summaryrefslogtreecommitdiff
path: root/security/apparmor/lib.c
blob: 90d4631ddafeb1f369805b0015791af282c3c95f (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
223
224
225
226
227
228
229
230
231
232
233
/*
 * AppArmor security module
 *
 * This file contains basic common functions used in AppArmor
 *
 * 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.
 */

#include <linux/ctype.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/vmalloc.h>

#include "include/audit.h"
#include "include/apparmor.h"
#include "include/lib.h"
#include "include/perms.h"
#include "include/policy.h"

/**
 * aa_split_fqname - split a fqname into a profile and namespace name
 * @fqname: a full qualified name in namespace profile format (NOT NULL)
 * @ns_name: pointer to portion of the string containing the ns name (NOT NULL)
 *
 * Returns: profile name or NULL if one is not specified
 *
 * Split a namespace name from a profile name (see policy.c for naming
 * description).  If a portion of the name is missing it returns NULL for
 * that portion.
 *
 * NOTE: may modify the @fqname string.  The pointers returned point
 *       into the @fqname string.
 */
char *aa_split_fqname(char *fqname, char **ns_name)
{
	char *name = strim(fqname);

	*ns_name = NULL;
	if (name[0] == ':') {
		char *split = strchr(&name[1], ':');
		*ns_name = skip_spaces(&name[1]);
		if (split) {
			/* overwrite ':' with \0 */
			*split++ = 0;
			if (strncmp(split, "//", 2) == 0)
				split += 2;
			name = skip_spaces(split);
		} else
			/* a ns name without a following profile is allowed */
			name = NULL;
	}
	if (name && *name == 0)
		name = NULL;

	return name;
}

/**
 * skipn_spaces - Removes leading whitespace from @str.
 * @str: The string to be stripped.
 *
 * Returns a pointer to the first non-whitespace character in @str.
 * if all whitespace will return NULL
 */

const char *skipn_spaces(const char *str, size_t n)
{
	for (; n && isspace(*str); --n)
		++str;
	if (n)
		return (char *)str;
	return NULL;
}

const char *aa_splitn_fqname(const char *fqname, size_t n, const char **ns_name,
			     size_t *ns_len)
{
	const char *end = fqname + n;
	const char *name = skipn_spaces(fqname, n);

	if (!name)
		return NULL;
	*ns_name = NULL;
	*ns_len = 0;
	if (name[0] == ':') {
		char *split = strnchr(&name[1], end - &name[1], ':');
		*ns_name = skipn_spaces(&name[1], end - &name[1]);
		if (!*ns_name)
			return NULL;
		if (split) {
			*ns_len = split - *ns_name;
			if (*ns_len == 0)
				*ns_name = NULL;
			split++;
			if (end - split > 1 && strncmp(split, "//", 2) == 0)
				split += 2;
			name = skipn_spaces(split, end - split);
		} else {
			/* a ns name without a following profile is allowed */
			name = NULL;
			*ns_len = end - *ns_name;
		}
	}
	if (name && *name == 0)
		name = NULL;

	return name;
}

/**
 * aa_info_message - log a none profile related status message
 * @str: message to log
 */
void aa_info_message(const char *str)
{
	if (audit_enabled) {
		DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, NULL);

		aad(&sa)->info = str;
		aa_audit_msg(AUDIT_APPARMOR_STATUS, &sa, NULL);
	}
	printk(KERN_INFO "AppArmor: %s\n", str);
}

const char aa_file_perm_chrs[] = "xwracd         km l     ";
const char *aa_file_perm_names[] = {
	"exec",
	"write",
	"read",
	"append",

	"create",
	"delete",
	"open",
	"rename",

	"setattr",
	"getattr",
	"setcred",
	"getcred",

	"chmod",
	"chown",
	"chgrp",
	"lock",

	"mmap",
	"mprot",
	"link",
	"snapshot",

	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"unknown",
	"unknown",
	"unknown",
	"unknown",

	"stack",
	"change_onexec",
	"change_profile",
	"change_hat",
};

/**
 * aa_perm_mask_to_str - convert a perm mask to its short string
 * @str: character buffer to store string in (at least 10 characters)
 * @mask: permission mask to convert
 */
void aa_perm_mask_to_str(char *str, const char *chrs, u32 mask)
{
	unsigned int i, perm = 1;

	for (i = 0; i < 32; perm <<= 1, i++) {
		if (mask & perm)
			*str++ = chrs[i];
	}
	*str = '\0';
}

/**
 * aa_policy_init - initialize a policy structure
 * @policy: policy to initialize  (NOT NULL)
 * @prefix: prefix name if any is required.  (MAYBE NULL)
 * @name: name of the policy, init will make a copy of it  (NOT NULL)
 *
 * Note: this fn creates a copy of strings passed in
 *
 * Returns: true if policy init successful
 */
bool aa_policy_init(struct aa_policy *policy, const char *prefix,
		    const char *name, gfp_t gfp)
{
	/* freed by policy_free */
	if (prefix) {
		policy->hname = kmalloc(strlen(prefix) + strlen(name) + 3,
					gfp);
		if (policy->hname)
			sprintf((char *)policy->hname, "%s//%s", prefix, name);
	} else
		policy->hname = kstrdup(name, gfp);
	if (!policy->hname)
		return false;
	/* base.name is a substring of fqname */
	policy->name = basename(policy->hname);
	INIT_LIST_HEAD(&policy->list);
	INIT_LIST_HEAD(&policy->profiles);

	return true;
}

/**
 * aa_policy_destroy - free the elements referenced by @policy
 * @policy: policy that is to have its elements freed  (NOT NULL)
 */
void aa_policy_destroy(struct aa_policy *policy)
{
	AA_BUG(on_list_rcu(&policy->profiles));
	AA_BUG(on_list_rcu(&policy->list));

	/* don't free name as its a subset of hname */
	kzfree(policy->hname);
}