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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - security/apparmor/context.c
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_ctx and
17 * the aa_task_ctx.label, both of which are required and are not allowed
18 * to be NULL. The aa_task_ctx is not reference counted and is unique
19 * to each cred (which is reference count). The label pointed to by
20 * the task_ctx 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_ctx
34 * @flags: gfp flags for allocation
36 * Returns: allocated buffer or NULL on failure
38 struct aa_task_ctx
*aa_alloc_task_context(gfp_t flags
)
40 return kzalloc(sizeof(struct aa_task_ctx
), flags
);
44 * aa_free_task_context - free a task_ctx
45 * @ctx: task_ctx to free (MAYBE NULL)
47 void aa_free_task_context(struct aa_task_ctx
*ctx
)
50 aa_put_label(ctx
->label
);
51 aa_put_label(ctx
->previous
);
52 aa_put_label(ctx
->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_ctx
*new, const struct aa_task_ctx
*old
)
66 aa_get_label(new->label
);
67 aa_get_label(new->previous
);
68 aa_get_label(new->onexec
);
72 * aa_get_task_label - Get another task's label
73 * @task: task to query (NOT NULL)
75 * Returns: counted reference to @task's label
77 struct aa_label
*aa_get_task_label(struct task_struct
*task
)
82 p
= aa_get_newest_label(__aa_task_raw_label(task
));
89 * aa_replace_current_label - replace the current tasks label
90 * @label: new label (NOT NULL)
92 * Returns: 0 or error on failure
94 int aa_replace_current_label(struct aa_label
*label
)
96 struct aa_task_ctx
*ctx
= current_ctx();
100 if (ctx
->label
== label
)
103 if (current_cred() != current_real_cred())
106 new = prepare_creds();
111 if (unconfined(label
) || (labels_ns(ctx
->label
) != labels_ns(label
)))
112 /* if switching to unconfined or a different label namespace
113 * clear out context state
115 aa_clear_task_ctx_trans(ctx
);
118 aa_put_label(ctx
->label
);
126 * aa_set_current_onexec - set the tasks change_profile to happen onexec
127 * @label: system label to set at exec (MAYBE NULL to clear value)
128 * @stack: whether stacking should be done
129 * Returns: 0 or error on failure
131 int aa_set_current_onexec(struct aa_label
*label
, bool stack
)
133 struct aa_task_ctx
*ctx
;
134 struct cred
*new = prepare_creds();
140 aa_clear_task_ctx_trans(ctx
);
149 * aa_set_current_hat - set the current tasks hat
150 * @label: label 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_label
*label
, u64 token
)
160 struct aa_task_ctx
*ctx
;
161 struct cred
*new = prepare_creds();
167 if (!ctx
->previous
) {
168 /* transfer refcount */
169 ctx
->previous
= ctx
->label
;
171 } else if (ctx
->token
== token
) {
172 aa_put_label(ctx
->label
);
174 /* previous_profile && ctx->token != token */
178 ctx
->label
= aa_get_newest_label(label
);
179 /* clear exec on switching context */
180 aa_put_label(ctx
->onexec
);
188 * aa_restore_previous_label - exit from hat context restoring previous label
189 * @token: the token that must be matched to exit hat context
191 * Attempt to return out of a hat to the previous label. The token
192 * must match the stored token value.
194 * Returns: 0 or error of failure
196 int aa_restore_previous_label(u64 token
)
198 struct aa_task_ctx
*ctx
;
199 struct cred
*new = prepare_creds();
204 if (ctx
->token
!= token
) {
208 /* ignore restores when there is no saved label */
209 if (!ctx
->previous
) {
214 aa_put_label(ctx
->label
);
215 ctx
->label
= aa_get_newest_label(ctx
->previous
);
217 /* clear exec && prev information when restoring to previous context */
218 aa_clear_task_ctx_trans(ctx
);