Randy Dunlap | d410fa4 | 2011-05-19 15:59:38 -0700 | [diff] [blame] | 1 | /* Task credentials management - see Documentation/security/credentials.txt |
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> |
| 15 | #include <linux/key.h> |
| 16 | #include <linux/keyctl.h> |
| 17 | #include <linux/init_task.h> |
| 18 | #include <linux/security.h> |
Al Viro | 4040153 | 2012-02-13 03:58:52 +0000 | [diff] [blame] | 19 | #include <linux/binfmts.h> |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 20 | #include <linux/cn_proc.h> |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 21 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 22 | #if 0 |
| 23 | #define kdebug(FMT, ...) \ |
| 24 | printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid ,##__VA_ARGS__) |
| 25 | #else |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 26 | #define kdebug(FMT, ...) \ |
| 27 | no_printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid ,##__VA_ARGS__) |
| 28 | #endif |
| 29 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 30 | static struct kmem_cache *cred_jar; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 31 | |
| 32 | /* |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 33 | * The common credentials for the initial task's thread group |
| 34 | */ |
| 35 | #ifdef CONFIG_KEYS |
| 36 | static struct thread_group_cred init_tgcred = { |
| 37 | .usage = ATOMIC_INIT(2), |
| 38 | .tgid = 0, |
Thomas Gleixner | 10389a1 | 2011-01-23 15:25:56 +0100 | [diff] [blame] | 39 | .lock = __SPIN_LOCK_UNLOCKED(init_cred.tgcred.lock), |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 40 | }; |
| 41 | #endif |
| 42 | |
| 43 | /* |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 44 | * The initial credentials for the initial task |
| 45 | */ |
| 46 | struct cred init_cred = { |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 47 | .usage = ATOMIC_INIT(4), |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 48 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 49 | .subscribers = ATOMIC_INIT(2), |
| 50 | .magic = CRED_MAGIC, |
| 51 | #endif |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 52 | .uid = GLOBAL_ROOT_UID, |
| 53 | .gid = GLOBAL_ROOT_GID, |
| 54 | .suid = GLOBAL_ROOT_UID, |
| 55 | .sgid = GLOBAL_ROOT_GID, |
| 56 | .euid = GLOBAL_ROOT_UID, |
| 57 | .egid = GLOBAL_ROOT_GID, |
| 58 | .fsuid = GLOBAL_ROOT_UID, |
| 59 | .fsgid = GLOBAL_ROOT_GID, |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 60 | .securebits = SECUREBITS_DEFAULT, |
Eric Paris | a3232d2 | 2011-04-01 17:08:45 -0400 | [diff] [blame] | 61 | .cap_inheritable = CAP_EMPTY_SET, |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 62 | .cap_permitted = CAP_FULL_SET, |
Eric Paris | a3232d2 | 2011-04-01 17:08:45 -0400 | [diff] [blame] | 63 | .cap_effective = CAP_FULL_SET, |
| 64 | .cap_bset = CAP_FULL_SET, |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 65 | .user = INIT_USER, |
Serge E. Hallyn | 47a150e | 2011-05-13 04:27:54 +0100 | [diff] [blame] | 66 | .user_ns = &init_user_ns, |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 67 | .group_info = &init_groups, |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 68 | #ifdef CONFIG_KEYS |
| 69 | .tgcred = &init_tgcred, |
| 70 | #endif |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 71 | }; |
| 72 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 73 | static inline void set_cred_subscribers(struct cred *cred, int n) |
| 74 | { |
| 75 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 76 | atomic_set(&cred->subscribers, n); |
| 77 | #endif |
| 78 | } |
| 79 | |
| 80 | static inline int read_cred_subscribers(const struct cred *cred) |
| 81 | { |
| 82 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 83 | return atomic_read(&cred->subscribers); |
| 84 | #else |
| 85 | return 0; |
| 86 | #endif |
| 87 | } |
| 88 | |
| 89 | static inline void alter_cred_subscribers(const struct cred *_cred, int n) |
| 90 | { |
| 91 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 92 | struct cred *cred = (struct cred *) _cred; |
| 93 | |
| 94 | atomic_add(n, &cred->subscribers); |
| 95 | #endif |
| 96 | } |
| 97 | |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 98 | /* |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 99 | * Dispose of the shared task group credentials |
| 100 | */ |
| 101 | #ifdef CONFIG_KEYS |
| 102 | static void release_tgcred_rcu(struct rcu_head *rcu) |
| 103 | { |
| 104 | struct thread_group_cred *tgcred = |
| 105 | container_of(rcu, struct thread_group_cred, rcu); |
| 106 | |
| 107 | BUG_ON(atomic_read(&tgcred->usage) != 0); |
| 108 | |
| 109 | key_put(tgcred->session_keyring); |
| 110 | key_put(tgcred->process_keyring); |
| 111 | kfree(tgcred); |
| 112 | } |
| 113 | #endif |
| 114 | |
| 115 | /* |
| 116 | * Release a set of thread group credentials. |
| 117 | */ |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 118 | static void release_tgcred(struct cred *cred) |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 119 | { |
| 120 | #ifdef CONFIG_KEYS |
| 121 | struct thread_group_cred *tgcred = cred->tgcred; |
| 122 | |
| 123 | if (atomic_dec_and_test(&tgcred->usage)) |
| 124 | call_rcu(&tgcred->rcu, release_tgcred_rcu); |
| 125 | #endif |
| 126 | } |
| 127 | |
| 128 | /* |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 129 | * The RCU callback to actually dispose of a set of credentials |
| 130 | */ |
| 131 | static void put_cred_rcu(struct rcu_head *rcu) |
| 132 | { |
| 133 | struct cred *cred = container_of(rcu, struct cred, rcu); |
| 134 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 135 | kdebug("put_cred_rcu(%p)", cred); |
| 136 | |
| 137 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 138 | if (cred->magic != CRED_MAGIC_DEAD || |
| 139 | atomic_read(&cred->usage) != 0 || |
| 140 | read_cred_subscribers(cred) != 0) |
| 141 | panic("CRED: put_cred_rcu() sees %p with" |
| 142 | " mag %x, put %p, usage %d, subscr %d\n", |
| 143 | cred, cred->magic, cred->put_addr, |
| 144 | atomic_read(&cred->usage), |
| 145 | read_cred_subscribers(cred)); |
| 146 | #else |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 147 | if (atomic_read(&cred->usage) != 0) |
| 148 | panic("CRED: put_cred_rcu() sees %p with usage %d\n", |
| 149 | cred, atomic_read(&cred->usage)); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 150 | #endif |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 151 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 152 | security_cred_free(cred); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 153 | key_put(cred->thread_keyring); |
| 154 | key_put(cred->request_key_auth); |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 155 | release_tgcred(cred); |
David Howells | 4a5d6ba | 2009-09-14 12:45:39 +0100 | [diff] [blame] | 156 | if (cred->group_info) |
| 157 | put_group_info(cred->group_info); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 158 | free_uid(cred->user); |
Eric W. Biederman | 0093ccb | 2011-11-16 21:52:53 -0800 | [diff] [blame] | 159 | put_user_ns(cred->user_ns); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 160 | kmem_cache_free(cred_jar, cred); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 161 | } |
| 162 | |
| 163 | /** |
| 164 | * __put_cred - Destroy a set of credentials |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 165 | * @cred: The record to release |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 166 | * |
| 167 | * Destroy a set of credentials on which no references remain. |
| 168 | */ |
| 169 | void __put_cred(struct cred *cred) |
| 170 | { |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 171 | kdebug("__put_cred(%p{%d,%d})", cred, |
| 172 | atomic_read(&cred->usage), |
| 173 | read_cred_subscribers(cred)); |
| 174 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 175 | BUG_ON(atomic_read(&cred->usage) != 0); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 176 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 177 | BUG_ON(read_cred_subscribers(cred) != 0); |
| 178 | cred->magic = CRED_MAGIC_DEAD; |
| 179 | cred->put_addr = __builtin_return_address(0); |
| 180 | #endif |
| 181 | BUG_ON(cred == current->cred); |
| 182 | BUG_ON(cred == current->real_cred); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 183 | |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 184 | call_rcu(&cred->rcu, put_cred_rcu); |
| 185 | } |
| 186 | EXPORT_SYMBOL(__put_cred); |
| 187 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 188 | /* |
| 189 | * Clean up a task's credentials when it exits |
| 190 | */ |
| 191 | void exit_creds(struct task_struct *tsk) |
| 192 | { |
| 193 | struct cred *cred; |
| 194 | |
| 195 | kdebug("exit_creds(%u,%p,%p,{%d,%d})", tsk->pid, tsk->real_cred, tsk->cred, |
| 196 | atomic_read(&tsk->cred->usage), |
| 197 | read_cred_subscribers(tsk->cred)); |
| 198 | |
| 199 | cred = (struct cred *) tsk->real_cred; |
| 200 | tsk->real_cred = NULL; |
| 201 | validate_creds(cred); |
| 202 | alter_cred_subscribers(cred, -1); |
| 203 | put_cred(cred); |
| 204 | |
| 205 | cred = (struct cred *) tsk->cred; |
| 206 | tsk->cred = NULL; |
| 207 | validate_creds(cred); |
| 208 | alter_cred_subscribers(cred, -1); |
| 209 | put_cred(cred); |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 210 | } |
| 211 | |
David Howells | de09a97 | 2010-07-29 12:45:49 +0100 | [diff] [blame] | 212 | /** |
| 213 | * get_task_cred - Get another task's objective credentials |
| 214 | * @task: The task to query |
| 215 | * |
| 216 | * Get the objective credentials of a task, pinning them so that they can't go |
| 217 | * away. Accessing a task's credentials directly is not permitted. |
| 218 | * |
| 219 | * The caller must also make sure task doesn't get deleted, either by holding a |
| 220 | * ref on task or by holding tasklist_lock to prevent it from being unlinked. |
| 221 | */ |
| 222 | const struct cred *get_task_cred(struct task_struct *task) |
| 223 | { |
| 224 | const struct cred *cred; |
| 225 | |
| 226 | rcu_read_lock(); |
| 227 | |
| 228 | do { |
| 229 | cred = __task_cred((task)); |
| 230 | BUG_ON(!cred); |
| 231 | } while (!atomic_inc_not_zero(&((struct cred *)cred)->usage)); |
| 232 | |
| 233 | rcu_read_unlock(); |
| 234 | return cred; |
| 235 | } |
| 236 | |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 237 | /* |
| 238 | * Allocate blank credentials, such that the credentials can be filled in at a |
| 239 | * later date without risk of ENOMEM. |
| 240 | */ |
| 241 | struct cred *cred_alloc_blank(void) |
| 242 | { |
| 243 | struct cred *new; |
| 244 | |
| 245 | new = kmem_cache_zalloc(cred_jar, GFP_KERNEL); |
| 246 | if (!new) |
| 247 | return NULL; |
| 248 | |
| 249 | #ifdef CONFIG_KEYS |
| 250 | new->tgcred = kzalloc(sizeof(*new->tgcred), GFP_KERNEL); |
| 251 | if (!new->tgcred) { |
Julia Lawall | b8a1d37 | 2010-02-03 09:31:36 +1100 | [diff] [blame] | 252 | kmem_cache_free(cred_jar, new); |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 253 | return NULL; |
| 254 | } |
| 255 | atomic_set(&new->tgcred->usage, 1); |
| 256 | #endif |
| 257 | |
| 258 | atomic_set(&new->usage, 1); |
Tetsuo Handa | 2edeaa3 | 2011-02-07 13:36:10 +0000 | [diff] [blame] | 259 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 260 | new->magic = CRED_MAGIC; |
| 261 | #endif |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 262 | |
| 263 | if (security_cred_alloc_blank(new, GFP_KERNEL) < 0) |
| 264 | goto error; |
| 265 | |
David Howells | ee18d64 | 2009-09-02 09:14:21 +0100 | [diff] [blame] | 266 | return new; |
| 267 | |
| 268 | error: |
| 269 | abort_creds(new); |
| 270 | return NULL; |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 271 | } |
| 272 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 273 | /** |
| 274 | * prepare_creds - Prepare a new set of credentials for modification |
| 275 | * |
| 276 | * Prepare a new set of task credentials for modification. A task's creds |
| 277 | * shouldn't generally be modified directly, therefore this function is used to |
| 278 | * prepare a new copy, which the caller then modifies and then commits by |
| 279 | * calling commit_creds(). |
| 280 | * |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 281 | * Preparation involves making a copy of the objective creds for modification. |
| 282 | * |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 283 | * Returns a pointer to the new creds-to-be if successful, NULL otherwise. |
| 284 | * |
| 285 | * Call commit_creds() or abort_creds() to clean up. |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 286 | */ |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 287 | struct cred *prepare_creds(void) |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 288 | { |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 289 | struct task_struct *task = current; |
| 290 | const struct cred *old; |
| 291 | struct cred *new; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 292 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 293 | validate_process_creds(); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 294 | |
| 295 | new = kmem_cache_alloc(cred_jar, GFP_KERNEL); |
| 296 | if (!new) |
| 297 | return NULL; |
| 298 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 299 | kdebug("prepare_creds() alloc %p", new); |
| 300 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 301 | old = task->cred; |
| 302 | memcpy(new, old, sizeof(struct cred)); |
| 303 | |
| 304 | atomic_set(&new->usage, 1); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 305 | set_cred_subscribers(new, 0); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 306 | get_group_info(new->group_info); |
| 307 | get_uid(new->user); |
Eric W. Biederman | 0093ccb | 2011-11-16 21:52:53 -0800 | [diff] [blame] | 308 | get_user_ns(new->user_ns); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 309 | |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 310 | #ifdef CONFIG_KEYS |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 311 | key_get(new->thread_keyring); |
| 312 | key_get(new->request_key_auth); |
| 313 | atomic_inc(&new->tgcred->usage); |
David Howells | bb952bb | 2008-11-14 10:39:20 +1100 | [diff] [blame] | 314 | #endif |
| 315 | |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 316 | #ifdef CONFIG_SECURITY |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 317 | new->security = NULL; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 318 | #endif |
| 319 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 320 | if (security_prepare_creds(new, old, GFP_KERNEL) < 0) |
| 321 | goto error; |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 322 | validate_creds(new); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 323 | return new; |
| 324 | |
| 325 | error: |
| 326 | abort_creds(new); |
| 327 | return NULL; |
| 328 | } |
| 329 | EXPORT_SYMBOL(prepare_creds); |
| 330 | |
| 331 | /* |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 332 | * Prepare credentials for current to perform an execve() |
KOSAKI Motohiro | 9b1bf12 | 2010-10-27 15:34:08 -0700 | [diff] [blame] | 333 | * - The caller must hold ->cred_guard_mutex |
David Howells | a6f76f2 | 2008-11-14 10:39:24 +1100 | [diff] [blame] | 334 | */ |
| 335 | struct cred *prepare_exec_creds(void) |
| 336 | { |
| 337 | struct thread_group_cred *tgcred = NULL; |
| 338 | struct cred *new; |
| 339 | |
| 340 | #ifdef CONFIG_KEYS |
| 341 | tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL); |
| 342 | if (!tgcred) |
| 343 | return NULL; |
| 344 | #endif |
| 345 | |
| 346 | new = prepare_creds(); |
| 347 | if (!new) { |
| 348 | kfree(tgcred); |
| 349 | return new; |
| 350 | } |
| 351 | |
| 352 | #ifdef CONFIG_KEYS |
| 353 | /* newly exec'd tasks don't get a thread keyring */ |
| 354 | key_put(new->thread_keyring); |
| 355 | new->thread_keyring = NULL; |
| 356 | |
| 357 | /* create a new per-thread-group creds for all this set of threads to |
| 358 | * share */ |
| 359 | memcpy(tgcred, new->tgcred, sizeof(struct thread_group_cred)); |
| 360 | |
| 361 | atomic_set(&tgcred->usage, 1); |
| 362 | spin_lock_init(&tgcred->lock); |
| 363 | |
| 364 | /* inherit the session keyring; new process keyring */ |
| 365 | key_get(tgcred->session_keyring); |
| 366 | tgcred->process_keyring = NULL; |
| 367 | |
| 368 | release_tgcred(new); |
| 369 | new->tgcred = tgcred; |
| 370 | #endif |
| 371 | |
| 372 | return new; |
| 373 | } |
| 374 | |
| 375 | /* |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 376 | * Copy credentials for the new process created by fork() |
| 377 | * |
| 378 | * We share if we can, but under some circumstances we have to generate a new |
| 379 | * set. |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 380 | * |
| 381 | * The new process gets the current process's subjective credentials as its |
| 382 | * objective and subjective credentials |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 383 | */ |
| 384 | int copy_creds(struct task_struct *p, unsigned long clone_flags) |
| 385 | { |
| 386 | #ifdef CONFIG_KEYS |
| 387 | struct thread_group_cred *tgcred; |
| 388 | #endif |
| 389 | struct cred *new; |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 390 | int ret; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 391 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 392 | if ( |
| 393 | #ifdef CONFIG_KEYS |
| 394 | !p->cred->thread_keyring && |
| 395 | #endif |
| 396 | clone_flags & CLONE_THREAD |
| 397 | ) { |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 398 | p->real_cred = get_cred(p->cred); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 399 | get_cred(p->cred); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 400 | alter_cred_subscribers(p->cred, 2); |
| 401 | kdebug("share_creds(%p{%d,%d})", |
| 402 | p->cred, atomic_read(&p->cred->usage), |
| 403 | read_cred_subscribers(p->cred)); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 404 | atomic_inc(&p->cred->user->processes); |
| 405 | return 0; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 406 | } |
| 407 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 408 | new = prepare_creds(); |
| 409 | if (!new) |
| 410 | return -ENOMEM; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 411 | |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 412 | if (clone_flags & CLONE_NEWUSER) { |
| 413 | ret = create_user_ns(new); |
| 414 | if (ret < 0) |
| 415 | goto error_put; |
| 416 | } |
| 417 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 418 | #ifdef CONFIG_KEYS |
| 419 | /* new threads get their own thread keyrings if their parent already |
| 420 | * had one */ |
| 421 | if (new->thread_keyring) { |
| 422 | key_put(new->thread_keyring); |
| 423 | new->thread_keyring = NULL; |
| 424 | if (clone_flags & CLONE_THREAD) |
| 425 | install_thread_keyring_to_cred(new); |
| 426 | } |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 427 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 428 | /* we share the process and session keyrings between all the threads in |
| 429 | * a process - this is slightly icky as we violate COW credentials a |
| 430 | * bit */ |
| 431 | if (!(clone_flags & CLONE_THREAD)) { |
| 432 | tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL); |
| 433 | if (!tgcred) { |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 434 | ret = -ENOMEM; |
| 435 | goto error_put; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 436 | } |
| 437 | atomic_set(&tgcred->usage, 1); |
| 438 | spin_lock_init(&tgcred->lock); |
| 439 | tgcred->process_keyring = NULL; |
| 440 | tgcred->session_keyring = key_get(new->tgcred->session_keyring); |
| 441 | |
| 442 | release_tgcred(new); |
| 443 | new->tgcred = tgcred; |
| 444 | } |
| 445 | #endif |
| 446 | |
| 447 | atomic_inc(&new->user->processes); |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 448 | p->cred = p->real_cred = get_cred(new); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 449 | alter_cred_subscribers(new, 2); |
| 450 | validate_creds(new); |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 451 | return 0; |
Serge Hallyn | 18b6e04 | 2008-10-15 16:38:45 -0500 | [diff] [blame] | 452 | |
| 453 | error_put: |
| 454 | put_cred(new); |
| 455 | return ret; |
David Howells | f1752ee | 2008-11-14 10:39:17 +1100 | [diff] [blame] | 456 | } |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 457 | |
| 458 | /** |
| 459 | * commit_creds - Install new credentials upon the current task |
| 460 | * @new: The credentials to be assigned |
| 461 | * |
| 462 | * 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] | 463 | * the old set. Both the objective and the subjective credentials pointers are |
| 464 | * updated. This function may not be called if the subjective credentials are |
| 465 | * in an overridden state. |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 466 | * |
| 467 | * This function eats the caller's reference to the new credentials. |
| 468 | * |
| 469 | * Always returns 0 thus allowing this function to be tail-called at the end |
| 470 | * of, say, sys_setgid(). |
| 471 | */ |
| 472 | int commit_creds(struct cred *new) |
| 473 | { |
| 474 | struct task_struct *task = current; |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 475 | const struct cred *old = task->real_cred; |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 476 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 477 | kdebug("commit_creds(%p{%d,%d})", new, |
| 478 | atomic_read(&new->usage), |
| 479 | read_cred_subscribers(new)); |
| 480 | |
| 481 | BUG_ON(task->cred != old); |
| 482 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 483 | BUG_ON(read_cred_subscribers(old) < 2); |
| 484 | validate_creds(old); |
| 485 | validate_creds(new); |
| 486 | #endif |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 487 | BUG_ON(atomic_read(&new->usage) < 1); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 488 | |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 489 | get_cred(new); /* we will require a ref for the subj creds too */ |
| 490 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 491 | /* dumpability changes */ |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 492 | if (!uid_eq(old->euid, new->euid) || |
| 493 | !gid_eq(old->egid, new->egid) || |
| 494 | !uid_eq(old->fsuid, new->fsuid) || |
| 495 | !gid_eq(old->fsgid, new->fsgid) || |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 496 | !cap_issubset(new->cap_permitted, old->cap_permitted)) { |
David Howells | b945637 | 2009-01-08 11:18:31 +0000 | [diff] [blame] | 497 | if (task->mm) |
| 498 | set_dumpable(task->mm, suid_dumpable); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 499 | task->pdeath_signal = 0; |
| 500 | smp_wmb(); |
| 501 | } |
| 502 | |
| 503 | /* alter the thread keyring */ |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 504 | if (!uid_eq(new->fsuid, old->fsuid)) |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 505 | key_fsuid_changed(task); |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 506 | if (!gid_eq(new->fsgid, old->fsgid)) |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 507 | key_fsgid_changed(task); |
| 508 | |
| 509 | /* do it |
Vasiliy Kulikov | 72fa599 | 2011-08-08 19:02:04 +0400 | [diff] [blame] | 510 | * RLIMIT_NPROC limits on user->processes have already been checked |
| 511 | * in set_user(). |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 512 | */ |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 513 | alter_cred_subscribers(new, 2); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 514 | if (new->user != old->user) |
| 515 | atomic_inc(&new->user->processes); |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 516 | rcu_assign_pointer(task->real_cred, new); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 517 | rcu_assign_pointer(task->cred, new); |
| 518 | if (new->user != old->user) |
| 519 | atomic_dec(&old->user->processes); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 520 | alter_cred_subscribers(old, -2); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 521 | |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 522 | /* send notifications */ |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 523 | if (!uid_eq(new->uid, old->uid) || |
| 524 | !uid_eq(new->euid, old->euid) || |
| 525 | !uid_eq(new->suid, old->suid) || |
| 526 | !uid_eq(new->fsuid, old->fsuid)) |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 527 | proc_id_connector(task, PROC_EVENT_UID); |
| 528 | |
Eric W. Biederman | 078de5f | 2012-02-08 07:00:08 -0800 | [diff] [blame] | 529 | if (!gid_eq(new->gid, old->gid) || |
| 530 | !gid_eq(new->egid, old->egid) || |
| 531 | !gid_eq(new->sgid, old->sgid) || |
| 532 | !gid_eq(new->fsgid, old->fsgid)) |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 533 | proc_id_connector(task, PROC_EVENT_GID); |
| 534 | |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 535 | /* release the old obj and subj refs both */ |
| 536 | put_cred(old); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 537 | put_cred(old); |
| 538 | return 0; |
| 539 | } |
| 540 | EXPORT_SYMBOL(commit_creds); |
| 541 | |
| 542 | /** |
| 543 | * abort_creds - Discard a set of credentials and unlock the current task |
| 544 | * @new: The credentials that were going to be applied |
| 545 | * |
| 546 | * Discard a set of credentials that were under construction and unlock the |
| 547 | * current task. |
| 548 | */ |
| 549 | void abort_creds(struct cred *new) |
| 550 | { |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 551 | kdebug("abort_creds(%p{%d,%d})", new, |
| 552 | atomic_read(&new->usage), |
| 553 | read_cred_subscribers(new)); |
| 554 | |
| 555 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 556 | BUG_ON(read_cred_subscribers(new) != 0); |
| 557 | #endif |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 558 | BUG_ON(atomic_read(&new->usage) < 1); |
| 559 | put_cred(new); |
| 560 | } |
| 561 | EXPORT_SYMBOL(abort_creds); |
| 562 | |
| 563 | /** |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 564 | * override_creds - Override the current process's subjective credentials |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 565 | * @new: The credentials to be assigned |
| 566 | * |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 567 | * Install a set of temporary override subjective credentials on the current |
| 568 | * process, returning the old set for later reversion. |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 569 | */ |
| 570 | const struct cred *override_creds(const struct cred *new) |
| 571 | { |
| 572 | const struct cred *old = current->cred; |
| 573 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 574 | kdebug("override_creds(%p{%d,%d})", new, |
| 575 | atomic_read(&new->usage), |
| 576 | read_cred_subscribers(new)); |
| 577 | |
| 578 | validate_creds(old); |
| 579 | validate_creds(new); |
| 580 | get_cred(new); |
| 581 | alter_cred_subscribers(new, 1); |
| 582 | rcu_assign_pointer(current->cred, new); |
| 583 | alter_cred_subscribers(old, -1); |
| 584 | |
| 585 | kdebug("override_creds() = %p{%d,%d}", old, |
| 586 | atomic_read(&old->usage), |
| 587 | read_cred_subscribers(old)); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 588 | return old; |
| 589 | } |
| 590 | EXPORT_SYMBOL(override_creds); |
| 591 | |
| 592 | /** |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 593 | * revert_creds - Revert a temporary subjective credentials override |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 594 | * @old: The credentials to be restored |
| 595 | * |
David Howells | 3b11a1d | 2008-11-14 10:39:26 +1100 | [diff] [blame] | 596 | * Revert a temporary set of override subjective credentials to an old set, |
| 597 | * discarding the override set. |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 598 | */ |
| 599 | void revert_creds(const struct cred *old) |
| 600 | { |
| 601 | const struct cred *override = current->cred; |
| 602 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 603 | kdebug("revert_creds(%p{%d,%d})", old, |
| 604 | atomic_read(&old->usage), |
| 605 | read_cred_subscribers(old)); |
| 606 | |
| 607 | validate_creds(old); |
| 608 | validate_creds(override); |
| 609 | alter_cred_subscribers(old, 1); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 610 | rcu_assign_pointer(current->cred, old); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 611 | alter_cred_subscribers(override, -1); |
David Howells | d84f4f9 | 2008-11-14 10:39:23 +1100 | [diff] [blame] | 612 | put_cred(override); |
| 613 | } |
| 614 | EXPORT_SYMBOL(revert_creds); |
| 615 | |
| 616 | /* |
| 617 | * initialise the credentials stuff |
| 618 | */ |
| 619 | void __init cred_init(void) |
| 620 | { |
| 621 | /* allocate a slab in which we can store credentials */ |
| 622 | cred_jar = kmem_cache_create("cred_jar", sizeof(struct cred), |
| 623 | 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); |
| 624 | } |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 625 | |
| 626 | /** |
| 627 | * prepare_kernel_cred - Prepare a set of credentials for a kernel service |
| 628 | * @daemon: A userspace daemon to be used as a reference |
| 629 | * |
| 630 | * Prepare a set of credentials for a kernel service. This can then be used to |
| 631 | * override a task's own credentials so that work can be done on behalf of that |
| 632 | * task that requires a different subjective context. |
| 633 | * |
| 634 | * @daemon is used to provide a base for the security record, but can be NULL. |
| 635 | * If @daemon is supplied, then the security data will be derived from that; |
| 636 | * otherwise they'll be set to 0 and no groups, full capabilities and no keys. |
| 637 | * |
| 638 | * The caller may change these controls afterwards if desired. |
| 639 | * |
| 640 | * Returns the new credentials or NULL if out of memory. |
| 641 | * |
| 642 | * Does not take, and does not return holding current->cred_replace_mutex. |
| 643 | */ |
| 644 | struct cred *prepare_kernel_cred(struct task_struct *daemon) |
| 645 | { |
David Howells | 012146d | 2011-08-22 14:09:00 +0100 | [diff] [blame] | 646 | #ifdef CONFIG_KEYS |
| 647 | struct thread_group_cred *tgcred; |
| 648 | #endif |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 649 | const struct cred *old; |
| 650 | struct cred *new; |
| 651 | |
| 652 | new = kmem_cache_alloc(cred_jar, GFP_KERNEL); |
| 653 | if (!new) |
| 654 | return NULL; |
| 655 | |
Axel Lin | 8ad346c | 2011-08-23 15:23:51 +0800 | [diff] [blame] | 656 | #ifdef CONFIG_KEYS |
David Howells | 012146d | 2011-08-22 14:09:00 +0100 | [diff] [blame] | 657 | tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL); |
| 658 | if (!tgcred) { |
| 659 | kmem_cache_free(cred_jar, new); |
| 660 | return NULL; |
| 661 | } |
Axel Lin | 8ad346c | 2011-08-23 15:23:51 +0800 | [diff] [blame] | 662 | #endif |
David Howells | 012146d | 2011-08-22 14:09:00 +0100 | [diff] [blame] | 663 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 664 | kdebug("prepare_kernel_cred() alloc %p", new); |
| 665 | |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 666 | if (daemon) |
| 667 | old = get_task_cred(daemon); |
| 668 | else |
| 669 | old = get_cred(&init_cred); |
| 670 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 671 | validate_creds(old); |
| 672 | |
David Howells | 43529c9 | 2009-01-09 16:13:46 +0000 | [diff] [blame] | 673 | *new = *old; |
Tetsuo Handa | fb2b2a1 | 2011-02-07 13:36:16 +0000 | [diff] [blame] | 674 | atomic_set(&new->usage, 1); |
| 675 | set_cred_subscribers(new, 0); |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 676 | get_uid(new->user); |
Eric W. Biederman | 0093ccb | 2011-11-16 21:52:53 -0800 | [diff] [blame] | 677 | get_user_ns(new->user_ns); |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 678 | get_group_info(new->group_info); |
| 679 | |
| 680 | #ifdef CONFIG_KEYS |
David Howells | 012146d | 2011-08-22 14:09:00 +0100 | [diff] [blame] | 681 | atomic_set(&tgcred->usage, 1); |
| 682 | spin_lock_init(&tgcred->lock); |
| 683 | tgcred->process_keyring = NULL; |
| 684 | tgcred->session_keyring = NULL; |
| 685 | new->tgcred = tgcred; |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 686 | new->request_key_auth = NULL; |
| 687 | new->thread_keyring = NULL; |
| 688 | new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING; |
| 689 | #endif |
| 690 | |
| 691 | #ifdef CONFIG_SECURITY |
| 692 | new->security = NULL; |
| 693 | #endif |
| 694 | if (security_prepare_creds(new, old, GFP_KERNEL) < 0) |
| 695 | goto error; |
| 696 | |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 697 | put_cred(old); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 698 | validate_creds(new); |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 699 | return new; |
| 700 | |
| 701 | error: |
| 702 | put_cred(new); |
David Howells | 0de3368 | 2009-01-09 16:13:41 +0000 | [diff] [blame] | 703 | put_cred(old); |
David Howells | 3a3b7ce | 2008-11-14 10:39:28 +1100 | [diff] [blame] | 704 | return NULL; |
| 705 | } |
| 706 | EXPORT_SYMBOL(prepare_kernel_cred); |
| 707 | |
| 708 | /** |
| 709 | * set_security_override - Set the security ID in a set of credentials |
| 710 | * @new: The credentials to alter |
| 711 | * @secid: The LSM security ID to set |
| 712 | * |
| 713 | * Set the LSM security ID in a set of credentials so that the subjective |
| 714 | * security is overridden when an alternative set of credentials is used. |
| 715 | */ |
| 716 | int set_security_override(struct cred *new, u32 secid) |
| 717 | { |
| 718 | return security_kernel_act_as(new, secid); |
| 719 | } |
| 720 | EXPORT_SYMBOL(set_security_override); |
| 721 | |
| 722 | /** |
| 723 | * set_security_override_from_ctx - Set the security ID in a set of credentials |
| 724 | * @new: The credentials to alter |
| 725 | * @secctx: The LSM security context to generate the security ID from. |
| 726 | * |
| 727 | * Set the LSM security ID in a set of credentials so that the subjective |
| 728 | * security is overridden when an alternative set of credentials is used. The |
| 729 | * security ID is specified in string form as a security context to be |
| 730 | * interpreted by the LSM. |
| 731 | */ |
| 732 | int set_security_override_from_ctx(struct cred *new, const char *secctx) |
| 733 | { |
| 734 | u32 secid; |
| 735 | int ret; |
| 736 | |
| 737 | ret = security_secctx_to_secid(secctx, strlen(secctx), &secid); |
| 738 | if (ret < 0) |
| 739 | return ret; |
| 740 | |
| 741 | return set_security_override(new, secid); |
| 742 | } |
| 743 | EXPORT_SYMBOL(set_security_override_from_ctx); |
| 744 | |
| 745 | /** |
| 746 | * set_create_files_as - Set the LSM file create context in a set of credentials |
| 747 | * @new: The credentials to alter |
| 748 | * @inode: The inode to take the context from |
| 749 | * |
| 750 | * Change the LSM file creation context in a set of credentials to be the same |
| 751 | * as the object context of the specified inode, so that the new inodes have |
| 752 | * the same MAC context as that inode. |
| 753 | */ |
| 754 | int set_create_files_as(struct cred *new, struct inode *inode) |
| 755 | { |
| 756 | new->fsuid = inode->i_uid; |
| 757 | new->fsgid = inode->i_gid; |
| 758 | return security_kernel_create_files_as(new, inode); |
| 759 | } |
| 760 | EXPORT_SYMBOL(set_create_files_as); |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 761 | |
| 762 | #ifdef CONFIG_DEBUG_CREDENTIALS |
| 763 | |
Andrew Morton | 74908a0 | 2009-09-17 17:47:12 -0700 | [diff] [blame] | 764 | bool creds_are_invalid(const struct cred *cred) |
| 765 | { |
| 766 | if (cred->magic != CRED_MAGIC) |
| 767 | return true; |
Andrew Morton | 74908a0 | 2009-09-17 17:47:12 -0700 | [diff] [blame] | 768 | #ifdef CONFIG_SECURITY_SELINUX |
Tetsuo Handa | 2edeaa3 | 2011-02-07 13:36:10 +0000 | [diff] [blame] | 769 | /* |
| 770 | * cred->security == NULL if security_cred_alloc_blank() or |
| 771 | * security_prepare_creds() returned an error. |
| 772 | */ |
| 773 | if (selinux_is_enabled() && cred->security) { |
Andrew Morton | 74908a0 | 2009-09-17 17:47:12 -0700 | [diff] [blame] | 774 | if ((unsigned long) cred->security < PAGE_SIZE) |
| 775 | return true; |
| 776 | if ((*(u32 *)cred->security & 0xffffff00) == |
| 777 | (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8)) |
| 778 | return true; |
| 779 | } |
| 780 | #endif |
| 781 | return false; |
| 782 | } |
Randy Dunlap | 764db03 | 2009-09-18 11:06:47 -0700 | [diff] [blame] | 783 | EXPORT_SYMBOL(creds_are_invalid); |
Andrew Morton | 74908a0 | 2009-09-17 17:47:12 -0700 | [diff] [blame] | 784 | |
David Howells | e0e8173 | 2009-09-02 09:13:40 +0100 | [diff] [blame] | 785 | /* |
| 786 | * dump invalid credentials |
| 787 | */ |
| 788 | static void dump_invalid_creds(const struct cred *cred, const char *label, |
| 789 | const struct task_struct *tsk) |
| 790 | { |
| 791 | printk(KERN_ERR "CRED: %s credentials: %p %s%s%s\n", |
| 792 | label, cred, |
| 793 | cred == &init_cred ? "[init]" : "", |
| 794 | cred == tsk->real_cred ? "[real]" : "", |
| 795 | cred == tsk->cred ? "[eff]" : ""); |
| 796 | printk(KERN_ERR "CRED: ->magic=%x, put_addr=%p\n", |
| 797 | cred->magic, cred->put_addr); |
| 798 | printk(KERN_ERR "CRED: ->usage=%d, subscr=%d\n", |
| 799 | atomic_read(&cred->usage), |
| 800 | read_cred_subscribers(cred)); |
| 801 | printk(KERN_ERR "CRED: ->*uid = { %d,%d,%d,%d }\n", |
| 802 | cred->uid, cred->euid, cred->suid, cred->fsuid); |
| 803 | printk(KERN_ERR "CRED: ->*gid = { %d,%d,%d,%d }\n", |
| 804 | cred->gid, cred->egid, cred->sgid, cred->fsgid); |
| 805 | #ifdef CONFIG_SECURITY |
| 806 | printk(KERN_ERR "CRED: ->security is %p\n", cred->security); |
| 807 | if ((unsigned long) cred->security >= PAGE_SIZE && |
| 808 | (((unsigned long) cred->security & 0xffffff00) != |
| 809 | (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8))) |
| 810 | printk(KERN_ERR "CRED: ->security {%x, %x}\n", |
| 811 | ((u32*)cred->security)[0], |
| 812 | ((u32*)cred->security)[1]); |
| 813 | #endif |
| 814 | } |
| 815 | |
| 816 | /* |
| 817 | * report use of invalid credentials |
| 818 | */ |
| 819 | void __invalid_creds(const struct cred *cred, const char *file, unsigned line) |
| 820 | { |
| 821 | printk(KERN_ERR "CRED: Invalid credentials\n"); |
| 822 | printk(KERN_ERR "CRED: At %s:%u\n", file, line); |
| 823 | dump_invalid_creds(cred, "Specified", current); |
| 824 | BUG(); |
| 825 | } |
| 826 | EXPORT_SYMBOL(__invalid_creds); |
| 827 | |
| 828 | /* |
| 829 | * check the credentials on a process |
| 830 | */ |
| 831 | void __validate_process_creds(struct task_struct *tsk, |
| 832 | const char *file, unsigned line) |
| 833 | { |
| 834 | if (tsk->cred == tsk->real_cred) { |
| 835 | if (unlikely(read_cred_subscribers(tsk->cred) < 2 || |
| 836 | creds_are_invalid(tsk->cred))) |
| 837 | goto invalid_creds; |
| 838 | } else { |
| 839 | if (unlikely(read_cred_subscribers(tsk->real_cred) < 1 || |
| 840 | read_cred_subscribers(tsk->cred) < 1 || |
| 841 | creds_are_invalid(tsk->real_cred) || |
| 842 | creds_are_invalid(tsk->cred))) |
| 843 | goto invalid_creds; |
| 844 | } |
| 845 | return; |
| 846 | |
| 847 | invalid_creds: |
| 848 | printk(KERN_ERR "CRED: Invalid process credentials\n"); |
| 849 | printk(KERN_ERR "CRED: At %s:%u\n", file, line); |
| 850 | |
| 851 | dump_invalid_creds(tsk->real_cred, "Real", tsk); |
| 852 | if (tsk->cred != tsk->real_cred) |
| 853 | dump_invalid_creds(tsk->cred, "Effective", tsk); |
| 854 | else |
| 855 | printk(KERN_ERR "CRED: Effective creds == Real creds\n"); |
| 856 | BUG(); |
| 857 | } |
| 858 | EXPORT_SYMBOL(__validate_process_creds); |
| 859 | |
| 860 | /* |
| 861 | * check creds for do_exit() |
| 862 | */ |
| 863 | void validate_creds_for_do_exit(struct task_struct *tsk) |
| 864 | { |
| 865 | kdebug("validate_creds_for_do_exit(%p,%p{%d,%d})", |
| 866 | tsk->real_cred, tsk->cred, |
| 867 | atomic_read(&tsk->cred->usage), |
| 868 | read_cred_subscribers(tsk->cred)); |
| 869 | |
| 870 | __validate_process_creds(tsk, __FILE__, __LINE__); |
| 871 | } |
| 872 | |
| 873 | #endif /* CONFIG_DEBUG_CREDENTIALS */ |