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af777cd1 | 1 | /* Credentials management - see Documentation/security/credentials.rst |
9e2b2dc4 DH |
2 | * |
3 | * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public Licence | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the Licence, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #ifndef _LINUX_CRED_H | |
13 | #define _LINUX_CRED_H | |
14 | ||
b6dff3ec | 15 | #include <linux/capability.h> |
b2e1feaf | 16 | #include <linux/init.h> |
b6dff3ec | 17 | #include <linux/key.h> |
ed868a56 | 18 | #include <linux/selinux.h> |
60063497 | 19 | #include <linux/atomic.h> |
ae2975bc | 20 | #include <linux/uidgid.h> |
5b825c3a | 21 | #include <linux/sched.h> |
8703e8a4 | 22 | #include <linux/sched/user.h> |
b6dff3ec | 23 | |
b6dff3ec | 24 | struct cred; |
3a3b7ce9 | 25 | struct inode; |
b6dff3ec DH |
26 | |
27 | /* | |
28 | * COW Supplementary groups list | |
29 | */ | |
b6dff3ec DH |
30 | struct group_info { |
31 | atomic_t usage; | |
32 | int ngroups; | |
81243eac | 33 | kgid_t gid[0]; |
3859a271 | 34 | } __randomize_layout; |
b6dff3ec DH |
35 | |
36 | /** | |
37 | * get_group_info - Get a reference to a group info structure | |
38 | * @group_info: The group info to reference | |
39 | * | |
86a264ab DH |
40 | * This gets a reference to a set of supplementary groups. |
41 | * | |
42 | * If the caller is accessing a task's credentials, they must hold the RCU read | |
43 | * lock when reading. | |
b6dff3ec | 44 | */ |
86a264ab DH |
45 | static inline struct group_info *get_group_info(struct group_info *gi) |
46 | { | |
47 | atomic_inc(&gi->usage); | |
48 | return gi; | |
49 | } | |
b6dff3ec DH |
50 | |
51 | /** | |
52 | * put_group_info - Release a reference to a group info structure | |
53 | * @group_info: The group info to release | |
54 | */ | |
55 | #define put_group_info(group_info) \ | |
56 | do { \ | |
57 | if (atomic_dec_and_test(&(group_info)->usage)) \ | |
58 | groups_free(group_info); \ | |
59 | } while (0) | |
60 | ||
18b6e041 | 61 | extern struct group_info init_groups; |
2813893f IM |
62 | #ifdef CONFIG_MULTIUSER |
63 | extern struct group_info *groups_alloc(int); | |
b6dff3ec | 64 | extern void groups_free(struct group_info *); |
2813893f IM |
65 | |
66 | extern int in_group_p(kgid_t); | |
67 | extern int in_egroup_p(kgid_t); | |
4b09791b OM |
68 | extern int groups_search(const struct group_info *, kgid_t); |
69 | ||
70 | extern int set_current_groups(struct group_info *); | |
71 | extern void set_groups(struct cred *, struct group_info *); | |
72 | extern bool may_setgroups(void); | |
73 | extern void groups_sort(struct group_info *); | |
2813893f IM |
74 | #else |
75 | static inline void groups_free(struct group_info *group_info) | |
76 | { | |
77 | } | |
78 | ||
79 | static inline int in_group_p(kgid_t grp) | |
80 | { | |
81 | return 1; | |
82 | } | |
83 | static inline int in_egroup_p(kgid_t grp) | |
84 | { | |
85 | return 1; | |
86 | } | |
4b09791b OM |
87 | static inline int groups_search(const struct group_info *group_info, kgid_t grp) |
88 | { | |
89 | return 1; | |
90 | } | |
2813893f | 91 | #endif |
b6dff3ec | 92 | |
b6dff3ec DH |
93 | /* |
94 | * The security context of a task | |
95 | * | |
96 | * The parts of the context break down into two categories: | |
97 | * | |
98 | * (1) The objective context of a task. These parts are used when some other | |
99 | * task is attempting to affect this one. | |
100 | * | |
101 | * (2) The subjective context. These details are used when the task is acting | |
102 | * upon another object, be that a file, a task, a key or whatever. | |
103 | * | |
104 | * Note that some members of this structure belong to both categories - the | |
105 | * LSM security pointer for instance. | |
106 | * | |
107 | * A task has two security pointers. task->real_cred points to the objective | |
108 | * context that defines that task's actual details. The objective part of this | |
109 | * context is used whenever that task is acted upon. | |
110 | * | |
111 | * task->cred points to the subjective context that defines the details of how | |
112 | * that task is going to act upon another object. This may be overridden | |
113 | * temporarily to point to another security context, but normally points to the | |
114 | * same context as task->real_cred. | |
115 | */ | |
116 | struct cred { | |
117 | atomic_t usage; | |
e0e81739 DH |
118 | #ifdef CONFIG_DEBUG_CREDENTIALS |
119 | atomic_t subscribers; /* number of processes subscribed */ | |
120 | void *put_addr; | |
121 | unsigned magic; | |
122 | #define CRED_MAGIC 0x43736564 | |
123 | #define CRED_MAGIC_DEAD 0x44656144 | |
124 | #endif | |
078de5f7 EB |
125 | kuid_t uid; /* real UID of the task */ |
126 | kgid_t gid; /* real GID of the task */ | |
127 | kuid_t suid; /* saved UID of the task */ | |
128 | kgid_t sgid; /* saved GID of the task */ | |
129 | kuid_t euid; /* effective UID of the task */ | |
130 | kgid_t egid; /* effective GID of the task */ | |
131 | kuid_t fsuid; /* UID for VFS ops */ | |
132 | kgid_t fsgid; /* GID for VFS ops */ | |
b6dff3ec DH |
133 | unsigned securebits; /* SUID-less security management */ |
134 | kernel_cap_t cap_inheritable; /* caps our children can inherit */ | |
135 | kernel_cap_t cap_permitted; /* caps we're permitted */ | |
136 | kernel_cap_t cap_effective; /* caps we can actually use */ | |
137 | kernel_cap_t cap_bset; /* capability bounding set */ | |
58319057 | 138 | kernel_cap_t cap_ambient; /* Ambient capability set */ |
b6dff3ec DH |
139 | #ifdef CONFIG_KEYS |
140 | unsigned char jit_keyring; /* default keyring to attach requested | |
141 | * keys to */ | |
3a50597d DH |
142 | struct key __rcu *session_keyring; /* keyring inherited over fork */ |
143 | struct key *process_keyring; /* keyring private to this process */ | |
b6dff3ec DH |
144 | struct key *thread_keyring; /* keyring private to this thread */ |
145 | struct key *request_key_auth; /* assumed request_key authority */ | |
146 | #endif | |
147 | #ifdef CONFIG_SECURITY | |
148 | void *security; /* subjective LSM security */ | |
149 | #endif | |
150 | struct user_struct *user; /* real user ID subscription */ | |
0093ccb6 | 151 | struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */ |
b6dff3ec DH |
152 | struct group_info *group_info; /* supplementary groups for euid/fsgid */ |
153 | struct rcu_head rcu; /* RCU deletion hook */ | |
3859a271 | 154 | } __randomize_layout; |
b6dff3ec | 155 | |
f1752eec | 156 | extern void __put_cred(struct cred *); |
e0e81739 | 157 | extern void exit_creds(struct task_struct *); |
f1752eec | 158 | extern int copy_creds(struct task_struct *, unsigned long); |
de09a977 | 159 | extern const struct cred *get_task_cred(struct task_struct *); |
ee18d64c | 160 | extern struct cred *cred_alloc_blank(void); |
d84f4f99 | 161 | extern struct cred *prepare_creds(void); |
a6f76f23 | 162 | extern struct cred *prepare_exec_creds(void); |
d84f4f99 DH |
163 | extern int commit_creds(struct cred *); |
164 | extern void abort_creds(struct cred *); | |
3b11a1de DH |
165 | extern const struct cred *override_creds(const struct cred *); |
166 | extern void revert_creds(const struct cred *); | |
3a3b7ce9 DH |
167 | extern struct cred *prepare_kernel_cred(struct task_struct *); |
168 | extern int change_create_files_as(struct cred *, struct inode *); | |
169 | extern int set_security_override(struct cred *, u32); | |
170 | extern int set_security_override_from_ctx(struct cred *, const char *); | |
171 | extern int set_create_files_as(struct cred *, struct inode *); | |
d84f4f99 DH |
172 | extern void __init cred_init(void); |
173 | ||
e0e81739 DH |
174 | /* |
175 | * check for validity of credentials | |
176 | */ | |
177 | #ifdef CONFIG_DEBUG_CREDENTIALS | |
178 | extern void __invalid_creds(const struct cred *, const char *, unsigned); | |
179 | extern void __validate_process_creds(struct task_struct *, | |
180 | const char *, unsigned); | |
181 | ||
74908a00 | 182 | extern bool creds_are_invalid(const struct cred *cred); |
e0e81739 DH |
183 | |
184 | static inline void __validate_creds(const struct cred *cred, | |
185 | const char *file, unsigned line) | |
186 | { | |
187 | if (unlikely(creds_are_invalid(cred))) | |
188 | __invalid_creds(cred, file, line); | |
189 | } | |
190 | ||
191 | #define validate_creds(cred) \ | |
192 | do { \ | |
193 | __validate_creds((cred), __FILE__, __LINE__); \ | |
194 | } while(0) | |
195 | ||
196 | #define validate_process_creds() \ | |
197 | do { \ | |
198 | __validate_process_creds(current, __FILE__, __LINE__); \ | |
199 | } while(0) | |
200 | ||
201 | extern void validate_creds_for_do_exit(struct task_struct *); | |
202 | #else | |
203 | static inline void validate_creds(const struct cred *cred) | |
204 | { | |
205 | } | |
206 | static inline void validate_creds_for_do_exit(struct task_struct *tsk) | |
207 | { | |
208 | } | |
209 | static inline void validate_process_creds(void) | |
210 | { | |
211 | } | |
212 | #endif | |
213 | ||
58319057 AL |
214 | static inline bool cap_ambient_invariant_ok(const struct cred *cred) |
215 | { | |
216 | return cap_issubset(cred->cap_ambient, | |
217 | cap_intersect(cred->cap_permitted, | |
218 | cred->cap_inheritable)); | |
219 | } | |
220 | ||
d84f4f99 DH |
221 | /** |
222 | * get_new_cred - Get a reference on a new set of credentials | |
223 | * @cred: The new credentials to reference | |
224 | * | |
225 | * Get a reference on the specified set of new credentials. The caller must | |
226 | * release the reference. | |
227 | */ | |
228 | static inline struct cred *get_new_cred(struct cred *cred) | |
229 | { | |
230 | atomic_inc(&cred->usage); | |
231 | return cred; | |
232 | } | |
f1752eec DH |
233 | |
234 | /** | |
235 | * get_cred - Get a reference on a set of credentials | |
236 | * @cred: The credentials to reference | |
237 | * | |
238 | * Get a reference on the specified set of credentials. The caller must | |
239 | * release the reference. | |
98870ab0 DH |
240 | * |
241 | * This is used to deal with a committed set of credentials. Although the | |
242 | * pointer is const, this will temporarily discard the const and increment the | |
243 | * usage count. The purpose of this is to attempt to catch at compile time the | |
244 | * accidental alteration of a set of credentials that should be considered | |
245 | * immutable. | |
f1752eec | 246 | */ |
d84f4f99 | 247 | static inline const struct cred *get_cred(const struct cred *cred) |
f1752eec | 248 | { |
1c388ad0 | 249 | struct cred *nonconst_cred = (struct cred *) cred; |
e0e81739 | 250 | validate_creds(cred); |
1c388ad0 | 251 | return get_new_cred(nonconst_cred); |
f1752eec DH |
252 | } |
253 | ||
254 | /** | |
255 | * put_cred - Release a reference to a set of credentials | |
256 | * @cred: The credentials to release | |
257 | * | |
258 | * Release a reference to a set of credentials, deleting them when the last ref | |
259 | * is released. | |
98870ab0 DH |
260 | * |
261 | * This takes a const pointer to a set of credentials because the credentials | |
262 | * on task_struct are attached by const pointers to prevent accidental | |
263 | * alteration of otherwise immutable credential sets. | |
f1752eec | 264 | */ |
c69e8d9c | 265 | static inline void put_cred(const struct cred *_cred) |
f1752eec | 266 | { |
c69e8d9c | 267 | struct cred *cred = (struct cred *) _cred; |
d84f4f99 | 268 | |
e0e81739 | 269 | validate_creds(cred); |
f1752eec DH |
270 | if (atomic_dec_and_test(&(cred)->usage)) |
271 | __put_cred(cred); | |
272 | } | |
273 | ||
86a264ab | 274 | /** |
3b11a1de | 275 | * current_cred - Access the current task's subjective credentials |
86a264ab | 276 | * |
32955148 AV |
277 | * Access the subjective credentials of the current task. RCU-safe, |
278 | * since nobody else can modify it. | |
86a264ab DH |
279 | */ |
280 | #define current_cred() \ | |
27e4e436 | 281 | rcu_dereference_protected(current->cred, 1) |
86a264ab | 282 | |
ae4b884f JL |
283 | /** |
284 | * current_real_cred - Access the current task's objective credentials | |
285 | * | |
286 | * Access the objective credentials of the current task. RCU-safe, | |
287 | * since nobody else can modify it. | |
288 | */ | |
289 | #define current_real_cred() \ | |
290 | rcu_dereference_protected(current->real_cred, 1) | |
291 | ||
86a264ab | 292 | /** |
3b11a1de | 293 | * __task_cred - Access a task's objective credentials |
86a264ab DH |
294 | * @task: The task to query |
295 | * | |
3b11a1de | 296 | * Access the objective credentials of a task. The caller must hold the RCU |
43e13cc1 | 297 | * readlock. |
86a264ab | 298 | * |
8f92054e DH |
299 | * The result of this function should not be passed directly to get_cred(); |
300 | * rather get_task_cred() should be used instead. | |
86a264ab | 301 | */ |
43e13cc1 ON |
302 | #define __task_cred(task) \ |
303 | rcu_dereference((task)->real_cred) | |
86a264ab | 304 | |
86a264ab | 305 | /** |
3b11a1de | 306 | * get_current_cred - Get the current task's subjective credentials |
86a264ab | 307 | * |
3b11a1de DH |
308 | * Get the subjective credentials of the current task, pinning them so that |
309 | * they can't go away. Accessing the current task's credentials directly is | |
310 | * not permitted. | |
86a264ab DH |
311 | */ |
312 | #define get_current_cred() \ | |
313 | (get_cred(current_cred())) | |
314 | ||
315 | /** | |
316 | * get_current_user - Get the current task's user_struct | |
317 | * | |
318 | * Get the user record of the current task, pinning it so that it can't go | |
319 | * away. | |
320 | */ | |
321 | #define get_current_user() \ | |
322 | ({ \ | |
323 | struct user_struct *__u; \ | |
638a8439 | 324 | const struct cred *__cred; \ |
32955148 | 325 | __cred = current_cred(); \ |
86a264ab DH |
326 | __u = get_uid(__cred->user); \ |
327 | __u; \ | |
328 | }) | |
329 | ||
330 | /** | |
331 | * get_current_groups - Get the current task's supplementary group list | |
332 | * | |
333 | * Get the supplementary group list of the current task, pinning it so that it | |
334 | * can't go away. | |
335 | */ | |
336 | #define get_current_groups() \ | |
337 | ({ \ | |
338 | struct group_info *__groups; \ | |
638a8439 | 339 | const struct cred *__cred; \ |
32955148 | 340 | __cred = current_cred(); \ |
86a264ab DH |
341 | __groups = get_group_info(__cred->group_info); \ |
342 | __groups; \ | |
343 | }) | |
344 | ||
d84f4f99 DH |
345 | #define task_cred_xxx(task, xxx) \ |
346 | ({ \ | |
347 | __typeof__(((struct cred *)NULL)->xxx) ___val; \ | |
348 | rcu_read_lock(); \ | |
349 | ___val = __task_cred((task))->xxx; \ | |
350 | rcu_read_unlock(); \ | |
351 | ___val; \ | |
86a264ab DH |
352 | }) |
353 | ||
354 | #define task_uid(task) (task_cred_xxx((task), uid)) | |
355 | #define task_euid(task) (task_cred_xxx((task), euid)) | |
356 | ||
357 | #define current_cred_xxx(xxx) \ | |
358 | ({ \ | |
32955148 | 359 | current_cred()->xxx; \ |
86a264ab DH |
360 | }) |
361 | ||
362 | #define current_uid() (current_cred_xxx(uid)) | |
363 | #define current_gid() (current_cred_xxx(gid)) | |
364 | #define current_euid() (current_cred_xxx(euid)) | |
365 | #define current_egid() (current_cred_xxx(egid)) | |
366 | #define current_suid() (current_cred_xxx(suid)) | |
367 | #define current_sgid() (current_cred_xxx(sgid)) | |
368 | #define current_fsuid() (current_cred_xxx(fsuid)) | |
369 | #define current_fsgid() (current_cred_xxx(fsgid)) | |
370 | #define current_cap() (current_cred_xxx(cap_effective)) | |
371 | #define current_user() (current_cred_xxx(user)) | |
372 | #define current_security() (current_cred_xxx(security)) | |
373 | ||
7e6bd8fa | 374 | extern struct user_namespace init_user_ns; |
47a150ed | 375 | #ifdef CONFIG_USER_NS |
f1c84dae | 376 | #define current_user_ns() (current_cred_xxx(user_ns)) |
47a150ed | 377 | #else |
0335695d AB |
378 | static inline struct user_namespace *current_user_ns(void) |
379 | { | |
380 | return &init_user_ns; | |
381 | } | |
47a150ed SH |
382 | #endif |
383 | ||
3486740a | 384 | |
86a264ab DH |
385 | #define current_uid_gid(_uid, _gid) \ |
386 | do { \ | |
387 | const struct cred *__cred; \ | |
388 | __cred = current_cred(); \ | |
389 | *(_uid) = __cred->uid; \ | |
390 | *(_gid) = __cred->gid; \ | |
391 | } while(0) | |
392 | ||
393 | #define current_euid_egid(_euid, _egid) \ | |
394 | do { \ | |
395 | const struct cred *__cred; \ | |
396 | __cred = current_cred(); \ | |
397 | *(_euid) = __cred->euid; \ | |
398 | *(_egid) = __cred->egid; \ | |
399 | } while(0) | |
400 | ||
401 | #define current_fsuid_fsgid(_fsuid, _fsgid) \ | |
402 | do { \ | |
403 | const struct cred *__cred; \ | |
404 | __cred = current_cred(); \ | |
405 | *(_fsuid) = __cred->fsuid; \ | |
406 | *(_fsgid) = __cred->fsgid; \ | |
407 | } while(0) | |
408 | ||
9e2b2dc4 | 409 | #endif /* _LINUX_CRED_H */ |