2 * AppArmor security module
4 * This file contains AppArmor functions used to manipulate object security
7 * Copyright (C) 1998-2008 Novell/SUSE
8 * Copyright 2009-2010 Canonical Ltd.
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation, version 2 of the
16 * AppArmor sets confinement on every task, via the the aa_task_cxt and
17 * the aa_task_cxt.profile, both of which are required and are not allowed
18 * to be NULL. The aa_task_cxt is not reference counted and is unique
19 * to each cred (which is reference count). The profile pointed to by
20 * the task_cxt is reference counted.
23 * If a task uses change_hat it currently does not return to the old
24 * cred or task context but instead creates a new one. Ideally the task
25 * should return to the previous cred if it has not been modified.
29 #include "include/context.h"
30 #include "include/policy.h"
33 * aa_alloc_task_context - allocate a new task_cxt
34 * @flags: gfp flags for allocation
36 * Returns: allocated buffer or NULL on failure
38 struct aa_task_cxt
*aa_alloc_task_context(gfp_t flags
)
40 return kzalloc(sizeof(struct aa_task_cxt
), flags
);
44 * aa_free_task_context - free a task_cxt
45 * @cxt: task_cxt to free (MAYBE NULL)
47 void aa_free_task_context(struct aa_task_cxt
*cxt
)
50 aa_put_profile(cxt
->profile
);
51 aa_put_profile(cxt
->previous
);
52 aa_put_profile(cxt
->onexec
);
59 * aa_dup_task_context - duplicate a task context, incrementing reference counts
60 * @new: a blank task context (NOT NULL)
61 * @old: the task context to copy (NOT NULL)
63 void aa_dup_task_context(struct aa_task_cxt
*new, const struct aa_task_cxt
*old
)
66 aa_get_profile(new->profile
);
67 aa_get_profile(new->previous
);
68 aa_get_profile(new->onexec
);
72 * aa_get_task_profile - Get another task's profile
73 * @task: task to query (NOT NULL)
75 * Returns: counted reference to @task's profile
77 struct aa_profile
*aa_get_task_profile(struct task_struct
*task
)
82 p
= aa_get_profile(__aa_task_profile(task
));
89 * aa_replace_current_profile - replace the current tasks profiles
90 * @profile: new profile (NOT NULL)
92 * Returns: 0 or error on failure
94 int aa_replace_current_profile(struct aa_profile
*profile
)
96 struct aa_task_cxt
*cxt
= current_cxt();
100 if (cxt
->profile
== profile
)
103 new = prepare_creds();
108 if (unconfined(profile
) || (cxt
->profile
->ns
!= profile
->ns
))
109 /* if switching to unconfined or a different profile namespace
110 * clear out context state
112 aa_clear_task_cxt_trans(cxt
);
114 /* be careful switching cxt->profile, when racing replacement it
115 * is possible that cxt->profile->replacedby->profile is the reference
116 * keeping @profile valid, so make sure to get its reference before
117 * dropping the reference on cxt->profile */
118 aa_get_profile(profile
);
119 aa_put_profile(cxt
->profile
);
120 cxt
->profile
= profile
;
127 * aa_set_current_onexec - set the tasks change_profile to happen onexec
128 * @profile: system profile to set at exec (MAYBE NULL to clear value)
130 * Returns: 0 or error on failure
132 int aa_set_current_onexec(struct aa_profile
*profile
)
134 struct aa_task_cxt
*cxt
;
135 struct cred
*new = prepare_creds();
140 aa_get_profile(profile
);
141 aa_put_profile(cxt
->onexec
);
142 cxt
->onexec
= profile
;
149 * aa_set_current_hat - set the current tasks hat
150 * @profile: profile to set as the current hat (NOT NULL)
151 * @token: token value that must be specified to change from the hat
153 * Do switch of tasks hat. If the task is currently in a hat
154 * validate the token to match.
156 * Returns: 0 or error on failure
158 int aa_set_current_hat(struct aa_profile
*profile
, u64 token
)
160 struct aa_task_cxt
*cxt
;
161 struct cred
*new = prepare_creds();
167 if (!cxt
->previous
) {
168 /* transfer refcount */
169 cxt
->previous
= cxt
->profile
;
171 } else if (cxt
->token
== token
) {
172 aa_put_profile(cxt
->profile
);
174 /* previous_profile && cxt->token != token */
178 cxt
->profile
= aa_get_newest_profile(profile
);
179 /* clear exec on switching context */
180 aa_put_profile(cxt
->onexec
);
188 * aa_restore_previous_profile - exit from hat context restoring the profile
189 * @token: the token that must be matched to exit hat context
191 * Attempt to return out of a hat to the previous profile. The token
192 * must match the stored token value.
194 * Returns: 0 or error of failure
196 int aa_restore_previous_profile(u64 token
)
198 struct aa_task_cxt
*cxt
;
199 struct cred
*new = prepare_creds();
204 if (cxt
->token
!= token
) {
208 /* ignore restores when there is no saved profile */
209 if (!cxt
->previous
) {
214 aa_put_profile(cxt
->profile
);
215 cxt
->profile
= aa_get_newest_profile(cxt
->previous
);
216 BUG_ON(!cxt
->profile
);
217 /* clear exec && prev information when restoring to previous context */
218 aa_clear_task_cxt_trans(cxt
);
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