1// SPDX-License-Identifier: GPL-2.0
2/*
3 * security/tomoyo/securityfs_if.c
4 *
5 * Copyright (C) 2005-2011  NTT DATA CORPORATION
6 */
7
8#include <linux/security.h>
9#include "common.h"
10
11/**
12 * tomoyo_check_task_acl - Check permission for task operation.
13 *
14 * @r:   Pointer to "struct tomoyo_request_info".
15 * @ptr: Pointer to "struct tomoyo_acl_info".
16 *
17 * Returns true if granted, false otherwise.
18 */
19static bool tomoyo_check_task_acl(struct tomoyo_request_info *r,
20				  const struct tomoyo_acl_info *ptr)
21{
22	const struct tomoyo_task_acl *acl = container_of(ptr, typeof(*acl),
23							 head);
24
25	return !tomoyo_pathcmp(r->param.task.domainname, acl->domainname);
26}
27
28/**
29 * tomoyo_write_self - write() for /sys/kernel/security/tomoyo/self_domain interface.
30 *
31 * @file:  Pointer to "struct file".
32 * @buf:   Domainname to transit to.
33 * @count: Size of @buf.
34 * @ppos:  Unused.
35 *
36 * Returns @count on success, negative value otherwise.
37 *
38 * If domain transition was permitted but the domain transition failed, this
39 * function returns error rather than terminating current thread with SIGKILL.
40 */
41static ssize_t tomoyo_write_self(struct file *file, const char __user *buf,
42			      size_t count, loff_t *ppos)
43{
44	char *data;
45	int error;
46
47	if (!count || count >= TOMOYO_EXEC_TMPSIZE - 10)
48		return -ENOMEM;
49	data = memdup_user_nul(buf, count);
50	if (IS_ERR(data))
51		return PTR_ERR(data);
52	tomoyo_normalize_line(data);
53	if (tomoyo_correct_domain(data)) {
54		const int idx = tomoyo_read_lock();
55		struct tomoyo_path_info name;
56		struct tomoyo_request_info r;
57
58		name.name = data;
59		tomoyo_fill_path_info(&name);
60		/* Check "task manual_domain_transition" permission. */
61		tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_EXECUTE);
62		r.param_type = TOMOYO_TYPE_MANUAL_TASK_ACL;
63		r.param.task.domainname = &name;
64		tomoyo_check_acl(&r, tomoyo_check_task_acl);
65		if (!r.granted)
66			error = -EPERM;
67		else {
68			struct tomoyo_domain_info *new_domain =
69				tomoyo_assign_domain(data, true);
70			if (!new_domain) {
71				error = -ENOENT;
72			} else {
73				struct tomoyo_task *s = tomoyo_task(current);
74				struct tomoyo_domain_info *old_domain =
75					s->domain_info;
76
77				s->domain_info = new_domain;
78				atomic_inc(&new_domain->users);
79				atomic_dec(&old_domain->users);
80				error = 0;
81			}
82		}
83		tomoyo_read_unlock(idx);
84	} else
85		error = -EINVAL;
86	kfree(data);
87	return error ? error : count;
88}
89
90/**
91 * tomoyo_read_self - read() for /sys/kernel/security/tomoyo/self_domain interface.
92 *
93 * @file:  Pointer to "struct file".
94 * @buf:   Domainname which current thread belongs to.
95 * @count: Size of @buf.
96 * @ppos:  Bytes read by now.
97 *
98 * Returns read size on success, negative value otherwise.
99 */
100static ssize_t tomoyo_read_self(struct file *file, char __user *buf,
101				size_t count, loff_t *ppos)
102{
103	const char *domain = tomoyo_domain()->domainname->name;
104	loff_t len = strlen(domain);
105	loff_t pos = *ppos;
106
107	if (pos >= len || !count)
108		return 0;
109	len -= pos;
110	if (count < len)
111		len = count;
112	if (copy_to_user(buf, domain + pos, len))
113		return -EFAULT;
114	*ppos += len;
115	return len;
116}
117
118/* Operations for /sys/kernel/security/tomoyo/self_domain interface. */
119static const struct file_operations tomoyo_self_operations = {
120	.write = tomoyo_write_self,
121	.read  = tomoyo_read_self,
122};
123
124/**
125 * tomoyo_open - open() for /sys/kernel/security/tomoyo/ interface.
126 *
127 * @inode: Pointer to "struct inode".
128 * @file:  Pointer to "struct file".
129 *
130 * Returns 0 on success, negative value otherwise.
131 */
132static int tomoyo_open(struct inode *inode, struct file *file)
133{
134	const u8 key = (uintptr_t) file_inode(file)->i_private;
135
136	return tomoyo_open_control(key, file);
137}
138
139/**
140 * tomoyo_release - close() for /sys/kernel/security/tomoyo/ interface.
141 *
142 * @inode: Pointer to "struct inode".
143 * @file:  Pointer to "struct file".
144 *
145 */
146static int tomoyo_release(struct inode *inode, struct file *file)
147{
148	tomoyo_close_control(file->private_data);
149	return 0;
150}
151
152/**
153 * tomoyo_poll - poll() for /sys/kernel/security/tomoyo/ interface.
154 *
155 * @file: Pointer to "struct file".
156 * @wait: Pointer to "poll_table". Maybe NULL.
157 *
158 * Returns EPOLLIN | EPOLLRDNORM | EPOLLOUT | EPOLLWRNORM if ready to read/write,
159 * EPOLLOUT | EPOLLWRNORM otherwise.
160 */
161static __poll_t tomoyo_poll(struct file *file, poll_table *wait)
162{
163	return tomoyo_poll_control(file, wait);
164}
165
166/**
167 * tomoyo_read - read() for /sys/kernel/security/tomoyo/ interface.
168 *
169 * @file:  Pointer to "struct file".
170 * @buf:   Pointer to buffer.
171 * @count: Size of @buf.
172 * @ppos:  Unused.
173 *
174 * Returns bytes read on success, negative value otherwise.
175 */
176static ssize_t tomoyo_read(struct file *file, char __user *buf, size_t count,
177			   loff_t *ppos)
178{
179	return tomoyo_read_control(file->private_data, buf, count);
180}
181
182/**
183 * tomoyo_write - write() for /sys/kernel/security/tomoyo/ interface.
184 *
185 * @file:  Pointer to "struct file".
186 * @buf:   Pointer to buffer.
187 * @count: Size of @buf.
188 * @ppos:  Unused.
189 *
190 * Returns @count on success, negative value otherwise.
191 */
192static ssize_t tomoyo_write(struct file *file, const char __user *buf,
193			    size_t count, loff_t *ppos)
194{
195	return tomoyo_write_control(file->private_data, buf, count);
196}
197
198/*
199 * tomoyo_operations is a "struct file_operations" which is used for handling
200 * /sys/kernel/security/tomoyo/ interface.
201 *
202 * Some files under /sys/kernel/security/tomoyo/ directory accept open(O_RDWR).
203 * See tomoyo_io_buffer for internals.
204 */
205static const struct file_operations tomoyo_operations = {
206	.open    = tomoyo_open,
207	.release = tomoyo_release,
208	.poll    = tomoyo_poll,
209	.read    = tomoyo_read,
210	.write   = tomoyo_write,
211	.llseek  = noop_llseek,
212};
213
214/**
215 * tomoyo_create_entry - Create interface files under /sys/kernel/security/tomoyo/ directory.
216 *
217 * @name:   The name of the interface file.
218 * @mode:   The permission of the interface file.
219 * @parent: The parent directory.
220 * @key:    Type of interface.
221 *
222 * Returns nothing.
223 */
224static void __init tomoyo_create_entry(const char *name, const umode_t mode,
225				       struct dentry *parent, const u8 key)
226{
227	securityfs_create_file(name, mode, parent, (void *) (uintptr_t) key,
228			       &tomoyo_operations);
229}
230
231/**
232 * tomoyo_initerface_init - Initialize /sys/kernel/security/tomoyo/ interface.
233 *
234 * Returns 0.
235 */
236static int __init tomoyo_initerface_init(void)
237{
238	struct tomoyo_domain_info *domain;
239	struct dentry *tomoyo_dir;
240
241	if (!tomoyo_enabled)
242		return 0;
243	domain = tomoyo_domain();
244	/* Don't create securityfs entries unless registered. */
245	if (domain != &tomoyo_kernel_domain)
246		return 0;
247
248	tomoyo_dir = securityfs_create_dir("tomoyo", NULL);
249	tomoyo_create_entry("query",            0600, tomoyo_dir,
250			    TOMOYO_QUERY);
251	tomoyo_create_entry("domain_policy",    0600, tomoyo_dir,
252			    TOMOYO_DOMAINPOLICY);
253	tomoyo_create_entry("exception_policy", 0600, tomoyo_dir,
254			    TOMOYO_EXCEPTIONPOLICY);
255	tomoyo_create_entry("audit",            0400, tomoyo_dir,
256			    TOMOYO_AUDIT);
257	tomoyo_create_entry(".process_status",  0600, tomoyo_dir,
258			    TOMOYO_PROCESS_STATUS);
259	tomoyo_create_entry("stat",             0644, tomoyo_dir,
260			    TOMOYO_STAT);
261	tomoyo_create_entry("profile",          0600, tomoyo_dir,
262			    TOMOYO_PROFILE);
263	tomoyo_create_entry("manager",          0600, tomoyo_dir,
264			    TOMOYO_MANAGER);
265	tomoyo_create_entry("version",          0400, tomoyo_dir,
266			    TOMOYO_VERSION);
267	securityfs_create_file("self_domain", 0666, tomoyo_dir, NULL,
268			       &tomoyo_self_operations);
269	tomoyo_load_builtin_policy();
270	return 0;
271}
272
273fs_initcall(tomoyo_initerface_init);
274