1 // SPDX-License-Identifier: GPL-2.0-or-later 1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Task credentials management - see Documenta 2 /* Task credentials management - see Documentation/security/credentials.rst
3 * 3 *
4 * Copyright (C) 2008 Red Hat, Inc. All Rights 4 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.c 5 * Written by David Howells (dhowells@redhat.com)
6 */ 6 */
7 <<
8 #define pr_fmt(fmt) "CRED: " fmt <<
9 <<
10 #include <linux/export.h> 7 #include <linux/export.h>
11 #include <linux/cred.h> 8 #include <linux/cred.h>
12 #include <linux/slab.h> 9 #include <linux/slab.h>
13 #include <linux/sched.h> 10 #include <linux/sched.h>
14 #include <linux/sched/coredump.h> 11 #include <linux/sched/coredump.h>
15 #include <linux/key.h> 12 #include <linux/key.h>
16 #include <linux/keyctl.h> 13 #include <linux/keyctl.h>
17 #include <linux/init_task.h> 14 #include <linux/init_task.h>
18 #include <linux/security.h> 15 #include <linux/security.h>
19 #include <linux/binfmts.h> 16 #include <linux/binfmts.h>
20 #include <linux/cn_proc.h> 17 #include <linux/cn_proc.h>
21 #include <linux/uidgid.h> 18 #include <linux/uidgid.h>
22 19
23 #if 0 20 #if 0
24 #define kdebug(FMT, ...) 21 #define kdebug(FMT, ...) \
25 printk("[%-5.5s%5u] " FMT "\n", 22 printk("[%-5.5s%5u] " FMT "\n", \
26 current->comm, current->pid, ## 23 current->comm, current->pid, ##__VA_ARGS__)
27 #else 24 #else
28 #define kdebug(FMT, ...) 25 #define kdebug(FMT, ...) \
29 do { 26 do { \
30 if (0) 27 if (0) \
31 no_printk("[%-5.5s%5u] " FMT " 28 no_printk("[%-5.5s%5u] " FMT "\n", \
32 current->comm, curre 29 current->comm, current->pid, ##__VA_ARGS__); \
33 } while (0) 30 } while (0)
34 #endif 31 #endif
35 32
36 static struct kmem_cache *cred_jar; 33 static struct kmem_cache *cred_jar;
37 34
38 /* init to 2 - one for init_task, one to ensur 35 /* init to 2 - one for init_task, one to ensure it is never freed */
39 static struct group_info init_groups = { .usag !! 36 struct group_info init_groups = { .usage = ATOMIC_INIT(2) };
40 37
41 /* 38 /*
42 * The initial credentials for the initial tas 39 * The initial credentials for the initial task
43 */ 40 */
44 struct cred init_cred = { 41 struct cred init_cred = {
45 .usage = ATOMIC_INIT( 42 .usage = ATOMIC_INIT(4),
>> 43 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 44 .subscribers = ATOMIC_INIT(2),
>> 45 .magic = CRED_MAGIC,
>> 46 #endif
46 .uid = GLOBAL_ROOT_ 47 .uid = GLOBAL_ROOT_UID,
47 .gid = GLOBAL_ROOT_ 48 .gid = GLOBAL_ROOT_GID,
48 .suid = GLOBAL_ROOT_ 49 .suid = GLOBAL_ROOT_UID,
49 .sgid = GLOBAL_ROOT_ 50 .sgid = GLOBAL_ROOT_GID,
50 .euid = GLOBAL_ROOT_ 51 .euid = GLOBAL_ROOT_UID,
51 .egid = GLOBAL_ROOT_ 52 .egid = GLOBAL_ROOT_GID,
52 .fsuid = GLOBAL_ROOT_ 53 .fsuid = GLOBAL_ROOT_UID,
53 .fsgid = GLOBAL_ROOT_ 54 .fsgid = GLOBAL_ROOT_GID,
54 .securebits = SECUREBITS_D 55 .securebits = SECUREBITS_DEFAULT,
55 .cap_inheritable = CAP_EMPTY_SE 56 .cap_inheritable = CAP_EMPTY_SET,
56 .cap_permitted = CAP_FULL_SET 57 .cap_permitted = CAP_FULL_SET,
57 .cap_effective = CAP_FULL_SET 58 .cap_effective = CAP_FULL_SET,
58 .cap_bset = CAP_FULL_SET 59 .cap_bset = CAP_FULL_SET,
59 .user = INIT_USER, 60 .user = INIT_USER,
60 .user_ns = &init_user_n 61 .user_ns = &init_user_ns,
61 .group_info = &init_groups 62 .group_info = &init_groups,
62 .ucounts = &init_ucount <<
63 }; 63 };
64 64
>> 65 static inline void set_cred_subscribers(struct cred *cred, int n)
>> 66 {
>> 67 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 68 atomic_set(&cred->subscribers, n);
>> 69 #endif
>> 70 }
>> 71
>> 72 static inline int read_cred_subscribers(const struct cred *cred)
>> 73 {
>> 74 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 75 return atomic_read(&cred->subscribers);
>> 76 #else
>> 77 return 0;
>> 78 #endif
>> 79 }
>> 80
>> 81 static inline void alter_cred_subscribers(const struct cred *_cred, int n)
>> 82 {
>> 83 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 84 struct cred *cred = (struct cred *) _cred;
>> 85
>> 86 atomic_add(n, &cred->subscribers);
>> 87 #endif
>> 88 }
>> 89
65 /* 90 /*
66 * The RCU callback to actually dispose of a s 91 * The RCU callback to actually dispose of a set of credentials
67 */ 92 */
68 static void put_cred_rcu(struct rcu_head *rcu) 93 static void put_cred_rcu(struct rcu_head *rcu)
69 { 94 {
70 struct cred *cred = container_of(rcu, 95 struct cred *cred = container_of(rcu, struct cred, rcu);
71 96
72 kdebug("put_cred_rcu(%p)", cred); 97 kdebug("put_cred_rcu(%p)", cred);
73 98
>> 99 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 100 if (cred->magic != CRED_MAGIC_DEAD ||
>> 101 atomic_long_read(&cred->usage) != 0 ||
>> 102 read_cred_subscribers(cred) != 0)
>> 103 panic("CRED: put_cred_rcu() sees %p with"
>> 104 " mag %x, put %p, usage %ld, subscr %d\n",
>> 105 cred, cred->magic, cred->put_addr,
>> 106 atomic_long_read(&cred->usage),
>> 107 read_cred_subscribers(cred));
>> 108 #else
74 if (atomic_long_read(&cred->usage) != 109 if (atomic_long_read(&cred->usage) != 0)
75 panic("CRED: put_cred_rcu() se 110 panic("CRED: put_cred_rcu() sees %p with usage %ld\n",
76 cred, atomic_long_read(& 111 cred, atomic_long_read(&cred->usage));
>> 112 #endif
77 113
78 security_cred_free(cred); 114 security_cred_free(cred);
79 key_put(cred->session_keyring); 115 key_put(cred->session_keyring);
80 key_put(cred->process_keyring); 116 key_put(cred->process_keyring);
81 key_put(cred->thread_keyring); 117 key_put(cred->thread_keyring);
82 key_put(cred->request_key_auth); 118 key_put(cred->request_key_auth);
83 if (cred->group_info) 119 if (cred->group_info)
84 put_group_info(cred->group_inf 120 put_group_info(cred->group_info);
85 free_uid(cred->user); 121 free_uid(cred->user);
86 if (cred->ucounts) <<
87 put_ucounts(cred->ucounts); <<
88 put_user_ns(cred->user_ns); 122 put_user_ns(cred->user_ns);
89 kmem_cache_free(cred_jar, cred); 123 kmem_cache_free(cred_jar, cred);
90 } 124 }
91 125
92 /** 126 /**
93 * __put_cred - Destroy a set of credentials 127 * __put_cred - Destroy a set of credentials
94 * @cred: The record to release 128 * @cred: The record to release
95 * 129 *
96 * Destroy a set of credentials on which no re 130 * Destroy a set of credentials on which no references remain.
97 */ 131 */
98 void __put_cred(struct cred *cred) 132 void __put_cred(struct cred *cred)
99 { 133 {
100 kdebug("__put_cred(%p{%ld})", cred, !! 134 kdebug("__put_cred(%p{%ld,%d})", cred,
101 atomic_long_read(&cred->usage)) !! 135 atomic_long_read(&cred->usage),
>> 136 read_cred_subscribers(cred));
102 137
103 BUG_ON(atomic_long_read(&cred->usage) 138 BUG_ON(atomic_long_read(&cred->usage) != 0);
>> 139 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 140 BUG_ON(read_cred_subscribers(cred) != 0);
>> 141 cred->magic = CRED_MAGIC_DEAD;
>> 142 cred->put_addr = __builtin_return_address(0);
>> 143 #endif
104 BUG_ON(cred == current->cred); 144 BUG_ON(cred == current->cred);
105 BUG_ON(cred == current->real_cred); 145 BUG_ON(cred == current->real_cred);
106 146
107 if (cred->non_rcu) 147 if (cred->non_rcu)
108 put_cred_rcu(&cred->rcu); 148 put_cred_rcu(&cred->rcu);
109 else 149 else
110 call_rcu(&cred->rcu, put_cred_ 150 call_rcu(&cred->rcu, put_cred_rcu);
111 } 151 }
112 EXPORT_SYMBOL(__put_cred); 152 EXPORT_SYMBOL(__put_cred);
113 153
114 /* 154 /*
115 * Clean up a task's credentials when it exits 155 * Clean up a task's credentials when it exits
116 */ 156 */
117 void exit_creds(struct task_struct *tsk) 157 void exit_creds(struct task_struct *tsk)
118 { 158 {
119 struct cred *real_cred, *cred; !! 159 struct cred *cred;
120 160
121 kdebug("exit_creds(%u,%p,%p,{%ld})", t !! 161 kdebug("exit_creds(%u,%p,%p,{%ld,%d})", tsk->pid, tsk->real_cred, tsk->cred,
122 atomic_long_read(&tsk->cred->us !! 162 atomic_long_read(&tsk->cred->usage),
>> 163 read_cred_subscribers(tsk->cred));
123 164
124 real_cred = (struct cred *) tsk->real_ !! 165 cred = (struct cred *) tsk->real_cred;
125 tsk->real_cred = NULL; 166 tsk->real_cred = NULL;
>> 167 validate_creds(cred);
>> 168 alter_cred_subscribers(cred, -1);
>> 169 put_cred(cred);
126 170
127 cred = (struct cred *) tsk->cred; 171 cred = (struct cred *) tsk->cred;
128 tsk->cred = NULL; 172 tsk->cred = NULL;
129 !! 173 validate_creds(cred);
130 if (real_cred == cred) { !! 174 alter_cred_subscribers(cred, -1);
131 put_cred_many(cred, 2); !! 175 put_cred(cred);
132 } else { <<
133 put_cred(real_cred); <<
134 put_cred(cred); <<
135 } <<
136 176
137 #ifdef CONFIG_KEYS_REQUEST_CACHE 177 #ifdef CONFIG_KEYS_REQUEST_CACHE
138 key_put(tsk->cached_requested_key); 178 key_put(tsk->cached_requested_key);
139 tsk->cached_requested_key = NULL; 179 tsk->cached_requested_key = NULL;
140 #endif 180 #endif
141 } 181 }
142 182
143 /** 183 /**
144 * get_task_cred - Get another task's objectiv 184 * get_task_cred - Get another task's objective credentials
145 * @task: The task to query 185 * @task: The task to query
146 * 186 *
147 * Get the objective credentials of a task, pi 187 * Get the objective credentials of a task, pinning them so that they can't go
148 * away. Accessing a task's credentials direc 188 * away. Accessing a task's credentials directly is not permitted.
149 * 189 *
150 * The caller must also make sure task doesn't 190 * The caller must also make sure task doesn't get deleted, either by holding a
151 * ref on task or by holding tasklist_lock to 191 * ref on task or by holding tasklist_lock to prevent it from being unlinked.
152 */ 192 */
153 const struct cred *get_task_cred(struct task_s 193 const struct cred *get_task_cred(struct task_struct *task)
154 { 194 {
155 const struct cred *cred; 195 const struct cred *cred;
156 196
157 rcu_read_lock(); 197 rcu_read_lock();
158 198
159 do { 199 do {
160 cred = __task_cred((task)); 200 cred = __task_cred((task));
161 BUG_ON(!cred); 201 BUG_ON(!cred);
162 } while (!get_cred_rcu(cred)); 202 } while (!get_cred_rcu(cred));
163 203
164 rcu_read_unlock(); 204 rcu_read_unlock();
165 return cred; 205 return cred;
166 } 206 }
167 EXPORT_SYMBOL(get_task_cred); 207 EXPORT_SYMBOL(get_task_cred);
168 208
169 /* 209 /*
170 * Allocate blank credentials, such that the c 210 * Allocate blank credentials, such that the credentials can be filled in at a
171 * later date without risk of ENOMEM. 211 * later date without risk of ENOMEM.
172 */ 212 */
173 struct cred *cred_alloc_blank(void) 213 struct cred *cred_alloc_blank(void)
174 { 214 {
175 struct cred *new; 215 struct cred *new;
176 216
177 new = kmem_cache_zalloc(cred_jar, GFP_ 217 new = kmem_cache_zalloc(cred_jar, GFP_KERNEL);
178 if (!new) 218 if (!new)
179 return NULL; 219 return NULL;
180 220
181 atomic_long_set(&new->usage, 1); 221 atomic_long_set(&new->usage, 1);
>> 222 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 223 new->magic = CRED_MAGIC;
>> 224 #endif
>> 225
182 if (security_cred_alloc_blank(new, GFP 226 if (security_cred_alloc_blank(new, GFP_KERNEL_ACCOUNT) < 0)
183 goto error; 227 goto error;
184 228
185 return new; 229 return new;
186 230
187 error: 231 error:
188 abort_creds(new); 232 abort_creds(new);
189 return NULL; 233 return NULL;
190 } 234 }
191 235
192 /** 236 /**
193 * prepare_creds - Prepare a new set of creden 237 * prepare_creds - Prepare a new set of credentials for modification
194 * 238 *
195 * Prepare a new set of task credentials for m 239 * Prepare a new set of task credentials for modification. A task's creds
196 * shouldn't generally be modified directly, t 240 * shouldn't generally be modified directly, therefore this function is used to
197 * prepare a new copy, which the caller then m 241 * prepare a new copy, which the caller then modifies and then commits by
198 * calling commit_creds(). 242 * calling commit_creds().
199 * 243 *
200 * Preparation involves making a copy of the o 244 * Preparation involves making a copy of the objective creds for modification.
201 * 245 *
202 * Returns a pointer to the new creds-to-be if 246 * Returns a pointer to the new creds-to-be if successful, NULL otherwise.
203 * 247 *
204 * Call commit_creds() or abort_creds() to cle 248 * Call commit_creds() or abort_creds() to clean up.
205 */ 249 */
206 struct cred *prepare_creds(void) 250 struct cred *prepare_creds(void)
207 { 251 {
208 struct task_struct *task = current; 252 struct task_struct *task = current;
209 const struct cred *old; 253 const struct cred *old;
210 struct cred *new; 254 struct cred *new;
211 255
>> 256 validate_process_creds();
>> 257
212 new = kmem_cache_alloc(cred_jar, GFP_K 258 new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
213 if (!new) 259 if (!new)
214 return NULL; 260 return NULL;
215 261
216 kdebug("prepare_creds() alloc %p", new 262 kdebug("prepare_creds() alloc %p", new);
217 263
218 old = task->cred; 264 old = task->cred;
219 memcpy(new, old, sizeof(struct cred)); 265 memcpy(new, old, sizeof(struct cred));
220 266
221 new->non_rcu = 0; 267 new->non_rcu = 0;
222 atomic_long_set(&new->usage, 1); 268 atomic_long_set(&new->usage, 1);
>> 269 set_cred_subscribers(new, 0);
223 get_group_info(new->group_info); 270 get_group_info(new->group_info);
224 get_uid(new->user); 271 get_uid(new->user);
225 get_user_ns(new->user_ns); 272 get_user_ns(new->user_ns);
226 273
227 #ifdef CONFIG_KEYS 274 #ifdef CONFIG_KEYS
228 key_get(new->session_keyring); 275 key_get(new->session_keyring);
229 key_get(new->process_keyring); 276 key_get(new->process_keyring);
230 key_get(new->thread_keyring); 277 key_get(new->thread_keyring);
231 key_get(new->request_key_auth); 278 key_get(new->request_key_auth);
232 #endif 279 #endif
233 280
234 #ifdef CONFIG_SECURITY 281 #ifdef CONFIG_SECURITY
235 new->security = NULL; 282 new->security = NULL;
236 #endif 283 #endif
237 284
238 new->ucounts = get_ucounts(new->ucount <<
239 if (!new->ucounts) <<
240 goto error; <<
241 <<
242 if (security_prepare_creds(new, old, G 285 if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0)
243 goto error; 286 goto error;
244 !! 287 validate_creds(new);
245 return new; 288 return new;
246 289
247 error: 290 error:
248 abort_creds(new); 291 abort_creds(new);
249 return NULL; 292 return NULL;
250 } 293 }
251 EXPORT_SYMBOL(prepare_creds); 294 EXPORT_SYMBOL(prepare_creds);
252 295
253 /* 296 /*
254 * Prepare credentials for current to perform 297 * Prepare credentials for current to perform an execve()
255 * - The caller must hold ->cred_guard_mutex 298 * - The caller must hold ->cred_guard_mutex
256 */ 299 */
257 struct cred *prepare_exec_creds(void) 300 struct cred *prepare_exec_creds(void)
258 { 301 {
259 struct cred *new; 302 struct cred *new;
260 303
261 new = prepare_creds(); 304 new = prepare_creds();
262 if (!new) 305 if (!new)
263 return new; 306 return new;
264 307
265 #ifdef CONFIG_KEYS 308 #ifdef CONFIG_KEYS
266 /* newly exec'd tasks don't get a thre 309 /* newly exec'd tasks don't get a thread keyring */
267 key_put(new->thread_keyring); 310 key_put(new->thread_keyring);
268 new->thread_keyring = NULL; 311 new->thread_keyring = NULL;
269 312
270 /* inherit the session keyring; new pr 313 /* inherit the session keyring; new process keyring */
271 key_put(new->process_keyring); 314 key_put(new->process_keyring);
272 new->process_keyring = NULL; 315 new->process_keyring = NULL;
273 #endif 316 #endif
274 317
275 new->suid = new->fsuid = new->euid; 318 new->suid = new->fsuid = new->euid;
276 new->sgid = new->fsgid = new->egid; 319 new->sgid = new->fsgid = new->egid;
277 320
278 return new; 321 return new;
279 } 322 }
280 323
281 /* 324 /*
282 * Copy credentials for the new process create 325 * Copy credentials for the new process created by fork()
283 * 326 *
284 * We share if we can, but under some circumst 327 * We share if we can, but under some circumstances we have to generate a new
285 * set. 328 * set.
286 * 329 *
287 * The new process gets the current process's 330 * The new process gets the current process's subjective credentials as its
288 * objective and subjective credentials 331 * objective and subjective credentials
289 */ 332 */
290 int copy_creds(struct task_struct *p, unsigned 333 int copy_creds(struct task_struct *p, unsigned long clone_flags)
291 { 334 {
292 struct cred *new; 335 struct cred *new;
293 int ret; 336 int ret;
294 337
295 #ifdef CONFIG_KEYS_REQUEST_CACHE 338 #ifdef CONFIG_KEYS_REQUEST_CACHE
296 p->cached_requested_key = NULL; 339 p->cached_requested_key = NULL;
297 #endif 340 #endif
298 341
299 if ( 342 if (
300 #ifdef CONFIG_KEYS 343 #ifdef CONFIG_KEYS
301 !p->cred->thread_keyring && 344 !p->cred->thread_keyring &&
302 #endif 345 #endif
303 clone_flags & CLONE_THREAD 346 clone_flags & CLONE_THREAD
304 ) { 347 ) {
305 p->real_cred = get_cred_many(p !! 348 p->real_cred = get_cred(p->cred);
306 kdebug("share_creds(%p{%ld})", !! 349 get_cred(p->cred);
307 p->cred, atomic_long_re !! 350 alter_cred_subscribers(p->cred, 2);
308 inc_rlimit_ucounts(task_ucount !! 351 kdebug("share_creds(%p{%ld,%d})",
>> 352 p->cred, atomic_long_read(&p->cred->usage),
>> 353 read_cred_subscribers(p->cred));
>> 354 atomic_inc(&p->cred->user->processes);
309 return 0; 355 return 0;
310 } 356 }
311 357
312 new = prepare_creds(); 358 new = prepare_creds();
313 if (!new) 359 if (!new)
314 return -ENOMEM; 360 return -ENOMEM;
315 361
316 if (clone_flags & CLONE_NEWUSER) { 362 if (clone_flags & CLONE_NEWUSER) {
317 ret = create_user_ns(new); 363 ret = create_user_ns(new);
318 if (ret < 0) 364 if (ret < 0)
319 goto error_put; 365 goto error_put;
320 ret = set_cred_ucounts(new); <<
321 if (ret < 0) <<
322 goto error_put; <<
323 } 366 }
324 367
325 #ifdef CONFIG_KEYS 368 #ifdef CONFIG_KEYS
326 /* new threads get their own thread ke 369 /* new threads get their own thread keyrings if their parent already
327 * had one */ 370 * had one */
328 if (new->thread_keyring) { 371 if (new->thread_keyring) {
329 key_put(new->thread_keyring); 372 key_put(new->thread_keyring);
330 new->thread_keyring = NULL; 373 new->thread_keyring = NULL;
331 if (clone_flags & CLONE_THREAD 374 if (clone_flags & CLONE_THREAD)
332 install_thread_keyring 375 install_thread_keyring_to_cred(new);
333 } 376 }
334 377
335 /* The process keyring is only shared 378 /* The process keyring is only shared between the threads in a process;
336 * anything outside of those threads d 379 * anything outside of those threads doesn't inherit.
337 */ 380 */
338 if (!(clone_flags & CLONE_THREAD)) { 381 if (!(clone_flags & CLONE_THREAD)) {
339 key_put(new->process_keyring); 382 key_put(new->process_keyring);
340 new->process_keyring = NULL; 383 new->process_keyring = NULL;
341 } 384 }
342 #endif 385 #endif
343 386
>> 387 atomic_inc(&new->user->processes);
344 p->cred = p->real_cred = get_cred(new) 388 p->cred = p->real_cred = get_cred(new);
345 inc_rlimit_ucounts(task_ucounts(p), UC !! 389 alter_cred_subscribers(new, 2);
>> 390 validate_creds(new);
346 return 0; 391 return 0;
347 392
348 error_put: 393 error_put:
349 put_cred(new); 394 put_cred(new);
350 return ret; 395 return ret;
351 } 396 }
352 397
353 static bool cred_cap_issubset(const struct cre 398 static bool cred_cap_issubset(const struct cred *set, const struct cred *subset)
354 { 399 {
355 const struct user_namespace *set_ns = 400 const struct user_namespace *set_ns = set->user_ns;
356 const struct user_namespace *subset_ns 401 const struct user_namespace *subset_ns = subset->user_ns;
357 402
358 /* If the two credentials are in the s 403 /* If the two credentials are in the same user namespace see if
359 * the capabilities of subset are a su 404 * the capabilities of subset are a subset of set.
360 */ 405 */
361 if (set_ns == subset_ns) 406 if (set_ns == subset_ns)
362 return cap_issubset(subset->ca 407 return cap_issubset(subset->cap_permitted, set->cap_permitted);
363 408
364 /* The credentials are in a different 409 /* The credentials are in a different user namespaces
365 * therefore one is a subset of the ot 410 * therefore one is a subset of the other only if a set is an
366 * ancestor of subset and set->euid is 411 * ancestor of subset and set->euid is owner of subset or one
367 * of subsets ancestors. 412 * of subsets ancestors.
368 */ 413 */
369 for (;subset_ns != &init_user_ns; subs 414 for (;subset_ns != &init_user_ns; subset_ns = subset_ns->parent) {
370 if ((set_ns == subset_ns->pare 415 if ((set_ns == subset_ns->parent) &&
371 uid_eq(subset_ns->owner, s 416 uid_eq(subset_ns->owner, set->euid))
372 return true; 417 return true;
373 } 418 }
374 419
375 return false; 420 return false;
376 } 421 }
377 422
378 /** 423 /**
379 * commit_creds - Install new credentials upon 424 * commit_creds - Install new credentials upon the current task
380 * @new: The credentials to be assigned 425 * @new: The credentials to be assigned
381 * 426 *
382 * Install a new set of credentials to the cur 427 * Install a new set of credentials to the current task, using RCU to replace
383 * the old set. Both the objective and the su 428 * the old set. Both the objective and the subjective credentials pointers are
384 * updated. This function may not be called i 429 * updated. This function may not be called if the subjective credentials are
385 * in an overridden state. 430 * in an overridden state.
386 * 431 *
387 * This function eats the caller's reference t 432 * This function eats the caller's reference to the new credentials.
388 * 433 *
389 * Always returns 0 thus allowing this functio 434 * Always returns 0 thus allowing this function to be tail-called at the end
390 * of, say, sys_setgid(). 435 * of, say, sys_setgid().
391 */ 436 */
392 int commit_creds(struct cred *new) 437 int commit_creds(struct cred *new)
393 { 438 {
394 struct task_struct *task = current; 439 struct task_struct *task = current;
395 const struct cred *old = task->real_cr 440 const struct cred *old = task->real_cred;
396 441
397 kdebug("commit_creds(%p{%ld})", new, !! 442 kdebug("commit_creds(%p{%ld,%d})", new,
398 atomic_long_read(&new->usage)); !! 443 atomic_long_read(&new->usage),
>> 444 read_cred_subscribers(new));
399 445
400 BUG_ON(task->cred != old); 446 BUG_ON(task->cred != old);
>> 447 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 448 BUG_ON(read_cred_subscribers(old) < 2);
>> 449 validate_creds(old);
>> 450 validate_creds(new);
>> 451 #endif
401 BUG_ON(atomic_long_read(&new->usage) < 452 BUG_ON(atomic_long_read(&new->usage) < 1);
402 453
403 get_cred(new); /* we will require a re 454 get_cred(new); /* we will require a ref for the subj creds too */
404 455
405 /* dumpability changes */ 456 /* dumpability changes */
406 if (!uid_eq(old->euid, new->euid) || 457 if (!uid_eq(old->euid, new->euid) ||
407 !gid_eq(old->egid, new->egid) || 458 !gid_eq(old->egid, new->egid) ||
408 !uid_eq(old->fsuid, new->fsuid) || 459 !uid_eq(old->fsuid, new->fsuid) ||
409 !gid_eq(old->fsgid, new->fsgid) || 460 !gid_eq(old->fsgid, new->fsgid) ||
410 !cred_cap_issubset(old, new)) { 461 !cred_cap_issubset(old, new)) {
411 if (task->mm) 462 if (task->mm)
412 set_dumpable(task->mm, 463 set_dumpable(task->mm, suid_dumpable);
413 task->pdeath_signal = 0; 464 task->pdeath_signal = 0;
414 /* 465 /*
415 * If a task drops privileges 466 * If a task drops privileges and becomes nondumpable,
416 * the dumpability change must 467 * the dumpability change must become visible before
417 * the credential change; othe 468 * the credential change; otherwise, a __ptrace_may_access()
418 * racing with this change may 469 * racing with this change may be able to attach to a task it
419 * shouldn't be able to attach 470 * shouldn't be able to attach to (as if the task had dropped
420 * privileges without becoming 471 * privileges without becoming nondumpable).
421 * Pairs with a read barrier i 472 * Pairs with a read barrier in __ptrace_may_access().
422 */ 473 */
423 smp_wmb(); 474 smp_wmb();
424 } 475 }
425 476
426 /* alter the thread keyring */ 477 /* alter the thread keyring */
427 if (!uid_eq(new->fsuid, old->fsuid)) 478 if (!uid_eq(new->fsuid, old->fsuid))
428 key_fsuid_changed(new); 479 key_fsuid_changed(new);
429 if (!gid_eq(new->fsgid, old->fsgid)) 480 if (!gid_eq(new->fsgid, old->fsgid))
430 key_fsgid_changed(new); 481 key_fsgid_changed(new);
431 482
432 /* do it 483 /* do it
433 * RLIMIT_NPROC limits on user->proces 484 * RLIMIT_NPROC limits on user->processes have already been checked
434 * in set_user(). 485 * in set_user().
435 */ 486 */
436 if (new->user != old->user || new->use !! 487 alter_cred_subscribers(new, 2);
437 inc_rlimit_ucounts(new->ucount !! 488 if (new->user != old->user)
>> 489 atomic_inc(&new->user->processes);
438 rcu_assign_pointer(task->real_cred, ne 490 rcu_assign_pointer(task->real_cred, new);
439 rcu_assign_pointer(task->cred, new); 491 rcu_assign_pointer(task->cred, new);
440 if (new->user != old->user || new->use !! 492 if (new->user != old->user)
441 dec_rlimit_ucounts(old->ucount !! 493 atomic_dec(&old->user->processes);
>> 494 alter_cred_subscribers(old, -2);
442 495
443 /* send notifications */ 496 /* send notifications */
444 if (!uid_eq(new->uid, old->uid) || 497 if (!uid_eq(new->uid, old->uid) ||
445 !uid_eq(new->euid, old->euid) || 498 !uid_eq(new->euid, old->euid) ||
446 !uid_eq(new->suid, old->suid) || 499 !uid_eq(new->suid, old->suid) ||
447 !uid_eq(new->fsuid, old->fsuid)) 500 !uid_eq(new->fsuid, old->fsuid))
448 proc_id_connector(task, PROC_E 501 proc_id_connector(task, PROC_EVENT_UID);
449 502
450 if (!gid_eq(new->gid, old->gid) || 503 if (!gid_eq(new->gid, old->gid) ||
451 !gid_eq(new->egid, old->egid) || 504 !gid_eq(new->egid, old->egid) ||
452 !gid_eq(new->sgid, old->sgid) || 505 !gid_eq(new->sgid, old->sgid) ||
453 !gid_eq(new->fsgid, old->fsgid)) 506 !gid_eq(new->fsgid, old->fsgid))
454 proc_id_connector(task, PROC_E 507 proc_id_connector(task, PROC_EVENT_GID);
455 508
456 /* release the old obj and subj refs b 509 /* release the old obj and subj refs both */
457 put_cred_many(old, 2); !! 510 put_cred(old);
>> 511 put_cred(old);
458 return 0; 512 return 0;
459 } 513 }
460 EXPORT_SYMBOL(commit_creds); 514 EXPORT_SYMBOL(commit_creds);
461 515
462 /** 516 /**
463 * abort_creds - Discard a set of credentials 517 * abort_creds - Discard a set of credentials and unlock the current task
464 * @new: The credentials that were going to be 518 * @new: The credentials that were going to be applied
465 * 519 *
466 * Discard a set of credentials that were unde 520 * Discard a set of credentials that were under construction and unlock the
467 * current task. 521 * current task.
468 */ 522 */
469 void abort_creds(struct cred *new) 523 void abort_creds(struct cred *new)
470 { 524 {
471 kdebug("abort_creds(%p{%ld})", new, !! 525 kdebug("abort_creds(%p{%ld,%d})", new,
472 atomic_long_read(&new->usage)); !! 526 atomic_long_read(&new->usage),
>> 527 read_cred_subscribers(new));
473 528
>> 529 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 530 BUG_ON(read_cred_subscribers(new) != 0);
>> 531 #endif
474 BUG_ON(atomic_long_read(&new->usage) < 532 BUG_ON(atomic_long_read(&new->usage) < 1);
475 put_cred(new); 533 put_cred(new);
476 } 534 }
477 EXPORT_SYMBOL(abort_creds); 535 EXPORT_SYMBOL(abort_creds);
478 536
479 /** 537 /**
480 * override_creds - Override the current proce 538 * override_creds - Override the current process's subjective credentials
481 * @new: The credentials to be assigned 539 * @new: The credentials to be assigned
482 * 540 *
483 * Install a set of temporary override subject 541 * Install a set of temporary override subjective credentials on the current
484 * process, returning the old set for later re 542 * process, returning the old set for later reversion.
485 */ 543 */
486 const struct cred *override_creds(const struct 544 const struct cred *override_creds(const struct cred *new)
487 { 545 {
488 const struct cred *old = current->cred 546 const struct cred *old = current->cred;
489 547
490 kdebug("override_creds(%p{%ld})", new, !! 548 kdebug("override_creds(%p{%ld,%d})", new,
491 atomic_long_read(&new->usage)); !! 549 atomic_long_read(&new->usage),
>> 550 read_cred_subscribers(new));
>> 551
>> 552 validate_creds(old);
>> 553 validate_creds(new);
492 554
493 /* 555 /*
494 * NOTE! This uses 'get_new_cred()' ra 556 * NOTE! This uses 'get_new_cred()' rather than 'get_cred()'.
495 * 557 *
496 * That means that we do not clear the 558 * That means that we do not clear the 'non_rcu' flag, since
497 * we are only installing the cred int 559 * we are only installing the cred into the thread-synchronous
498 * '->cred' pointer, not the '->real_c 560 * '->cred' pointer, not the '->real_cred' pointer that is
499 * visible to other threads under RCU. 561 * visible to other threads under RCU.
>> 562 *
>> 563 * Also note that we did validate_creds() manually, not depending
>> 564 * on the validation in 'get_cred()'.
500 */ 565 */
501 get_new_cred((struct cred *)new); 566 get_new_cred((struct cred *)new);
>> 567 alter_cred_subscribers(new, 1);
502 rcu_assign_pointer(current->cred, new) 568 rcu_assign_pointer(current->cred, new);
>> 569 alter_cred_subscribers(old, -1);
503 570
504 kdebug("override_creds() = %p{%ld}", o !! 571 kdebug("override_creds() = %p{%ld,%d}", old,
505 atomic_long_read(&old->usage)); !! 572 atomic_long_read(&old->usage),
>> 573 read_cred_subscribers(old));
506 return old; 574 return old;
507 } 575 }
508 EXPORT_SYMBOL(override_creds); 576 EXPORT_SYMBOL(override_creds);
509 577
510 /** 578 /**
511 * revert_creds - Revert a temporary subjectiv 579 * revert_creds - Revert a temporary subjective credentials override
512 * @old: The credentials to be restored 580 * @old: The credentials to be restored
513 * 581 *
514 * Revert a temporary set of override subjecti 582 * Revert a temporary set of override subjective credentials to an old set,
515 * discarding the override set. 583 * discarding the override set.
516 */ 584 */
517 void revert_creds(const struct cred *old) 585 void revert_creds(const struct cred *old)
518 { 586 {
519 const struct cred *override = current- 587 const struct cred *override = current->cred;
520 588
521 kdebug("revert_creds(%p{%ld})", old, !! 589 kdebug("revert_creds(%p{%ld,%d})", old,
522 atomic_long_read(&old->usage)); !! 590 atomic_long_read(&old->usage),
523 !! 591 read_cred_subscribers(old));
>> 592
>> 593 validate_creds(old);
>> 594 validate_creds(override);
>> 595 alter_cred_subscribers(old, 1);
524 rcu_assign_pointer(current->cred, old) 596 rcu_assign_pointer(current->cred, old);
>> 597 alter_cred_subscribers(override, -1);
525 put_cred(override); 598 put_cred(override);
526 } 599 }
527 EXPORT_SYMBOL(revert_creds); 600 EXPORT_SYMBOL(revert_creds);
528 601
529 /** 602 /**
530 * cred_fscmp - Compare two credentials with r 603 * cred_fscmp - Compare two credentials with respect to filesystem access.
531 * @a: The first credential 604 * @a: The first credential
532 * @b: The second credential 605 * @b: The second credential
533 * 606 *
534 * cred_cmp() will return zero if both credent 607 * cred_cmp() will return zero if both credentials have the same
535 * fsuid, fsgid, and supplementary groups. Th 608 * fsuid, fsgid, and supplementary groups. That is, if they will both
536 * provide the same access to files based on m 609 * provide the same access to files based on mode/uid/gid.
537 * If the credentials are different, then eith 610 * If the credentials are different, then either -1 or 1 will
538 * be returned depending on whether @a comes b 611 * be returned depending on whether @a comes before or after @b
539 * respectively in an arbitrary, but stable, o 612 * respectively in an arbitrary, but stable, ordering of credentials.
540 * 613 *
541 * Return: -1, 0, or 1 depending on comparison 614 * Return: -1, 0, or 1 depending on comparison
542 */ 615 */
543 int cred_fscmp(const struct cred *a, const str 616 int cred_fscmp(const struct cred *a, const struct cred *b)
544 { 617 {
545 struct group_info *ga, *gb; 618 struct group_info *ga, *gb;
546 int g; 619 int g;
547 620
548 if (a == b) 621 if (a == b)
549 return 0; 622 return 0;
550 if (uid_lt(a->fsuid, b->fsuid)) 623 if (uid_lt(a->fsuid, b->fsuid))
551 return -1; 624 return -1;
552 if (uid_gt(a->fsuid, b->fsuid)) 625 if (uid_gt(a->fsuid, b->fsuid))
553 return 1; 626 return 1;
554 627
555 if (gid_lt(a->fsgid, b->fsgid)) 628 if (gid_lt(a->fsgid, b->fsgid))
556 return -1; 629 return -1;
557 if (gid_gt(a->fsgid, b->fsgid)) 630 if (gid_gt(a->fsgid, b->fsgid))
558 return 1; 631 return 1;
559 632
560 ga = a->group_info; 633 ga = a->group_info;
561 gb = b->group_info; 634 gb = b->group_info;
562 if (ga == gb) 635 if (ga == gb)
563 return 0; 636 return 0;
564 if (ga == NULL) 637 if (ga == NULL)
565 return -1; 638 return -1;
566 if (gb == NULL) 639 if (gb == NULL)
567 return 1; 640 return 1;
568 if (ga->ngroups < gb->ngroups) 641 if (ga->ngroups < gb->ngroups)
569 return -1; 642 return -1;
570 if (ga->ngroups > gb->ngroups) 643 if (ga->ngroups > gb->ngroups)
571 return 1; 644 return 1;
572 645
573 for (g = 0; g < ga->ngroups; g++) { 646 for (g = 0; g < ga->ngroups; g++) {
574 if (gid_lt(ga->gid[g], gb->gid 647 if (gid_lt(ga->gid[g], gb->gid[g]))
575 return -1; 648 return -1;
576 if (gid_gt(ga->gid[g], gb->gid 649 if (gid_gt(ga->gid[g], gb->gid[g]))
577 return 1; 650 return 1;
578 } 651 }
579 return 0; 652 return 0;
580 } 653 }
581 EXPORT_SYMBOL(cred_fscmp); 654 EXPORT_SYMBOL(cred_fscmp);
582 655
583 int set_cred_ucounts(struct cred *new) <<
584 { <<
585 struct ucounts *new_ucounts, *old_ucou <<
586 <<
587 /* <<
588 * This optimization is needed because <<
589 * for table lookups. <<
590 */ <<
591 if (old_ucounts->ns == new->user_ns && <<
592 return 0; <<
593 <<
594 if (!(new_ucounts = alloc_ucounts(new- <<
595 return -EAGAIN; <<
596 <<
597 new->ucounts = new_ucounts; <<
598 put_ucounts(old_ucounts); <<
599 <<
600 return 0; <<
601 } <<
602 <<
603 /* 656 /*
604 * initialise the credentials stuff 657 * initialise the credentials stuff
605 */ 658 */
606 void __init cred_init(void) 659 void __init cred_init(void)
607 { 660 {
608 /* allocate a slab in which we can sto 661 /* allocate a slab in which we can store credentials */
609 cred_jar = KMEM_CACHE(cred, !! 662 cred_jar = kmem_cache_create("cred_jar", sizeof(struct cred), 0,
610 SLAB_HWCACHE_ALI !! 663 SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL);
611 } 664 }
612 665
613 /** 666 /**
614 * prepare_kernel_cred - Prepare a set of cred 667 * prepare_kernel_cred - Prepare a set of credentials for a kernel service
615 * @daemon: A userspace daemon to be used as a 668 * @daemon: A userspace daemon to be used as a reference
616 * 669 *
617 * Prepare a set of credentials for a kernel s 670 * Prepare a set of credentials for a kernel service. This can then be used to
618 * override a task's own credentials so that w 671 * override a task's own credentials so that work can be done on behalf of that
619 * task that requires a different subjective c 672 * task that requires a different subjective context.
620 * 673 *
621 * @daemon is used to provide a base cred, wit !! 674 * @daemon is used to provide a base for the security record, but can be NULL.
622 * that; if this is "&init_task", they'll be s !! 675 * If @daemon is supplied, then the security data will be derived from that;
623 * capabilities, and no keys. !! 676 * otherwise they'll be set to 0 and no groups, full capabilities and no keys.
624 * 677 *
625 * The caller may change these controls afterw 678 * The caller may change these controls afterwards if desired.
626 * 679 *
627 * Returns the new credentials or NULL if out 680 * Returns the new credentials or NULL if out of memory.
628 */ 681 */
629 struct cred *prepare_kernel_cred(struct task_s 682 struct cred *prepare_kernel_cred(struct task_struct *daemon)
630 { 683 {
631 const struct cred *old; 684 const struct cred *old;
632 struct cred *new; 685 struct cred *new;
633 686
634 if (WARN_ON_ONCE(!daemon)) <<
635 return NULL; <<
636 <<
637 new = kmem_cache_alloc(cred_jar, GFP_K 687 new = kmem_cache_alloc(cred_jar, GFP_KERNEL);
638 if (!new) 688 if (!new)
639 return NULL; 689 return NULL;
640 690
641 kdebug("prepare_kernel_cred() alloc %p 691 kdebug("prepare_kernel_cred() alloc %p", new);
642 692
643 old = get_task_cred(daemon); !! 693 if (daemon)
>> 694 old = get_task_cred(daemon);
>> 695 else
>> 696 old = get_cred(&init_cred);
>> 697
>> 698 validate_creds(old);
644 699
645 *new = *old; 700 *new = *old;
646 new->non_rcu = 0; 701 new->non_rcu = 0;
647 atomic_long_set(&new->usage, 1); 702 atomic_long_set(&new->usage, 1);
>> 703 set_cred_subscribers(new, 0);
648 get_uid(new->user); 704 get_uid(new->user);
649 get_user_ns(new->user_ns); 705 get_user_ns(new->user_ns);
650 get_group_info(new->group_info); 706 get_group_info(new->group_info);
651 707
652 #ifdef CONFIG_KEYS 708 #ifdef CONFIG_KEYS
653 new->session_keyring = NULL; 709 new->session_keyring = NULL;
654 new->process_keyring = NULL; 710 new->process_keyring = NULL;
655 new->thread_keyring = NULL; 711 new->thread_keyring = NULL;
656 new->request_key_auth = NULL; 712 new->request_key_auth = NULL;
657 new->jit_keyring = KEY_REQKEY_DEFL_THR 713 new->jit_keyring = KEY_REQKEY_DEFL_THREAD_KEYRING;
658 #endif 714 #endif
659 715
660 #ifdef CONFIG_SECURITY 716 #ifdef CONFIG_SECURITY
661 new->security = NULL; 717 new->security = NULL;
662 #endif 718 #endif
663 new->ucounts = get_ucounts(new->ucount <<
664 if (!new->ucounts) <<
665 goto error; <<
666 <<
667 if (security_prepare_creds(new, old, G 719 if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0)
668 goto error; 720 goto error;
669 721
670 put_cred(old); 722 put_cred(old);
>> 723 validate_creds(new);
671 return new; 724 return new;
672 725
673 error: 726 error:
674 put_cred(new); 727 put_cred(new);
675 put_cred(old); 728 put_cred(old);
676 return NULL; 729 return NULL;
677 } 730 }
678 EXPORT_SYMBOL(prepare_kernel_cred); 731 EXPORT_SYMBOL(prepare_kernel_cred);
679 732
680 /** 733 /**
681 * set_security_override - Set the security ID 734 * set_security_override - Set the security ID in a set of credentials
682 * @new: The credentials to alter 735 * @new: The credentials to alter
683 * @secid: The LSM security ID to set 736 * @secid: The LSM security ID to set
684 * 737 *
685 * Set the LSM security ID in a set of credent 738 * Set the LSM security ID in a set of credentials so that the subjective
686 * security is overridden when an alternative 739 * security is overridden when an alternative set of credentials is used.
687 */ 740 */
688 int set_security_override(struct cred *new, u3 741 int set_security_override(struct cred *new, u32 secid)
689 { 742 {
690 return security_kernel_act_as(new, sec 743 return security_kernel_act_as(new, secid);
691 } 744 }
692 EXPORT_SYMBOL(set_security_override); 745 EXPORT_SYMBOL(set_security_override);
693 746
694 /** 747 /**
695 * set_security_override_from_ctx - Set the se 748 * set_security_override_from_ctx - Set the security ID in a set of credentials
696 * @new: The credentials to alter 749 * @new: The credentials to alter
697 * @secctx: The LSM security context to genera 750 * @secctx: The LSM security context to generate the security ID from.
698 * 751 *
699 * Set the LSM security ID in a set of credent 752 * Set the LSM security ID in a set of credentials so that the subjective
700 * security is overridden when an alternative 753 * security is overridden when an alternative set of credentials is used. The
701 * security ID is specified in string form as 754 * security ID is specified in string form as a security context to be
702 * interpreted by the LSM. 755 * interpreted by the LSM.
703 */ 756 */
704 int set_security_override_from_ctx(struct cred 757 int set_security_override_from_ctx(struct cred *new, const char *secctx)
705 { 758 {
706 u32 secid; 759 u32 secid;
707 int ret; 760 int ret;
708 761
709 ret = security_secctx_to_secid(secctx, 762 ret = security_secctx_to_secid(secctx, strlen(secctx), &secid);
710 if (ret < 0) 763 if (ret < 0)
711 return ret; 764 return ret;
712 765
713 return set_security_override(new, seci 766 return set_security_override(new, secid);
714 } 767 }
715 EXPORT_SYMBOL(set_security_override_from_ctx); 768 EXPORT_SYMBOL(set_security_override_from_ctx);
716 769
717 /** 770 /**
718 * set_create_files_as - Set the LSM file crea 771 * set_create_files_as - Set the LSM file create context in a set of credentials
719 * @new: The credentials to alter 772 * @new: The credentials to alter
720 * @inode: The inode to take the context from 773 * @inode: The inode to take the context from
721 * 774 *
722 * Change the LSM file creation context in a s 775 * Change the LSM file creation context in a set of credentials to be the same
723 * as the object context of the specified inod 776 * as the object context of the specified inode, so that the new inodes have
724 * the same MAC context as that inode. 777 * the same MAC context as that inode.
725 */ 778 */
726 int set_create_files_as(struct cred *new, stru 779 int set_create_files_as(struct cred *new, struct inode *inode)
727 { 780 {
728 if (!uid_valid(inode->i_uid) || !gid_v 781 if (!uid_valid(inode->i_uid) || !gid_valid(inode->i_gid))
729 return -EINVAL; 782 return -EINVAL;
730 new->fsuid = inode->i_uid; 783 new->fsuid = inode->i_uid;
731 new->fsgid = inode->i_gid; 784 new->fsgid = inode->i_gid;
732 return security_kernel_create_files_as 785 return security_kernel_create_files_as(new, inode);
733 } 786 }
734 EXPORT_SYMBOL(set_create_files_as); 787 EXPORT_SYMBOL(set_create_files_as);
>> 788
>> 789 #ifdef CONFIG_DEBUG_CREDENTIALS
>> 790
>> 791 bool creds_are_invalid(const struct cred *cred)
>> 792 {
>> 793 if (cred->magic != CRED_MAGIC)
>> 794 return true;
>> 795 return false;
>> 796 }
>> 797 EXPORT_SYMBOL(creds_are_invalid);
>> 798
>> 799 /*
>> 800 * dump invalid credentials
>> 801 */
>> 802 static void dump_invalid_creds(const struct cred *cred, const char *label,
>> 803 const struct task_struct *tsk)
>> 804 {
>> 805 printk(KERN_ERR "CRED: %s credentials: %p %s%s%s\n",
>> 806 label, cred,
>> 807 cred == &init_cred ? "[init]" : "",
>> 808 cred == tsk->real_cred ? "[real]" : "",
>> 809 cred == tsk->cred ? "[eff]" : "");
>> 810 printk(KERN_ERR "CRED: ->magic=%x, put_addr=%p\n",
>> 811 cred->magic, cred->put_addr);
>> 812 printk(KERN_ERR "CRED: ->usage=%ld, subscr=%d\n",
>> 813 atomic_long_read(&cred->usage),
>> 814 read_cred_subscribers(cred));
>> 815 printk(KERN_ERR "CRED: ->*uid = { %d,%d,%d,%d }\n",
>> 816 from_kuid_munged(&init_user_ns, cred->uid),
>> 817 from_kuid_munged(&init_user_ns, cred->euid),
>> 818 from_kuid_munged(&init_user_ns, cred->suid),
>> 819 from_kuid_munged(&init_user_ns, cred->fsuid));
>> 820 printk(KERN_ERR "CRED: ->*gid = { %d,%d,%d,%d }\n",
>> 821 from_kgid_munged(&init_user_ns, cred->gid),
>> 822 from_kgid_munged(&init_user_ns, cred->egid),
>> 823 from_kgid_munged(&init_user_ns, cred->sgid),
>> 824 from_kgid_munged(&init_user_ns, cred->fsgid));
>> 825 #ifdef CONFIG_SECURITY
>> 826 printk(KERN_ERR "CRED: ->security is %p\n", cred->security);
>> 827 if ((unsigned long) cred->security >= PAGE_SIZE &&
>> 828 (((unsigned long) cred->security & 0xffffff00) !=
>> 829 (POISON_FREE << 24 | POISON_FREE << 16 | POISON_FREE << 8)))
>> 830 printk(KERN_ERR "CRED: ->security {%x, %x}\n",
>> 831 ((u32*)cred->security)[0],
>> 832 ((u32*)cred->security)[1]);
>> 833 #endif
>> 834 }
>> 835
>> 836 /*
>> 837 * report use of invalid credentials
>> 838 */
>> 839 void __invalid_creds(const struct cred *cred, const char *file, unsigned line)
>> 840 {
>> 841 printk(KERN_ERR "CRED: Invalid credentials\n");
>> 842 printk(KERN_ERR "CRED: At %s:%u\n", file, line);
>> 843 dump_invalid_creds(cred, "Specified", current);
>> 844 BUG();
>> 845 }
>> 846 EXPORT_SYMBOL(__invalid_creds);
>> 847
>> 848 /*
>> 849 * check the credentials on a process
>> 850 */
>> 851 void __validate_process_creds(struct task_struct *tsk,
>> 852 const char *file, unsigned line)
>> 853 {
>> 854 if (tsk->cred == tsk->real_cred) {
>> 855 if (unlikely(read_cred_subscribers(tsk->cred) < 2 ||
>> 856 creds_are_invalid(tsk->cred)))
>> 857 goto invalid_creds;
>> 858 } else {
>> 859 if (unlikely(read_cred_subscribers(tsk->real_cred) < 1 ||
>> 860 read_cred_subscribers(tsk->cred) < 1 ||
>> 861 creds_are_invalid(tsk->real_cred) ||
>> 862 creds_are_invalid(tsk->cred)))
>> 863 goto invalid_creds;
>> 864 }
>> 865 return;
>> 866
>> 867 invalid_creds:
>> 868 printk(KERN_ERR "CRED: Invalid process credentials\n");
>> 869 printk(KERN_ERR "CRED: At %s:%u\n", file, line);
>> 870
>> 871 dump_invalid_creds(tsk->real_cred, "Real", tsk);
>> 872 if (tsk->cred != tsk->real_cred)
>> 873 dump_invalid_creds(tsk->cred, "Effective", tsk);
>> 874 else
>> 875 printk(KERN_ERR "CRED: Effective creds == Real creds\n");
>> 876 BUG();
>> 877 }
>> 878 EXPORT_SYMBOL(__validate_process_creds);
>> 879
>> 880 /*
>> 881 * check creds for do_exit()
>> 882 */
>> 883 void validate_creds_for_do_exit(struct task_struct *tsk)
>> 884 {
>> 885 kdebug("validate_creds_for_do_exit(%p,%p{%ld,%d})",
>> 886 tsk->real_cred, tsk->cred,
>> 887 atomic_long_read(&tsk->cred->usage),
>> 888 read_cred_subscribers(tsk->cred));
>> 889
>> 890 __validate_process_creds(tsk, __FILE__, __LINE__);
>> 891 }
>> 892
>> 893 #endif /* CONFIG_DEBUG_CREDENTIALS */
735 894
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