blob: f8ffb06d0297d2151d7ad4f01922589dea3344ab [file] [log] [blame]
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/init.h>
13#include <linux/sched.h>
Ingo Molnar8703e8a2017-02-08 18:51:30 +010014#include <linux/sched/user.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/keyctl.h>
16#include <linux/fs.h>
17#include <linux/err.h>
Ingo Molnarbb0030792006-03-22 00:09:14 -080018#include <linux/mutex.h>
David Howellsee18d642009-09-02 09:14:21 +010019#include <linux/security.h>
Serge E. Hallyn1d1e9752009-02-26 18:27:38 -060020#include <linux/user_namespace.h>
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080021#include <linux/uaccess.h>
David Howells822ad642019-02-14 16:20:25 +000022#include <keys/request_key_auth-type.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
Jann Horn0b9dc6c2019-03-27 16:55:08 +010061 if (READ_ONCE(user->uid_keyring) && READ_ONCE(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 */
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100114 /* paired with READ_ONCE() */
115 smp_store_release(&user->uid_keyring, uid_keyring);
116 /* paired with READ_ONCE() */
117 smp_store_release(&user->session_keyring, session_keyring);
David Howells69664cf2008-04-29 01:01:31 -0700118 }
119
120 mutex_unlock(&key_user_keyring_mutex);
121 kleave(" = 0");
122 return 0;
123
124error_release_both:
125 key_put(session_keyring);
126error_release:
127 key_put(uid_keyring);
128error:
129 mutex_unlock(&key_user_keyring_mutex);
130 kleave(" = %d", ret);
131 return ret;
132}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100135 * Install a thread keyring to the given credentials struct if it didn't have
136 * one already. This is allowed to overrun the quota.
137 *
138 * Return: 0 if a thread keyring is now present; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 */
David Howellsd84f4f92008-11-14 10:39:23 +1100140int install_thread_keyring_to_cred(struct cred *new)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141{
David Howellsd84f4f92008-11-14 10:39:23 +1100142 struct key *keyring;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Eric Biggersc9f838d2017-04-18 15:31:09 +0100144 if (new->thread_keyring)
145 return 0;
146
David Howellsd84f4f92008-11-14 10:39:23 +1100147 keyring = keyring_alloc("_tid", new->uid, new->gid, new,
David Howells96b5c8f2012-10-02 19:24:56 +0100148 KEY_POS_ALL | KEY_USR_VIEW,
David Howells5ac7eac2016-04-06 16:14:24 +0100149 KEY_ALLOC_QUOTA_OVERRUN,
150 NULL, NULL);
David Howellsd84f4f92008-11-14 10:39:23 +1100151 if (IS_ERR(keyring))
152 return PTR_ERR(keyring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
David Howellsd84f4f92008-11-14 10:39:23 +1100154 new->thread_keyring = keyring;
155 return 0;
156}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100159 * Install a thread keyring to the current task if it didn't have one already.
160 *
161 * Return: 0 if a thread keyring is now present; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 */
David Howellsd84f4f92008-11-14 10:39:23 +1100163static int install_thread_keyring(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164{
David Howellsd84f4f92008-11-14 10:39:23 +1100165 struct cred *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 int ret;
167
David Howellsd84f4f92008-11-14 10:39:23 +1100168 new = prepare_creds();
169 if (!new)
170 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
David Howellsd84f4f92008-11-14 10:39:23 +1100172 ret = install_thread_keyring_to_cred(new);
173 if (ret < 0) {
174 abort_creds(new);
175 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 }
177
David Howellsd84f4f92008-11-14 10:39:23 +1100178 return commit_creds(new);
179}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180
David Howellsd84f4f92008-11-14 10:39:23 +1100181/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100182 * Install a process keyring to the given credentials struct if it didn't have
183 * one already. This is allowed to overrun the quota.
David Howells973c9f42011-01-20 16:38:33 +0000184 *
Eric Biggersc9f838d2017-04-18 15:31:09 +0100185 * Return: 0 if a process keyring is now present; -errno on failure.
David Howellsd84f4f92008-11-14 10:39:23 +1100186 */
187int install_process_keyring_to_cred(struct cred *new)
188{
189 struct key *keyring;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190
David Howells3a505972012-10-02 19:24:29 +0100191 if (new->process_keyring)
Eric Biggersc9f838d2017-04-18 15:31:09 +0100192 return 0;
David Howellsd84f4f92008-11-14 10:39:23 +1100193
David Howells96b5c8f2012-10-02 19:24:56 +0100194 keyring = keyring_alloc("_pid", new->uid, new->gid, new,
195 KEY_POS_ALL | KEY_USR_VIEW,
David Howells5ac7eac2016-04-06 16:14:24 +0100196 KEY_ALLOC_QUOTA_OVERRUN,
197 NULL, NULL);
David Howellsd84f4f92008-11-14 10:39:23 +1100198 if (IS_ERR(keyring))
199 return PTR_ERR(keyring);
200
David Howells3a505972012-10-02 19:24:29 +0100201 new->process_keyring = keyring;
202 return 0;
David Howellsd84f4f92008-11-14 10:39:23 +1100203}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100206 * Install a process keyring to the current task if it didn't have one already.
David Howells973c9f42011-01-20 16:38:33 +0000207 *
Eric Biggersc9f838d2017-04-18 15:31:09 +0100208 * Return: 0 if a process keyring is now present; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 */
David Howellsd84f4f92008-11-14 10:39:23 +1100210static int install_process_keyring(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211{
David Howellsd84f4f92008-11-14 10:39:23 +1100212 struct cred *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 int ret;
214
David Howellsd84f4f92008-11-14 10:39:23 +1100215 new = prepare_creds();
216 if (!new)
217 return -ENOMEM;
David Howells1a26feb2006-04-10 22:54:26 -0700218
David Howellsd84f4f92008-11-14 10:39:23 +1100219 ret = install_process_keyring_to_cred(new);
220 if (ret < 0) {
221 abort_creds(new);
Eric Biggersc9f838d2017-04-18 15:31:09 +0100222 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 }
224
David Howellsd84f4f92008-11-14 10:39:23 +1100225 return commit_creds(new);
226}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100229 * Install the given keyring as the session keyring of the given credentials
230 * struct, replacing the existing one if any. If the given keyring is NULL,
231 * then install a new anonymous session keyring.
Jann Horn5c7e3722019-03-27 16:39:38 +0100232 * @cred can not be in use by any task yet.
Eric Biggersc9f838d2017-04-18 15:31:09 +0100233 *
234 * Return: 0 on success; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 */
Oleg Nesterov685bfd22010-05-26 14:43:00 -0700236int install_session_keyring_to_cred(struct cred *cred, struct key *keyring)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237{
David Howells7e047ef2006-06-26 00:24:50 -0700238 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 struct key *old;
David Howells1a26feb2006-04-10 22:54:26 -0700240
241 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242
243 /* create an empty session keyring */
244 if (!keyring) {
David Howells7e047ef2006-06-26 00:24:50 -0700245 flags = KEY_ALLOC_QUOTA_OVERRUN;
David Howells3a505972012-10-02 19:24:29 +0100246 if (cred->session_keyring)
David Howells7e047ef2006-06-26 00:24:50 -0700247 flags = KEY_ALLOC_IN_QUOTA;
248
David Howells96b5c8f2012-10-02 19:24:56 +0100249 keyring = keyring_alloc("_ses", cred->uid, cred->gid, cred,
250 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ,
David Howells5ac7eac2016-04-06 16:14:24 +0100251 flags, NULL, NULL);
David Howells1a26feb2006-04-10 22:54:26 -0700252 if (IS_ERR(keyring))
253 return PTR_ERR(keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100254 } else {
David Howellsccc3e6d2013-09-24 10:35:16 +0100255 __key_get(keyring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 }
257
258 /* install the keyring */
David Howells3a505972012-10-02 19:24:29 +0100259 old = cred->session_keyring;
Jann Horn5c7e3722019-03-27 16:39:38 +0100260 cred->session_keyring = keyring;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261
David Howells3a505972012-10-02 19:24:29 +0100262 if (old)
David Howells1a26feb2006-04-10 22:54:26 -0700263 key_put(old);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
David Howells1a26feb2006-04-10 22:54:26 -0700265 return 0;
David Howellsd84f4f92008-11-14 10:39:23 +1100266}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268/*
Eric Biggersc9f838d2017-04-18 15:31:09 +0100269 * Install the given keyring as the session keyring of the current task,
270 * replacing the existing one if any. If the given keyring is NULL, then
271 * install a new anonymous session keyring.
272 *
273 * Return: 0 on success; -errno on failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 */
David Howellsd84f4f92008-11-14 10:39:23 +1100275static int install_session_keyring(struct key *keyring)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276{
David Howellsd84f4f92008-11-14 10:39:23 +1100277 struct cred *new;
278 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
David Howellsd84f4f92008-11-14 10:39:23 +1100280 new = prepare_creds();
281 if (!new)
282 return -ENOMEM;
David Howellsb5f545c2006-01-08 01:02:47 -0800283
David Howells995995372011-08-22 14:08:33 +0100284 ret = install_session_keyring_to_cred(new, keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100285 if (ret < 0) {
286 abort_creds(new);
287 return ret;
288 }
David Howellsb5f545c2006-01-08 01:02:47 -0800289
David Howellsd84f4f92008-11-14 10:39:23 +1100290 return commit_creds(new);
291}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293/*
David Howells973c9f42011-01-20 16:38:33 +0000294 * Handle the fsuid changing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 */
David Howells2e218652019-05-22 14:06:51 +0100296void key_fsuid_changed(struct cred *new_cred)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297{
298 /* update the ownership of the thread keyring */
David Howells2e218652019-05-22 14:06:51 +0100299 if (new_cred->thread_keyring) {
300 down_write(&new_cred->thread_keyring->sem);
301 new_cred->thread_keyring->uid = new_cred->fsuid;
302 up_write(&new_cred->thread_keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000304}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306/*
David Howells973c9f42011-01-20 16:38:33 +0000307 * Handle the fsgid changing.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 */
David Howells2e218652019-05-22 14:06:51 +0100309void key_fsgid_changed(struct cred *new_cred)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310{
311 /* update the ownership of the thread keyring */
David Howells2e218652019-05-22 14:06:51 +0100312 if (new_cred->thread_keyring) {
313 down_write(&new_cred->thread_keyring->sem);
314 new_cred->thread_keyring->gid = new_cred->fsgid;
315 up_write(&new_cred->thread_keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000317}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319/*
David Howells973c9f42011-01-20 16:38:33 +0000320 * Search the process keyrings attached to the supplied cred for the first
David Howellse59428f2019-06-19 16:10:15 +0100321 * matching key under RCU conditions (the caller must be holding the RCU read
322 * lock).
David Howells973c9f42011-01-20 16:38:33 +0000323 *
324 * The search criteria are the type and the match function. The description is
325 * given to the match function as a parameter, but doesn't otherwise influence
326 * the search. Typically the match function will compare the description
327 * parameter to the key's description.
328 *
329 * This can only search keyrings that grant Search permission to the supplied
330 * credentials. Keyrings linked to searched keyrings will also be searched if
331 * they grant Search permission too. Keys can only be found if they grant
332 * Search permission to the credentials.
333 *
334 * Returns a pointer to the key with the key usage count incremented if
335 * successful, -EAGAIN if we didn't find any matching key or -ENOKEY if we only
336 * matched negative keys.
337 *
338 * In the case of a successful return, the possession attribute is set on the
339 * returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 */
David Howellse59428f2019-06-19 16:10:15 +0100341key_ref_t search_cred_keyrings_rcu(struct keyring_search_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342{
David Howellsb5f545c2006-01-08 01:02:47 -0800343 key_ref_t key_ref, ret, err;
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100344 const struct cred *cred = ctx->cred;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345
346 /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
347 * searchable, but we failed to find a key or we found a negative key;
348 * otherwise we want to return a sample error (probably -EACCES) if
349 * none of the keyrings were searchable
350 *
351 * in terms of priority: success > -ENOKEY > -EAGAIN > other error
352 */
David Howells664cceb2005-09-28 17:03:15 +0100353 key_ref = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 ret = NULL;
355 err = ERR_PTR(-EAGAIN);
356
357 /* search the thread keyring first */
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100358 if (cred->thread_keyring) {
David Howellse59428f2019-06-19 16:10:15 +0100359 key_ref = keyring_search_rcu(
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100360 make_key_ref(cred->thread_keyring, 1), ctx);
David Howells664cceb2005-09-28 17:03:15 +0100361 if (!IS_ERR(key_ref))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 goto found;
363
David Howells664cceb2005-09-28 17:03:15 +0100364 switch (PTR_ERR(key_ref)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 case -EAGAIN: /* no key */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 case -ENOKEY: /* negative key */
David Howells664cceb2005-09-28 17:03:15 +0100367 ret = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368 break;
369 default:
David Howells664cceb2005-09-28 17:03:15 +0100370 err = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371 break;
372 }
373 }
374
375 /* search the process keyring second */
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100376 if (cred->process_keyring) {
David Howellse59428f2019-06-19 16:10:15 +0100377 key_ref = keyring_search_rcu(
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100378 make_key_ref(cred->process_keyring, 1), ctx);
David Howells664cceb2005-09-28 17:03:15 +0100379 if (!IS_ERR(key_ref))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 goto found;
381
David Howells664cceb2005-09-28 17:03:15 +0100382 switch (PTR_ERR(key_ref)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 case -EAGAIN: /* no key */
David Howellsfe9453a2013-02-21 12:00:25 +0000384 if (ret)
385 break;
Mathieu Malaterre0f949bc2019-01-14 21:17:24 +0100386 /* fall through */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 case -ENOKEY: /* negative key */
David Howells664cceb2005-09-28 17:03:15 +0100388 ret = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 break;
390 default:
David Howells664cceb2005-09-28 17:03:15 +0100391 err = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 break;
393 }
394 }
395
David Howells3e301482005-06-23 22:00:56 -0700396 /* search the session keyring */
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100397 if (cred->session_keyring) {
David Howellse59428f2019-06-19 16:10:15 +0100398 key_ref = keyring_search_rcu(
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100399 make_key_ref(cred->session_keyring, 1), ctx);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400
David Howells664cceb2005-09-28 17:03:15 +0100401 if (!IS_ERR(key_ref))
David Howells3e301482005-06-23 22:00:56 -0700402 goto found;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403
David Howells664cceb2005-09-28 17:03:15 +0100404 switch (PTR_ERR(key_ref)) {
David Howells3e301482005-06-23 22:00:56 -0700405 case -EAGAIN: /* no key */
406 if (ret)
407 break;
Mathieu Malaterre0f949bc2019-01-14 21:17:24 +0100408 /* fall through */
David Howells3e301482005-06-23 22:00:56 -0700409 case -ENOKEY: /* negative key */
David Howells664cceb2005-09-28 17:03:15 +0100410 ret = key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 break;
David Howells3e301482005-06-23 22:00:56 -0700412 default:
David Howells664cceb2005-09-28 17:03:15 +0100413 err = key_ref;
David Howells3e301482005-06-23 22:00:56 -0700414 break;
415 }
David Howells3e301482005-06-23 22:00:56 -0700416 }
417 /* or search the user-session keyring */
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100418 else if (READ_ONCE(cred->user->session_keyring)) {
David Howellse59428f2019-06-19 16:10:15 +0100419 key_ref = keyring_search_rcu(
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100420 make_key_ref(READ_ONCE(cred->user->session_keyring), 1),
David Howells4bdf0bc2013-09-24 10:35:15 +0100421 ctx);
David Howells664cceb2005-09-28 17:03:15 +0100422 if (!IS_ERR(key_ref))
David Howells3e301482005-06-23 22:00:56 -0700423 goto found;
424
David Howells664cceb2005-09-28 17:03:15 +0100425 switch (PTR_ERR(key_ref)) {
David Howells3e301482005-06-23 22:00:56 -0700426 case -EAGAIN: /* no key */
427 if (ret)
428 break;
Mathieu Malaterre0f949bc2019-01-14 21:17:24 +0100429 /* fall through */
David Howells3e301482005-06-23 22:00:56 -0700430 case -ENOKEY: /* negative key */
David Howells664cceb2005-09-28 17:03:15 +0100431 ret = key_ref;
David Howells3e301482005-06-23 22:00:56 -0700432 break;
433 default:
David Howells664cceb2005-09-28 17:03:15 +0100434 err = key_ref;
David Howells3e301482005-06-23 22:00:56 -0700435 break;
436 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 }
438
David Howells927942a2010-06-11 17:31:10 +0100439 /* no key - decide on the error we're going to go for */
440 key_ref = ret ? ret : err;
441
442found:
443 return key_ref;
444}
445
David Howells927942a2010-06-11 17:31:10 +0100446/*
David Howells973c9f42011-01-20 16:38:33 +0000447 * Search the process keyrings attached to the supplied cred for the first
448 * matching key in the manner of search_my_process_keyrings(), but also search
449 * the keys attached to the assumed authorisation key using its credentials if
450 * one is available.
451 *
David Howellse59428f2019-06-19 16:10:15 +0100452 * The caller must be holding the RCU read lock.
453 *
454 * Return same as search_cred_keyrings_rcu().
David Howells927942a2010-06-11 17:31:10 +0100455 */
David Howellse59428f2019-06-19 16:10:15 +0100456key_ref_t search_process_keyrings_rcu(struct keyring_search_context *ctx)
David Howells927942a2010-06-11 17:31:10 +0100457{
458 struct request_key_auth *rka;
459 key_ref_t key_ref, ret = ERR_PTR(-EACCES), err;
460
David Howellse59428f2019-06-19 16:10:15 +0100461 key_ref = search_cred_keyrings_rcu(ctx);
David Howells927942a2010-06-11 17:31:10 +0100462 if (!IS_ERR(key_ref))
463 goto found;
464 err = key_ref;
465
David Howellsb5f545c2006-01-08 01:02:47 -0800466 /* if this process has an instantiation authorisation key, then we also
467 * search the keyrings of the process mentioned there
468 * - we don't permit access to request_key auth keys via this method
469 */
David Howells4bdf0bc2013-09-24 10:35:15 +0100470 if (ctx->cred->request_key_auth &&
471 ctx->cred == current_cred() &&
472 ctx->index_key.type != &key_type_request_key_auth
David Howellsb5f545c2006-01-08 01:02:47 -0800473 ) {
David Howells4bdf0bc2013-09-24 10:35:15 +0100474 const struct cred *cred = ctx->cred;
475
David Howellse59428f2019-06-19 16:10:15 +0100476 if (key_validate(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 Howellse59428f2019-06-19 16:10:15 +0100479 //// was search_process_keyrings() [ie. recursive]
David Howells4bdf0bc2013-09-24 10:35:15 +0100480 ctx->cred = rka->cred;
David Howellse59428f2019-06-19 16:10:15 +0100481 key_ref = search_cred_keyrings_rcu(ctx);
David Howells4bdf0bc2013-09-24 10:35:15 +0100482 ctx->cred = cred;
David Howellsb5f545c2006-01-08 01:02:47 -0800483
David Howells04c567d2006-06-22 14:47:18 -0700484 if (!IS_ERR(key_ref))
485 goto found;
David Howells927942a2010-06-11 17:31:10 +0100486 ret = key_ref;
David Howellsb5f545c2006-01-08 01:02:47 -0800487 }
488 }
489
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 /* no key - decide on the error we're going to go for */
David Howells927942a2010-06-11 17:31:10 +0100491 if (err == ERR_PTR(-ENOKEY) || ret == ERR_PTR(-ENOKEY))
492 key_ref = ERR_PTR(-ENOKEY);
493 else if (err == ERR_PTR(-EACCES))
494 key_ref = ret;
495 else
496 key_ref = err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497
David Howells3e301482005-06-23 22:00:56 -0700498found:
David Howells664cceb2005-09-28 17:03:15 +0100499 return key_ref;
David Howellsa8b17ed2011-01-20 16:38:27 +0000500}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501/*
David Howells973c9f42011-01-20 16:38:33 +0000502 * See if the key we're looking at is the target key.
David Howells664cceb2005-09-28 17:03:15 +0100503 */
David Howells0c903ab2014-09-16 17:36:08 +0100504bool lookup_user_key_possessed(const struct key *key,
505 const struct key_match_data *match_data)
David Howells664cceb2005-09-28 17:03:15 +0100506{
David Howells46291952014-09-16 17:36:02 +0100507 return key == match_data->raw_data;
David Howellsa8b17ed2011-01-20 16:38:27 +0000508}
David Howells664cceb2005-09-28 17:03:15 +0100509
David Howells664cceb2005-09-28 17:03:15 +0100510/*
David Howells973c9f42011-01-20 16:38:33 +0000511 * Look up a key ID given us by userspace with a given permissions mask to get
512 * the key it refers to.
513 *
514 * Flags can be passed to request that special keyrings be created if referred
515 * to directly, to permit partially constructed keys to be found and to skip
516 * validity and permission checks on the found key.
517 *
518 * Returns a pointer to the key with an incremented usage count if successful;
519 * -EINVAL if the key ID is invalid; -ENOKEY if the key ID does not correspond
520 * to a key or the best found key was a negative key; -EKEYREVOKED or
521 * -EKEYEXPIRED if the best found key was revoked or expired; -EACCES if the
522 * found key doesn't grant the requested permit or the LSM denied access to it;
523 * or -ENOMEM if a special keyring couldn't be created.
524 *
525 * In the case of a successful return, the possession attribute is set on the
526 * returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 */
David Howells55931222009-09-02 09:13:45 +0100528key_ref_t lookup_user_key(key_serial_t id, unsigned long lflags,
David Howells8bbf49762008-11-14 10:39:14 +1100529 key_perm_t perm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530{
David Howells4bdf0bc2013-09-24 10:35:15 +0100531 struct keyring_search_context ctx = {
David Howells46291952014-09-16 17:36:02 +0100532 .match_data.cmp = lookup_user_key_possessed,
533 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
534 .flags = KEYRING_SEARCH_NO_STATE_CHECK,
David Howells4bdf0bc2013-09-24 10:35:15 +0100535 };
David Howells8bbf49762008-11-14 10:39:14 +1100536 struct request_key_auth *rka;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 struct key *key;
David Howellsb6dff3e2008-11-14 10:39:16 +1100538 key_ref_t key_ref, skey_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 int ret;
540
David Howellsbb952bb2008-11-14 10:39:20 +1100541try_again:
David Howells4bdf0bc2013-09-24 10:35:15 +0100542 ctx.cred = get_current_cred();
David Howells664cceb2005-09-28 17:03:15 +0100543 key_ref = ERR_PTR(-ENOKEY);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544
545 switch (id) {
546 case KEY_SPEC_THREAD_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100547 if (!ctx.cred->thread_keyring) {
David Howells55931222009-09-02 09:13:45 +0100548 if (!(lflags & KEY_LOOKUP_CREATE))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549 goto error;
550
David Howells8bbf49762008-11-14 10:39:14 +1100551 ret = install_thread_keyring();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 if (ret < 0) {
Dan Carpenter4d09ec02010-05-17 14:42:35 +0100553 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 goto error;
555 }
David Howellsbb952bb2008-11-14 10:39:20 +1100556 goto reget_creds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 }
558
David Howells4bdf0bc2013-09-24 10:35:15 +0100559 key = ctx.cred->thread_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100560 __key_get(key);
David Howells664cceb2005-09-28 17:03:15 +0100561 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 break;
563
564 case KEY_SPEC_PROCESS_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100565 if (!ctx.cred->process_keyring) {
David Howells55931222009-09-02 09:13:45 +0100566 if (!(lflags & KEY_LOOKUP_CREATE))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 goto error;
568
David Howells8bbf49762008-11-14 10:39:14 +1100569 ret = install_process_keyring();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 if (ret < 0) {
Dan Carpenter4d09ec02010-05-17 14:42:35 +0100571 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 goto error;
573 }
David Howellsbb952bb2008-11-14 10:39:20 +1100574 goto reget_creds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 }
576
David Howells4bdf0bc2013-09-24 10:35:15 +0100577 key = ctx.cred->process_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100578 __key_get(key);
David Howells664cceb2005-09-28 17:03:15 +0100579 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580 break;
581
582 case KEY_SPEC_SESSION_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100583 if (!ctx.cred->session_keyring) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 /* always install a session keyring upon access if one
585 * doesn't exist yet */
David Howells8bbf49762008-11-14 10:39:14 +1100586 ret = install_user_keyrings();
David Howells69664cf2008-04-29 01:01:31 -0700587 if (ret < 0)
588 goto error;
David Howells3ecf1b42011-08-22 14:08:43 +0100589 if (lflags & KEY_LOOKUP_CREATE)
590 ret = join_session_keyring(NULL);
591 else
592 ret = install_session_keyring(
David Howells4bdf0bc2013-09-24 10:35:15 +0100593 ctx.cred->user->session_keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100594
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 if (ret < 0)
596 goto error;
David Howellsbb952bb2008-11-14 10:39:20 +1100597 goto reget_creds;
David Howells4bdf0bc2013-09-24 10:35:15 +0100598 } else if (ctx.cred->session_keyring ==
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100599 READ_ONCE(ctx.cred->user->session_keyring) &&
David Howells3ecf1b42011-08-22 14:08:43 +0100600 lflags & KEY_LOOKUP_CREATE) {
601 ret = join_session_keyring(NULL);
602 if (ret < 0)
603 goto error;
604 goto reget_creds;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 }
606
Jann Horn5c7e3722019-03-27 16:39:38 +0100607 key = ctx.cred->session_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100608 __key_get(key);
David Howells664cceb2005-09-28 17:03:15 +0100609 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 break;
611
612 case KEY_SPEC_USER_KEYRING:
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100613 if (!READ_ONCE(ctx.cred->user->uid_keyring)) {
David Howells8bbf49762008-11-14 10:39:14 +1100614 ret = install_user_keyrings();
David Howells69664cf2008-04-29 01:01:31 -0700615 if (ret < 0)
616 goto error;
617 }
618
David Howells4bdf0bc2013-09-24 10:35:15 +0100619 key = ctx.cred->user->uid_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100620 __key_get(key);
David Howells664cceb2005-09-28 17:03:15 +0100621 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 break;
623
624 case KEY_SPEC_USER_SESSION_KEYRING:
Jann Horn0b9dc6c2019-03-27 16:55:08 +0100625 if (!READ_ONCE(ctx.cred->user->session_keyring)) {
David Howells8bbf49762008-11-14 10:39:14 +1100626 ret = install_user_keyrings();
David Howells69664cf2008-04-29 01:01:31 -0700627 if (ret < 0)
628 goto error;
629 }
630
David Howells4bdf0bc2013-09-24 10:35:15 +0100631 key = ctx.cred->user->session_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100632 __key_get(key);
David Howells664cceb2005-09-28 17:03:15 +0100633 key_ref = make_key_ref(key, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 break;
635
636 case KEY_SPEC_GROUP_KEYRING:
637 /* group keyrings are not yet supported */
Dan Carpenter4d09ec02010-05-17 14:42:35 +0100638 key_ref = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 goto error;
640
David Howellsb5f545c2006-01-08 01:02:47 -0800641 case KEY_SPEC_REQKEY_AUTH_KEY:
David Howells4bdf0bc2013-09-24 10:35:15 +0100642 key = ctx.cred->request_key_auth;
David Howellsb5f545c2006-01-08 01:02:47 -0800643 if (!key)
644 goto error;
645
David Howellsccc3e6d2013-09-24 10:35:16 +0100646 __key_get(key);
David Howellsb5f545c2006-01-08 01:02:47 -0800647 key_ref = make_key_ref(key, 1);
648 break;
649
David Howells8bbf49762008-11-14 10:39:14 +1100650 case KEY_SPEC_REQUESTOR_KEYRING:
David Howells4bdf0bc2013-09-24 10:35:15 +0100651 if (!ctx.cred->request_key_auth)
David Howells8bbf49762008-11-14 10:39:14 +1100652 goto error;
653
David Howells4bdf0bc2013-09-24 10:35:15 +0100654 down_read(&ctx.cred->request_key_auth->sem);
Dan Carpenterf67dabb2012-03-06 13:32:16 +0000655 if (test_bit(KEY_FLAG_REVOKED,
David Howells4bdf0bc2013-09-24 10:35:15 +0100656 &ctx.cred->request_key_auth->flags)) {
David Howells8bbf49762008-11-14 10:39:14 +1100657 key_ref = ERR_PTR(-EKEYREVOKED);
658 key = NULL;
659 } else {
David Howells146aa8b2015-10-21 14:04:48 +0100660 rka = ctx.cred->request_key_auth->payload.data[0];
David Howells8bbf49762008-11-14 10:39:14 +1100661 key = rka->dest_keyring;
David Howellsccc3e6d2013-09-24 10:35:16 +0100662 __key_get(key);
David Howells8bbf49762008-11-14 10:39:14 +1100663 }
David Howells4bdf0bc2013-09-24 10:35:15 +0100664 up_read(&ctx.cred->request_key_auth->sem);
David Howells8bbf49762008-11-14 10:39:14 +1100665 if (!key)
666 goto error;
667 key_ref = make_key_ref(key, 1);
668 break;
669
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 default:
David Howells664cceb2005-09-28 17:03:15 +0100671 key_ref = ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 if (id < 1)
673 goto error;
674
675 key = key_lookup(id);
David Howells664cceb2005-09-28 17:03:15 +0100676 if (IS_ERR(key)) {
David Howellse231c2e2008-02-07 00:15:26 -0800677 key_ref = ERR_CAST(key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 goto error;
David Howells664cceb2005-09-28 17:03:15 +0100679 }
680
681 key_ref = make_key_ref(key, 0);
682
683 /* check to see if we possess the key */
Eric Biggers47546202019-05-29 14:01:52 -0700684 ctx.index_key = key->index_key;
David Howells46291952014-09-16 17:36:02 +0100685 ctx.match_data.raw_data = key;
David Howells4bdf0bc2013-09-24 10:35:15 +0100686 kdebug("check possessed");
David Howellse59428f2019-06-19 16:10:15 +0100687 rcu_read_lock();
688 skey_ref = search_process_keyrings_rcu(&ctx);
689 rcu_read_unlock();
David Howells4bdf0bc2013-09-24 10:35:15 +0100690 kdebug("possessed=%p", skey_ref);
David Howells664cceb2005-09-28 17:03:15 +0100691
692 if (!IS_ERR(skey_ref)) {
693 key_put(key);
694 key_ref = skey_ref;
695 }
696
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 break;
698 }
699
David Howells55931222009-09-02 09:13:45 +0100700 /* unlink does not use the nominated key in any way, so can skip all
701 * the permission checks as it is only concerned with the keyring */
702 if (lflags & KEY_LOOKUP_FOR_UNLINK) {
703 ret = 0;
704 goto error;
705 }
706
707 if (!(lflags & KEY_LOOKUP_PARTIAL)) {
David Howells76181c12007-10-16 23:29:46 -0700708 ret = wait_for_key_construction(key, true);
709 switch (ret) {
710 case -ERESTARTSYS:
711 goto invalid_key;
712 default:
713 if (perm)
714 goto invalid_key;
715 case 0:
716 break;
717 }
718 } else if (perm) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 ret = key_validate(key);
720 if (ret < 0)
721 goto invalid_key;
722 }
723
724 ret = -EIO;
David Howells55931222009-09-02 09:13:45 +0100725 if (!(lflags & KEY_LOOKUP_PARTIAL) &&
David Howells363b02d2017-10-04 16:43:25 +0100726 key_read_state(key) == KEY_IS_UNINSTANTIATED)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 goto invalid_key;
728
David Howells3e301482005-06-23 22:00:56 -0700729 /* check the permissions */
David Howells4bdf0bc2013-09-24 10:35:15 +0100730 ret = key_task_permission(key_ref, ctx.cred, perm);
David Howells29db9192005-10-30 15:02:44 -0800731 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 goto invalid_key;
733
Baolin Wang074d5892017-11-15 16:38:45 +0000734 key->last_used_at = ktime_get_real_seconds();
David Howells31d5a792012-05-11 10:56:56 +0100735
David Howells664cceb2005-09-28 17:03:15 +0100736error:
David Howells4bdf0bc2013-09-24 10:35:15 +0100737 put_cred(ctx.cred);
David Howells664cceb2005-09-28 17:03:15 +0100738 return key_ref;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739
David Howells664cceb2005-09-28 17:03:15 +0100740invalid_key:
741 key_ref_put(key_ref);
742 key_ref = ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 goto error;
744
David Howellsbb952bb2008-11-14 10:39:20 +1100745 /* if we attempted to install a keyring, then it may have caused new
746 * creds to be installed */
747reget_creds:
David Howells4bdf0bc2013-09-24 10:35:15 +0100748 put_cred(ctx.cred);
David Howellsbb952bb2008-11-14 10:39:20 +1100749 goto try_again;
David Howellsa8b17ed2011-01-20 16:38:27 +0000750}
Dave Jiang76ef5e12018-12-04 10:31:27 -0800751EXPORT_SYMBOL(lookup_user_key);
David Howellsbb952bb2008-11-14 10:39:20 +1100752
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753/*
David Howells973c9f42011-01-20 16:38:33 +0000754 * Join the named keyring as the session keyring if possible else attempt to
755 * create a new one of that name and join that.
756 *
757 * If the name is NULL, an empty anonymous keyring will be installed as the
758 * session keyring.
759 *
760 * Named session keyrings are joined with a semaphore held to prevent the
761 * keyrings from going away whilst the attempt is made to going them and also
762 * to prevent a race in creating compatible session keyrings.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 */
764long join_session_keyring(const char *name)
765{
David Howellsd84f4f92008-11-14 10:39:23 +1100766 const struct cred *old;
767 struct cred *new;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 struct key *keyring;
David Howellsd84f4f92008-11-14 10:39:23 +1100769 long ret, serial;
770
David Howellsd84f4f92008-11-14 10:39:23 +1100771 new = prepare_creds();
772 if (!new)
773 return -ENOMEM;
774 old = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
776 /* if no name is provided, install an anonymous keyring */
777 if (!name) {
David Howellsd84f4f92008-11-14 10:39:23 +1100778 ret = install_session_keyring_to_cred(new, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 if (ret < 0)
780 goto error;
781
David Howells3a505972012-10-02 19:24:29 +0100782 serial = new->session_keyring->serial;
David Howellsd84f4f92008-11-14 10:39:23 +1100783 ret = commit_creds(new);
784 if (ret == 0)
785 ret = serial;
786 goto okay;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 }
788
789 /* allow the user to join or create a named keyring */
Ingo Molnarbb0030792006-03-22 00:09:14 -0800790 mutex_lock(&key_session_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791
792 /* look for an existing keyring of this name */
David Howells69664cf2008-04-29 01:01:31 -0700793 keyring = find_keyring_by_name(name, false);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 if (PTR_ERR(keyring) == -ENOKEY) {
795 /* not found - try and create a new one */
David Howells96b5c8f2012-10-02 19:24:56 +0100796 keyring = keyring_alloc(
797 name, old->uid, old->gid, old,
798 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ | KEY_USR_LINK,
David Howells5ac7eac2016-04-06 16:14:24 +0100799 KEY_ALLOC_IN_QUOTA, NULL, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800 if (IS_ERR(keyring)) {
801 ret = PTR_ERR(keyring);
David Howellsbcf945d2005-08-04 13:07:06 -0700802 goto error2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 }
David Howellsd84f4f92008-11-14 10:39:23 +1100804 } else if (IS_ERR(keyring)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 ret = PTR_ERR(keyring);
806 goto error2;
David Howells3a505972012-10-02 19:24:29 +0100807 } else if (keyring == new->session_keyring) {
808 ret = 0;
Eric Biggersd636bd92017-06-08 14:48:03 +0100809 goto error3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 }
811
812 /* we've got a keyring - now to install it */
David Howellsd84f4f92008-11-14 10:39:23 +1100813 ret = install_session_keyring_to_cred(new, keyring);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 if (ret < 0)
Eric Biggersd636bd92017-06-08 14:48:03 +0100815 goto error3;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
David Howellsd84f4f92008-11-14 10:39:23 +1100817 commit_creds(new);
818 mutex_unlock(&key_session_mutex);
819
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 ret = keyring->serial;
821 key_put(keyring);
David Howellsd84f4f92008-11-14 10:39:23 +1100822okay:
823 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824
Eric Biggersd636bd92017-06-08 14:48:03 +0100825error3:
826 key_put(keyring);
David Howells664cceb2005-09-28 17:03:15 +0100827error2:
Ingo Molnarbb0030792006-03-22 00:09:14 -0800828 mutex_unlock(&key_session_mutex);
David Howells664cceb2005-09-28 17:03:15 +0100829error:
David Howellsd84f4f92008-11-14 10:39:23 +1100830 abort_creds(new);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 return ret;
David Howellsd84f4f92008-11-14 10:39:23 +1100832}
David Howellsee18d642009-09-02 09:14:21 +0100833
834/*
David Howells973c9f42011-01-20 16:38:33 +0000835 * Replace a process's session keyring on behalf of one of its children when
836 * the target process is about to resume userspace execution.
David Howellsee18d642009-09-02 09:14:21 +0100837 */
Al Viro67d12142012-06-27 11:07:19 +0400838void key_change_session_keyring(struct callback_head *twork)
David Howellsee18d642009-09-02 09:14:21 +0100839{
Oleg Nesterov413cd3d2012-05-11 10:59:08 +1000840 const struct cred *old = current_cred();
Al Viro67d12142012-06-27 11:07:19 +0400841 struct cred *new = container_of(twork, struct cred, rcu);
David Howellsee18d642009-09-02 09:14:21 +0100842
Oleg Nesterov413cd3d2012-05-11 10:59:08 +1000843 if (unlikely(current->flags & PF_EXITING)) {
844 put_cred(new);
David Howellsee18d642009-09-02 09:14:21 +0100845 return;
Oleg Nesterov413cd3d2012-05-11 10:59:08 +1000846 }
David Howellsee18d642009-09-02 09:14:21 +0100847
David Howellsee18d642009-09-02 09:14:21 +0100848 new-> uid = old-> uid;
849 new-> euid = old-> euid;
850 new-> suid = old-> suid;
851 new->fsuid = old->fsuid;
852 new-> gid = old-> gid;
853 new-> egid = old-> egid;
854 new-> sgid = old-> sgid;
855 new->fsgid = old->fsgid;
856 new->user = get_uid(old->user);
Eric W. Biedermanba0e3422013-03-02 19:14:03 -0800857 new->user_ns = get_user_ns(old->user_ns);
David Howellsee18d642009-09-02 09:14:21 +0100858 new->group_info = get_group_info(old->group_info);
859
860 new->securebits = old->securebits;
861 new->cap_inheritable = old->cap_inheritable;
862 new->cap_permitted = old->cap_permitted;
863 new->cap_effective = old->cap_effective;
Andy Lutomirski58319052015-09-04 15:42:45 -0700864 new->cap_ambient = old->cap_ambient;
David Howellsee18d642009-09-02 09:14:21 +0100865 new->cap_bset = old->cap_bset;
866
867 new->jit_keyring = old->jit_keyring;
868 new->thread_keyring = key_get(old->thread_keyring);
David Howells3a505972012-10-02 19:24:29 +0100869 new->process_keyring = key_get(old->process_keyring);
David Howellsee18d642009-09-02 09:14:21 +0100870
871 security_transfer_creds(new, old);
872
873 commit_creds(new);
874}
Mimi Zoharc124bde2013-09-04 13:26:22 +0100875
876/*
877 * Make sure that root's user and user-session keyrings exist.
878 */
879static int __init init_root_keyring(void)
880{
881 return install_user_keyrings();
882}
883
884late_initcall(init_root_keyring);