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1 | /* Credentials management |
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 DH |
15 | #include <linux/capability.h> |
16 | #include <linux/key.h> | |
17 | #include <asm/atomic.h> | |
18 | ||
19 | struct user_struct; | |
20 | struct cred; | |
21 | ||
22 | /* | |
23 | * COW Supplementary groups list | |
24 | */ | |
25 | #define NGROUPS_SMALL 32 | |
26 | #define NGROUPS_PER_BLOCK ((unsigned int)(PAGE_SIZE / sizeof(gid_t))) | |
27 | ||
28 | struct group_info { | |
29 | atomic_t usage; | |
30 | int ngroups; | |
31 | int nblocks; | |
32 | gid_t small_block[NGROUPS_SMALL]; | |
33 | gid_t *blocks[0]; | |
34 | }; | |
35 | ||
36 | /** | |
37 | * get_group_info - Get a reference to a group info structure | |
38 | * @group_info: The group info to reference | |
39 | * | |
40 | * This must be called with the owning task locked (via task_lock()) when task | |
41 | * != current. The reason being that the vast majority of callers are looking | |
42 | * at current->group_info, which can not be changed except by the current task. | |
43 | * Changing current->group_info requires the task lock, too. | |
44 | */ | |
45 | #define get_group_info(group_info) \ | |
46 | do { \ | |
47 | atomic_inc(&(group_info)->usage); \ | |
48 | } while (0) | |
49 | ||
50 | /** | |
51 | * put_group_info - Release a reference to a group info structure | |
52 | * @group_info: The group info to release | |
53 | */ | |
54 | #define put_group_info(group_info) \ | |
55 | do { \ | |
56 | if (atomic_dec_and_test(&(group_info)->usage)) \ | |
57 | groups_free(group_info); \ | |
58 | } while (0) | |
59 | ||
60 | extern struct group_info *groups_alloc(int); | |
61 | extern void groups_free(struct group_info *); | |
62 | extern int set_current_groups(struct group_info *); | |
63 | extern int set_groups(struct cred *, struct group_info *); | |
64 | extern int groups_search(struct group_info *, gid_t); | |
65 | ||
66 | /* access the groups "array" with this macro */ | |
67 | #define GROUP_AT(gi, i) \ | |
68 | ((gi)->blocks[(i) / NGROUPS_PER_BLOCK][(i) % NGROUPS_PER_BLOCK]) | |
69 | ||
70 | extern int in_group_p(gid_t); | |
71 | extern int in_egroup_p(gid_t); | |
72 | ||
73 | /* | |
74 | * The security context of a task | |
75 | * | |
76 | * The parts of the context break down into two categories: | |
77 | * | |
78 | * (1) The objective context of a task. These parts are used when some other | |
79 | * task is attempting to affect this one. | |
80 | * | |
81 | * (2) The subjective context. These details are used when the task is acting | |
82 | * upon another object, be that a file, a task, a key or whatever. | |
83 | * | |
84 | * Note that some members of this structure belong to both categories - the | |
85 | * LSM security pointer for instance. | |
86 | * | |
87 | * A task has two security pointers. task->real_cred points to the objective | |
88 | * context that defines that task's actual details. The objective part of this | |
89 | * context is used whenever that task is acted upon. | |
90 | * | |
91 | * task->cred points to the subjective context that defines the details of how | |
92 | * that task is going to act upon another object. This may be overridden | |
93 | * temporarily to point to another security context, but normally points to the | |
94 | * same context as task->real_cred. | |
95 | */ | |
96 | struct cred { | |
97 | atomic_t usage; | |
98 | uid_t uid; /* real UID of the task */ | |
99 | gid_t gid; /* real GID of the task */ | |
100 | uid_t suid; /* saved UID of the task */ | |
101 | gid_t sgid; /* saved GID of the task */ | |
102 | uid_t euid; /* effective UID of the task */ | |
103 | gid_t egid; /* effective GID of the task */ | |
104 | uid_t fsuid; /* UID for VFS ops */ | |
105 | gid_t fsgid; /* GID for VFS ops */ | |
106 | unsigned securebits; /* SUID-less security management */ | |
107 | kernel_cap_t cap_inheritable; /* caps our children can inherit */ | |
108 | kernel_cap_t cap_permitted; /* caps we're permitted */ | |
109 | kernel_cap_t cap_effective; /* caps we can actually use */ | |
110 | kernel_cap_t cap_bset; /* capability bounding set */ | |
111 | #ifdef CONFIG_KEYS | |
112 | unsigned char jit_keyring; /* default keyring to attach requested | |
113 | * keys to */ | |
114 | struct key *thread_keyring; /* keyring private to this thread */ | |
115 | struct key *request_key_auth; /* assumed request_key authority */ | |
116 | #endif | |
117 | #ifdef CONFIG_SECURITY | |
118 | void *security; /* subjective LSM security */ | |
119 | #endif | |
120 | struct user_struct *user; /* real user ID subscription */ | |
121 | struct group_info *group_info; /* supplementary groups for euid/fsgid */ | |
122 | struct rcu_head rcu; /* RCU deletion hook */ | |
123 | spinlock_t lock; /* lock for pointer changes */ | |
124 | }; | |
125 | ||
126 | #define get_current_user() (get_uid(current->cred->user)) | |
127 | ||
128 | #define task_uid(task) ((task)->cred->uid) | |
129 | #define task_gid(task) ((task)->cred->gid) | |
130 | #define task_euid(task) ((task)->cred->euid) | |
131 | #define task_egid(task) ((task)->cred->egid) | |
132 | ||
133 | #define current_uid() (current->cred->uid) | |
134 | #define current_gid() (current->cred->gid) | |
135 | #define current_euid() (current->cred->euid) | |
136 | #define current_egid() (current->cred->egid) | |
137 | #define current_suid() (current->cred->suid) | |
138 | #define current_sgid() (current->cred->sgid) | |
139 | #define current_fsuid() (current->cred->fsuid) | |
140 | #define current_fsgid() (current->cred->fsgid) | |
141 | #define current_cap() (current->cred->cap_effective) | |
9e2b2dc4 DH |
142 | |
143 | #define current_uid_gid(_uid, _gid) \ | |
144 | do { \ | |
b6dff3ec DH |
145 | *(_uid) = current->cred->uid; \ |
146 | *(_gid) = current->cred->gid; \ | |
9e2b2dc4 DH |
147 | } while(0) |
148 | ||
149 | #define current_euid_egid(_uid, _gid) \ | |
150 | do { \ | |
b6dff3ec DH |
151 | *(_uid) = current->cred->euid; \ |
152 | *(_gid) = current->cred->egid; \ | |
9e2b2dc4 DH |
153 | } while(0) |
154 | ||
155 | #define current_fsuid_fsgid(_uid, _gid) \ | |
156 | do { \ | |
b6dff3ec DH |
157 | *(_uid) = current->cred->fsuid; \ |
158 | *(_gid) = current->cred->fsgid; \ | |
9e2b2dc4 DH |
159 | } while(0) |
160 | ||
161 | #endif /* _LINUX_CRED_H */ |