blob: 70e4a094add85378c3916db3acda409e867d5ba0 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
/*
* AppArmor security module
*
* This file contains AppArmor functions used to manipulate object security
* contexts.
*
* Copyright (C) 1998-2008 Novell/SUSE
* Copyright 2009-2010 Canonical Ltd.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*
*
* AppArmor sets confinement on every task, via the cred_label() which
* is required and are not allowed to be NULL. The cred_label is
* reference counted.
*
* TODO
* If a task uses change_hat it currently does not return to the old
* cred or task context but instead creates a new one. Ideally the task
* should return to the previous cred if it has not been modified.
*
*/
#include "include/context.h"
#include "include/policy.h"
/**
* aa_get_task_label - Get another task's label
* @task: task to query (NOT NULL)
*
* Returns: counted reference to @task's label
*/
struct aa_label *aa_get_task_label(struct task_struct *task)
{
struct aa_label *p;
rcu_read_lock();
p = aa_get_newest_label(__aa_task_raw_label(task));
rcu_read_unlock();
return p;
}
/**
* aa_alloc_task_ctx - allocate a new task_ctx
* @flags: gfp flags for allocation
*
* Returns: allocated buffer or NULL on failure
*/
struct aa_task_ctx *aa_alloc_task_ctx(gfp_t flags)
{
return kzalloc(sizeof(struct aa_task_ctx), flags);
}
/**
* aa_free_task_ctx - free a task_ctx
* @ctx: task_ctx to free (MAYBE NULL)
*/
void aa_free_task_ctx(struct aa_task_ctx *ctx)
{
if (ctx) {
aa_put_label(ctx->previous);
aa_put_label(ctx->onexec);
kzfree(ctx);
}
}
/**
* aa_dup_task_ctx - duplicate a task context, incrementing reference counts
* @new: a blank task context (NOT NULL)
* @old: the task context to copy (NOT NULL)
*/
void aa_dup_task_ctx(struct aa_task_ctx *new, const struct aa_task_ctx *old)
{
*new = *old;
aa_get_label(new->previous);
aa_get_label(new->onexec);
}
/**
* aa_replace_current_label - replace the current tasks label
* @label: new label (NOT NULL)
*
* Returns: 0 or error on failure
*/
int aa_replace_current_label(struct aa_label *label)
{
struct aa_label *old = aa_current_raw_label();
struct cred *new;
AA_BUG(!label);
if (old == label)
return 0;
if (current_cred() != current_real_cred())
return -EBUSY;
new = prepare_creds();
if (!new)
return -ENOMEM;
if (unconfined(label) || (labels_ns(old) != labels_ns(label)))
/*
* if switching to unconfined or a different label namespace
* clear out context state
*/
aa_clear_task_ctx_trans(current_task_ctx());
/*
* be careful switching cred label, when racing replacement it
* is possible that the cred labels's->proxy->label is the reference
* keeping @label valid, so make sure to get its reference before
* dropping the reference on the cred's label
*/
aa_get_label(label);
aa_put_label(cred_label(new));
cred_label(new) = label;
commit_creds(new);
return 0;
}
/**
* aa_set_current_onexec - set the tasks change_profile to happen onexec
* @label: system label to set at exec (MAYBE NULL to clear value)
* @stack: whether stacking should be done
* Returns: 0 or error on failure
*/
int aa_set_current_onexec(struct aa_label *label, bool stack)
{
struct aa_task_ctx *ctx = current_task_ctx();
aa_get_label(label);
aa_put_label(ctx->onexec);
ctx->onexec = label;
ctx->token = stack;
return 0;
}
/**
* aa_set_current_hat - set the current tasks hat
* @label: label to set as the current hat (NOT NULL)
* @token: token value that must be specified to change from the hat
*
* Do switch of tasks hat. If the task is currently in a hat
* validate the token to match.
*
* Returns: 0 or error on failure
*/
int aa_set_current_hat(struct aa_label *label, u64 token)
{
struct aa_task_ctx *tctx = current_task_ctx();
struct aa_cred_ctx *ctx;
struct cred *new;
new = prepare_creds();
if (!new)
return -ENOMEM;
AA_BUG(!label);
if (!tctx->previous) {
/* transfer refcount */
tctx->previous = cred_label(new);
tctx->token = token;
} else if (tctx->token == token) {
aa_put_label(cred_label(new));
} else {
/* previous_profile && ctx->token != token */
abort_creds(new);
return -EACCES;
}
cred_label(new) = aa_get_newest_label(label);
/* clear exec on switching context */
aa_put_label(tctx->onexec);
tctx->onexec = NULL;
commit_creds(new);
return 0;
}
/**
* aa_restore_previous_label - exit from hat context restoring previous label
* @token: the token that must be matched to exit hat context
*
* Attempt to return out of a hat to the previous label. The token
* must match the stored token value.
*
* Returns: 0 or error of failure
*/
int aa_restore_previous_label(u64 token)
{
struct aa_task_ctx *tctx = current_task_ctx();
struct cred *new;
if (tctx->token != token)
return -EACCES;
/* ignore restores when there is no saved label */
if (!tctx->previous)
return 0;
new = prepare_creds();
if (!new)
return -ENOMEM;
aa_put_label(cred_label(new));
cred_label(new) = aa_get_newest_label(tctx->previous);
AA_BUG(!cred_label(new));
/* clear exec && prev information when restoring to previous context */
aa_clear_task_ctx_trans(tctx);
commit_creds(new);
return 0;
}
|
