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Tetsuo Handa2106ccd2010-05-17 10:10:31 +09001/*
2 * security/tomoyo/mount.c
3 *
4 * Copyright (C) 2005-2010 NTT DATA CORPORATION
5 */
6
7#include <linux/slab.h>
8#include "common.h"
9
10/* Keywords for mount restrictions. */
11
12/* Allow to call 'mount --bind /source_dir /dest_dir' */
13#define TOMOYO_MOUNT_BIND_KEYWORD "--bind"
14/* Allow to call 'mount --move /old_dir /new_dir ' */
15#define TOMOYO_MOUNT_MOVE_KEYWORD "--move"
16/* Allow to call 'mount -o remount /dir ' */
17#define TOMOYO_MOUNT_REMOUNT_KEYWORD "--remount"
18/* Allow to call 'mount --make-unbindable /dir' */
19#define TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD "--make-unbindable"
20/* Allow to call 'mount --make-private /dir' */
21#define TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD "--make-private"
22/* Allow to call 'mount --make-slave /dir' */
23#define TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD "--make-slave"
24/* Allow to call 'mount --make-shared /dir' */
25#define TOMOYO_MOUNT_MAKE_SHARED_KEYWORD "--make-shared"
26
27/**
Tetsuo Handa99a85252010-06-16 16:22:51 +090028 * tomoyo_audit_mount_log - Audit mount log.
29 *
30 * @r: Pointer to "struct tomoyo_request_info".
31 *
32 * Returns 0 on success, negative value otherwise.
33 */
34static int tomoyo_audit_mount_log(struct tomoyo_request_info *r)
35{
36 const char *dev = r->param.mount.dev->name;
37 const char *dir = r->param.mount.dir->name;
38 const char *type = r->param.mount.type->name;
39 const unsigned long flags = r->param.mount.flags;
40 if (r->granted)
41 return 0;
42 if (!strcmp(type, TOMOYO_MOUNT_REMOUNT_KEYWORD))
43 tomoyo_warn_log(r, "mount -o remount %s 0x%lX", dir, flags);
44 else if (!strcmp(type, TOMOYO_MOUNT_BIND_KEYWORD)
45 || !strcmp(type, TOMOYO_MOUNT_MOVE_KEYWORD))
46 tomoyo_warn_log(r, "mount %s %s %s 0x%lX", type, dev, dir,
47 flags);
48 else if (!strcmp(type, TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD) ||
49 !strcmp(type, TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD) ||
50 !strcmp(type, TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD) ||
51 !strcmp(type, TOMOYO_MOUNT_MAKE_SHARED_KEYWORD))
52 tomoyo_warn_log(r, "mount %s %s 0x%lX", type, dir, flags);
53 else
54 tomoyo_warn_log(r, "mount -t %s %s %s 0x%lX", type, dev, dir,
55 flags);
56 return tomoyo_supervisor(r,
57 TOMOYO_KEYWORD_ALLOW_MOUNT "%s %s %s 0x%lX\n",
Tetsuo Handae2bf6902010-06-25 11:16:00 +090058 tomoyo_pattern(r->param.mount.dev),
59 tomoyo_pattern(r->param.mount.dir), type,
Tetsuo Handa99a85252010-06-16 16:22:51 +090060 flags);
61}
62
Tetsuo Handa484ca792010-07-29 14:29:55 +090063static bool tomoyo_check_mount_acl(struct tomoyo_request_info *r,
Tetsuo Handa99a85252010-06-16 16:22:51 +090064 const struct tomoyo_acl_info *ptr)
65{
66 const struct tomoyo_mount_acl *acl =
67 container_of(ptr, typeof(*acl), head);
68 return tomoyo_compare_number_union(r->param.mount.flags, &acl->flags) &&
69 tomoyo_compare_name_union(r->param.mount.type, &acl->fs_type) &&
70 tomoyo_compare_name_union(r->param.mount.dir, &acl->dir_name) &&
71 (!r->param.mount.need_dev ||
72 tomoyo_compare_name_union(r->param.mount.dev, &acl->dev_name));
73}
74
75/**
Tetsuo Handad795ef9e2010-06-16 16:24:58 +090076 * tomoyo_mount_acl - Check permission for mount() operation.
Tetsuo Handa2106ccd2010-05-17 10:10:31 +090077 *
78 * @r: Pointer to "struct tomoyo_request_info".
79 * @dev_name: Name of device file.
80 * @dir: Pointer to "struct path".
81 * @type: Name of filesystem type.
82 * @flags: Mount options.
83 *
84 * Returns 0 on success, negative value otherwise.
85 *
86 * Caller holds tomoyo_read_lock().
87 */
Tetsuo Handad795ef9e2010-06-16 16:24:58 +090088static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
89 struct path *dir, char *type, unsigned long flags)
Tetsuo Handa2106ccd2010-05-17 10:10:31 +090090{
91 struct path path;
Tetsuo Handa2106ccd2010-05-17 10:10:31 +090092 struct file_system_type *fstype = NULL;
93 const char *requested_type = NULL;
94 const char *requested_dir_name = NULL;
95 const char *requested_dev_name = NULL;
96 struct tomoyo_path_info rtype;
97 struct tomoyo_path_info rdev;
98 struct tomoyo_path_info rdir;
99 int need_dev = 0;
100 int error = -ENOMEM;
101
102 /* Get fstype. */
Tetsuo Handac8c57e82010-06-03 20:36:43 +0900103 requested_type = tomoyo_encode(type);
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900104 if (!requested_type)
105 goto out;
106 rtype.name = requested_type;
107 tomoyo_fill_path_info(&rtype);
108
109 /* Get mount point. */
110 requested_dir_name = tomoyo_realpath_from_path(dir);
111 if (!requested_dir_name) {
112 error = -ENOMEM;
113 goto out;
114 }
115 rdir.name = requested_dir_name;
116 tomoyo_fill_path_info(&rdir);
117
118 /* Compare fs name. */
119 if (!strcmp(type, TOMOYO_MOUNT_REMOUNT_KEYWORD)) {
120 /* dev_name is ignored. */
121 } else if (!strcmp(type, TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD) ||
122 !strcmp(type, TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD) ||
123 !strcmp(type, TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD) ||
124 !strcmp(type, TOMOYO_MOUNT_MAKE_SHARED_KEYWORD)) {
125 /* dev_name is ignored. */
126 } else if (!strcmp(type, TOMOYO_MOUNT_BIND_KEYWORD) ||
127 !strcmp(type, TOMOYO_MOUNT_MOVE_KEYWORD)) {
128 need_dev = -1; /* dev_name is a directory */
129 } else {
130 fstype = get_fs_type(type);
131 if (!fstype) {
132 error = -ENODEV;
133 goto out;
134 }
135 if (fstype->fs_flags & FS_REQUIRES_DEV)
136 /* dev_name is a block device file. */
137 need_dev = 1;
138 }
139 if (need_dev) {
140 /* Get mount point or device file. */
141 if (kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
142 error = -ENOENT;
143 goto out;
144 }
145 requested_dev_name = tomoyo_realpath_from_path(&path);
146 if (!requested_dev_name) {
147 error = -ENOENT;
148 goto out;
149 }
150 } else {
151 /* Map dev_name to "<NULL>" if no dev_name given. */
152 if (!dev_name)
153 dev_name = "<NULL>";
Tetsuo Handac8c57e82010-06-03 20:36:43 +0900154 requested_dev_name = tomoyo_encode(dev_name);
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900155 if (!requested_dev_name) {
156 error = -ENOMEM;
157 goto out;
158 }
159 }
160 rdev.name = requested_dev_name;
161 tomoyo_fill_path_info(&rdev);
Tetsuo Handacf6e9a62010-06-16 16:21:36 +0900162 r->param_type = TOMOYO_TYPE_MOUNT_ACL;
163 r->param.mount.need_dev = need_dev;
164 r->param.mount.dev = &rdev;
165 r->param.mount.dir = &rdir;
166 r->param.mount.type = &rtype;
167 r->param.mount.flags = flags;
Tetsuo Handa99a85252010-06-16 16:22:51 +0900168 do {
169 tomoyo_check_acl(r, tomoyo_check_mount_acl);
170 error = tomoyo_audit_mount_log(r);
171 } while (error == TOMOYO_RETRY_REQUEST);
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900172 out:
173 kfree(requested_dev_name);
174 kfree(requested_dir_name);
175 if (fstype)
176 put_filesystem(fstype);
177 kfree(requested_type);
178 return error;
179}
180
181/**
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900182 * tomoyo_mount_permission - Check permission for mount() operation.
183 *
184 * @dev_name: Name of device file.
185 * @path: Pointer to "struct path".
186 * @type: Name of filesystem type. May be NULL.
187 * @flags: Mount options.
188 * @data_page: Optional data. May be NULL.
189 *
190 * Returns 0 on success, negative value otherwise.
191 */
192int tomoyo_mount_permission(char *dev_name, struct path *path, char *type,
193 unsigned long flags, void *data_page)
194{
195 struct tomoyo_request_info r;
196 int error;
197 int idx;
198
Tetsuo Handa57c25902010-06-03 20:38:44 +0900199 if (tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_MOUNT)
200 == TOMOYO_CONFIG_DISABLED)
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900201 return 0;
Tetsuo Handad795ef9e2010-06-16 16:24:58 +0900202 if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
203 flags &= ~MS_MGC_MSK;
204 if (flags & MS_REMOUNT) {
205 type = TOMOYO_MOUNT_REMOUNT_KEYWORD;
206 flags &= ~MS_REMOUNT;
207 }
208 if (flags & MS_MOVE) {
209 type = TOMOYO_MOUNT_MOVE_KEYWORD;
210 flags &= ~MS_MOVE;
211 }
212 if (flags & MS_BIND) {
213 type = TOMOYO_MOUNT_BIND_KEYWORD;
214 flags &= ~MS_BIND;
215 }
216 if (flags & MS_UNBINDABLE) {
217 type = TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD;
218 flags &= ~MS_UNBINDABLE;
219 }
220 if (flags & MS_PRIVATE) {
221 type = TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD;
222 flags &= ~MS_PRIVATE;
223 }
224 if (flags & MS_SLAVE) {
225 type = TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD;
226 flags &= ~MS_SLAVE;
227 }
228 if (flags & MS_SHARED) {
229 type = TOMOYO_MOUNT_MAKE_SHARED_KEYWORD;
230 flags &= ~MS_SHARED;
231 }
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900232 if (!type)
233 type = "<NULL>";
234 idx = tomoyo_read_lock();
235 error = tomoyo_mount_acl(&r, dev_name, path, type, flags);
236 tomoyo_read_unlock(idx);
237 return error;
238}
239
Tetsuo Handa237ab452010-06-12 20:46:22 +0900240static bool tomoyo_same_mount_acl(const struct tomoyo_acl_info *a,
241 const struct tomoyo_acl_info *b)
242{
243 const struct tomoyo_mount_acl *p1 = container_of(a, typeof(*p1), head);
244 const struct tomoyo_mount_acl *p2 = container_of(b, typeof(*p2), head);
Tetsuo Handa75093152010-06-16 16:23:55 +0900245 return tomoyo_same_acl_head(&p1->head, &p2->head) &&
246 tomoyo_same_name_union(&p1->dev_name, &p2->dev_name) &&
247 tomoyo_same_name_union(&p1->dir_name, &p2->dir_name) &&
248 tomoyo_same_name_union(&p1->fs_type, &p2->fs_type) &&
249 tomoyo_same_number_union(&p1->flags, &p2->flags);
Tetsuo Handa237ab452010-06-12 20:46:22 +0900250}
251
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900252/**
Tetsuo Handae2bf6902010-06-25 11:16:00 +0900253 * tomoyo_write_mount - Write "struct tomoyo_mount_acl" list.
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900254 *
255 * @data: String to parse.
256 * @domain: Pointer to "struct tomoyo_domain_info".
257 * @is_delete: True if it is a delete request.
258 *
259 * Returns 0 on success, negative value otherwise.
Tetsuo Handa237ab452010-06-12 20:46:22 +0900260 *
261 * Caller holds tomoyo_read_lock().
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900262 */
Tetsuo Handae2bf6902010-06-25 11:16:00 +0900263int tomoyo_write_mount(char *data, struct tomoyo_domain_info *domain,
264 const bool is_delete)
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900265{
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900266 struct tomoyo_mount_acl e = { .head.type = TOMOYO_TYPE_MOUNT_ACL };
267 int error = is_delete ? -ENOENT : -ENOMEM;
268 char *w[4];
269 if (!tomoyo_tokenize(data, w, sizeof(w)) || !w[3][0])
270 return -EINVAL;
271 if (!tomoyo_parse_name_union(w[0], &e.dev_name) ||
272 !tomoyo_parse_name_union(w[1], &e.dir_name) ||
273 !tomoyo_parse_name_union(w[2], &e.fs_type) ||
274 !tomoyo_parse_number_union(w[3], &e.flags))
275 goto out;
Tetsuo Handa237ab452010-06-12 20:46:22 +0900276 error = tomoyo_update_domain(&e.head, sizeof(e), is_delete, domain,
277 tomoyo_same_mount_acl, NULL);
Tetsuo Handa2106ccd2010-05-17 10:10:31 +0900278 out:
279 tomoyo_put_name_union(&e.dev_name);
280 tomoyo_put_name_union(&e.dir_name);
281 tomoyo_put_name_union(&e.fs_type);
282 tomoyo_put_number_union(&e.flags);
283 return error;
284}