Kees Cook | af777cd | 2017-05-13 04:51:40 -0700 | [diff] [blame] | 1 | /* Task credentials management - see Documentation/security/credentials.rst |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 2 | * |
| 3 | * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. |
| 4 | * 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 Licence |
| 8 | * as published by the Free Software Foundation; either version |
| 9 | * 2 of the Licence, or (at your option) any later version. |
| 10 | */ |
Paul Gortmaker | 9984de1 | 2011-05-23 14:51:41 -0400 | [diff] [blame] | 11 | #include <linux/export.h> |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 12 | #include <linux/cred.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 13 | #include <linux/slab.h> |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 14 | #include <linux/sched.h> |
Ingo Molnar | f7ccbae | 2017-02-08 18:51:30 +0100 | [diff] [blame] | 15 | #include <linux/sched/coredump.h> |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 16 | #include <linux/key.h> |
| 17 | #include <linux/keyctl.h> |
| 18 | #include <linux/init_task.h> |
| 19 | #include <linux/security.h> |
Al Viro | 4040153 | 2012-02-13 03:58:52 +0000 | [diff] [blame] | 20 | #include <linux/binfmts.h> |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 21 | #include <linux/cn_proc.h> |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 22 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 23 | #if 0 |
Joe Perches | 52aa853 | 2015-09-09 15:36:09 -0700 | [diff] [blame] | 24 | #define kdebug(FMT, ...) \ |
| 25 | printk("[%-5.5s%5u] " FMT "\n", \ |
| 26 | current->comm, current->pid, ##__VA_ARGS__) |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 27 | #else |
Joe Perches | 52aa853 | 2015-09-09 15:36:09 -0700 | [diff] [blame] | 28 | #define kdebug(FMT, ...) \ |
| 29 | do { \ |
| 30 | if (0) \ |
| 31 | no_printk("[%-5.5s%5u] " FMT "\n", \ |
| 32 | current->comm, current->pid, ##__VA_ARGS__); \ |
| 33 | } while (0) |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 34 | #endif |
| 35 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 36 | static struct kmem_cache *cred_jar; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 37 | |
Iulia Manda | 2813893 | 2015-04-15 16:16:41 -0700 | [diff] [blame] | 38 | /* init to 2 - one for init_task, one to ensure it is never freed */ |
| 39 | struct group_info init_groups = { .usage = ATOMIC_INIT(2) }; |
| 40 | |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 41 | /* |
| 42 | * The initial credentials for the initial task |
| 43 | */ |
| 44 | struct cred init_cred = { |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 45 | .usage = ATOMIC_INIT(4), |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 46 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 47 | .subscribers = ATOMIC_INIT(2), |
| 48 | .magic = CRED_MAGIC, |
| 49 | #endif |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 50 | .uid = GLOBAL_ROOT_UID, |
| 51 | .gid = GLOBAL_ROOT_GID, |
| 52 | .suid = GLOBAL_ROOT_UID, |
| 53 | .sgid = GLOBAL_ROOT_GID, |
| 54 | .euid = GLOBAL_ROOT_UID, |
| 55 | .egid = GLOBAL_ROOT_GID, |
| 56 | .fsuid = GLOBAL_ROOT_UID, |
| 57 | .fsgid = GLOBAL_ROOT_GID, |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 58 | .securebits = SECUREBITS_DEFAULT, |
Eric Paris | a3232d2 | 2011-04-01 17:08:45 -0400 | [diff] [blame] | 59 | .cap_inheritable = CAP_EMPTY_SET, |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 60 | .cap_permitted = CAP_FULL_SET, |
Eric Paris | a3232d2 | 2011-04-01 17:08:45 -0400 | [diff] [blame] | 61 | .cap_effective = CAP_FULL_SET, |
| 62 | .cap_bset = CAP_FULL_SET, |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 63 | .user = INIT_USER, |
Serge E. Hallyn | 47a150e | 2011-05-13 04:27:54 +0100 | [diff] [blame] | 64 | .user_ns = &init_user_ns, |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 65 | .group_info = &init_groups, |
| 66 | }; |
| 67 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 68 | static inline void set_cred_subscribers(struct cred *cred, int n) |
| 69 | { |
| 70 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 71 | atomic_set(&cred->subscribers, n); |
| 72 | #endif |
| 73 | } |
| 74 | |
| 75 | static inline int read_cred_subscribers(const struct cred *cred) |
| 76 | { |
| 77 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 78 | return atomic_read(&cred->subscribers); |
| 79 | #else |
| 80 | return 0; |
| 81 | #endif |
| 82 | } |
| 83 | |
| 84 | static inline void alter_cred_subscribers(const struct cred *_cred, int n) |
| 85 | { |
| 86 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 87 | struct cred *cred = (struct cred *) _cred; |
| 88 | |
| 89 | atomic_add(n, &cred->subscribers); |
| 90 | #endif |
| 91 | } |
| 92 | |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 93 | /* |
| 94 | * The RCU callback to actually dispose of a set of credentials |
| 95 | */ |
| 96 | static void put_cred_rcu(struct rcu_head *rcu) |
| 97 | { |
| 98 | struct cred *cred = container_of(rcu, struct cred, rcu); |
| 99 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 100 | kdebug("put_cred_rcu(%p)", cred); |
| 101 | |
| 102 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 103 | if (cred->magic != CRED_MAGIC_DEAD || |
| 104 | atomic_read(&cred->usage) != 0 || |
| 105 | read_cred_subscribers(cred) != 0) |
| 106 | panic("CRED: put_cred_rcu() sees %p with" |
| 107 | " mag %x, put %p, usage %d, subscr %d\n", |
| 108 | cred, cred->magic, cred->put_addr, |
| 109 | atomic_read(&cred->usage), |
| 110 | read_cred_subscribers(cred)); |
| 111 | #else |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 112 | if (atomic_read(&cred->usage) != 0) |
| 113 | panic("CRED: put_cred_rcu() sees %p with usage %d\n", |
| 114 | cred, atomic_read(&cred->usage)); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 115 | #endif |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 116 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 117 | security_cred_free(cred); |
David Howells | 3a50597 | 2012-10-02 19:24:29 +0100 | [diff] [blame] | 118 | key_put(cred->session_keyring); |
| 119 | key_put(cred->process_keyring); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 120 | key_put(cred->thread_keyring); |
| 121 | key_put(cred->request_key_auth); |
David Howells | 4a5d6ba | 2009-09-14 12:45:39 +0100 | [diff] [blame] | 122 | if (cred->group_info) |
| 123 | put_group_info(cred->group_info); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 124 | free_uid(cred->user); |
Eric W. Biederman | 0093ccb | 2011-11-16 21:52:53 -0800 | [diff] [blame] | 125 | put_user_ns(cred->user_ns); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 126 | kmem_cache_free(cred_jar, cred); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 127 | } |
| 128 | |
| 129 | /** |
| 130 | * __put_cred - Destroy a set of credentials |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 131 | * @cred: The record to release |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 132 | * |
| 133 | * Destroy a set of credentials on which no references remain. |
| 134 | */ |
| 135 | void __put_cred(struct cred *cred) |
| 136 | { |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 137 | kdebug("__put_cred(%p{%d,%d})", cred, |
| 138 | atomic_read(&cred->usage), |
| 139 | read_cred_subscribers(cred)); |
| 140 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 141 | BUG_ON(atomic_read(&cred->usage) != 0); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 142 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 143 | BUG_ON(read_cred_subscribers(cred) != 0); |
| 144 | cred->magic = CRED_MAGIC_DEAD; |
| 145 | cred->put_addr = __builtin_return_address(0); |
| 146 | #endif |
| 147 | BUG_ON(cred == current->cred); |
| 148 | BUG_ON(cred == current->real_cred); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 149 | |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 150 | call_rcu(&cred->rcu, put_cred_rcu); |
| 151 | } |
| 152 | EXPORT_SYMBOL(__put_cred); |
| 153 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 154 | /* |
| 155 | * Clean up a task's credentials when it exits |
| 156 | */ |
| 157 | void exit_creds(struct task_struct *tsk) |
| 158 | { |
| 159 | struct cred *cred; |
| 160 | |
| 161 | kdebug("exit_creds(%u,%p,%p,{%d,%d})", tsk->pid, tsk->real_cred, tsk->cred, |
| 162 | atomic_read(&tsk->cred->usage), |
| 163 | read_cred_subscribers(tsk->cred)); |
| 164 | |
| 165 | cred = (struct cred *) tsk->real_cred; |
| 166 | tsk->real_cred = NULL; |
| 167 | validate_creds(cred); |
| 168 | alter_cred_subscribers(cred, -1); |
| 169 | put_cred(cred); |
| 170 | |
| 171 | cred = (struct cred *) tsk->cred; |
| 172 | tsk->cred = NULL; |
| 173 | validate_creds(cred); |
| 174 | alter_cred_subscribers(cred, -1); |
| 175 | put_cred(cred); |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 176 | } |
| 177 | |
David Howells | de09a97 | 2010-07-29 12:45:49 +0100 | [diff] [blame] | 178 | /** |
| 179 | * get_task_cred - Get another task's objective credentials |
| 180 | * @task: The task to query |
| 181 | * |
| 182 | * Get the objective credentials of a task, pinning them so that they can't go |
| 183 | * away. Accessing a task's credentials directly is not permitted. |
| 184 | * |
| 185 | * The caller must also make sure task doesn't get deleted, either by holding a |
| 186 | * ref on task or by holding tasklist_lock to prevent it from being unlinked. |
| 187 | */ |
| 188 | const struct cred *get_task_cred(struct task_struct *task) |
| 189 | { |
| 190 | const struct cred *cred; |
| 191 | |
| 192 | rcu_read_lock(); |
| 193 | |
| 194 | do { |
| 195 | cred = __task_cred((task)); |
| 196 | BUG_ON(!cred); |
| 197 | } while (!atomic_inc_not_zero(&((struct cred *)cred)->usage)); |
| 198 | |
| 199 | rcu_read_unlock(); |
| 200 | return cred; |
| 201 | } |
| 202 | |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 203 | /* |
| 204 | * Allocate blank credentials, such that the credentials can be filled in at a |
| 205 | * later date without risk of ENOMEM. |
| 206 | */ |
| 207 | struct cred *cred_alloc_blank(void) |
| 208 | { |
| 209 | struct cred *new; |
| 210 | |
| 211 | new = kmem_cache_zalloc(cred_jar, GFP_KERNEL); |
| 212 | if (!new) |
| 213 | return NULL; |
| 214 | |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 215 | atomic_set(&new->usage, 1); |
Tetsuo Handa | 2edeaa3 | 2011-02-07 13:36:10 +0000 | [diff] [blame] | 216 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 217 | new->magic = CRED_MAGIC; |
| 218 | #endif |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 219 | |
| 220 | if (security_cred_alloc_blank(new, GFP_KERNEL) < 0) |
| 221 | goto error; |
| 222 | |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 223 | return new; |
| 224 | |
| 225 | error: |
| 226 | abort_creds(new); |
| 227 | return NULL; |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 228 | } |
| 229 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 230 | /** |
| 231 | * prepare_creds - Prepare a new set of credentials for modification |
| 232 | * |
| 233 | * Prepare a new set of task credentials for modification. A task's creds |
| 234 | * shouldn't generally be modified directly, therefore this function is used to |
| 235 | * prepare a new copy, which the caller then modifies and then commits by |
| 236 | * calling commit_creds(). |
| 237 | * |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 238 | * Preparation involves making a copy of the objective creds for modification. |
| 239 | * |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 240 | * Returns a pointer to the new creds-to-be if successful, NULL otherwise. |
| 241 | * |
| 242 | * Call commit_creds() or abort_creds() to clean up. |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 243 | */ |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 244 | struct cred *prepare_creds(void) |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 245 | { |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 246 | struct task_struct *task = current; |
| 247 | const struct cred *old; |
| 248 | struct cred *new; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 249 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 250 | validate_process_creds(); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 251 | |
| 252 | new = kmem_cache_alloc(cred_jar, GFP_KERNEL); |
| 253 | if (!new) |
| 254 | return NULL; |
| 255 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 256 | kdebug("prepare_creds() alloc %p", new); |
| 257 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 258 | old = task->cred; |
| 259 | memcpy(new, old, sizeof(struct cred)); |
| 260 | |
| 261 | atomic_set(&new->usage, 1); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 262 | set_cred_subscribers(new, 0); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 263 | get_group_info(new->group_info); |
| 264 | get_uid(new->user); |
Eric W. Biederman | 0093ccb | 2011-11-16 21:52:53 -0800 | [diff] [blame] | 265 | get_user_ns(new->user_ns); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 266 | |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 267 | #ifdef CONFIG_KEYS |
David Howells | 3a50597 | 2012-10-02 19:24:29 +0100 | [diff] [blame] | 268 | key_get(new->session_keyring); |
| 269 | key_get(new->process_keyring); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 270 | key_get(new->thread_keyring); |
| 271 | key_get(new->request_key_auth); |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 272 | #endif |
| 273 | |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 274 | #ifdef CONFIG_SECURITY |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 275 | new->security = NULL; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 276 | #endif |
| 277 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 278 | if (security_prepare_creds(new, old, GFP_KERNEL) < 0) |
| 279 | goto error; |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 280 | validate_creds(new); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 281 | return new; |
| 282 | |
| 283 | error: |
| 284 | abort_creds(new); |
| 285 | return NULL; |
| 286 | } |
| 287 | EXPORT_SYMBOL(prepare_creds); |
| 288 | |
| 289 | /* |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 290 | * Prepare credentials for current to perform an execve() |
KOSAKI Motohiro | 9b1bf12 | 2010-10-27 15:34:08 -0700 | [diff] [blame] | 291 | * - The caller must hold ->cred_guard_mutex |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 292 | */ |
| 293 | struct cred *prepare_exec_creds(void) |
| 294 | { |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 295 | struct cred *new; |
| 296 | |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 297 | new = prepare_creds(); |
David Howells | 3a50597 | 2012-10-02 19:24:29 +0100 | [diff] [blame] | 298 | if (!new) |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 299 | return new; |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 300 | |
| 301 | #ifdef CONFIG_KEYS |
| 302 | /* newly exec'd tasks don't get a thread keyring */ |
| 303 | key_put(new->thread_keyring); |
| 304 | new->thread_keyring = NULL; |
| 305 | |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 306 | /* inherit the session keyring; new process keyring */ |
David Howells | 3a50597 | 2012-10-02 19:24:29 +0100 | [diff] [blame] | 307 | key_put(new->process_keyring); |
| 308 | new->process_keyring = NULL; |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 309 | #endif |
| 310 | |
| 311 | return new; |
| 312 | } |
| 313 | |
| 314 | /* |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 315 | * Copy credentials for the new process created by fork() |
| 316 | * |
| 317 | * We share if we can, but under some circumstances we have to generate a new |
| 318 | * set. |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 319 | * |
| 320 | * The new process gets the current process's subjective credentials as its |
| 321 | * objective and subjective credentials |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 322 | */ |
| 323 | int copy_creds(struct task_struct *p, unsigned long clone_flags) |
| 324 | { |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 325 | struct cred *new; |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 326 | int ret; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 327 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 328 | if ( |
| 329 | #ifdef CONFIG_KEYS |
| 330 | !p->cred->thread_keyring && |
| 331 | #endif |
| 332 | clone_flags & CLONE_THREAD |
| 333 | ) { |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 334 | p->real_cred = get_cred(p->cred); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 335 | get_cred(p->cred); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 336 | alter_cred_subscribers(p->cred, 2); |
| 337 | kdebug("share_creds(%p{%d,%d})", |
| 338 | p->cred, atomic_read(&p->cred->usage), |
| 339 | read_cred_subscribers(p->cred)); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 340 | atomic_inc(&p->cred->user->processes); |
| 341 | return 0; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 342 | } |
| 343 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 344 | new = prepare_creds(); |
| 345 | if (!new) |
| 346 | return -ENOMEM; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 347 | |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 348 | if (clone_flags & CLONE_NEWUSER) { |
| 349 | ret = create_user_ns(new); |
| 350 | if (ret < 0) |
| 351 | goto error_put; |
| 352 | } |
| 353 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 354 | #ifdef CONFIG_KEYS |
| 355 | /* new threads get their own thread keyrings if their parent already |
| 356 | * had one */ |
| 357 | if (new->thread_keyring) { |
| 358 | key_put(new->thread_keyring); |
| 359 | new->thread_keyring = NULL; |
| 360 | if (clone_flags & CLONE_THREAD) |
| 361 | install_thread_keyring_to_cred(new); |
| 362 | } |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 363 | |
David Howells | 3a50597 | 2012-10-02 19:24:29 +0100 | [diff] [blame] | 364 | /* The process keyring is only shared between the threads in a process; |
| 365 | * anything outside of those threads doesn't inherit. |
| 366 | */ |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 367 | if (!(clone_flags & CLONE_THREAD)) { |
David Howells | 3a50597 | 2012-10-02 19:24:29 +0100 | [diff] [blame] | 368 | key_put(new->process_keyring); |
| 369 | new->process_keyring = NULL; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 370 | } |
| 371 | #endif |
| 372 | |
| 373 | atomic_inc(&new->user->processes); |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 374 | p->cred = p->real_cred = get_cred(new); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 375 | alter_cred_subscribers(new, 2); |
| 376 | validate_creds(new); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 377 | return 0; |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 378 | |
| 379 | error_put: |
| 380 | put_cred(new); |
| 381 | return ret; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 382 | } |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 383 | |
Eric W. Biederman | aa6d054 | 2012-12-14 08:50:54 -0800 | [diff] [blame] | 384 | static bool cred_cap_issubset(const struct cred *set, const struct cred *subset) |
| 385 | { |
| 386 | const struct user_namespace *set_ns = set->user_ns; |
| 387 | const struct user_namespace *subset_ns = subset->user_ns; |
| 388 | |
| 389 | /* If the two credentials are in the same user namespace see if |
| 390 | * the capabilities of subset are a subset of set. |
| 391 | */ |
| 392 | if (set_ns == subset_ns) |
| 393 | return cap_issubset(subset->cap_permitted, set->cap_permitted); |
| 394 | |
| 395 | /* The credentials are in a different user namespaces |
| 396 | * therefore one is a subset of the other only if a set is an |
| 397 | * ancestor of subset and set->euid is owner of subset or one |
| 398 | * of subsets ancestors. |
| 399 | */ |
| 400 | for (;subset_ns != &init_user_ns; subset_ns = subset_ns->parent) { |
| 401 | if ((set_ns == subset_ns->parent) && |
| 402 | uid_eq(subset_ns->owner, set->euid)) |
| 403 | return true; |
| 404 | } |
| 405 | |
| 406 | return false; |
| 407 | } |
| 408 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 409 | /** |
| 410 | * commit_creds - Install new credentials upon the current task |
| 411 | * @new: The credentials to be assigned |
| 412 | * |
| 413 | * Install a new set of credentials to the current task, using RCU to replace |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 414 | * the old set. Both the objective and the subjective credentials pointers are |
| 415 | * updated. This function may not be called if the subjective credentials are |
| 416 | * in an overridden state. |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 417 | * |
| 418 | * This function eats the caller's reference to the new credentials. |
| 419 | * |
| 420 | * Always returns 0 thus allowing this function to be tail-called at the end |
| 421 | * of, say, sys_setgid(). |
| 422 | */ |
| 423 | int commit_creds(struct cred *new) |
| 424 | { |
| 425 | struct task_struct *task = current; |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 426 | const struct cred *old = task->real_cred; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 427 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 428 | kdebug("commit_creds(%p{%d,%d})", new, |
| 429 | atomic_read(&new->usage), |
| 430 | read_cred_subscribers(new)); |
| 431 | |
| 432 | BUG_ON(task->cred != old); |
| 433 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 434 | BUG_ON(read_cred_subscribers(old) < 2); |
| 435 | validate_creds(old); |
| 436 | validate_creds(new); |
| 437 | #endif |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 438 | BUG_ON(atomic_read(&new->usage) < 1); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 439 | |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 440 | get_cred(new); /* we will require a ref for the subj creds too */ |
| 441 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 442 | /* dumpability changes */ |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 443 | if (!uid_eq(old->euid, new->euid) || |
| 444 | !gid_eq(old->egid, new->egid) || |
| 445 | !uid_eq(old->fsuid, new->fsuid) || |
| 446 | !gid_eq(old->fsgid, new->fsgid) || |
Eric W. Biederman | aa6d054 | 2012-12-14 08:50:54 -0800 | [diff] [blame] | 447 | !cred_cap_issubset(old, new)) { |
David Howells | b945637 | 2009-01-08 11:18:31 +0000 | [diff] [blame] | 448 | if (task->mm) |
| 449 | set_dumpable(task->mm, suid_dumpable); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 450 | task->pdeath_signal = 0; |
| 451 | smp_wmb(); |
| 452 | } |
| 453 | |
| 454 | /* alter the thread keyring */ |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 455 | if (!uid_eq(new->fsuid, old->fsuid)) |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 456 | key_fsuid_changed(task); |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 457 | if (!gid_eq(new->fsgid, old->fsgid)) |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 458 | key_fsgid_changed(task); |
| 459 | |
| 460 | /* do it |
Vasiliy Kulikov | 72fa599 | 2011-08-08 19:02:04 +0400 | [diff] [blame] | 461 | * RLIMIT_NPROC limits on user->processes have already been checked |
| 462 | * in set_user(). |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 463 | */ |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 464 | alter_cred_subscribers(new, 2); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 465 | if (new->user != old->user) |
| 466 | atomic_inc(&new->user->processes); |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 467 | rcu_assign_pointer(task->real_cred, new); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 468 | rcu_assign_pointer(task->cred, new); |
| 469 | if (new->user != old->user) |
| 470 | atomic_dec(&old->user->processes); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 471 | alter_cred_subscribers(old, -2); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 472 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 473 | /* send notifications */ |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 474 | if (!uid_eq(new->uid, old->uid) || |
| 475 | !uid_eq(new->euid, old->euid) || |
| 476 | !uid_eq(new->suid, old->suid) || |
| 477 | !uid_eq(new->fsuid, old->fsuid)) |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 478 | proc_id_connector(task, PROC_EVENT_UID); |
| 479 | |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 480 | if (!gid_eq(new->gid, old->gid) || |
| 481 | !gid_eq(new->egid, old->egid) || |
| 482 | !gid_eq(new->sgid, old->sgid) || |
| 483 | !gid_eq(new->fsgid, old->fsgid)) |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 484 | proc_id_connector(task, PROC_EVENT_GID); |
| 485 | |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 486 | /* release the old obj and subj refs both */ |
| 487 | put_cred(old); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 488 | put_cred(old); |
| 489 | return 0; |
| 490 | } |
| 491 | EXPORT_SYMBOL(commit_creds); |
| 492 | |
| 493 | /** |
| 494 | * abort_creds - Discard a set of credentials and unlock the current task |
| 495 | * @new: The credentials that were going to be applied |
| 496 | * |
| 497 | * Discard a set of credentials that were under construction and unlock the |
| 498 | * current task. |
| 499 | */ |
| 500 | void abort_creds(struct cred *new) |
| 501 | { |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 502 | kdebug("abort_creds(%p{%d,%d})", new, |
| 503 | atomic_read(&new->usage), |
| 504 | read_cred_subscribers(new)); |
| 505 | |
| 506 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 507 | BUG_ON(read_cred_subscribers(new) != 0); |
| 508 | #endif |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 509 | BUG_ON(atomic_read(&new->usage) < 1); |
| 510 | put_cred(new); |
| 511 | } |
| 512 | EXPORT_SYMBOL(abort_creds); |
| 513 | |
| 514 | /** |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 515 | * override_creds - Override the current process's subjective credentials |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 516 | * @new: The credentials to be assigned |
| 517 | * |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 518 | * Install a set of temporary override subjective credentials on the current |
| 519 | * process, returning the old set for later reversion. |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 520 | */ |
| 521 | const struct cred *override_creds(const struct cred *new) |
| 522 | { |
| 523 | const struct cred *old = current->cred; |
| 524 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 525 | kdebug("override_creds(%p{%d,%d})", new, |
| 526 | atomic_read(&new->usage), |
| 527 | read_cred_subscribers(new)); |
| 528 | |
| 529 | validate_creds(old); |
| 530 | validate_creds(new); |
| 531 | get_cred(new); |
| 532 | alter_cred_subscribers(new, 1); |
| 533 | rcu_assign_pointer(current->cred, new); |
| 534 | alter_cred_subscribers(old, -1); |
| 535 | |
| 536 | kdebug("override_creds() = %p{%d,%d}", old, |
| 537 | atomic_read(&old->usage), |
| 538 | read_cred_subscribers(old)); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 539 | return old; |
| 540 | } |
| 541 | EXPORT_SYMBOL(override_creds); |
| 542 | |
| 543 | /** |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 544 | * revert_creds - Revert a temporary subjective credentials override |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 545 | * @old: The credentials to be restored |
| 546 | * |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 547 | * Revert a temporary set of override subjective credentials to an old set, |
| 548 | * discarding the override set. |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 549 | */ |
| 550 | void revert_creds(const struct cred *old) |
| 551 | { |
| 552 | const struct cred *override = current->cred; |
| 553 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 554 | kdebug("revert_creds(%p{%d,%d})", old, |
| 555 | atomic_read(&old->usage), |
| 556 | read_cred_subscribers(old)); |
| 557 | |
| 558 | validate_creds(old); |
| 559 | validate_creds(override); |
| 560 | alter_cred_subscribers(old, 1); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 561 | rcu_assign_pointer(current->cred, old); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 562 | alter_cred_subscribers(override, -1); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 563 | put_cred(override); |
| 564 | } |
| 565 | EXPORT_SYMBOL(revert_creds); |
| 566 | |
| 567 | /* |
| 568 | * initialise the credentials stuff |
| 569 | */ |
| 570 | void __init cred_init(void) |
| 571 | { |
| 572 | /* allocate a slab in which we can store credentials */ |
Vladimir Davydov | 5d09705 | 2016-01-14 15:18:21 -0800 | [diff] [blame] | 573 | cred_jar = kmem_cache_create("cred_jar", sizeof(struct cred), 0, |
| 574 | SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 575 | } |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 576 | |
| 577 | /** |
| 578 | * prepare_kernel_cred - Prepare a set of credentials for a kernel service |
| 579 | * @daemon: A userspace daemon to be used as a reference |
| 580 | * |
| 581 | * Prepare a set of credentials for a kernel service. This can then be used to |
| 582 | * override a task's own credentials so that work can be done on behalf of that |
| 583 | * task that requires a different subjective context. |
| 584 | * |
| 585 | * @daemon is used to provide a base for the security record, but can be NULL. |
| 586 | * If @daemon is supplied, then the security data will be derived from that; |
| 587 | * otherwise they'll be set to 0 and no groups, full capabilities and no keys. |
| 588 | * |
| 589 | * The caller may change these controls afterwards if desired. |
| 590 | * |
| 591 | * Returns the new credentials or NULL if out of memory. |
| 592 | * |
| 593 | * Does not take, and does not return holding current->cred_replace_mutex. |
| 594 | */ |
| 595 | struct cred *prepare_kernel_cred(struct task_struct *daemon) |
| 596 | { |
| 597 | const struct cred *old; |
| 598 | struct cred *new; |
| 599 | |
| 600 | new = kmem_cache_alloc(cred_jar, GFP_KERNEL); |
| 601 | if (!new) |
| 602 | return NULL; |
| 603 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 604 | kdebug("prepare_kernel_cred() alloc %p", new); |
| 605 | |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 606 | if (daemon) |
| 607 | old = get_task_cred(daemon); |
| 608 | else |
| 609 | old = get_cred(&init_cred); |
| 610 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 611 | validate_creds(old); |
| 612 | |
David Howells | 43529c9 | 2009-01-09 16:13:46 +0000 | [diff] [blame] | 613 | *new = *old; |
Tetsuo Handa | fb2b2a1 | 2011-02-07 13:36:16 +0000 | [diff] [blame] | 614 | atomic_set(&new->usage, 1); |
| 615 | set_cred_subscribers(new, 0); |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 616 | get_uid(new->user); |
Eric W. Biederman | 0093ccb | 2011-11-16 21:52:53 -0800 | [diff] [blame] | 617 | get_user_ns(new->user_ns); |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 618 | get_group_info(new->group_info); |
| 619 | |
| 620 | #ifdef CONFIG_KEYS |
David Howells | 3a50597 | 2012-10-02 19:24:29 +0100 | [diff] [blame] | 621 | new->session_keyring = NULL; |
| 622 | new->process_keyring = NULL; |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 623 | new->thread_keyring = NULL; |
David Howells | 3a50597 | 2012-10-02 19:24:29 +0100 | [diff] [blame] | 624 | new->request_key_auth = NULL; |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 625 | new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING; |
| 626 | #endif |
| 627 | |
| 628 | #ifdef CONFIG_SECURITY |
| 629 | new->security = NULL; |
| 630 | #endif |
| 631 | if (security_prepare_creds(new, old, GFP_KERNEL) < 0) |
| 632 | goto error; |
| 633 | |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 634 | put_cred(old); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 635 | validate_creds(new); |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 636 | return new; |
| 637 | |
| 638 | error: |
| 639 | put_cred(new); |
David Howells | 0de3368 | 2009-01-09 16:13:41 +0000 | [diff] [blame] | 640 | put_cred(old); |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 641 | return NULL; |
| 642 | } |
| 643 | EXPORT_SYMBOL(prepare_kernel_cred); |
| 644 | |
| 645 | /** |
| 646 | * set_security_override - Set the security ID in a set of credentials |
| 647 | * @new: The credentials to alter |
| 648 | * @secid: The LSM security ID to set |
| 649 | * |
| 650 | * Set the LSM security ID in a set of credentials so that the subjective |
| 651 | * security is overridden when an alternative set of credentials is used. |
| 652 | */ |
| 653 | int set_security_override(struct cred *new, u32 secid) |
| 654 | { |
| 655 | return security_kernel_act_as(new, secid); |
| 656 | } |
| 657 | EXPORT_SYMBOL(set_security_override); |
| 658 | |
| 659 | /** |
| 660 | * set_security_override_from_ctx - Set the security ID in a set of credentials |
| 661 | * @new: The credentials to alter |
| 662 | * @secctx: The LSM security context to generate the security ID from. |
| 663 | * |
| 664 | * Set the LSM security ID in a set of credentials so that the subjective |
| 665 | * security is overridden when an alternative set of credentials is used. The |
| 666 | * security ID is specified in string form as a security context to be |
| 667 | * interpreted by the LSM. |
| 668 | */ |
| 669 | int set_security_override_from_ctx(struct cred *new, const char *secctx) |
| 670 | { |
| 671 | u32 secid; |
| 672 | int ret; |
| 673 | |
| 674 | ret = security_secctx_to_secid(secctx, strlen(secctx), &secid); |
| 675 | if (ret < 0) |
| 676 | return ret; |
| 677 | |
| 678 | return set_security_override(new, secid); |
| 679 | } |
| 680 | EXPORT_SYMBOL(set_security_override_from_ctx); |
| 681 | |
| 682 | /** |
| 683 | * set_create_files_as - Set the LSM file create context in a set of credentials |
| 684 | * @new: The credentials to alter |
| 685 | * @inode: The inode to take the context from |
| 686 | * |
| 687 | * Change the LSM file creation context in a set of credentials to be the same |
| 688 | * as the object context of the specified inode, so that the new inodes have |
| 689 | * the same MAC context as that inode. |
| 690 | */ |
| 691 | int set_create_files_as(struct cred *new, struct inode *inode) |
| 692 | { |
Seth Forshee | 5f65e5c | 2016-04-26 14:36:24 -0500 | [diff] [blame] | 693 | if (!uid_valid(inode->i_uid) || !gid_valid(inode->i_gid)) |
| 694 | return -EINVAL; |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 695 | new->fsuid = inode->i_uid; |
| 696 | new->fsgid = inode->i_gid; |
| 697 | return security_kernel_create_files_as(new, inode); |
| 698 | } |
| 699 | EXPORT_SYMBOL(set_create_files_as); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 700 | |
| 701 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 702 | |
Andrew Morton | 74908a0 | 2009-09-17 17:47:12 -0700 | [diff] [blame] | 703 | bool creds_are_invalid(const struct cred *cred) |
| 704 | { |
| 705 | if (cred->magic != CRED_MAGIC) |
| 706 | return true; |
Andrew Morton | 74908a0 | 2009-09-17 17:47:12 -0700 | [diff] [blame] | 707 | #ifdef CONFIG_SECURITY_SELINUX |
Tetsuo Handa | 2edeaa3 | 2011-02-07 13:36:10 +0000 | [diff] [blame] | 708 | /* |
| 709 | * cred->security == NULL if security_cred_alloc_blank() or |
| 710 | * security_prepare_creds() returned an error. |
| 711 | */ |
| 712 | if (selinux_is_enabled() && cred->security) { |
Andrew Morton | 74908a0 | 2009-09-17 17:47:12 -0700 | [diff] [blame] | 713 | if ((unsigned long) cred->security < PAGE_SIZE) |
| 714 | return true; |
| 715 | if ((*(u32 *)cred->security & 0xffffff00) == |
| 716 | (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8)) |
| 717 | return true; |
| 718 | } |
| 719 | #endif |
| 720 | return false; |
| 721 | } |
Randy Dunlap | 764db03 | 2009-09-18 11:06:47 -0700 | [diff] [blame] | 722 | EXPORT_SYMBOL(creds_are_invalid); |
Andrew Morton | 74908a0 | 2009-09-17 17:47:12 -0700 | [diff] [blame] | 723 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 724 | /* |
| 725 | * dump invalid credentials |
| 726 | */ |
| 727 | static void dump_invalid_creds(const struct cred *cred, const char *label, |
| 728 | const struct task_struct *tsk) |
| 729 | { |
| 730 | printk(KERN_ERR "CRED: %s credentials: %p %s%s%s\n", |
| 731 | label, cred, |
| 732 | cred == &init_cred ? "[init]" : "", |
| 733 | cred == tsk->real_cred ? "[real]" : "", |
| 734 | cred == tsk->cred ? "[eff]" : ""); |
| 735 | printk(KERN_ERR "CRED: ->magic=%x, put_addr=%p\n", |
| 736 | cred->magic, cred->put_addr); |
| 737 | printk(KERN_ERR "CRED: ->usage=%d, subscr=%d\n", |
| 738 | atomic_read(&cred->usage), |
| 739 | read_cred_subscribers(cred)); |
| 740 | printk(KERN_ERR "CRED: ->*uid = { %d,%d,%d,%d }\n", |
Eric W. Biederman | c9235f4 | 2012-04-23 17:06:34 -0700 | [diff] [blame] | 741 | from_kuid_munged(&init_user_ns, cred->uid), |
| 742 | from_kuid_munged(&init_user_ns, cred->euid), |
| 743 | from_kuid_munged(&init_user_ns, cred->suid), |
| 744 | from_kuid_munged(&init_user_ns, cred->fsuid)); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 745 | printk(KERN_ERR "CRED: ->*gid = { %d,%d,%d,%d }\n", |
Eric W. Biederman | c9235f4 | 2012-04-23 17:06:34 -0700 | [diff] [blame] | 746 | from_kgid_munged(&init_user_ns, cred->gid), |
| 747 | from_kgid_munged(&init_user_ns, cred->egid), |
| 748 | from_kgid_munged(&init_user_ns, cred->sgid), |
| 749 | from_kgid_munged(&init_user_ns, cred->fsgid)); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 750 | #ifdef CONFIG_SECURITY |
| 751 | printk(KERN_ERR "CRED: ->security is %p\n", cred->security); |
| 752 | if ((unsigned long) cred->security >= PAGE_SIZE && |
| 753 | (((unsigned long) cred->security & 0xffffff00) != |
| 754 | (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8))) |
| 755 | printk(KERN_ERR "CRED: ->security {%x, %x}\n", |
| 756 | ((u32*)cred->security)[0], |
| 757 | ((u32*)cred->security)[1]); |
| 758 | #endif |
| 759 | } |
| 760 | |
| 761 | /* |
| 762 | * report use of invalid credentials |
| 763 | */ |
| 764 | void __invalid_creds(const struct cred *cred, const char *file, unsigned line) |
| 765 | { |
| 766 | printk(KERN_ERR "CRED: Invalid credentials\n"); |
| 767 | printk(KERN_ERR "CRED: At %s:%u\n", file, line); |
| 768 | dump_invalid_creds(cred, "Specified", current); |
| 769 | BUG(); |
| 770 | } |
| 771 | EXPORT_SYMBOL(__invalid_creds); |
| 772 | |
| 773 | /* |
| 774 | * check the credentials on a process |
| 775 | */ |
| 776 | void __validate_process_creds(struct task_struct *tsk, |
| 777 | const char *file, unsigned line) |
| 778 | { |
| 779 | if (tsk->cred == tsk->real_cred) { |
| 780 | if (unlikely(read_cred_subscribers(tsk->cred) < 2 || |
| 781 | creds_are_invalid(tsk->cred))) |
| 782 | goto invalid_creds; |
| 783 | } else { |
| 784 | if (unlikely(read_cred_subscribers(tsk->real_cred) < 1 || |
| 785 | read_cred_subscribers(tsk->cred) < 1 || |
| 786 | creds_are_invalid(tsk->real_cred) || |
| 787 | creds_are_invalid(tsk->cred))) |
| 788 | goto invalid_creds; |
| 789 | } |
| 790 | return; |
| 791 | |
| 792 | invalid_creds: |
| 793 | printk(KERN_ERR "CRED: Invalid process credentials\n"); |
| 794 | printk(KERN_ERR "CRED: At %s:%u\n", file, line); |
| 795 | |
| 796 | dump_invalid_creds(tsk->real_cred, "Real", tsk); |
| 797 | if (tsk->cred != tsk->real_cred) |
| 798 | dump_invalid_creds(tsk->cred, "Effective", tsk); |
| 799 | else |
| 800 | printk(KERN_ERR "CRED: Effective creds == Real creds\n"); |
| 801 | BUG(); |
| 802 | } |
| 803 | EXPORT_SYMBOL(__validate_process_creds); |
| 804 | |
| 805 | /* |
| 806 | * check creds for do_exit() |
| 807 | */ |
| 808 | void validate_creds_for_do_exit(struct task_struct *tsk) |
| 809 | { |
| 810 | kdebug("validate_creds_for_do_exit(%p,%p{%d,%d})", |
| 811 | tsk->real_cred, tsk->cred, |
| 812 | atomic_read(&tsk->cred->usage), |
| 813 | read_cred_subscribers(tsk->cred)); |
| 814 | |
| 815 | __validate_process_creds(tsk, __FILE__, __LINE__); |
| 816 | } |
| 817 | |
| 818 | #endif /* CONFIG_DEBUG_CREDENTIALS */ |