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c75afcd1 JJ |
1 | /* |
2 | * AppArmor security module | |
3 | * | |
4 | * This file contains AppArmor contexts used to associate "labels" to objects. | |
5 | * | |
6 | * Copyright (C) 1998-2008 Novell/SUSE | |
7 | * Copyright 2009-2010 Canonical Ltd. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public License as | |
11 | * published by the Free Software Foundation, version 2 of the | |
12 | * License. | |
13 | */ | |
14 | ||
15 | #ifndef __AA_CONTEXT_H | |
16 | #define __AA_CONTEXT_H | |
17 | ||
18 | #include <linux/cred.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/sched.h> | |
98738d70 | 21 | #include <linux/lsm_hooks.h> |
c75afcd1 | 22 | |
637f688d | 23 | #include "label.h" |
2bd8dbbf | 24 | #include "policy_ns.h" |
c75afcd1 | 25 | |
98738d70 | 26 | #define cred_ctx(X) apparmor_cred(X) |
55a26ebf | 27 | #define current_ctx() cred_ctx(current_cred()) |
214beaca | 28 | |
c75afcd1 | 29 | /** |
55a26ebf | 30 | * struct aa_task_ctx - primary label for confined tasks |
637f688d JJ |
31 | * @label: the current label (NOT NULL) |
32 | * @exec: label to transition to on next exec (MAYBE NULL) | |
33 | * @previous: label the task may return to (MAYBE NULL) | |
34 | * @token: magic value the task must know for returning to @previous | |
c75afcd1 | 35 | * |
637f688d | 36 | * Contains the task's current label (which could change due to |
c75afcd1 JJ |
37 | * change_hat). Plus the hat_magic needed during change_hat. |
38 | * | |
39 | * TODO: make so a task can be confined by a stack of contexts | |
40 | */ | |
55a26ebf | 41 | struct aa_task_ctx { |
637f688d JJ |
42 | struct aa_label *label; |
43 | struct aa_label *onexec; | |
44 | struct aa_label *previous; | |
c75afcd1 JJ |
45 | u64 token; |
46 | }; | |
47 | ||
55a26ebf JJ |
48 | struct aa_task_ctx *aa_alloc_task_context(gfp_t flags); |
49 | void aa_free_task_context(struct aa_task_ctx *ctx); | |
50 | void aa_dup_task_context(struct aa_task_ctx *new, | |
51 | const struct aa_task_ctx *old); | |
637f688d JJ |
52 | int aa_replace_current_label(struct aa_label *label); |
53 | int aa_set_current_onexec(struct aa_label *label, bool stack); | |
54 | int aa_set_current_hat(struct aa_label *label, u64 token); | |
55 | int aa_restore_previous_label(u64 cookie); | |
56 | struct aa_label *aa_get_task_label(struct task_struct *task); | |
c75afcd1 | 57 | |
98738d70 CS |
58 | static inline struct aa_task_ctx *apparmor_cred(const struct cred *cred) |
59 | { | |
60 | return cred->security; | |
61 | } | |
c75afcd1 JJ |
62 | |
63 | /** | |
637f688d JJ |
64 | * aa_cred_raw_label - obtain cred's label |
65 | * @cred: cred to obtain label from (NOT NULL) | |
c75afcd1 | 66 | * |
637f688d | 67 | * Returns: confining label |
c75afcd1 JJ |
68 | * |
69 | * does NOT increment reference count | |
70 | */ | |
637f688d | 71 | static inline struct aa_label *aa_cred_raw_label(const struct cred *cred) |
c75afcd1 | 72 | { |
98738d70 | 73 | struct aa_task_ctx *ctx = apparmor_cred(cred); |
55a26ebf | 74 | |
637f688d JJ |
75 | AA_BUG(!ctx || !ctx->label); |
76 | return ctx->label; | |
c75afcd1 JJ |
77 | } |
78 | ||
3cfcc19e | 79 | /** |
637f688d JJ |
80 | * aa_get_newest_cred_label - obtain the newest label on a cred |
81 | * @cred: cred to obtain label from (NOT NULL) | |
cf797c0e | 82 | * |
637f688d | 83 | * Returns: newest version of confining label |
cf797c0e | 84 | */ |
637f688d | 85 | static inline struct aa_label *aa_get_newest_cred_label(const struct cred *cred) |
cf797c0e | 86 | { |
637f688d | 87 | return aa_get_newest_label(aa_cred_raw_label(cred)); |
cf797c0e JJ |
88 | } |
89 | ||
90 | /** | |
637f688d | 91 | * __aa_task_raw_label - retrieve another task's label |
3cfcc19e JJ |
92 | * @task: task to query (NOT NULL) |
93 | * | |
637f688d | 94 | * Returns: @task's label without incrementing its ref count |
3cfcc19e JJ |
95 | * |
96 | * If @task != current needs to be called in RCU safe critical section | |
97 | */ | |
637f688d | 98 | static inline struct aa_label *__aa_task_raw_label(struct task_struct *task) |
3cfcc19e | 99 | { |
637f688d | 100 | return aa_cred_raw_label(__task_cred(task)); |
3cfcc19e JJ |
101 | } |
102 | ||
103 | /** | |
104 | * __aa_task_is_confined - determine if @task has any confinement | |
105 | * @task: task to check confinement of (NOT NULL) | |
106 | * | |
107 | * If @task != current needs to be called in RCU safe critical section | |
108 | */ | |
109 | static inline bool __aa_task_is_confined(struct task_struct *task) | |
110 | { | |
637f688d | 111 | return !unconfined(__aa_task_raw_label(task)); |
3cfcc19e JJ |
112 | } |
113 | ||
c75afcd1 | 114 | /** |
637f688d | 115 | * aa_current_raw_label - find the current tasks confining label |
c75afcd1 | 116 | * |
637f688d | 117 | * Returns: up to date confining label or the ns unconfined label (NOT NULL) |
c75afcd1 JJ |
118 | * |
119 | * This fn will not update the tasks cred to the most up to date version | |
637f688d | 120 | * of the label so it is safe to call when inside of locks. |
c75afcd1 | 121 | */ |
637f688d | 122 | static inline struct aa_label *aa_current_raw_label(void) |
c75afcd1 | 123 | { |
637f688d | 124 | return aa_cred_raw_label(current_cred()); |
c75afcd1 JJ |
125 | } |
126 | ||
127 | /** | |
637f688d | 128 | * aa_get_current_label - get the newest version of the current tasks label |
c75afcd1 | 129 | * |
637f688d | 130 | * Returns: newest version of confining label (NOT NULL) |
cf797c0e JJ |
131 | * |
132 | * This fn will not update the tasks cred, so it is safe inside of locks | |
c75afcd1 | 133 | * |
637f688d | 134 | * The returned reference must be put with aa_put_label() |
c75afcd1 | 135 | */ |
637f688d | 136 | static inline struct aa_label *aa_get_current_label(void) |
c75afcd1 | 137 | { |
637f688d | 138 | struct aa_label *l = aa_current_raw_label(); |
c75afcd1 | 139 | |
637f688d JJ |
140 | if (label_is_stale(l)) |
141 | return aa_get_newest_label(l); | |
142 | return aa_get_label(l); | |
cf797c0e | 143 | } |
55a26ebf | 144 | |
637f688d | 145 | #define __end_current_label_crit_section(X) end_current_label_crit_section(X) |
cf797c0e JJ |
146 | |
147 | /** | |
637f688d JJ |
148 | * end_label_crit_section - put a reference found with begin_current_label.. |
149 | * @label: label reference to put | |
cf797c0e JJ |
150 | * |
151 | * Should only be used with a reference obtained with | |
637f688d | 152 | * begin_current_label_crit_section and never used in situations where the |
cf797c0e JJ |
153 | * task cred may be updated |
154 | */ | |
637f688d | 155 | static inline void end_current_label_crit_section(struct aa_label *label) |
cf797c0e | 156 | { |
637f688d JJ |
157 | if (label != aa_current_raw_label()) |
158 | aa_put_label(label); | |
cf797c0e JJ |
159 | } |
160 | ||
161 | /** | |
637f688d | 162 | * __begin_current_label_crit_section - current's confining label |
cf797c0e | 163 | * |
637f688d | 164 | * Returns: up to date confining label or the ns unconfined label (NOT NULL) |
cf797c0e JJ |
165 | * |
166 | * safe to call inside locks | |
167 | * | |
637f688d | 168 | * The returned reference must be put with __end_current_label_crit_section() |
cf797c0e | 169 | * This must NOT be used if the task cred could be updated within the |
637f688d JJ |
170 | * critical section between __begin_current_label_crit_section() .. |
171 | * __end_current_label_crit_section() | |
cf797c0e | 172 | */ |
637f688d | 173 | static inline struct aa_label *__begin_current_label_crit_section(void) |
cf797c0e | 174 | { |
637f688d | 175 | struct aa_label *label = aa_current_raw_label(); |
cf797c0e | 176 | |
637f688d JJ |
177 | if (label_is_stale(label)) |
178 | label = aa_get_newest_label(label); | |
cf797c0e | 179 | |
637f688d | 180 | return label; |
cf797c0e JJ |
181 | } |
182 | ||
183 | /** | |
637f688d | 184 | * begin_current_label_crit_section - current's confining label and update it |
cf797c0e | 185 | * |
637f688d | 186 | * Returns: up to date confining label or the ns unconfined label (NOT NULL) |
cf797c0e JJ |
187 | * |
188 | * Not safe to call inside locks | |
189 | * | |
637f688d | 190 | * The returned reference must be put with end_current_label_crit_section() |
cf797c0e | 191 | * This must NOT be used if the task cred could be updated within the |
637f688d JJ |
192 | * critical section between begin_current_label_crit_section() .. |
193 | * end_current_label_crit_section() | |
cf797c0e | 194 | */ |
637f688d | 195 | static inline struct aa_label *begin_current_label_crit_section(void) |
cf797c0e | 196 | { |
637f688d | 197 | struct aa_label *label = aa_current_raw_label(); |
cf797c0e | 198 | |
637f688d JJ |
199 | if (label_is_stale(label)) { |
200 | label = aa_get_newest_label(label); | |
201 | if (aa_replace_current_label(label) == 0) | |
cf797c0e | 202 | /* task cred will keep the reference */ |
637f688d | 203 | aa_put_label(label); |
77b071b3 | 204 | } |
c75afcd1 | 205 | |
637f688d | 206 | return label; |
c75afcd1 JJ |
207 | } |
208 | ||
2bd8dbbf JJ |
209 | static inline struct aa_ns *aa_get_current_ns(void) |
210 | { | |
637f688d | 211 | struct aa_label *label; |
cf797c0e JJ |
212 | struct aa_ns *ns; |
213 | ||
637f688d JJ |
214 | label = __begin_current_label_crit_section(); |
215 | ns = aa_get_ns(labels_ns(label)); | |
216 | __end_current_label_crit_section(label); | |
cf797c0e JJ |
217 | |
218 | return ns; | |
2bd8dbbf JJ |
219 | } |
220 | ||
7a2871b5 | 221 | /** |
55a26ebf JJ |
222 | * aa_clear_task_ctx_trans - clear transition tracking info from the ctx |
223 | * @ctx: task context to clear (NOT NULL) | |
7a2871b5 | 224 | */ |
55a26ebf | 225 | static inline void aa_clear_task_ctx_trans(struct aa_task_ctx *ctx) |
7a2871b5 | 226 | { |
637f688d JJ |
227 | aa_put_label(ctx->previous); |
228 | aa_put_label(ctx->onexec); | |
55a26ebf JJ |
229 | ctx->previous = NULL; |
230 | ctx->onexec = NULL; | |
231 | ctx->token = 0; | |
7a2871b5 JJ |
232 | } |
233 | ||
c75afcd1 | 234 | #endif /* __AA_CONTEXT_H */ |