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