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