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b4d0d230 | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
af777cd1 | 2 | /* Credentials management - see Documentation/security/credentials.rst |
9e2b2dc4 DH |
3 | * |
4 | * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
9e2b2dc4 DH |
6 | */ |
7 | ||
8 | #ifndef _LINUX_CRED_H | |
9 | #define _LINUX_CRED_H | |
10 | ||
b6dff3ec | 11 | #include <linux/capability.h> |
b2e1feaf | 12 | #include <linux/init.h> |
b6dff3ec | 13 | #include <linux/key.h> |
60063497 | 14 | #include <linux/atomic.h> |
ae2975bc | 15 | #include <linux/uidgid.h> |
5b825c3a | 16 | #include <linux/sched.h> |
8703e8a4 | 17 | #include <linux/sched/user.h> |
b6dff3ec | 18 | |
b6dff3ec | 19 | struct cred; |
3a3b7ce9 | 20 | struct inode; |
b6dff3ec DH |
21 | |
22 | /* | |
23 | * COW Supplementary groups list | |
24 | */ | |
b6dff3ec DH |
25 | struct group_info { |
26 | atomic_t usage; | |
27 | int ngroups; | |
c1f26493 | 28 | kgid_t gid[]; |
3859a271 | 29 | } __randomize_layout; |
b6dff3ec DH |
30 | |
31 | /** | |
32 | * get_group_info - Get a reference to a group info structure | |
33 | * @group_info: The group info to reference | |
34 | * | |
86a264ab DH |
35 | * This gets a reference to a set of supplementary groups. |
36 | * | |
37 | * If the caller is accessing a task's credentials, they must hold the RCU read | |
38 | * lock when reading. | |
b6dff3ec | 39 | */ |
86a264ab DH |
40 | static inline struct group_info *get_group_info(struct group_info *gi) |
41 | { | |
42 | atomic_inc(&gi->usage); | |
43 | return gi; | |
44 | } | |
b6dff3ec DH |
45 | |
46 | /** | |
47 | * put_group_info - Release a reference to a group info structure | |
48 | * @group_info: The group info to release | |
49 | */ | |
50 | #define put_group_info(group_info) \ | |
51 | do { \ | |
52 | if (atomic_dec_and_test(&(group_info)->usage)) \ | |
53 | groups_free(group_info); \ | |
54 | } while (0) | |
55 | ||
2813893f IM |
56 | #ifdef CONFIG_MULTIUSER |
57 | extern struct group_info *groups_alloc(int); | |
b6dff3ec | 58 | extern void groups_free(struct group_info *); |
2813893f IM |
59 | |
60 | extern int in_group_p(kgid_t); | |
61 | extern int in_egroup_p(kgid_t); | |
4b09791b OM |
62 | extern int groups_search(const struct group_info *, kgid_t); |
63 | ||
64 | extern int set_current_groups(struct group_info *); | |
65 | extern void set_groups(struct cred *, struct group_info *); | |
66 | extern bool may_setgroups(void); | |
67 | extern void groups_sort(struct group_info *); | |
2813893f IM |
68 | #else |
69 | static inline void groups_free(struct group_info *group_info) | |
70 | { | |
71 | } | |
72 | ||
73 | static inline int in_group_p(kgid_t grp) | |
74 | { | |
75 | return 1; | |
76 | } | |
77 | static inline int in_egroup_p(kgid_t grp) | |
78 | { | |
79 | return 1; | |
80 | } | |
4b09791b OM |
81 | static inline int groups_search(const struct group_info *group_info, kgid_t grp) |
82 | { | |
83 | return 1; | |
84 | } | |
2813893f | 85 | #endif |
b6dff3ec | 86 | |
b6dff3ec DH |
87 | /* |
88 | * The security context of a task | |
89 | * | |
90 | * The parts of the context break down into two categories: | |
91 | * | |
92 | * (1) The objective context of a task. These parts are used when some other | |
93 | * task is attempting to affect this one. | |
94 | * | |
95 | * (2) The subjective context. These details are used when the task is acting | |
96 | * upon another object, be that a file, a task, a key or whatever. | |
97 | * | |
98 | * Note that some members of this structure belong to both categories - the | |
99 | * LSM security pointer for instance. | |
100 | * | |
101 | * A task has two security pointers. task->real_cred points to the objective | |
102 | * context that defines that task's actual details. The objective part of this | |
103 | * context is used whenever that task is acted upon. | |
104 | * | |
105 | * task->cred points to the subjective context that defines the details of how | |
106 | * that task is going to act upon another object. This may be overridden | |
107 | * temporarily to point to another security context, but normally points to the | |
108 | * same context as task->real_cred. | |
109 | */ | |
110 | struct cred { | |
111 | atomic_t usage; | |
e0e81739 DH |
112 | #ifdef CONFIG_DEBUG_CREDENTIALS |
113 | atomic_t subscribers; /* number of processes subscribed */ | |
114 | void *put_addr; | |
115 | unsigned magic; | |
116 | #define CRED_MAGIC 0x43736564 | |
117 | #define CRED_MAGIC_DEAD 0x44656144 | |
118 | #endif | |
078de5f7 EB |
119 | kuid_t uid; /* real UID of the task */ |
120 | kgid_t gid; /* real GID of the task */ | |
121 | kuid_t suid; /* saved UID of the task */ | |
122 | kgid_t sgid; /* saved GID of the task */ | |
123 | kuid_t euid; /* effective UID of the task */ | |
124 | kgid_t egid; /* effective GID of the task */ | |
125 | kuid_t fsuid; /* UID for VFS ops */ | |
126 | kgid_t fsgid; /* GID for VFS ops */ | |
b6dff3ec DH |
127 | unsigned securebits; /* SUID-less security management */ |
128 | kernel_cap_t cap_inheritable; /* caps our children can inherit */ | |
129 | kernel_cap_t cap_permitted; /* caps we're permitted */ | |
130 | kernel_cap_t cap_effective; /* caps we can actually use */ | |
131 | kernel_cap_t cap_bset; /* capability bounding set */ | |
58319057 | 132 | kernel_cap_t cap_ambient; /* Ambient capability set */ |
b6dff3ec DH |
133 | #ifdef CONFIG_KEYS |
134 | unsigned char jit_keyring; /* default keyring to attach requested | |
135 | * keys to */ | |
5c7e372c | 136 | struct key *session_keyring; /* keyring inherited over fork */ |
3a50597d | 137 | struct key *process_keyring; /* keyring private to this process */ |
b6dff3ec DH |
138 | struct key *thread_keyring; /* keyring private to this thread */ |
139 | struct key *request_key_auth; /* assumed request_key authority */ | |
140 | #endif | |
141 | #ifdef CONFIG_SECURITY | |
4ebd7651 | 142 | void *security; /* LSM security */ |
b6dff3ec DH |
143 | #endif |
144 | struct user_struct *user; /* real user ID subscription */ | |
0093ccb6 | 145 | struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */ |
b6dff3ec | 146 | struct group_info *group_info; /* supplementary groups for euid/fsgid */ |
d7852fbd LT |
147 | /* RCU deletion */ |
148 | union { | |
149 | int non_rcu; /* Can we skip RCU deletion? */ | |
150 | struct rcu_head rcu; /* RCU deletion hook */ | |
151 | }; | |
3859a271 | 152 | } __randomize_layout; |
b6dff3ec | 153 | |
f1752eec | 154 | extern void __put_cred(struct cred *); |
e0e81739 | 155 | extern void exit_creds(struct task_struct *); |
f1752eec | 156 | extern int copy_creds(struct task_struct *, unsigned long); |
de09a977 | 157 | extern const struct cred *get_task_cred(struct task_struct *); |
ee18d64c | 158 | extern struct cred *cred_alloc_blank(void); |
d84f4f99 | 159 | extern struct cred *prepare_creds(void); |
a6f76f23 | 160 | extern struct cred *prepare_exec_creds(void); |
d84f4f99 DH |
161 | extern int commit_creds(struct cred *); |
162 | extern void abort_creds(struct cred *); | |
3b11a1de DH |
163 | extern const struct cred *override_creds(const struct cred *); |
164 | extern void revert_creds(const struct cred *); | |
3a3b7ce9 DH |
165 | extern struct cred *prepare_kernel_cred(struct task_struct *); |
166 | extern int change_create_files_as(struct cred *, struct inode *); | |
167 | extern int set_security_override(struct cred *, u32); | |
168 | extern int set_security_override_from_ctx(struct cred *, const char *); | |
169 | extern int set_create_files_as(struct cred *, struct inode *); | |
d89b22d4 | 170 | extern int cred_fscmp(const struct cred *, const struct cred *); |
d84f4f99 DH |
171 | extern void __init cred_init(void); |
172 | ||
e0e81739 DH |
173 | /* |
174 | * check for validity of credentials | |
175 | */ | |
176 | #ifdef CONFIG_DEBUG_CREDENTIALS | |
177 | extern void __invalid_creds(const struct cred *, const char *, unsigned); | |
178 | extern void __validate_process_creds(struct task_struct *, | |
179 | const char *, unsigned); | |
180 | ||
74908a00 | 181 | extern bool creds_are_invalid(const struct cred *cred); |
e0e81739 DH |
182 | |
183 | static inline void __validate_creds(const struct cred *cred, | |
184 | const char *file, unsigned line) | |
185 | { | |
186 | if (unlikely(creds_are_invalid(cred))) | |
187 | __invalid_creds(cred, file, line); | |
188 | } | |
189 | ||
190 | #define validate_creds(cred) \ | |
191 | do { \ | |
192 | __validate_creds((cred), __FILE__, __LINE__); \ | |
193 | } while(0) | |
194 | ||
195 | #define validate_process_creds() \ | |
196 | do { \ | |
197 | __validate_process_creds(current, __FILE__, __LINE__); \ | |
198 | } while(0) | |
199 | ||
200 | extern void validate_creds_for_do_exit(struct task_struct *); | |
201 | #else | |
202 | static inline void validate_creds(const struct cred *cred) | |
203 | { | |
204 | } | |
205 | static inline void validate_creds_for_do_exit(struct task_struct *tsk) | |
206 | { | |
207 | } | |
208 | static inline void validate_process_creds(void) | |
209 | { | |
210 | } | |
211 | #endif | |
212 | ||
58319057 AL |
213 | static inline bool cap_ambient_invariant_ok(const struct cred *cred) |
214 | { | |
215 | return cap_issubset(cred->cap_ambient, | |
216 | cap_intersect(cred->cap_permitted, | |
217 | cred->cap_inheritable)); | |
218 | } | |
219 | ||
d84f4f99 DH |
220 | /** |
221 | * get_new_cred - Get a reference on a new set of credentials | |
222 | * @cred: The new credentials to reference | |
223 | * | |
224 | * Get a reference on the specified set of new credentials. The caller must | |
225 | * release the reference. | |
226 | */ | |
227 | static inline struct cred *get_new_cred(struct cred *cred) | |
228 | { | |
229 | atomic_inc(&cred->usage); | |
230 | return cred; | |
231 | } | |
f1752eec DH |
232 | |
233 | /** | |
234 | * get_cred - Get a reference on a set of credentials | |
235 | * @cred: The credentials to reference | |
236 | * | |
237 | * Get a reference on the specified set of credentials. The caller must | |
f06bc033 | 238 | * release the reference. If %NULL is passed, it is returned with no action. |
98870ab0 DH |
239 | * |
240 | * This is used to deal with a committed set of credentials. Although the | |
241 | * pointer is const, this will temporarily discard the const and increment the | |
242 | * usage count. The purpose of this is to attempt to catch at compile time the | |
243 | * accidental alteration of a set of credentials that should be considered | |
244 | * immutable. | |
f1752eec | 245 | */ |
d84f4f99 | 246 | static inline const struct cred *get_cred(const struct cred *cred) |
f1752eec | 247 | { |
1c388ad0 | 248 | struct cred *nonconst_cred = (struct cred *) cred; |
f06bc033 N |
249 | if (!cred) |
250 | return cred; | |
e0e81739 | 251 | validate_creds(cred); |
d7852fbd | 252 | nonconst_cred->non_rcu = 0; |
1c388ad0 | 253 | return get_new_cred(nonconst_cred); |
f1752eec DH |
254 | } |
255 | ||
97d0fb23 N |
256 | static inline const struct cred *get_cred_rcu(const struct cred *cred) |
257 | { | |
258 | struct cred *nonconst_cred = (struct cred *) cred; | |
259 | if (!cred) | |
260 | return NULL; | |
261 | if (!atomic_inc_not_zero(&nonconst_cred->usage)) | |
262 | return NULL; | |
263 | validate_creds(cred); | |
d7852fbd | 264 | nonconst_cred->non_rcu = 0; |
97d0fb23 N |
265 | return cred; |
266 | } | |
267 | ||
f1752eec DH |
268 | /** |
269 | * put_cred - Release a reference to a set of credentials | |
270 | * @cred: The credentials to release | |
271 | * | |
272 | * Release a reference to a set of credentials, deleting them when the last ref | |
f06bc033 | 273 | * is released. If %NULL is passed, nothing is done. |
98870ab0 DH |
274 | * |
275 | * This takes a const pointer to a set of credentials because the credentials | |
276 | * on task_struct are attached by const pointers to prevent accidental | |
277 | * alteration of otherwise immutable credential sets. | |
f1752eec | 278 | */ |
c69e8d9c | 279 | static inline void put_cred(const struct cred *_cred) |
f1752eec | 280 | { |
c69e8d9c | 281 | struct cred *cred = (struct cred *) _cred; |
d84f4f99 | 282 | |
f06bc033 N |
283 | if (cred) { |
284 | validate_creds(cred); | |
285 | if (atomic_dec_and_test(&(cred)->usage)) | |
286 | __put_cred(cred); | |
287 | } | |
f1752eec DH |
288 | } |
289 | ||
86a264ab | 290 | /** |
3b11a1de | 291 | * current_cred - Access the current task's subjective credentials |
86a264ab | 292 | * |
32955148 AV |
293 | * Access the subjective credentials of the current task. RCU-safe, |
294 | * since nobody else can modify it. | |
86a264ab DH |
295 | */ |
296 | #define current_cred() \ | |
27e4e436 | 297 | rcu_dereference_protected(current->cred, 1) |
86a264ab | 298 | |
ae4b884f JL |
299 | /** |
300 | * current_real_cred - Access the current task's objective credentials | |
301 | * | |
302 | * Access the objective credentials of the current task. RCU-safe, | |
303 | * since nobody else can modify it. | |
304 | */ | |
305 | #define current_real_cred() \ | |
306 | rcu_dereference_protected(current->real_cred, 1) | |
307 | ||
86a264ab | 308 | /** |
3b11a1de | 309 | * __task_cred - Access a task's objective credentials |
86a264ab DH |
310 | * @task: The task to query |
311 | * | |
3b11a1de | 312 | * Access the objective credentials of a task. The caller must hold the RCU |
43e13cc1 | 313 | * readlock. |
86a264ab | 314 | * |
8f92054e DH |
315 | * The result of this function should not be passed directly to get_cred(); |
316 | * rather get_task_cred() should be used instead. | |
86a264ab | 317 | */ |
43e13cc1 ON |
318 | #define __task_cred(task) \ |
319 | rcu_dereference((task)->real_cred) | |
86a264ab | 320 | |
86a264ab | 321 | /** |
3b11a1de | 322 | * get_current_cred - Get the current task's subjective credentials |
86a264ab | 323 | * |
3b11a1de DH |
324 | * Get the subjective credentials of the current task, pinning them so that |
325 | * they can't go away. Accessing the current task's credentials directly is | |
326 | * not permitted. | |
86a264ab DH |
327 | */ |
328 | #define get_current_cred() \ | |
329 | (get_cred(current_cred())) | |
330 | ||
331 | /** | |
332 | * get_current_user - Get the current task's user_struct | |
333 | * | |
334 | * Get the user record of the current task, pinning it so that it can't go | |
335 | * away. | |
336 | */ | |
337 | #define get_current_user() \ | |
338 | ({ \ | |
339 | struct user_struct *__u; \ | |
638a8439 | 340 | const struct cred *__cred; \ |
32955148 | 341 | __cred = current_cred(); \ |
86a264ab DH |
342 | __u = get_uid(__cred->user); \ |
343 | __u; \ | |
344 | }) | |
345 | ||
346 | /** | |
347 | * get_current_groups - Get the current task's supplementary group list | |
348 | * | |
349 | * Get the supplementary group list of the current task, pinning it so that it | |
350 | * can't go away. | |
351 | */ | |
352 | #define get_current_groups() \ | |
353 | ({ \ | |
354 | struct group_info *__groups; \ | |
638a8439 | 355 | const struct cred *__cred; \ |
32955148 | 356 | __cred = current_cred(); \ |
86a264ab DH |
357 | __groups = get_group_info(__cred->group_info); \ |
358 | __groups; \ | |
359 | }) | |
360 | ||
d84f4f99 DH |
361 | #define task_cred_xxx(task, xxx) \ |
362 | ({ \ | |
363 | __typeof__(((struct cred *)NULL)->xxx) ___val; \ | |
364 | rcu_read_lock(); \ | |
365 | ___val = __task_cred((task))->xxx; \ | |
366 | rcu_read_unlock(); \ | |
367 | ___val; \ | |
86a264ab DH |
368 | }) |
369 | ||
370 | #define task_uid(task) (task_cred_xxx((task), uid)) | |
371 | #define task_euid(task) (task_cred_xxx((task), euid)) | |
372 | ||
373 | #define current_cred_xxx(xxx) \ | |
374 | ({ \ | |
32955148 | 375 | current_cred()->xxx; \ |
86a264ab DH |
376 | }) |
377 | ||
378 | #define current_uid() (current_cred_xxx(uid)) | |
379 | #define current_gid() (current_cred_xxx(gid)) | |
380 | #define current_euid() (current_cred_xxx(euid)) | |
381 | #define current_egid() (current_cred_xxx(egid)) | |
382 | #define current_suid() (current_cred_xxx(suid)) | |
383 | #define current_sgid() (current_cred_xxx(sgid)) | |
384 | #define current_fsuid() (current_cred_xxx(fsuid)) | |
385 | #define current_fsgid() (current_cred_xxx(fsgid)) | |
386 | #define current_cap() (current_cred_xxx(cap_effective)) | |
387 | #define current_user() (current_cred_xxx(user)) | |
86a264ab | 388 | |
7e6bd8fa | 389 | extern struct user_namespace init_user_ns; |
47a150ed | 390 | #ifdef CONFIG_USER_NS |
f1c84dae | 391 | #define current_user_ns() (current_cred_xxx(user_ns)) |
47a150ed | 392 | #else |
0335695d AB |
393 | static inline struct user_namespace *current_user_ns(void) |
394 | { | |
395 | return &init_user_ns; | |
396 | } | |
47a150ed SH |
397 | #endif |
398 | ||
3486740a | 399 | |
86a264ab DH |
400 | #define current_uid_gid(_uid, _gid) \ |
401 | do { \ | |
402 | const struct cred *__cred; \ | |
403 | __cred = current_cred(); \ | |
404 | *(_uid) = __cred->uid; \ | |
405 | *(_gid) = __cred->gid; \ | |
406 | } while(0) | |
407 | ||
408 | #define current_euid_egid(_euid, _egid) \ | |
409 | do { \ | |
410 | const struct cred *__cred; \ | |
411 | __cred = current_cred(); \ | |
412 | *(_euid) = __cred->euid; \ | |
413 | *(_egid) = __cred->egid; \ | |
414 | } while(0) | |
415 | ||
416 | #define current_fsuid_fsgid(_fsuid, _fsgid) \ | |
417 | do { \ | |
418 | const struct cred *__cred; \ | |
419 | __cred = current_cred(); \ | |
420 | *(_fsuid) = __cred->fsuid; \ | |
421 | *(_fsgid) = __cred->fsgid; \ | |
422 | } while(0) | |
423 | ||
9e2b2dc4 | 424 | #endif /* _LINUX_CRED_H */ |