]> git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blame - security/tomoyo/mount.c
Linux 3.0-rc3
[mirror_ubuntu-bionic-kernel.git] / security / tomoyo / mount.c
CommitLineData
2106ccd9
TH
1/*
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
99a85259
TH
27/**
28 * 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",
e2bf6907
TH
58 tomoyo_pattern(r->param.mount.dev),
59 tomoyo_pattern(r->param.mount.dir), type,
99a85259
TH
60 flags);
61}
62
484ca79c 63static bool tomoyo_check_mount_acl(struct tomoyo_request_info *r,
99a85259
TH
64 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
2106ccd9 75/**
d795ef9e 76 * tomoyo_mount_acl - Check permission for mount() operation.
2106ccd9
TH
77 *
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 */
d795ef9e
TH
88static int tomoyo_mount_acl(struct tomoyo_request_info *r, char *dev_name,
89 struct path *dir, char *type, unsigned long flags)
2106ccd9
TH
90{
91 struct path path;
2106ccd9
TH
92 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. */
c8c57e84 103 requested_type = tomoyo_encode(type);
2106ccd9
TH
104 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);
db5ca356 146 path_put(&path);
2106ccd9
TH
147 if (!requested_dev_name) {
148 error = -ENOENT;
149 goto out;
150 }
151 } else {
152 /* Map dev_name to "<NULL>" if no dev_name given. */
153 if (!dev_name)
154 dev_name = "<NULL>";
c8c57e84 155 requested_dev_name = tomoyo_encode(dev_name);
2106ccd9
TH
156 if (!requested_dev_name) {
157 error = -ENOMEM;
158 goto out;
159 }
160 }
161 rdev.name = requested_dev_name;
162 tomoyo_fill_path_info(&rdev);
cf6e9a64
TH
163 r->param_type = TOMOYO_TYPE_MOUNT_ACL;
164 r->param.mount.need_dev = need_dev;
165 r->param.mount.dev = &rdev;
166 r->param.mount.dir = &rdir;
167 r->param.mount.type = &rtype;
168 r->param.mount.flags = flags;
99a85259
TH
169 do {
170 tomoyo_check_acl(r, tomoyo_check_mount_acl);
171 error = tomoyo_audit_mount_log(r);
172 } while (error == TOMOYO_RETRY_REQUEST);
2106ccd9
TH
173 out:
174 kfree(requested_dev_name);
175 kfree(requested_dir_name);
176 if (fstype)
177 put_filesystem(fstype);
178 kfree(requested_type);
179 return error;
180}
181
2106ccd9
TH
182/**
183 * tomoyo_mount_permission - Check permission for mount() operation.
184 *
185 * @dev_name: Name of device file.
186 * @path: Pointer to "struct path".
187 * @type: Name of filesystem type. May be NULL.
188 * @flags: Mount options.
189 * @data_page: Optional data. May be NULL.
190 *
191 * Returns 0 on success, negative value otherwise.
192 */
193int tomoyo_mount_permission(char *dev_name, struct path *path, char *type,
194 unsigned long flags, void *data_page)
195{
196 struct tomoyo_request_info r;
197 int error;
198 int idx;
199
57c2590f
TH
200 if (tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_MOUNT)
201 == TOMOYO_CONFIG_DISABLED)
2106ccd9 202 return 0;
d795ef9e
TH
203 if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
204 flags &= ~MS_MGC_MSK;
205 if (flags & MS_REMOUNT) {
206 type = TOMOYO_MOUNT_REMOUNT_KEYWORD;
207 flags &= ~MS_REMOUNT;
208 }
209 if (flags & MS_MOVE) {
210 type = TOMOYO_MOUNT_MOVE_KEYWORD;
211 flags &= ~MS_MOVE;
212 }
213 if (flags & MS_BIND) {
214 type = TOMOYO_MOUNT_BIND_KEYWORD;
215 flags &= ~MS_BIND;
216 }
217 if (flags & MS_UNBINDABLE) {
218 type = TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD;
219 flags &= ~MS_UNBINDABLE;
220 }
221 if (flags & MS_PRIVATE) {
222 type = TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD;
223 flags &= ~MS_PRIVATE;
224 }
225 if (flags & MS_SLAVE) {
226 type = TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD;
227 flags &= ~MS_SLAVE;
228 }
229 if (flags & MS_SHARED) {
230 type = TOMOYO_MOUNT_MAKE_SHARED_KEYWORD;
231 flags &= ~MS_SHARED;
232 }
2106ccd9
TH
233 if (!type)
234 type = "<NULL>";
235 idx = tomoyo_read_lock();
236 error = tomoyo_mount_acl(&r, dev_name, path, type, flags);
237 tomoyo_read_unlock(idx);
238 return error;
239}
240
237ab459
TH
241static bool tomoyo_same_mount_acl(const struct tomoyo_acl_info *a,
242 const struct tomoyo_acl_info *b)
243{
244 const struct tomoyo_mount_acl *p1 = container_of(a, typeof(*p1), head);
245 const struct tomoyo_mount_acl *p2 = container_of(b, typeof(*p2), head);
75093152
TH
246 return tomoyo_same_acl_head(&p1->head, &p2->head) &&
247 tomoyo_same_name_union(&p1->dev_name, &p2->dev_name) &&
248 tomoyo_same_name_union(&p1->dir_name, &p2->dir_name) &&
249 tomoyo_same_name_union(&p1->fs_type, &p2->fs_type) &&
250 tomoyo_same_number_union(&p1->flags, &p2->flags);
237ab459
TH
251}
252
2106ccd9 253/**
e2bf6907 254 * tomoyo_write_mount - Write "struct tomoyo_mount_acl" list.
2106ccd9
TH
255 *
256 * @data: String to parse.
257 * @domain: Pointer to "struct tomoyo_domain_info".
258 * @is_delete: True if it is a delete request.
259 *
260 * Returns 0 on success, negative value otherwise.
237ab459
TH
261 *
262 * Caller holds tomoyo_read_lock().
2106ccd9 263 */
e2bf6907
TH
264int tomoyo_write_mount(char *data, struct tomoyo_domain_info *domain,
265 const bool is_delete)
2106ccd9 266{
2106ccd9
TH
267 struct tomoyo_mount_acl e = { .head.type = TOMOYO_TYPE_MOUNT_ACL };
268 int error = is_delete ? -ENOENT : -ENOMEM;
269 char *w[4];
270 if (!tomoyo_tokenize(data, w, sizeof(w)) || !w[3][0])
271 return -EINVAL;
272 if (!tomoyo_parse_name_union(w[0], &e.dev_name) ||
273 !tomoyo_parse_name_union(w[1], &e.dir_name) ||
274 !tomoyo_parse_name_union(w[2], &e.fs_type) ||
275 !tomoyo_parse_number_union(w[3], &e.flags))
276 goto out;
237ab459
TH
277 error = tomoyo_update_domain(&e.head, sizeof(e), is_delete, domain,
278 tomoyo_same_mount_acl, NULL);
2106ccd9
TH
279 out:
280 tomoyo_put_name_union(&e.dev_name);
281 tomoyo_put_name_union(&e.dir_name);
282 tomoyo_put_name_union(&e.fs_type);
283 tomoyo_put_number_union(&e.flags);
284 return error;
285}