Merge tag 'media/v4.20-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab...
[linux-2.6-microblaze.git] / security / tomoyo / securityfs_if.c
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);