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d410fa4e | 1 | /* Credentials management - see Documentation/security/credentials.txt |
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> |
b6dff3ec DH |
21 | |
22 | struct user_struct; | |
23 | struct cred; | |
3a3b7ce9 | 24 | struct inode; |
b6dff3ec DH |
25 | |
26 | /* | |
27 | * COW Supplementary groups list | |
28 | */ | |
29 | #define NGROUPS_SMALL 32 | |
ae2975bc | 30 | #define NGROUPS_PER_BLOCK ((unsigned int)(PAGE_SIZE / sizeof(kgid_t))) |
b6dff3ec DH |
31 | |
32 | struct group_info { | |
33 | atomic_t usage; | |
34 | int ngroups; | |
35 | int nblocks; | |
ae2975bc EB |
36 | kgid_t small_block[NGROUPS_SMALL]; |
37 | kgid_t *blocks[0]; | |
b6dff3ec DH |
38 | }; |
39 | ||
40 | /** | |
41 | * get_group_info - Get a reference to a group info structure | |
42 | * @group_info: The group info to reference | |
43 | * | |
86a264ab DH |
44 | * This gets a reference to a set of supplementary groups. |
45 | * | |
46 | * If the caller is accessing a task's credentials, they must hold the RCU read | |
47 | * lock when reading. | |
b6dff3ec | 48 | */ |
86a264ab DH |
49 | static inline struct group_info *get_group_info(struct group_info *gi) |
50 | { | |
51 | atomic_inc(&gi->usage); | |
52 | return gi; | |
53 | } | |
b6dff3ec DH |
54 | |
55 | /** | |
56 | * put_group_info - Release a reference to a group info structure | |
57 | * @group_info: The group info to release | |
58 | */ | |
59 | #define put_group_info(group_info) \ | |
60 | do { \ | |
61 | if (atomic_dec_and_test(&(group_info)->usage)) \ | |
62 | groups_free(group_info); \ | |
63 | } while (0) | |
64 | ||
18b6e041 | 65 | extern struct group_info init_groups; |
2813893f IM |
66 | #ifdef CONFIG_MULTIUSER |
67 | extern struct group_info *groups_alloc(int); | |
b6dff3ec | 68 | extern void groups_free(struct group_info *); |
2813893f IM |
69 | |
70 | extern int in_group_p(kgid_t); | |
71 | extern int in_egroup_p(kgid_t); | |
72 | #else | |
73 | static inline void groups_free(struct group_info *group_info) | |
74 | { | |
75 | } | |
76 | ||
77 | static inline int in_group_p(kgid_t grp) | |
78 | { | |
79 | return 1; | |
80 | } | |
81 | static inline int in_egroup_p(kgid_t grp) | |
82 | { | |
83 | return 1; | |
84 | } | |
85 | #endif | |
b6dff3ec | 86 | extern int set_current_groups(struct group_info *); |
8f6c5ffc | 87 | extern void set_groups(struct cred *, struct group_info *); |
ae2975bc | 88 | extern int groups_search(const struct group_info *, kgid_t); |
7ff4d90b | 89 | extern bool may_setgroups(void); |
b6dff3ec DH |
90 | |
91 | /* access the groups "array" with this macro */ | |
92 | #define GROUP_AT(gi, i) \ | |
93 | ((gi)->blocks[(i) / NGROUPS_PER_BLOCK][(i) % NGROUPS_PER_BLOCK]) | |
94 | ||
b6dff3ec DH |
95 | /* |
96 | * The security context of a task | |
97 | * | |
98 | * The parts of the context break down into two categories: | |
99 | * | |
100 | * (1) The objective context of a task. These parts are used when some other | |
101 | * task is attempting to affect this one. | |
102 | * | |
103 | * (2) The subjective context. These details are used when the task is acting | |
104 | * upon another object, be that a file, a task, a key or whatever. | |
105 | * | |
106 | * Note that some members of this structure belong to both categories - the | |
107 | * LSM security pointer for instance. | |
108 | * | |
109 | * A task has two security pointers. task->real_cred points to the objective | |
110 | * context that defines that task's actual details. The objective part of this | |
111 | * context is used whenever that task is acted upon. | |
112 | * | |
113 | * task->cred points to the subjective context that defines the details of how | |
114 | * that task is going to act upon another object. This may be overridden | |
115 | * temporarily to point to another security context, but normally points to the | |
116 | * same context as task->real_cred. | |
117 | */ | |
118 | struct cred { | |
119 | atomic_t usage; | |
e0e81739 DH |
120 | #ifdef CONFIG_DEBUG_CREDENTIALS |
121 | atomic_t subscribers; /* number of processes subscribed */ | |
122 | void *put_addr; | |
123 | unsigned magic; | |
124 | #define CRED_MAGIC 0x43736564 | |
125 | #define CRED_MAGIC_DEAD 0x44656144 | |
126 | #endif | |
078de5f7 EB |
127 | kuid_t uid; /* real UID of the task */ |
128 | kgid_t gid; /* real GID of the task */ | |
129 | kuid_t suid; /* saved UID of the task */ | |
130 | kgid_t sgid; /* saved GID of the task */ | |
131 | kuid_t euid; /* effective UID of the task */ | |
132 | kgid_t egid; /* effective GID of the task */ | |
133 | kuid_t fsuid; /* UID for VFS ops */ | |
134 | kgid_t fsgid; /* GID for VFS ops */ | |
b6dff3ec DH |
135 | unsigned securebits; /* SUID-less security management */ |
136 | kernel_cap_t cap_inheritable; /* caps our children can inherit */ | |
137 | kernel_cap_t cap_permitted; /* caps we're permitted */ | |
138 | kernel_cap_t cap_effective; /* caps we can actually use */ | |
139 | kernel_cap_t cap_bset; /* capability bounding set */ | |
140 | #ifdef CONFIG_KEYS | |
141 | unsigned char jit_keyring; /* default keyring to attach requested | |
142 | * keys to */ | |
3a50597d DH |
143 | struct key __rcu *session_keyring; /* keyring inherited over fork */ |
144 | struct key *process_keyring; /* keyring private to this process */ | |
b6dff3ec DH |
145 | struct key *thread_keyring; /* keyring private to this thread */ |
146 | struct key *request_key_auth; /* assumed request_key authority */ | |
147 | #endif | |
148 | #ifdef CONFIG_SECURITY | |
149 | void *security; /* subjective LSM security */ | |
150 | #endif | |
151 | struct user_struct *user; /* real user ID subscription */ | |
0093ccb6 | 152 | struct user_namespace *user_ns; /* user_ns the caps and keyrings are relative to. */ |
b6dff3ec DH |
153 | struct group_info *group_info; /* supplementary groups for euid/fsgid */ |
154 | struct rcu_head rcu; /* RCU deletion hook */ | |
b6dff3ec DH |
155 | }; |
156 | ||
f1752eec | 157 | extern void __put_cred(struct cred *); |
e0e81739 | 158 | extern void exit_creds(struct task_struct *); |
f1752eec | 159 | extern int copy_creds(struct task_struct *, unsigned long); |
de09a977 | 160 | extern const struct cred *get_task_cred(struct task_struct *); |
ee18d64c | 161 | extern struct cred *cred_alloc_blank(void); |
d84f4f99 | 162 | extern struct cred *prepare_creds(void); |
a6f76f23 | 163 | extern struct cred *prepare_exec_creds(void); |
d84f4f99 DH |
164 | extern int commit_creds(struct cred *); |
165 | extern void abort_creds(struct cred *); | |
3b11a1de DH |
166 | extern const struct cred *override_creds(const struct cred *); |
167 | extern void revert_creds(const struct cred *); | |
3a3b7ce9 DH |
168 | extern struct cred *prepare_kernel_cred(struct task_struct *); |
169 | extern int change_create_files_as(struct cred *, struct inode *); | |
170 | extern int set_security_override(struct cred *, u32); | |
171 | extern int set_security_override_from_ctx(struct cred *, const char *); | |
172 | extern int set_create_files_as(struct cred *, struct inode *); | |
d84f4f99 DH |
173 | extern void __init cred_init(void); |
174 | ||
e0e81739 DH |
175 | /* |
176 | * check for validity of credentials | |
177 | */ | |
178 | #ifdef CONFIG_DEBUG_CREDENTIALS | |
179 | extern void __invalid_creds(const struct cred *, const char *, unsigned); | |
180 | extern void __validate_process_creds(struct task_struct *, | |
181 | const char *, unsigned); | |
182 | ||
74908a00 | 183 | extern bool creds_are_invalid(const struct cred *cred); |
e0e81739 DH |
184 | |
185 | static inline void __validate_creds(const struct cred *cred, | |
186 | const char *file, unsigned line) | |
187 | { | |
188 | if (unlikely(creds_are_invalid(cred))) | |
189 | __invalid_creds(cred, file, line); | |
190 | } | |
191 | ||
192 | #define validate_creds(cred) \ | |
193 | do { \ | |
194 | __validate_creds((cred), __FILE__, __LINE__); \ | |
195 | } while(0) | |
196 | ||
197 | #define validate_process_creds() \ | |
198 | do { \ | |
199 | __validate_process_creds(current, __FILE__, __LINE__); \ | |
200 | } while(0) | |
201 | ||
202 | extern void validate_creds_for_do_exit(struct task_struct *); | |
203 | #else | |
204 | static inline void validate_creds(const struct cred *cred) | |
205 | { | |
206 | } | |
207 | static inline void validate_creds_for_do_exit(struct task_struct *tsk) | |
208 | { | |
209 | } | |
210 | static inline void validate_process_creds(void) | |
211 | { | |
212 | } | |
213 | #endif | |
214 | ||
d84f4f99 DH |
215 | /** |
216 | * get_new_cred - Get a reference on a new set of credentials | |
217 | * @cred: The new credentials to reference | |
218 | * | |
219 | * Get a reference on the specified set of new credentials. The caller must | |
220 | * release the reference. | |
221 | */ | |
222 | static inline struct cred *get_new_cred(struct cred *cred) | |
223 | { | |
224 | atomic_inc(&cred->usage); | |
225 | return cred; | |
226 | } | |
f1752eec DH |
227 | |
228 | /** | |
229 | * get_cred - Get a reference on a set of credentials | |
230 | * @cred: The credentials to reference | |
231 | * | |
232 | * Get a reference on the specified set of credentials. The caller must | |
233 | * release the reference. | |
98870ab0 DH |
234 | * |
235 | * This is used to deal with a committed set of credentials. Although the | |
236 | * pointer is const, this will temporarily discard the const and increment the | |
237 | * usage count. The purpose of this is to attempt to catch at compile time the | |
238 | * accidental alteration of a set of credentials that should be considered | |
239 | * immutable. | |
f1752eec | 240 | */ |
d84f4f99 | 241 | static inline const struct cred *get_cred(const struct cred *cred) |
f1752eec | 242 | { |
1c388ad0 | 243 | struct cred *nonconst_cred = (struct cred *) cred; |
e0e81739 | 244 | validate_creds(cred); |
1c388ad0 | 245 | return get_new_cred(nonconst_cred); |
f1752eec DH |
246 | } |
247 | ||
248 | /** | |
249 | * put_cred - Release a reference to a set of credentials | |
250 | * @cred: The credentials to release | |
251 | * | |
252 | * Release a reference to a set of credentials, deleting them when the last ref | |
253 | * is released. | |
98870ab0 DH |
254 | * |
255 | * This takes a const pointer to a set of credentials because the credentials | |
256 | * on task_struct are attached by const pointers to prevent accidental | |
257 | * alteration of otherwise immutable credential sets. | |
f1752eec | 258 | */ |
c69e8d9c | 259 | static inline void put_cred(const struct cred *_cred) |
f1752eec | 260 | { |
c69e8d9c | 261 | struct cred *cred = (struct cred *) _cred; |
d84f4f99 | 262 | |
e0e81739 | 263 | validate_creds(cred); |
f1752eec DH |
264 | if (atomic_dec_and_test(&(cred)->usage)) |
265 | __put_cred(cred); | |
266 | } | |
267 | ||
86a264ab | 268 | /** |
3b11a1de | 269 | * current_cred - Access the current task's subjective credentials |
86a264ab | 270 | * |
32955148 AV |
271 | * Access the subjective credentials of the current task. RCU-safe, |
272 | * since nobody else can modify it. | |
86a264ab DH |
273 | */ |
274 | #define current_cred() \ | |
27e4e436 | 275 | rcu_dereference_protected(current->cred, 1) |
86a264ab | 276 | |
ae4b884f JL |
277 | /** |
278 | * current_real_cred - Access the current task's objective credentials | |
279 | * | |
280 | * Access the objective credentials of the current task. RCU-safe, | |
281 | * since nobody else can modify it. | |
282 | */ | |
283 | #define current_real_cred() \ | |
284 | rcu_dereference_protected(current->real_cred, 1) | |
285 | ||
86a264ab | 286 | /** |
3b11a1de | 287 | * __task_cred - Access a task's objective credentials |
86a264ab DH |
288 | * @task: The task to query |
289 | * | |
3b11a1de | 290 | * Access the objective credentials of a task. The caller must hold the RCU |
43e13cc1 | 291 | * readlock. |
86a264ab | 292 | * |
8f92054e DH |
293 | * The result of this function should not be passed directly to get_cred(); |
294 | * rather get_task_cred() should be used instead. | |
86a264ab | 295 | */ |
43e13cc1 ON |
296 | #define __task_cred(task) \ |
297 | rcu_dereference((task)->real_cred) | |
86a264ab | 298 | |
86a264ab | 299 | /** |
3b11a1de | 300 | * get_current_cred - Get the current task's subjective credentials |
86a264ab | 301 | * |
3b11a1de DH |
302 | * Get the subjective credentials of the current task, pinning them so that |
303 | * they can't go away. Accessing the current task's credentials directly is | |
304 | * not permitted. | |
86a264ab DH |
305 | */ |
306 | #define get_current_cred() \ | |
307 | (get_cred(current_cred())) | |
308 | ||
309 | /** | |
310 | * get_current_user - Get the current task's user_struct | |
311 | * | |
312 | * Get the user record of the current task, pinning it so that it can't go | |
313 | * away. | |
314 | */ | |
315 | #define get_current_user() \ | |
316 | ({ \ | |
317 | struct user_struct *__u; \ | |
638a8439 | 318 | const struct cred *__cred; \ |
32955148 | 319 | __cred = current_cred(); \ |
86a264ab DH |
320 | __u = get_uid(__cred->user); \ |
321 | __u; \ | |
322 | }) | |
323 | ||
324 | /** | |
325 | * get_current_groups - Get the current task's supplementary group list | |
326 | * | |
327 | * Get the supplementary group list of the current task, pinning it so that it | |
328 | * can't go away. | |
329 | */ | |
330 | #define get_current_groups() \ | |
331 | ({ \ | |
332 | struct group_info *__groups; \ | |
638a8439 | 333 | const struct cred *__cred; \ |
32955148 | 334 | __cred = current_cred(); \ |
86a264ab DH |
335 | __groups = get_group_info(__cred->group_info); \ |
336 | __groups; \ | |
337 | }) | |
338 | ||
d84f4f99 DH |
339 | #define task_cred_xxx(task, xxx) \ |
340 | ({ \ | |
341 | __typeof__(((struct cred *)NULL)->xxx) ___val; \ | |
342 | rcu_read_lock(); \ | |
343 | ___val = __task_cred((task))->xxx; \ | |
344 | rcu_read_unlock(); \ | |
345 | ___val; \ | |
86a264ab DH |
346 | }) |
347 | ||
348 | #define task_uid(task) (task_cred_xxx((task), uid)) | |
349 | #define task_euid(task) (task_cred_xxx((task), euid)) | |
350 | ||
351 | #define current_cred_xxx(xxx) \ | |
352 | ({ \ | |
32955148 | 353 | current_cred()->xxx; \ |
86a264ab DH |
354 | }) |
355 | ||
356 | #define current_uid() (current_cred_xxx(uid)) | |
357 | #define current_gid() (current_cred_xxx(gid)) | |
358 | #define current_euid() (current_cred_xxx(euid)) | |
359 | #define current_egid() (current_cred_xxx(egid)) | |
360 | #define current_suid() (current_cred_xxx(suid)) | |
361 | #define current_sgid() (current_cred_xxx(sgid)) | |
362 | #define current_fsuid() (current_cred_xxx(fsuid)) | |
363 | #define current_fsgid() (current_cred_xxx(fsgid)) | |
364 | #define current_cap() (current_cred_xxx(cap_effective)) | |
365 | #define current_user() (current_cred_xxx(user)) | |
366 | #define current_security() (current_cred_xxx(security)) | |
367 | ||
7e6bd8fa | 368 | extern struct user_namespace init_user_ns; |
47a150ed | 369 | #ifdef CONFIG_USER_NS |
f1c84dae | 370 | #define current_user_ns() (current_cred_xxx(user_ns)) |
47a150ed | 371 | #else |
f1c84dae | 372 | #define current_user_ns() (&init_user_ns) |
47a150ed SH |
373 | #endif |
374 | ||
3486740a | 375 | |
86a264ab DH |
376 | #define current_uid_gid(_uid, _gid) \ |
377 | do { \ | |
378 | const struct cred *__cred; \ | |
379 | __cred = current_cred(); \ | |
380 | *(_uid) = __cred->uid; \ | |
381 | *(_gid) = __cred->gid; \ | |
382 | } while(0) | |
383 | ||
384 | #define current_euid_egid(_euid, _egid) \ | |
385 | do { \ | |
386 | const struct cred *__cred; \ | |
387 | __cred = current_cred(); \ | |
388 | *(_euid) = __cred->euid; \ | |
389 | *(_egid) = __cred->egid; \ | |
390 | } while(0) | |
391 | ||
392 | #define current_fsuid_fsgid(_fsuid, _fsgid) \ | |
393 | do { \ | |
394 | const struct cred *__cred; \ | |
395 | __cred = current_cred(); \ | |
396 | *(_fsuid) = __cred->fsuid; \ | |
397 | *(_fsgid) = __cred->fsgid; \ | |
398 | } while(0) | |
399 | ||
9e2b2dc4 | 400 | #endif /* _LINUX_CRED_H */ |