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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
22#include "policy.h"
23#include "policy_ns.h"
24
25#define cred_ctx(X) ((X)->security)
26#define current_ctx() cred_ctx(current_cred())
27
28/* struct aa_file_ctx - the AppArmor context the file was opened in
29 * @perms: the permission the file was opened with
30 *
31 * The file_ctx could currently be directly stored in file->f_security
32 * as the profile reference is now stored in the f_cred. However the
33 * ctx struct will expand in the future so we keep the struct.
34 */
35struct aa_file_ctx {
36 u16 allow;
37};
38
39/**
40 * aa_alloc_file_context - allocate file_ctx
41 * @gfp: gfp flags for allocation
42 *
43 * Returns: file_ctx or NULL on failure
44 */
45static inline struct aa_file_ctx *aa_alloc_file_context(gfp_t gfp)
46{
47 return kzalloc(sizeof(struct aa_file_ctx), gfp);
48}
49
50/**
51 * aa_free_file_context - free a file_ctx
52 * @ctx: file_ctx to free (MAYBE_NULL)
53 */
54static inline void aa_free_file_context(struct aa_file_ctx *ctx)
55{
56 if (ctx)
57 kzfree(ctx);
58}
59
60/**
61 * struct aa_task_ctx - primary label for confined tasks
62 * @profile: the current profile (NOT NULL)
63 * @exec: profile to transition to on next exec (MAYBE NULL)
64 * @previous: profile the task may return to (MAYBE NULL)
65 * @token: magic value the task must know for returning to @previous_profile
66 *
67 * Contains the task's current profile (which could change due to
68 * change_hat). Plus the hat_magic needed during change_hat.
69 *
70 * TODO: make so a task can be confined by a stack of contexts
71 */
72struct aa_task_ctx {
73 struct aa_profile *profile;
74 struct aa_profile *onexec;
75 struct aa_profile *previous;
76 u64 token;
77};
78
79struct aa_task_ctx *aa_alloc_task_context(gfp_t flags);
80void aa_free_task_context(struct aa_task_ctx *ctx);
81void aa_dup_task_context(struct aa_task_ctx *new,
82 const struct aa_task_ctx *old);
83int aa_replace_current_profile(struct aa_profile *profile);
84int aa_set_current_onexec(struct aa_profile *profile);
85int aa_set_current_hat(struct aa_profile *profile, u64 token);
86int aa_restore_previous_profile(u64 cookie);
87struct aa_profile *aa_get_task_profile(struct task_struct *task);
88
89
90/**
91 * aa_cred_profile - obtain cred's profiles
92 * @cred: cred to obtain profiles from (NOT NULL)
93 *
94 * Returns: confining profile
95 *
96 * does NOT increment reference count
97 */
98static inline struct aa_profile *aa_cred_profile(const struct cred *cred)
99{
100 struct aa_task_ctx *ctx = cred_ctx(cred);
101
102 AA_BUG(!ctx || !ctx->profile);
103 return ctx->profile;
104}
105
106/**
107 * __aa_task_profile - retrieve another task's profile
108 * @task: task to query (NOT NULL)
109 *
110 * Returns: @task's profile without incrementing its ref count
111 *
112 * If @task != current needs to be called in RCU safe critical section
113 */
114static inline struct aa_profile *__aa_task_profile(struct task_struct *task)
115{
116 return aa_cred_profile(__task_cred(task));
117}
118
119/**
120 * __aa_task_is_confined - determine if @task has any confinement
121 * @task: task to check confinement of (NOT NULL)
122 *
123 * If @task != current needs to be called in RCU safe critical section
124 */
125static inline bool __aa_task_is_confined(struct task_struct *task)
126{
127 return !unconfined(__aa_task_profile(task));
128}
129
130/**
131 * __aa_current_profile - find the current tasks confining profile
132 *
133 * Returns: up to date confining profile or the ns unconfined profile (NOT NULL)
134 *
135 * This fn will not update the tasks cred to the most up to date version
136 * of the profile so it is safe to call when inside of locks.
137 */
138static inline struct aa_profile *__aa_current_profile(void)
139{
140 return aa_cred_profile(current_cred());
141}
142
143/**
144 * aa_current_profile - find the current tasks confining profile and do updates
145 *
146 * Returns: up to date confining profile or the ns unconfined profile (NOT NULL)
147 *
148 * This fn will update the tasks cred structure if the profile has been
149 * replaced. Not safe to call inside locks
150 */
151static inline struct aa_profile *aa_current_profile(void)
152{
153 const struct aa_task_ctx *ctx = current_ctx();
154 struct aa_profile *profile;
155
156 AA_BUG(!ctx || !ctx->profile);
157
158 if (profile_is_stale(ctx->profile)) {
159 profile = aa_get_newest_profile(ctx->profile);
160 aa_replace_current_profile(profile);
161 aa_put_profile(profile);
162 ctx = current_ctx();
163 }
164
165 return ctx->profile;
166}
167
168static inline struct aa_ns *aa_get_current_ns(void)
169{
170 return aa_get_ns(__aa_current_profile()->ns);
171}
172
173/**
174 * aa_clear_task_ctx_trans - clear transition tracking info from the ctx
175 * @ctx: task context to clear (NOT NULL)
176 */
177static inline void aa_clear_task_ctx_trans(struct aa_task_ctx *ctx)
178{
179 aa_put_profile(ctx->previous);
180 aa_put_profile(ctx->onexec);
181 ctx->previous = NULL;
182 ctx->onexec = NULL;
183 ctx->token = 0;
184}
185
186#endif /* __AA_CONTEXT_H */