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