Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor security identifier (secid) manipulation fns
5 *
6 * Copyright 2009-2017 Canonical Ltd.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation, version 2 of the
11 * License.
12 *
13 *
14 * AppArmor allocates a unique secid for every label used. If a label
15 * is replaced it receives the secid of the label it is replacing.
16 */
17
18#include <linux/errno.h>
19#include <linux/err.h>
20#include <linux/gfp.h>
21#include <linux/idr.h>
22#include <linux/slab.h>
23#include <linux/spinlock.h>
24
25#include "include/cred.h"
26#include "include/lib.h"
27#include "include/secid.h"
28#include "include/label.h"
29#include "include/policy_ns.h"
30
31/*
32 * secids - do not pin labels with a refcount. They rely on the label
33 * properly updating/freeing them
34 */
35#define AA_FIRST_SECID 2
36
37static DEFINE_IDR(aa_secids);
38static DEFINE_SPINLOCK(secid_lock);
39
40/*
41 * TODO: allow policy to reserve a secid range?
42 * TODO: add secid pinning
43 * TODO: use secid_update in label replace
44 */
45
46/**
47 * aa_secid_update - update a secid mapping to a new label
48 * @secid: secid to update
49 * @label: label the secid will now map to
50 */
51void aa_secid_update(u32 secid, struct aa_label *label)
52{
53 unsigned long flags;
54
55 spin_lock_irqsave(&secid_lock, flags);
56 idr_replace(&aa_secids, label, secid);
57 spin_unlock_irqrestore(&secid_lock, flags);
58}
59
60/**
61 *
62 * see label for inverse aa_label_to_secid
63 */
64struct aa_label *aa_secid_to_label(u32 secid)
65{
66 struct aa_label *label;
67
68 rcu_read_lock();
69 label = idr_find(&aa_secids, secid);
70 rcu_read_unlock();
71
72 return label;
73}
74
75int apparmor_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
76{
77 /* TODO: cache secctx and ref count so we don't have to recreate */
78 struct aa_label *label = aa_secid_to_label(secid);
79 int len;
80
81 AA_BUG(!seclen);
82
83 if (!label)
84 return -EINVAL;
85
86 if (secdata)
87 len = aa_label_asxprint(secdata, root_ns, label,
88 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
89 FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT,
90 GFP_ATOMIC);
91 else
92 len = aa_label_snxprint(NULL, 0, root_ns, label,
93 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
94 FLAG_HIDDEN_UNCONFINED | FLAG_ABS_ROOT);
95 if (len < 0)
96 return -ENOMEM;
97
98 *seclen = len;
99
100 return 0;
101}
102
103int apparmor_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
104{
105 struct aa_label *label;
106
107 label = aa_label_strn_parse(&root_ns->unconfined->label, secdata,
108 seclen, GFP_KERNEL, false, false);
109 if (IS_ERR(label))
110 return PTR_ERR(label);
111 *secid = label->secid;
112
113 return 0;
114}
115
116void apparmor_release_secctx(char *secdata, u32 seclen)
117{
118 kfree(secdata);
119}
120
121/**
122 * aa_alloc_secid - allocate a new secid for a profile
123 * @label: the label to allocate a secid for
124 * @gfp: memory allocation flags
125 *
126 * Returns: 0 with @label->secid initialized
127 * <0 returns error with @label->secid set to AA_SECID_INVALID
128 */
129int aa_alloc_secid(struct aa_label *label, gfp_t gfp)
130{
131 unsigned long flags;
132 int ret;
133
134 idr_preload(gfp);
135 spin_lock_irqsave(&secid_lock, flags);
136 ret = idr_alloc(&aa_secids, label, AA_FIRST_SECID, 0, GFP_ATOMIC);
137 spin_unlock_irqrestore(&secid_lock, flags);
138 idr_preload_end();
139
140 if (ret < 0) {
141 label->secid = AA_SECID_INVALID;
142 return ret;
143 }
144
145 AA_BUG(ret == AA_SECID_INVALID);
146 label->secid = ret;
147 return 0;
148}
149
150/**
151 * aa_free_secid - free a secid
152 * @secid: secid to free
153 */
154void aa_free_secid(u32 secid)
155{
156 unsigned long flags;
157
158 spin_lock_irqsave(&secid_lock, flags);
159 idr_remove(&aa_secids, secid);
160 spin_unlock_irqrestore(&secid_lock, flags);
161}
162
163void aa_secids_init(void)
164{
165 idr_init_base(&aa_secids, AA_FIRST_SECID);
166}