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  */
19 static 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  */
41 static 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  */
100 static 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. */
119 static 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  */
132 static 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  */
146 static 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  */
161 static __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  */
176 static 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  */
192 static 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  */
205 static 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  */
224 static 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  */
236 static 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 
273 fs_initcall(tomoyo_initerface_init);
274