Merge branch 'master' of /pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / include / linux / cred.h
blob4aaeab3764469961f1106d988e57e58a91e1a16e
1 /* Credentials management - see Documentation/credentials.txt
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #ifndef _LINUX_CRED_H
13 #define _LINUX_CRED_H
15 #include <linux/capability.h>
16 #include <linux/init.h>
17 #include <linux/key.h>
18 #include <linux/selinux.h>
19 #include <asm/atomic.h>
21 struct user_struct;
22 struct cred;
23 struct inode;
26 * COW Supplementary groups list
28 #define NGROUPS_SMALL 32
29 #define NGROUPS_PER_BLOCK ((unsigned int)(PAGE_SIZE / sizeof(gid_t)))
31 struct group_info {
32 atomic_t usage;
33 int ngroups;
34 int nblocks;
35 gid_t small_block[NGROUPS_SMALL];
36 gid_t *blocks[0];
39 /**
40 * get_group_info - Get a reference to a group info structure
41 * @group_info: The group info to reference
43 * This gets a reference to a set of supplementary groups.
45 * If the caller is accessing a task's credentials, they must hold the RCU read
46 * lock when reading.
48 static inline struct group_info *get_group_info(struct group_info *gi)
50 atomic_inc(&gi->usage);
51 return gi;
54 /**
55 * put_group_info - Release a reference to a group info structure
56 * @group_info: The group info to release
58 #define put_group_info(group_info) \
59 do { \
60 if (atomic_dec_and_test(&(group_info)->usage)) \
61 groups_free(group_info); \
62 } while (0)
64 extern struct group_info *groups_alloc(int);
65 extern struct group_info init_groups;
66 extern void groups_free(struct group_info *);
67 extern int set_current_groups(struct group_info *);
68 extern int set_groups(struct cred *, struct group_info *);
69 extern int groups_search(const struct group_info *, gid_t);
71 /* access the groups "array" with this macro */
72 #define GROUP_AT(gi, i) \
73 ((gi)->blocks[(i) / NGROUPS_PER_BLOCK][(i) % NGROUPS_PER_BLOCK])
75 extern int in_group_p(gid_t);
76 extern int in_egroup_p(gid_t);
79 * The common credentials for a thread group
80 * - shared by CLONE_THREAD
82 #ifdef CONFIG_KEYS
83 struct thread_group_cred {
84 atomic_t usage;
85 pid_t tgid; /* thread group process ID */
86 spinlock_t lock;
87 struct key __rcu *session_keyring; /* keyring inherited over fork */
88 struct key *process_keyring; /* keyring private to this process */
89 struct rcu_head rcu; /* RCU deletion hook */
91 #endif
94 * The security context of a task
96 * The parts of the context break down into two categories:
98 * (1) The objective context of a task. These parts are used when some other
99 * task is attempting to affect this one.
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.
104 * Note that some members of this structure belong to both categories - the
105 * LSM security pointer for instance.
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.
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.
116 struct cred {
117 atomic_t usage;
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
125 uid_t uid; /* real UID of the task */
126 gid_t gid; /* real GID of the task */
127 uid_t suid; /* saved UID of the task */
128 gid_t sgid; /* saved GID of the task */
129 uid_t euid; /* effective UID of the task */
130 gid_t egid; /* effective GID of the task */
131 uid_t fsuid; /* UID for VFS ops */
132 gid_t fsgid; /* GID for VFS ops */
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 */
138 #ifdef CONFIG_KEYS
139 unsigned char jit_keyring; /* default keyring to attach requested
140 * keys to */
141 struct key *thread_keyring; /* keyring private to this thread */
142 struct key *request_key_auth; /* assumed request_key authority */
143 struct thread_group_cred *tgcred; /* thread-group shared credentials */
144 #endif
145 #ifdef CONFIG_SECURITY
146 void *security; /* subjective LSM security */
147 #endif
148 struct user_struct *user; /* real user ID subscription */
149 struct group_info *group_info; /* supplementary groups for euid/fsgid */
150 struct rcu_head rcu; /* RCU deletion hook */
153 extern void __put_cred(struct cred *);
154 extern void exit_creds(struct task_struct *);
155 extern int copy_creds(struct task_struct *, unsigned long);
156 extern const struct cred *get_task_cred(struct task_struct *);
157 extern struct cred *cred_alloc_blank(void);
158 extern struct cred *prepare_creds(void);
159 extern struct cred *prepare_exec_creds(void);
160 extern int commit_creds(struct cred *);
161 extern void abort_creds(struct cred *);
162 extern const struct cred *override_creds(const struct cred *);
163 extern void revert_creds(const struct cred *);
164 extern struct cred *prepare_kernel_cred(struct task_struct *);
165 extern int change_create_files_as(struct cred *, struct inode *);
166 extern int set_security_override(struct cred *, u32);
167 extern int set_security_override_from_ctx(struct cred *, const char *);
168 extern int set_create_files_as(struct cred *, struct inode *);
169 extern void __init cred_init(void);
172 * check for validity of credentials
174 #ifdef CONFIG_DEBUG_CREDENTIALS
175 extern void __invalid_creds(const struct cred *, const char *, unsigned);
176 extern void __validate_process_creds(struct task_struct *,
177 const char *, unsigned);
179 extern bool creds_are_invalid(const struct cred *cred);
181 static inline void __validate_creds(const struct cred *cred,
182 const char *file, unsigned line)
184 if (unlikely(creds_are_invalid(cred)))
185 __invalid_creds(cred, file, line);
188 #define validate_creds(cred) \
189 do { \
190 __validate_creds((cred), __FILE__, __LINE__); \
191 } while(0)
193 #define validate_process_creds() \
194 do { \
195 __validate_process_creds(current, __FILE__, __LINE__); \
196 } while(0)
198 extern void validate_creds_for_do_exit(struct task_struct *);
199 #else
200 static inline void validate_creds(const struct cred *cred)
203 static inline void validate_creds_for_do_exit(struct task_struct *tsk)
206 static inline void validate_process_creds(void)
209 #endif
212 * get_new_cred - Get a reference on a new set of credentials
213 * @cred: The new credentials to reference
215 * Get a reference on the specified set of new credentials. The caller must
216 * release the reference.
218 static inline struct cred *get_new_cred(struct cred *cred)
220 atomic_inc(&cred->usage);
221 return cred;
225 * get_cred - Get a reference on a set of credentials
226 * @cred: The credentials to reference
228 * Get a reference on the specified set of credentials. The caller must
229 * release the reference.
231 * This is used to deal with a committed set of credentials. Although the
232 * pointer is const, this will temporarily discard the const and increment the
233 * usage count. The purpose of this is to attempt to catch at compile time the
234 * accidental alteration of a set of credentials that should be considered
235 * immutable.
237 static inline const struct cred *get_cred(const struct cred *cred)
239 struct cred *nonconst_cred = (struct cred *) cred;
240 validate_creds(cred);
241 return get_new_cred(nonconst_cred);
245 * put_cred - Release a reference to a set of credentials
246 * @cred: The credentials to release
248 * Release a reference to a set of credentials, deleting them when the last ref
249 * is released.
251 * This takes a const pointer to a set of credentials because the credentials
252 * on task_struct are attached by const pointers to prevent accidental
253 * alteration of otherwise immutable credential sets.
255 static inline void put_cred(const struct cred *_cred)
257 struct cred *cred = (struct cred *) _cred;
259 validate_creds(cred);
260 if (atomic_dec_and_test(&(cred)->usage))
261 __put_cred(cred);
265 * current_cred - Access the current task's subjective credentials
267 * Access the subjective credentials of the current task.
269 #define current_cred() \
270 (current->cred)
273 * __task_cred - Access a task's objective credentials
274 * @task: The task to query
276 * Access the objective credentials of a task. The caller must hold the RCU
277 * readlock or the task must be dead and unable to change its own credentials.
279 * The result of this function should not be passed directly to get_cred();
280 * rather get_task_cred() should be used instead.
282 #define __task_cred(task) \
283 ({ \
284 const struct task_struct *__t = (task); \
285 rcu_dereference_check(__t->real_cred, \
286 rcu_read_lock_held() || \
287 task_is_dead(__t)); \
291 * get_current_cred - Get the current task's subjective credentials
293 * Get the subjective credentials of the current task, pinning them so that
294 * they can't go away. Accessing the current task's credentials directly is
295 * not permitted.
297 #define get_current_cred() \
298 (get_cred(current_cred()))
301 * get_current_user - Get the current task's user_struct
303 * Get the user record of the current task, pinning it so that it can't go
304 * away.
306 #define get_current_user() \
307 ({ \
308 struct user_struct *__u; \
309 struct cred *__cred; \
310 __cred = (struct cred *) current_cred(); \
311 __u = get_uid(__cred->user); \
312 __u; \
316 * get_current_groups - Get the current task's supplementary group list
318 * Get the supplementary group list of the current task, pinning it so that it
319 * can't go away.
321 #define get_current_groups() \
322 ({ \
323 struct group_info *__groups; \
324 struct cred *__cred; \
325 __cred = (struct cred *) current_cred(); \
326 __groups = get_group_info(__cred->group_info); \
327 __groups; \
330 #define task_cred_xxx(task, xxx) \
331 ({ \
332 __typeof__(((struct cred *)NULL)->xxx) ___val; \
333 rcu_read_lock(); \
334 ___val = __task_cred((task))->xxx; \
335 rcu_read_unlock(); \
336 ___val; \
339 #define task_uid(task) (task_cred_xxx((task), uid))
340 #define task_euid(task) (task_cred_xxx((task), euid))
342 #define current_cred_xxx(xxx) \
343 ({ \
344 current->cred->xxx; \
347 #define current_uid() (current_cred_xxx(uid))
348 #define current_gid() (current_cred_xxx(gid))
349 #define current_euid() (current_cred_xxx(euid))
350 #define current_egid() (current_cred_xxx(egid))
351 #define current_suid() (current_cred_xxx(suid))
352 #define current_sgid() (current_cred_xxx(sgid))
353 #define current_fsuid() (current_cred_xxx(fsuid))
354 #define current_fsgid() (current_cred_xxx(fsgid))
355 #define current_cap() (current_cred_xxx(cap_effective))
356 #define current_user() (current_cred_xxx(user))
357 #define current_user_ns() (current_cred_xxx(user)->user_ns)
358 #define current_security() (current_cred_xxx(security))
360 #define current_uid_gid(_uid, _gid) \
361 do { \
362 const struct cred *__cred; \
363 __cred = current_cred(); \
364 *(_uid) = __cred->uid; \
365 *(_gid) = __cred->gid; \
366 } while(0)
368 #define current_euid_egid(_euid, _egid) \
369 do { \
370 const struct cred *__cred; \
371 __cred = current_cred(); \
372 *(_euid) = __cred->euid; \
373 *(_egid) = __cred->egid; \
374 } while(0)
376 #define current_fsuid_fsgid(_fsuid, _fsgid) \
377 do { \
378 const struct cred *__cred; \
379 __cred = current_cred(); \
380 *(_fsuid) = __cred->fsuid; \
381 *(_fsgid) = __cred->fsgid; \
382 } while(0)
384 #endif /* _LINUX_CRED_H */