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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> |
d7700842 | 15 | #include <linux/refcount.h> |
ae2975bc | 16 | #include <linux/uidgid.h> |
5b825c3a | 17 | #include <linux/sched.h> |
8703e8a4 | 18 | #include <linux/sched/user.h> |
b6dff3ec | 19 | |
b6dff3ec | 20 | struct cred; |
3a3b7ce9 | 21 | struct inode; |
b6dff3ec DH |
22 | |
23 | /* | |
24 | * COW Supplementary groups list | |
25 | */ | |
b6dff3ec | 26 | struct group_info { |
d7700842 | 27 | refcount_t usage; |
b6dff3ec | 28 | int ngroups; |
c1f26493 | 29 | kgid_t gid[]; |
3859a271 | 30 | } __randomize_layout; |
b6dff3ec DH |
31 | |
32 | /** | |
33 | * get_group_info - Get a reference to a group info structure | |
34 | * @group_info: The group info to reference | |
35 | * | |
86a264ab DH |
36 | * This gets a reference to a set of supplementary groups. |
37 | * | |
38 | * If the caller is accessing a task's credentials, they must hold the RCU read | |
39 | * lock when reading. | |
b6dff3ec | 40 | */ |
86a264ab DH |
41 | static inline struct group_info *get_group_info(struct group_info *gi) |
42 | { | |
d7700842 | 43 | refcount_inc(&gi->usage); |
86a264ab DH |
44 | return gi; |
45 | } | |
b6dff3ec DH |
46 | |
47 | /** | |
48 | * put_group_info - Release a reference to a group info structure | |
49 | * @group_info: The group info to release | |
50 | */ | |
51 | #define put_group_info(group_info) \ | |
52 | do { \ | |
d7700842 | 53 | if (refcount_dec_and_test(&(group_info)->usage)) \ |
b6dff3ec DH |
54 | groups_free(group_info); \ |
55 | } while (0) | |
56 | ||
2813893f IM |
57 | #ifdef CONFIG_MULTIUSER |
58 | extern struct group_info *groups_alloc(int); | |
b6dff3ec | 59 | extern void groups_free(struct group_info *); |
2813893f IM |
60 | |
61 | extern int in_group_p(kgid_t); | |
62 | extern int in_egroup_p(kgid_t); | |
4b09791b OM |
63 | extern int groups_search(const struct group_info *, kgid_t); |
64 | ||
65 | extern int set_current_groups(struct group_info *); | |
66 | extern void set_groups(struct cred *, struct group_info *); | |
67 | extern bool may_setgroups(void); | |
68 | extern void groups_sort(struct group_info *); | |
2813893f IM |
69 | #else |
70 | static inline void groups_free(struct group_info *group_info) | |
71 | { | |
72 | } | |
73 | ||
74 | static inline int in_group_p(kgid_t grp) | |
75 | { | |
76 | return 1; | |
77 | } | |
78 | static inline int in_egroup_p(kgid_t grp) | |
79 | { | |
80 | return 1; | |
81 | } | |
4b09791b OM |
82 | static inline int groups_search(const struct group_info *group_info, kgid_t grp) |
83 | { | |
84 | return 1; | |
85 | } | |
2813893f | 86 | #endif |
b6dff3ec | 87 | |
b6dff3ec DH |
88 | /* |
89 | * The security context of a task | |
90 | * | |
91 | * The parts of the context break down into two categories: | |
92 | * | |
93 | * (1) The objective context of a task. These parts are used when some other | |
94 | * task is attempting to affect this one. | |
95 | * | |
96 | * (2) The subjective context. These details are used when the task is acting | |
97 | * upon another object, be that a file, a task, a key or whatever. | |
98 | * | |
99 | * Note that some members of this structure belong to both categories - the | |
100 | * LSM security pointer for instance. | |
101 | * | |
102 | * A task has two security pointers. task->real_cred points to the objective | |
103 | * context that defines that task's actual details. The objective part of this | |
104 | * context is used whenever that task is acted upon. | |
105 | * | |
106 | * task->cred points to the subjective context that defines the details of how | |
107 | * that task is going to act upon another object. This may be overridden | |
108 | * temporarily to point to another security context, but normally points to the | |
109 | * same context as task->real_cred. | |
110 | */ | |
111 | struct cred { | |
f8fa5d76 | 112 | atomic_long_t usage; |
078de5f7 EB |
113 | kuid_t uid; /* real UID of the task */ |
114 | kgid_t gid; /* real GID of the task */ | |
115 | kuid_t suid; /* saved UID of the task */ | |
116 | kgid_t sgid; /* saved GID of the task */ | |
117 | kuid_t euid; /* effective UID of the task */ | |
118 | kgid_t egid; /* effective GID of the task */ | |
119 | kuid_t fsuid; /* UID for VFS ops */ | |
120 | kgid_t fsgid; /* GID for VFS ops */ | |
b6dff3ec DH |
121 | unsigned securebits; /* SUID-less security management */ |
122 | kernel_cap_t cap_inheritable; /* caps our children can inherit */ | |
123 | kernel_cap_t cap_permitted; /* caps we're permitted */ | |
124 | kernel_cap_t cap_effective; /* caps we can actually use */ | |
125 | kernel_cap_t cap_bset; /* capability bounding set */ | |
58319057 | 126 | kernel_cap_t cap_ambient; /* Ambient capability set */ |
b6dff3ec DH |
127 | #ifdef CONFIG_KEYS |
128 | unsigned char jit_keyring; /* default keyring to attach requested | |
129 | * keys to */ | |
5c7e372c | 130 | struct key *session_keyring; /* keyring inherited over fork */ |
3a50597d | 131 | struct key *process_keyring; /* keyring private to this process */ |
b6dff3ec DH |
132 | struct key *thread_keyring; /* keyring private to this thread */ |
133 | struct key *request_key_auth; /* assumed request_key authority */ | |
134 | #endif | |
135 | #ifdef CONFIG_SECURITY | |
4ebd7651 | 136 | void *security; /* LSM security */ |
b6dff3ec DH |
137 | #endif |
138 | struct user_struct *user; /* real user ID subscription */ | |
0093ccb6 | 139 | struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */ |
905ae01c | 140 | struct ucounts *ucounts; |
b6dff3ec | 141 | struct group_info *group_info; /* supplementary groups for euid/fsgid */ |
d7852fbd LT |
142 | /* RCU deletion */ |
143 | union { | |
144 | int non_rcu; /* Can we skip RCU deletion? */ | |
145 | struct rcu_head rcu; /* RCU deletion hook */ | |
146 | }; | |
3859a271 | 147 | } __randomize_layout; |
b6dff3ec | 148 | |
f1752eec | 149 | extern void __put_cred(struct cred *); |
e0e81739 | 150 | extern void exit_creds(struct task_struct *); |
f1752eec | 151 | extern int copy_creds(struct task_struct *, unsigned long); |
de09a977 | 152 | extern const struct cred *get_task_cred(struct task_struct *); |
ee18d64c | 153 | extern struct cred *cred_alloc_blank(void); |
d84f4f99 | 154 | extern struct cred *prepare_creds(void); |
a6f76f23 | 155 | extern struct cred *prepare_exec_creds(void); |
d84f4f99 DH |
156 | extern int commit_creds(struct cred *); |
157 | extern void abort_creds(struct cred *); | |
3b11a1de DH |
158 | extern const struct cred *override_creds(const struct cred *); |
159 | extern void revert_creds(const struct cred *); | |
3a3b7ce9 | 160 | extern struct cred *prepare_kernel_cred(struct task_struct *); |
3a3b7ce9 DH |
161 | extern int set_security_override(struct cred *, u32); |
162 | extern int set_security_override_from_ctx(struct cred *, const char *); | |
163 | extern int set_create_files_as(struct cred *, struct inode *); | |
d89b22d4 | 164 | extern int cred_fscmp(const struct cred *, const struct cred *); |
d84f4f99 | 165 | extern void __init cred_init(void); |
905ae01c | 166 | extern int set_cred_ucounts(struct cred *); |
d84f4f99 | 167 | |
58319057 AL |
168 | static inline bool cap_ambient_invariant_ok(const struct cred *cred) |
169 | { | |
170 | return cap_issubset(cred->cap_ambient, | |
171 | cap_intersect(cred->cap_permitted, | |
172 | cred->cap_inheritable)); | |
173 | } | |
174 | ||
41e84562 MG |
175 | /** |
176 | * get_new_cred_many - Get references on a new set of credentials | |
177 | * @cred: The new credentials to reference | |
178 | * @nr: Number of references to acquire | |
179 | * | |
180 | * Get references on the specified set of new credentials. The caller must | |
181 | * release all acquired references. | |
182 | */ | |
183 | static inline struct cred *get_new_cred_many(struct cred *cred, int nr) | |
184 | { | |
f8fa5d76 | 185 | atomic_long_add(nr, &cred->usage); |
41e84562 MG |
186 | return cred; |
187 | } | |
188 | ||
d84f4f99 DH |
189 | /** |
190 | * get_new_cred - Get a reference on a new set of credentials | |
191 | * @cred: The new credentials to reference | |
192 | * | |
193 | * Get a reference on the specified set of new credentials. The caller must | |
194 | * release the reference. | |
195 | */ | |
196 | static inline struct cred *get_new_cred(struct cred *cred) | |
197 | { | |
41e84562 | 198 | return get_new_cred_many(cred, 1); |
d84f4f99 | 199 | } |
f1752eec DH |
200 | |
201 | /** | |
41e84562 | 202 | * get_cred_many - Get references on a set of credentials |
f1752eec | 203 | * @cred: The credentials to reference |
41e84562 | 204 | * @nr: Number of references to acquire |
f1752eec | 205 | * |
41e84562 MG |
206 | * Get references on the specified set of credentials. The caller must release |
207 | * all acquired reference. If %NULL is passed, it is returned with no action. | |
98870ab0 DH |
208 | * |
209 | * This is used to deal with a committed set of credentials. Although the | |
210 | * pointer is const, this will temporarily discard the const and increment the | |
211 | * usage count. The purpose of this is to attempt to catch at compile time the | |
212 | * accidental alteration of a set of credentials that should be considered | |
213 | * immutable. | |
f1752eec | 214 | */ |
41e84562 | 215 | static inline const struct cred *get_cred_many(const struct cred *cred, int nr) |
f1752eec | 216 | { |
1c388ad0 | 217 | struct cred *nonconst_cred = (struct cred *) cred; |
f06bc033 N |
218 | if (!cred) |
219 | return cred; | |
d7852fbd | 220 | nonconst_cred->non_rcu = 0; |
41e84562 MG |
221 | return get_new_cred_many(nonconst_cred, nr); |
222 | } | |
223 | ||
224 | /* | |
225 | * get_cred - Get a reference on a set of credentials | |
226 | * @cred: The credentials to reference | |
227 | * | |
228 | * Get a reference on the specified set of credentials. The caller must | |
229 | * release the reference. If %NULL is passed, it is returned with no action. | |
230 | * | |
231 | * This is used to deal with a committed set of credentials. | |
232 | */ | |
233 | static inline const struct cred *get_cred(const struct cred *cred) | |
234 | { | |
235 | return get_cred_many(cred, 1); | |
f1752eec DH |
236 | } |
237 | ||
97d0fb23 N |
238 | static inline const struct cred *get_cred_rcu(const struct cred *cred) |
239 | { | |
240 | struct cred *nonconst_cred = (struct cred *) cred; | |
241 | if (!cred) | |
242 | return NULL; | |
f8fa5d76 | 243 | if (!atomic_long_inc_not_zero(&nonconst_cred->usage)) |
97d0fb23 | 244 | return NULL; |
d7852fbd | 245 | nonconst_cred->non_rcu = 0; |
97d0fb23 N |
246 | return cred; |
247 | } | |
248 | ||
f1752eec DH |
249 | /** |
250 | * put_cred - Release a reference to a set of credentials | |
251 | * @cred: The credentials to release | |
41e84562 | 252 | * @nr: Number of references to release |
f1752eec DH |
253 | * |
254 | * Release a reference to a set of credentials, deleting them when the last ref | |
f06bc033 | 255 | * is released. If %NULL is passed, nothing is done. |
98870ab0 DH |
256 | * |
257 | * This takes a const pointer to a set of credentials because the credentials | |
258 | * on task_struct are attached by const pointers to prevent accidental | |
259 | * alteration of otherwise immutable credential sets. | |
f1752eec | 260 | */ |
41e84562 | 261 | static inline void put_cred_many(const struct cred *_cred, int nr) |
f1752eec | 262 | { |
c69e8d9c | 263 | struct cred *cred = (struct cred *) _cred; |
d84f4f99 | 264 | |
f06bc033 | 265 | if (cred) { |
f8fa5d76 | 266 | if (atomic_long_sub_and_test(nr, &cred->usage)) |
f06bc033 N |
267 | __put_cred(cred); |
268 | } | |
f1752eec DH |
269 | } |
270 | ||
41e84562 MG |
271 | /* |
272 | * put_cred - Release a reference to a set of credentials | |
273 | * @cred: The credentials to release | |
274 | * | |
275 | * Release a reference to a set of credentials, deleting them when the last ref | |
276 | * is released. If %NULL is passed, nothing is done. | |
277 | */ | |
278 | static inline void put_cred(const struct cred *cred) | |
279 | { | |
280 | put_cred_many(cred, 1); | |
281 | } | |
282 | ||
86a264ab | 283 | /** |
3b11a1de | 284 | * current_cred - Access the current task's subjective credentials |
86a264ab | 285 | * |
32955148 AV |
286 | * Access the subjective credentials of the current task. RCU-safe, |
287 | * since nobody else can modify it. | |
86a264ab DH |
288 | */ |
289 | #define current_cred() \ | |
27e4e436 | 290 | rcu_dereference_protected(current->cred, 1) |
86a264ab | 291 | |
ae4b884f JL |
292 | /** |
293 | * current_real_cred - Access the current task's objective credentials | |
294 | * | |
295 | * Access the objective credentials of the current task. RCU-safe, | |
296 | * since nobody else can modify it. | |
297 | */ | |
298 | #define current_real_cred() \ | |
299 | rcu_dereference_protected(current->real_cred, 1) | |
300 | ||
86a264ab | 301 | /** |
3b11a1de | 302 | * __task_cred - Access a task's objective credentials |
86a264ab DH |
303 | * @task: The task to query |
304 | * | |
3b11a1de | 305 | * Access the objective credentials of a task. The caller must hold the RCU |
43e13cc1 | 306 | * readlock. |
86a264ab | 307 | * |
8f92054e DH |
308 | * The result of this function should not be passed directly to get_cred(); |
309 | * rather get_task_cred() should be used instead. | |
86a264ab | 310 | */ |
43e13cc1 ON |
311 | #define __task_cred(task) \ |
312 | rcu_dereference((task)->real_cred) | |
86a264ab | 313 | |
86a264ab | 314 | /** |
3b11a1de | 315 | * get_current_cred - Get the current task's subjective credentials |
86a264ab | 316 | * |
3b11a1de DH |
317 | * Get the subjective credentials of the current task, pinning them so that |
318 | * they can't go away. Accessing the current task's credentials directly is | |
319 | * not permitted. | |
86a264ab DH |
320 | */ |
321 | #define get_current_cred() \ | |
322 | (get_cred(current_cred())) | |
323 | ||
324 | /** | |
325 | * get_current_user - Get the current task's user_struct | |
326 | * | |
327 | * Get the user record of the current task, pinning it so that it can't go | |
328 | * away. | |
329 | */ | |
330 | #define get_current_user() \ | |
331 | ({ \ | |
332 | struct user_struct *__u; \ | |
638a8439 | 333 | const struct cred *__cred; \ |
32955148 | 334 | __cred = current_cred(); \ |
86a264ab DH |
335 | __u = get_uid(__cred->user); \ |
336 | __u; \ | |
337 | }) | |
338 | ||
339 | /** | |
340 | * get_current_groups - Get the current task's supplementary group list | |
341 | * | |
342 | * Get the supplementary group list of the current task, pinning it so that it | |
343 | * can't go away. | |
344 | */ | |
345 | #define get_current_groups() \ | |
346 | ({ \ | |
347 | struct group_info *__groups; \ | |
638a8439 | 348 | const struct cred *__cred; \ |
32955148 | 349 | __cred = current_cred(); \ |
86a264ab DH |
350 | __groups = get_group_info(__cred->group_info); \ |
351 | __groups; \ | |
352 | }) | |
353 | ||
d84f4f99 DH |
354 | #define task_cred_xxx(task, xxx) \ |
355 | ({ \ | |
356 | __typeof__(((struct cred *)NULL)->xxx) ___val; \ | |
357 | rcu_read_lock(); \ | |
358 | ___val = __task_cred((task))->xxx; \ | |
359 | rcu_read_unlock(); \ | |
360 | ___val; \ | |
86a264ab DH |
361 | }) |
362 | ||
363 | #define task_uid(task) (task_cred_xxx((task), uid)) | |
364 | #define task_euid(task) (task_cred_xxx((task), euid)) | |
21d1c5e3 | 365 | #define task_ucounts(task) (task_cred_xxx((task), ucounts)) |
86a264ab DH |
366 | |
367 | #define current_cred_xxx(xxx) \ | |
368 | ({ \ | |
32955148 | 369 | current_cred()->xxx; \ |
86a264ab DH |
370 | }) |
371 | ||
372 | #define current_uid() (current_cred_xxx(uid)) | |
373 | #define current_gid() (current_cred_xxx(gid)) | |
374 | #define current_euid() (current_cred_xxx(euid)) | |
375 | #define current_egid() (current_cred_xxx(egid)) | |
376 | #define current_suid() (current_cred_xxx(suid)) | |
377 | #define current_sgid() (current_cred_xxx(sgid)) | |
378 | #define current_fsuid() (current_cred_xxx(fsuid)) | |
379 | #define current_fsgid() (current_cred_xxx(fsgid)) | |
380 | #define current_cap() (current_cred_xxx(cap_effective)) | |
381 | #define current_user() (current_cred_xxx(user)) | |
21d1c5e3 | 382 | #define current_ucounts() (current_cred_xxx(ucounts)) |
86a264ab | 383 | |
7e6bd8fa | 384 | extern struct user_namespace init_user_ns; |
47a150ed | 385 | #ifdef CONFIG_USER_NS |
f1c84dae | 386 | #define current_user_ns() (current_cred_xxx(user_ns)) |
47a150ed | 387 | #else |
0335695d AB |
388 | static inline struct user_namespace *current_user_ns(void) |
389 | { | |
390 | return &init_user_ns; | |
391 | } | |
47a150ed SH |
392 | #endif |
393 | ||
3486740a | 394 | |
86a264ab DH |
395 | #define current_uid_gid(_uid, _gid) \ |
396 | do { \ | |
397 | const struct cred *__cred; \ | |
398 | __cred = current_cred(); \ | |
399 | *(_uid) = __cred->uid; \ | |
400 | *(_gid) = __cred->gid; \ | |
401 | } while(0) | |
402 | ||
403 | #define current_euid_egid(_euid, _egid) \ | |
404 | do { \ | |
405 | const struct cred *__cred; \ | |
406 | __cred = current_cred(); \ | |
407 | *(_euid) = __cred->euid; \ | |
408 | *(_egid) = __cred->egid; \ | |
409 | } while(0) | |
410 | ||
411 | #define current_fsuid_fsgid(_fsuid, _fsgid) \ | |
412 | do { \ | |
413 | const struct cred *__cred; \ | |
414 | __cred = current_cred(); \ | |
415 | *(_fsuid) = __cred->fsuid; \ | |
416 | *(_fsgid) = __cred->fsgid; \ | |
417 | } while(0) | |
418 | ||
9e2b2dc4 | 419 | #endif /* _LINUX_CRED_H */ |