aboutsummaryrefslogtreecommitdiff
path: root/security/tomoyo/tomoyo.c
blob: 3eeeae12c4dcde1569e9b809bc97aa6dbf07d464 (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
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
/*
 * security/tomoyo/tomoyo.c
 *
 * LSM hooks for TOMOYO Linux.
 *
 * Copyright (C) 2005-2009  NTT DATA CORPORATION
 *
 * Version: 2.2.0-pre   2009/02/01
 *
 */

#include <linux/security.h>
#include "common.h"
#include "tomoyo.h"
#include "realpath.h"

static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
			       gfp_t gfp)
{
	/*
	 * Since "struct tomoyo_domain_info *" is a sharable pointer,
	 * we don't need to duplicate.
	 */
	new->security = old->security;
	return 0;
}

static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
{
	/*
	 * Do only if this function is called for the first time of an execve
	 * operation.
	 */
	if (bprm->cred_prepared)
		return 0;
	/*
	 * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
	 * for the first time.
	 */
	if (!tomoyo_policy_loaded)
		tomoyo_load_policy(bprm->filename);
	/*
	 * Tell tomoyo_bprm_check_security() is called for the first time of an
	 * execve operation.
	 */
	bprm->cred->security = NULL;
	return 0;
}

static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
{
	struct tomoyo_domain_info *domain = bprm->cred->security;

	/*
	 * Execute permission is checked against pathname passed to do_execve()
	 * using current domain.
	 */
	if (!domain) {
		struct tomoyo_domain_info *next_domain = NULL;
		int retval = tomoyo_find_next_domain(bprm, &next_domain);

		if (!retval)
			bprm->cred->security = next_domain;
		return retval;
	}
	/*
	 * Read permission is checked against interpreters using next domain.
	 * '1' is the result of open_to_namei_flags(O_RDONLY).
	 */
	return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
}

#ifdef CONFIG_SYSCTL

static int tomoyo_prepend(char **buffer, int *buflen, const char *str)
{
	int namelen = strlen(str);

	if (*buflen < namelen)
		return -ENOMEM;
	*buflen -= namelen;
	*buffer -= namelen;
	memcpy(*buffer, str, namelen);
	return 0;
}

/**
 * tomoyo_sysctl_path - return the realpath of a ctl_table.
 * @table: pointer to "struct ctl_table".
 *
 * Returns realpath(3) of the @table on success.
 * Returns NULL on failure.
 *
 * This function uses tomoyo_alloc(), so the caller must call tomoyo_free()
 * if this function didn't return NULL.
 */
static char *tomoyo_sysctl_path(struct ctl_table *table)
{
	int buflen = TOMOYO_MAX_PATHNAME_LEN;
	char *buf = tomoyo_alloc(buflen);
	char *end = buf + buflen;
	int error = -ENOMEM;

	if (!buf)
		return NULL;

	*--end = '\0';
	buflen--;
	while (table) {
		char num[32];
		const char *sp = table->procname;

		if (!sp) {
			memset(num, 0, sizeof(num));
			snprintf(num, sizeof(num) - 1, "=%d=", table->ctl_name);
			sp = num;
		}
		if (tomoyo_prepend(&end, &buflen, sp) ||
		    tomoyo_prepend(&end, &buflen, "/"))
			goto out;
		table = table->parent;
	}
	if (tomoyo_prepend(&end, &buflen, "/proc/sys"))
		goto out;
	error = tomoyo_encode(buf, end - buf, end);
 out:
	if (!error)
		return buf;
	tomoyo_free(buf);
	return NULL;
}

static int tomoyo_sysctl(struct ctl_table *table, int op)
{
	int error;
	char *name;

	op &= MAY_READ | MAY_WRITE;
	if (!op)
		return 0;
	name = tomoyo_sysctl_path(table);
	if (!name)
		return -ENOMEM;
	error = tomoyo_check_file_perm(tomoyo_domain(), name, op);
	tomoyo_free(name);
	return error;
}
#endif

static int tomoyo_path_truncate(struct path *path, loff_t length,
				unsigned int time_attrs)
{
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_TRUNCATE_ACL,
				       path);
}

static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
{
	struct path path = { parent->mnt, dentry };
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_UNLINK_ACL,
				       &path);
}

static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
			     int mode)
{
	struct path path = { parent->mnt, dentry };
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_MKDIR_ACL,
				       &path);
}

static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
{
	struct path path = { parent->mnt, dentry };
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_RMDIR_ACL,
				       &path);
}

static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
			       const char *old_name)
{
	struct path path = { parent->mnt, dentry };
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_SYMLINK_ACL,
				       &path);
}

static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
			     int mode, unsigned int dev)
{
	struct path path = { parent->mnt, dentry };
	int type = TOMOYO_TYPE_CREATE_ACL;

	switch (mode & S_IFMT) {
	case S_IFCHR:
		type = TOMOYO_TYPE_MKCHAR_ACL;
		break;
	case S_IFBLK:
		type = TOMOYO_TYPE_MKBLOCK_ACL;
		break;
	case S_IFIFO:
		type = TOMOYO_TYPE_MKFIFO_ACL;
		break;
	case S_IFSOCK:
		type = TOMOYO_TYPE_MKSOCK_ACL;
		break;
	}
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       type, &path);
}

static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
			    struct dentry *new_dentry)
{
	struct path path1 = { new_dir->mnt, old_dentry };
	struct path path2 = { new_dir->mnt, new_dentry };
	return tomoyo_check_2path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_LINK_ACL,
				       &path1, &path2);
}

static int tomoyo_path_rename(struct path *old_parent,
			      struct dentry *old_dentry,
			      struct path *new_parent,
			      struct dentry *new_dentry)
{
	struct path path1 = { old_parent->mnt, old_dentry };
	struct path path2 = { new_parent->mnt, new_dentry };
	return tomoyo_check_2path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_RENAME_ACL,
				       &path1, &path2);
}

static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
			     unsigned long arg)
{
	if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
		return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
	return 0;
}

static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
{
	int flags = f->f_flags;

	if ((flags + 1) & O_ACCMODE)
		flags++;
	flags |= f->f_flags & (O_APPEND | O_TRUNC);
	/* Don't check read permission here if called from do_execve(). */
	if (current->in_execve)
		return 0;
	return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
}

static struct security_operations tomoyo_security_ops = {
	.name                = "tomoyo",
	.cred_prepare        = tomoyo_cred_prepare,
	.bprm_set_creds      = tomoyo_bprm_set_creds,
	.bprm_check_security = tomoyo_bprm_check_security,
#ifdef CONFIG_SYSCTL
	.sysctl              = tomoyo_sysctl,
#endif
	.file_fcntl          = tomoyo_file_fcntl,
	.dentry_open         = tomoyo_dentry_open,
	.path_truncate       = tomoyo_path_truncate,
	.path_unlink         = tomoyo_path_unlink,
	.path_mkdir          = tomoyo_path_mkdir,
	.path_rmdir          = tomoyo_path_rmdir,
	.path_symlink        = tomoyo_path_symlink,
	.path_mknod          = tomoyo_path_mknod,
	.path_link           = tomoyo_path_link,
	.path_rename         = tomoyo_path_rename,
};

static int __init tomoyo_init(void)
{
	struct cred *cred = (struct cred *) current_cred();

	if (!security_module_enable(&tomoyo_security_ops))
		return 0;
	/* register ourselves with the security framework */
	if (register_security(&tomoyo_security_ops))
		panic("Failure registering TOMOYO Linux");
	printk(KERN_INFO "TOMOYO Linux initialized\n");
	cred->security = &tomoyo_kernel_domain;
	tomoyo_realpath_init();
	return 0;
}

security_initcall(tomoyo_init);