if (ret < 0) {
Dan Carpenter4d09ec02010-05-17 14:42:35 +0100558 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 goto error;
560 }
David Howellsbb952bb2008-11-14 10:39:20 +1100561 goto reget_creds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 }
563
David Howells4bdf0bc2013-09-24 10:35:15 +0100564 key = ctx.cred->thread_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100565 __key_get(key);
David Howells664cceb2005-09-28 17:03:15 +0100566 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 break;
568
569 case KEY_SPEC_PROCESS_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100570 if (!ctx.cred->process_keyring) {
David Howells55931222009-09-02 09:13:45 +0100571 if (!(lflags & KEY_LOOKUP_CREATE))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 goto error;
573
David Howells8bbf49762008-11-14 10:39:14 +1100574 ret = install_process_keyring();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 if (ret < 0) {
Dan Carpenter4d09ec02010-05-17 14:42:35 +0100576 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 goto error;
578 }
David Howellsbb952bb2008-11-14 10:39:20 +1100579 goto reget_creds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580 }
581
David Howells4bdf0bc2013-09-24 10:35:15 +0100582 key = ctx.cred->process_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100583 __key_get(key);
David Howells664cceb2005-09-28 17:03:15 +0100584 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 break;
586
587 case KEY_SPEC_SESSION_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100588 if (!ctx.cred->session_keyring) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 /* always install a session keyring upon access if one
590 * doesn't exist yet */
David Howells8bbf49762008-11-14 10:39:14 +1100591 ret = install_user_keyrings();
David Howells69664cf2008-04-29 01:01:31 -0700592 if (ret < 0)
593 goto error;
David Howells3ecf1b42011-08-22 14:08:43 +0100594 if (lflags & KEY_LOOKUP_CREATE)
595 ret = join_session_keyring(NULL);
596 else
597 ret = install_session_keyring(
David Howells4bdf0bc2013-09-24 10:35:15 +0100598 ctx.cred->user->session_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100599
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 if (ret < 0)
601 goto error;
David Howellsbb952bb2008-11-14 10:39:20 +1100602 goto reget_creds;
David Howells4bdf0bc2013-09-24 10:35:15 +0100603 } else if (ctx.cred->session_keyring ==
604 ctx.cred->user->session_keyring &&
David Howells3ecf1b42011-08-22 14:08:43 +0100605 lflags & KEY_LOOKUP_CREATE) {
606 ret = join_session_keyring(NULL);
607 if (ret < 0)
608 goto error;
609 goto reget_creds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 }
611
David Howells3e301482005-06-23 22:00:56 -0700612 rcu_read_lock();
David Howells4bdf0bc2013-09-24 10:35:15 +0100613 key = rcu_dereference(ctx.cred->session_keyring);
David Howellsccc3e6d2013-09-24 10:35:16 +0100614 __key_get(key);
David Howells3e301482005-06-23 22:00:56 -0700615 rcu_read_unlock();
David Howells664cceb2005-09-28 17:03:15 +0100616 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 break;
618
619 case KEY_SPEC_USER_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100620 if (!ctx.cred->user->uid_keyring) {
David Howells8bbf49762008-11-14 10:39:14 +1100621 ret = install_user_keyrings();
David Howells69664cf2008-04-29 01:01:31 -0700622 if (ret < 0)
623 goto error;
624 }
625
David Howells4bdf0bc2013-09-24 10:35:15 +0100626 key = ctx.cred->user->uid_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100627 __key_get(key);
David Howells664cceb2005-09-28 17:03:15 +0100628 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 break;
630
631 case KEY_SPEC_USER_SESSION_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100632 if (!ctx.cred->user->session_keyring) {
David Howells8bbf49762008-11-14 10:39:14 +1100633 ret = install_user_keyrings();
David Howells69664cf2008-04-29 01:01:31 -0700634 if (ret < 0)
635 goto error;
636 }
637
David Howells4bdf0bc2013-09-24 10:35:15 +0100638 key = ctx.cred->user->session_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100639 __key_get(key);
David Howells664cceb2005-09-28 17:03:15 +0100640 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 break;
642
643 case KEY_SPEC_GROUP_KEYRING:
644 /* group keyrings are not yet supported */
Dan Carpenter4d09ec02010-05-17 14:42:35 +0100645 key_ref = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 goto error;
647
David Howellsb5f545c2006-01-08 01:02:47 -0800648 case KEY_SPEC_REQKEY_AUTH_KEY:
David Howells4bdf0bc2013-09-24 10:35:15 +0100649 key = ctx.cred->request_key_auth;
David Howellsb5f545c2006-01-08 01:02:47 -0800650 if (!key)
651 goto error;
652
David Howellsccc3e6d2013-09-24 10:35:16 +0100653 __key_get(key);
David Howellsb5f545c2006-01-08 01:02:47 -0800654 key_ref = make_key_ref(key, 1);
655 break;
656
David Howells8bbf49762008-11-14 10:39:14 +1100657 case KEY_SPEC_REQUESTOR_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100658 if (!ctx.cred->request_key_auth)
David Howells8bbf49762008-11-14 10:39:14 +1100659 goto error;
660
David Howells4bdf0bc2013-09-24 10:35:15 +0100661 down_read(&ctx.cred->request_key_auth->sem);
Dan Carpenterf67dabb2012-03-06 13:32:16 +0000662 if (test_bit(KEY_FLAG_REVOKED,
David Howells4bdf0bc2013-09-24 10:35:15 +0100663 &ctx.cred->request_key_auth->flags)) {
David Howells8bbf49762008-11-14 10:39:14 +1100664 key_ref = ERR_PTR(-EKEYREVOKED);
665 key = NULL;
666 } else {
David Howells146aa8b2015-10-21 14:04:48 +0100667 rka = ctx.cred->request_key_auth->payload.data[0];
David Howells8bbf49762008-11-14 10:39:14 +1100668 key = rka->dest_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100669 __key_get(key);
David Howells8bbf49762008-11-14 10:39:14 +1100670 }
David Howells4bdf0bc2013-09-24 10:35:15 +0100671 up_read(&ctx.cred->request_key_auth->sem);
David Howells8bbf49762008-11-14 10:39:14 +1100672 if (!key)
673 goto error;
674 key_ref = make_key_ref(key, 1);
675 break;
676
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 default:
David Howells664cceb2005-09-28 17:03:15 +0100678 key_ref = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 if (id < 1)
680 goto error;
681
682 key = key_lookup(id);
David Howells664cceb2005-09-28 17:03:15 +0100683 if (IS_ERR(key)) {
David Howellse231c2e2008-02-07 00:15:26 -0800684 key_ref = ERR_CAST(key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 goto error;
David Howells664cceb2005-09-28 17:03:15 +0100686 }
687
688 key_ref = make_key_ref(key, 0);
689
690 /* check to see if we possess the key */
David Howells4bdf0bc2013-09-24 10:35:15 +0100691 ctx.index_key.type = key->type;
692 ctx.index_key.description = key->description;
693 ctx.index_key.desc_len = strlen(key->description);
David Howells46291952014-09-16 17:36:02 +0100694 ctx.match_data.raw_data = key;
David Howells4bdf0bc2013-09-24 10:35:15 +0100695 kdebug("check possessed");
696 skey_ref = search_process_keyrings(&ctx);
697 kdebug("possessed=%p", skey_ref);
David Howells664cceb2005-09-28 17:03:15 +0100698
699 if (!IS_ERR(skey_ref)) {
700 key_put(key);
701 key_ref = skey_ref;
702 }
703
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 break;
705 }
706
David Howells55931222009-09-02 09:13:45 +0100707 /* unlink does not use the nominated key in any way, so can skip all
708 * the permission checks as it is only concerned with the keyring */
709 if (lflags & KEY_LOOKUP_FOR_UNLINK) {
710 ret = 0;
711 goto error;
712 }
713
714 if (!(lflags & KEY_LOOKUP_PARTIAL)) {
David Howells76181c12007-10-16 23:29:46 -0700715 ret = wait_for_key_construction(key, true);
716 switch (ret) {
717 case -ERESTARTSYS:
718 goto invalid_key;
719 default:
720 if (perm)
721 goto invalid_key;
722 case 0:
723 break;
724 }
725 } else if (perm) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 ret = key_validate(key);
727 if (ret < 0)
728 goto invalid_key;
729 }
730
731 ret = -EIO;
David Howells55931222009-09-02 09:13:45 +0100732 if (!(lflags & KEY_LOOKUP_PARTIAL) &&
David Howells363b02d2017-10-04 16:43:25 +0100733 key_read_state(key) == KEY_IS_UNINSTANTIATED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 goto invalid_key;
735
David Howells3e301482005-06-23 22:00:56 -0700736 /* check the permissions */
David Howells4bdf0bc2013-09-24 10:35:15 +0100737 ret = key_task_permission(key_ref, ctx.cred, perm);
David Howells29db9192005-10-30 15:02:44 -0800738 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 goto invalid_key;
740
Baolin Wang074d5892017-11-15 16:38:45 +0000741 key->last_used_at = ktime_get_real_seconds();
David Howells31d5a792012-05-11 10:56:56 +0100742
David Howells664cceb2005-09-28 17:03:15 +0100743error:
David Howells4bdf0bc2013-09-24 10:35:15 +0100744 put_cred(ctx.cred);
David Howells664cceb2005-09-28 17:03:15 +0100745 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746
David Howells664cceb2005-09-28 17:03:15 +0100747invalid_key:
748 key_ref_put(key_ref);
749 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 goto error;
751
David Howellsbb952bb2008-11-14 10:39:20 +1100752 /* if we attempted to install a keyring, then it may have caused new
753 * creds to be installed */
754reget_creds:
David Howells4bdf0bc2013-09-24 10:35:15 +0100755 put_cred(ctx.cred);
David Howellsbb952bb2008-11-14 10:39:20 +1100756 goto try_again;
David Howellsa8b17ed2011-01-20 16:38:27 +0000757}
David Howellsbb952bb2008-11-14 10:39:20 +1100758
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759/*
David Howells973c9f42011-01-20 16:38:33 +0000760 * Join the named keyring as the session keyring if possible else attempt to
761 * create a new one of that name and join that.
762 *
763 * If the name is NULL, an empty anonymous keyring will be installed as the
764 * session keyring.
765 *
766 * Named session keyrings are joined with a semaphore held to prevent the
767 * keyrings from going away whilst the attempt is made to going them and also
768 * to prevent a race in creating compatible session keyrings.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 */
770long join_session_keyring(const char *name)
771{
David Howellsd84f4f92008-11-14 10:39:23 +1100772 const struct cred *old;
773 struct cred *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 struct key *keyring;
David Howellsd84f4f92008-11-14 10:39:23 +1100775 long ret, serial;
776
David Howellsd84f4f92008-11-14 10:39:23 +1100777 new = prepare_creds();
778 if (!new)
779 return -ENOMEM;
780 old = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781
782 /* if no name is provided, install an anonymous keyring */
783 if (!name) {
David Howellsd84f4f92008-11-14 10:39:23 +1100784 ret = install_session_keyring_to_cred(new, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 if (ret < 0)
786 goto error;
787
David Howells3a505972012-10-02 19:24:29 +0100788 serial = new->session_keyring->serial;
David Howellsd84f4f92008-11-14 10:39:23 +1100789 ret = commit_creds(new);
790 if (ret == 0)
791 ret = serial;
792 goto okay;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793 }
794
795 /* allow the user to join or create a named keyring */
Ingo Molnarbb0030792006-03-22 00:09:14 -0800796 mutex_lock(&key_session_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797
798 /* look for an existing keyring of this name */
David Howells69664cf2008-04-29 01:01:31 -0700799 keyring = find_keyring_by_name(name, false);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 if (PTR_ERR(keyring) == -ENOKEY) {
801 /* not found - try and create a new one */
David Howells96b5c8f2012-10-02 19:24:56 +0100802 keyring = keyring_alloc(
803 name, old->uid, old->gid, old,
804 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
David Howells5ac7eac2016-04-06 16:14:24 +0100805 KEY_ALLOC_IN_QUOTA, NULL, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 if (IS_ERR(keyring)) {
807 ret = PTR_ERR(keyring);
David Howellsbcf945d2005-08-04 13:07:06 -0700808 goto error2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 }
David Howellsd84f4f92008-11-14 10:39:23 +1100810 } else if (IS_ERR(keyring)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 ret = PTR_ERR(keyring);
812 goto error2;
David Howells3a505972012-10-02 19:24:29 +0100813 } else if (keyring == new->session_keyring) {
814 ret = 0;
Eric Biggersd636bd92017-06-08 14:48:03 +0100815 goto error3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 }
817
818 /* we've got a keyring - now to install it */
David Howellsd84f4f92008-11-14 10:39:23 +1100819 ret = install_session_keyring_to_cred(new, keyring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 if (ret < 0)
Eric Biggersd636bd92017-06-08 14:48:03 +0100821 goto error3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822
David Howellsd84f4f92008-11-14 10:39:23 +1100823 commit_creds(new);
824 mutex_unlock(&key_session_mutex);
825
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 ret = keyring->serial;
827 key_put(keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100828okay:
829 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830
Eric Biggersd636bd92017-06-08 14:48:03 +0100831error3:
832 key_put(keyring);
David Howells664cceb2005-09-28 17:03:15 +0100833error2:
Ingo Molnarbb0030792006-03-22 00:09:14 -0800834 mutex_unlock(&key_session_mutex);
David Howells664cceb2005-09-28 17:03:15 +0100835error:
David Howellsd84f4f92008-11-14 10:39:23 +1100836 abort_creds(new);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 return ret;
David Howellsd84f4f92008-11-14 10:39:23 +1100838}
David Howellsee18d642009-09-02 09:14:21 +0100839
840/*
David Howells973c9f42011-01-20 16:38:33 +0000841 * Replace a process's session keyring on behalf of one of its children when
842 * the target process is about to resume userspace execution.
David Howellsee18d642009-09-02 09:14:21 +0100843 */
Al Viro67d12142012-06-27 11:07:19 +0400844void key_change_session_keyring(struct callback_head *twork)
David Howellsee18d642009-09-02 09:14:21 +0100845{
Oleg Nesterov413cd3d2012-05-11 10:59:08 +1000846 const struct cred *old = current_cred();
Al Viro67d12142012-06-27 11:07:19 +0400847 struct cred *new = container_of(twork, struct cred, rcu);
David Howellsee18d642009-09-02 09:14:21 +0100848
Oleg Nesterov413cd3d2012-05-11 10:59:08 +1000849 if (unlikely(current->flags & PF_EXITING)) {
850 put_cred(new);
David Howellsee18d642009-09-02 09:14:21 +0100851 return;
Oleg Nesterov413cd3d2012-05-11 10:59:08 +1000852 }
David Howellsee18d642009-09-02 09:14:21 +0100853
David Howellsee18d642009-09-02 09:14:21 +0100854 new-> uid = old-> uid;
855 new-> euid = old-> euid;
856 new-> suid = old-> suid;
857 new->fsuid = old->fsuid;
858 new-> gid = old-> gid;
859 new-> egid = old-> egid;
860 new-> sgid = old-> sgid;
861 new->fsgid = old->fsgid;
862 new->user = get_uid(old->user);
Eric W. Biedermanba0e3422013-03-02 19:14:03 -0800863 new->user_ns = get_user_ns(old->user_ns);
David Howellsee18d642009-09-02 09:14:21 +0100864 new->group_info = get_group_info(old->group_info);
865
866 new->securebits = old->securebits;
867 new->cap_inheritable = old->cap_inheritable;
868 new->cap_permitted = old->cap_permitted;
869 new->cap_effective = old->cap_effective;
Andy Lutomirski58319052015-09-04 15:42:45 -0700870 new->cap_ambient = old->cap_ambient;
David Howellsee18d642009-09-02 09:14:21 +0100871 new->cap_bset = old->cap_bset;
872
873 new->jit_keyring = old->jit_keyring;
874 new->thread_keyring = key_get(old->thread_keyring);
David Howells3a505972012-10-02 19:24:29 +0100875 new->process_keyring = key_get(old->process_keyring);
David Howellsee18d642009-09-02 09:14:21 +0100876
877 security_transfer_creds(new, old);
878
879 commit_creds(new);
880}
Mimi Zoharc124bde2013-09-04 13:26:22 +0100881
882/*
883 * Make sure that root's user and user-session keyrings exist.
884 */
885static int __init init_root_keyring(void)
886{
887 return install_user_keyrings();
888}
889
890late_initcall(init_root_keyring);