tomoyo.c revision 4572befe248fd0d94aedc98775e3f0ddc8a26651 
1/*
2 * security/tomoyo/tomoyo.c
3 *
4 * Copyright (C) 2005-2011  NTT DATA CORPORATION
5 */
6
7#include <linux/security.h>
8#include "common.h"
9
10/**
11 * tomoyo_cred_alloc_blank - Target for security_cred_alloc_blank().
12 *
13 * @new: Pointer to "struct cred".
14 * @gfp: Memory allocation flags.
15 *
16 * Returns 0.
17 */
18static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
19{
20	new->security = NULL;
21	return 0;
22}
23
24/**
25 * tomoyo_cred_prepare - Target for security_prepare_creds().
26 *
27 * @new: Pointer to "struct cred".
28 * @old: Pointer to "struct cred".
29 * @gfp: Memory allocation flags.
30 *
31 * Returns 0.
32 */
33static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
34			       gfp_t gfp)
35{
36	struct tomoyo_domain_info *domain = old->security;
37	new->security = domain;
38	if (domain)
39		atomic_inc(&domain->users);
40	return 0;
41}
42
43/**
44 * tomoyo_cred_transfer - Target for security_transfer_creds().
45 *
46 * @new: Pointer to "struct cred".
47 * @old: Pointer to "struct cred".
48 */
49static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
50{
51	tomoyo_cred_prepare(new, old, 0);
52}
53
54/**
55 * tomoyo_cred_free - Target for security_cred_free().
56 *
57 * @cred: Pointer to "struct cred".
58 */
59static void tomoyo_cred_free(struct cred *cred)
60{
61	struct tomoyo_domain_info *domain = cred->security;
62	if (domain)
63		atomic_dec(&domain->users);
64}
65
66/**
67 * tomoyo_bprm_set_creds - Target for security_bprm_set_creds().
68 *
69 * @bprm: Pointer to "struct linux_binprm".
70 *
71 * Returns 0 on success, negative value otherwise.
72 */
73static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
74{
75	int rc;
76
77	rc = cap_bprm_set_creds(bprm);
78	if (rc)
79		return rc;
80
81	/*
82	 * Do only if this function is called for the first time of an execve
83	 * operation.
84	 */
85	if (bprm->cred_prepared)
86		return 0;
87#ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
88	/*
89	 * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
90	 * for the first time.
91	 */
92	if (!tomoyo_policy_loaded)
93		tomoyo_load_policy(bprm->filename);
94#endif
95	/*
96	 * Release reference to "struct tomoyo_domain_info" stored inside
97	 * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
98	 * stored inside "bprm->cred->security" will be acquired later inside
99	 * tomoyo_find_next_domain().
100	 */
101	atomic_dec(&((struct tomoyo_domain_info *)
102		     bprm->cred->security)->users);
103	/*
104	 * Tell tomoyo_bprm_check_security() is called for the first time of an
105	 * execve operation.
106	 */
107	bprm->cred->security = NULL;
108	return 0;
109}
110
111/**
112 * tomoyo_bprm_check_security - Target for security_bprm_check().
113 *
114 * @bprm: Pointer to "struct linux_binprm".
115 *
116 * Returns 0 on success, negative value otherwise.
117 */
118static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
119{
120	struct tomoyo_domain_info *domain = bprm->cred->security;
121
122	/*
123	 * Execute permission is checked against pathname passed to do_execve()
124	 * using current domain.
125	 */
126	if (!domain) {
127		const int idx = tomoyo_read_lock();
128		const int err = tomoyo_find_next_domain(bprm);
129		tomoyo_read_unlock(idx);
130		return err;
131	}
132	/*
133	 * Read permission is checked against interpreters using next domain.
134	 */
135	return tomoyo_check_open_permission(domain, &bprm->file->f_path,
136					    O_RDONLY);
137}
138
139/**
140 * tomoyo_inode_getattr - Target for security_inode_getattr().
141 *
142 * @mnt:    Pointer to "struct vfsmount".
143 * @dentry: Pointer to "struct dentry".
144 *
145 * Returns 0 on success, negative value otherwise.
146 */
147static int tomoyo_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
148{
149	struct path path = { mnt, dentry };
150	return tomoyo_path_perm(TOMOYO_TYPE_GETATTR, &path, NULL);
151}
152
153/**
154 * tomoyo_path_truncate - Target for security_path_truncate().
155 *
156 * @path: Pointer to "struct path".
157 *
158 * Returns 0 on success, negative value otherwise.
159 */
160static int tomoyo_path_truncate(struct path *path)
161{
162	return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path, NULL);
163}
164
165/**
166 * tomoyo_path_unlink - Target for security_path_unlink().
167 *
168 * @parent: Pointer to "struct path".
169 * @dentry: Pointer to "struct dentry".
170 *
171 * Returns 0 on success, negative value otherwise.
172 */
173static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
174{
175	struct path path = { parent->mnt, dentry };
176	return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path, NULL);
177}
178
179/**
180 * tomoyo_path_mkdir - Target for security_path_mkdir().
181 *
182 * @parent: Pointer to "struct path".
183 * @dentry: Pointer to "struct dentry".
184 * @mode:   DAC permission mode.
185 *
186 * Returns 0 on success, negative value otherwise.
187 */
188static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
189			     umode_t mode)
190{
191	struct path path = { parent->mnt, dentry };
192	return tomoyo_path_number_perm(TOMOYO_TYPE_MKDIR, &path,
193				       mode & S_IALLUGO);
194}
195
196/**
197 * tomoyo_path_rmdir - Target for security_path_rmdir().
198 *
199 * @parent: Pointer to "struct path".
200 * @dentry: Pointer to "struct dentry".
201 *
202 * Returns 0 on success, negative value otherwise.
203 */
204static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
205{
206	struct path path = { parent->mnt, dentry };
207	return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path, NULL);
208}
209
210/**
211 * tomoyo_path_symlink - Target for security_path_symlink().
212 *
213 * @parent:   Pointer to "struct path".
214 * @dentry:   Pointer to "struct dentry".
215 * @old_name: Symlink's content.
216 *
217 * Returns 0 on success, negative value otherwise.
218 */
219static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
220			       const char *old_name)
221{
222	struct path path = { parent->mnt, dentry };
223	return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path, old_name);
224}
225
226/**
227 * tomoyo_path_mknod - Target for security_path_mknod().
228 *
229 * @parent: Pointer to "struct path".
230 * @dentry: Pointer to "struct dentry".
231 * @mode:   DAC permission mode.
232 * @dev:    Device attributes.
233 *
234 * Returns 0 on success, negative value otherwise.
235 */
236static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
237			     int mode, unsigned int dev)
238{
239	struct path path = { parent->mnt, dentry };
240	int type = TOMOYO_TYPE_CREATE;
241	const unsigned int perm = mode & S_IALLUGO;
242
243	switch (mode & S_IFMT) {
244	case S_IFCHR:
245		type = TOMOYO_TYPE_MKCHAR;
246		break;
247	case S_IFBLK:
248		type = TOMOYO_TYPE_MKBLOCK;
249		break;
250	default:
251		goto no_dev;
252	}
253	return tomoyo_mkdev_perm(type, &path, perm, dev);
254 no_dev:
255	switch (mode & S_IFMT) {
256	case S_IFIFO:
257		type = TOMOYO_TYPE_MKFIFO;
258		break;
259	case S_IFSOCK:
260		type = TOMOYO_TYPE_MKSOCK;
261		break;
262	}
263	return tomoyo_path_number_perm(type, &path, perm);
264}
265
266/**
267 * tomoyo_path_link - Target for security_path_link().
268 *
269 * @old_dentry: Pointer to "struct dentry".
270 * @new_dir:    Pointer to "struct path".
271 * @new_dentry: Pointer to "struct dentry".
272 *
273 * Returns 0 on success, negative value otherwise.
274 */
275static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
276			    struct dentry *new_dentry)
277{
278	struct path path1 = { new_dir->mnt, old_dentry };
279	struct path path2 = { new_dir->mnt, new_dentry };
280	return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2);
281}
282
283/**
284 * tomoyo_path_rename - Target for security_path_rename().
285 *
286 * @old_parent: Pointer to "struct path".
287 * @old_dentry: Pointer to "struct dentry".
288 * @new_parent: Pointer to "struct path".
289 * @new_dentry: Pointer to "struct dentry".
290 *
291 * Returns 0 on success, negative value otherwise.
292 */
293static int tomoyo_path_rename(struct path *old_parent,
294			      struct dentry *old_dentry,
295			      struct path *new_parent,
296			      struct dentry *new_dentry)
297{
298	struct path path1 = { old_parent->mnt, old_dentry };
299	struct path path2 = { new_parent->mnt, new_dentry };
300	return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2);
301}
302
303/**
304 * tomoyo_file_fcntl - Target for security_file_fcntl().
305 *
306 * @file: Pointer to "struct file".
307 * @cmd:  Command for fcntl().
308 * @arg:  Argument for @cmd.
309 *
310 * Returns 0 on success, negative value otherwise.
311 */
312static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
313			     unsigned long arg)
314{
315	if (!(cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND)))
316		return 0;
317	return tomoyo_check_open_permission(tomoyo_domain(), &file->f_path,
318					    O_WRONLY | (arg & O_APPEND));
319}
320
321/**
322 * tomoyo_dentry_open - Target for security_dentry_open().
323 *
324 * @f:    Pointer to "struct file".
325 * @cred: Pointer to "struct cred".
326 *
327 * Returns 0 on success, negative value otherwise.
328 */
329static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
330{
331	int flags = f->f_flags;
332	/* Don't check read permission here if called from do_execve(). */
333	if (current->in_execve)
334		return 0;
335	return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
336}
337
338/**
339 * tomoyo_file_ioctl - Target for security_file_ioctl().
340 *
341 * @file: Pointer to "struct file".
342 * @cmd:  Command for ioctl().
343 * @arg:  Argument for @cmd.
344 *
345 * Returns 0 on success, negative value otherwise.
346 */
347static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
348			     unsigned long arg)
349{
350	return tomoyo_path_number_perm(TOMOYO_TYPE_IOCTL, &file->f_path, cmd);
351}
352
353/**
354 * tomoyo_path_chmod - Target for security_path_chmod().
355 *
356 * @dentry: Pointer to "struct dentry".
357 * @mnt:    Pointer to "struct vfsmount".
358 * @mode:   DAC permission mode.
359 *
360 * Returns 0 on success, negative value otherwise.
361 */
362static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
363			     umode_t mode)
364{
365	struct path path = { mnt, dentry };
366	return tomoyo_path_number_perm(TOMOYO_TYPE_CHMOD, &path,
367				       mode & S_IALLUGO);
368}
369
370/**
371 * tomoyo_path_chown - Target for security_path_chown().
372 *
373 * @path: Pointer to "struct path".
374 * @uid:  Owner ID.
375 * @gid:  Group ID.
376 *
377 * Returns 0 on success, negative value otherwise.
378 */
379static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
380{
381	int error = 0;
382	if (uid != (uid_t) -1)
383		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path, uid);
384	if (!error && gid != (gid_t) -1)
385		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path, gid);
386	return error;
387}
388
389/**
390 * tomoyo_path_chroot - Target for security_path_chroot().
391 *
392 * @path: Pointer to "struct path".
393 *
394 * Returns 0 on success, negative value otherwise.
395 */
396static int tomoyo_path_chroot(struct path *path)
397{
398	return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path, NULL);
399}
400
401/**
402 * tomoyo_sb_mount - Target for security_sb_mount().
403 *
404 * @dev_name: Name of device file. Maybe NULL.
405 * @path:     Pointer to "struct path".
406 * @type:     Name of filesystem type. Maybe NULL.
407 * @flags:    Mount options.
408 * @data:     Optional data. Maybe NULL.
409 *
410 * Returns 0 on success, negative value otherwise.
411 */
412static int tomoyo_sb_mount(char *dev_name, struct path *path,
413			   char *type, unsigned long flags, void *data)
414{
415	return tomoyo_mount_permission(dev_name, path, type, flags, data);
416}
417
418/**
419 * tomoyo_sb_umount - Target for security_sb_umount().
420 *
421 * @mnt:   Pointer to "struct vfsmount".
422 * @flags: Unmount options.
423 *
424 * Returns 0 on success, negative value otherwise.
425 */
426static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
427{
428	struct path path = { mnt, mnt->mnt_root };
429	return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path, NULL);
430}
431
432/**
433 * tomoyo_sb_pivotroot - Target for security_sb_pivotroot().
434 *
435 * @old_path: Pointer to "struct path".
436 * @new_path: Pointer to "struct path".
437 *
438 * Returns 0 on success, negative value otherwise.
439 */
440static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
441{
442	return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path);
443}
444
445/**
446 * tomoyo_socket_listen - Check permission for listen().
447 *
448 * @sock:    Pointer to "struct socket".
449 * @backlog: Backlog parameter.
450 *
451 * Returns 0 on success, negative value otherwise.
452 */
453static int tomoyo_socket_listen(struct socket *sock, int backlog)
454{
455	return tomoyo_socket_listen_permission(sock);
456}
457
458/**
459 * tomoyo_socket_connect - Check permission for connect().
460 *
461 * @sock:     Pointer to "struct socket".
462 * @addr:     Pointer to "struct sockaddr".
463 * @addr_len: Size of @addr.
464 *
465 * Returns 0 on success, negative value otherwise.
466 */
467static int tomoyo_socket_connect(struct socket *sock, struct sockaddr *addr,
468				 int addr_len)
469{
470	return tomoyo_socket_connect_permission(sock, addr, addr_len);
471}
472
473/**
474 * tomoyo_socket_bind - Check permission for bind().
475 *
476 * @sock:     Pointer to "struct socket".
477 * @addr:     Pointer to "struct sockaddr".
478 * @addr_len: Size of @addr.
479 *
480 * Returns 0 on success, negative value otherwise.
481 */
482static int tomoyo_socket_bind(struct socket *sock, struct sockaddr *addr,
483			      int addr_len)
484{
485	return tomoyo_socket_bind_permission(sock, addr, addr_len);
486}
487
488/**
489 * tomoyo_socket_sendmsg - Check permission for sendmsg().
490 *
491 * @sock: Pointer to "struct socket".
492 * @msg:  Pointer to "struct msghdr".
493 * @size: Size of message.
494 *
495 * Returns 0 on success, negative value otherwise.
496 */
497static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg,
498				 int size)
499{
500	return tomoyo_socket_sendmsg_permission(sock, msg, size);
501}
502
503/*
504 * tomoyo_security_ops is a "struct security_operations" which is used for
505 * registering TOMOYO.
506 */
507static struct security_operations tomoyo_security_ops = {
508	.name                = "tomoyo",
509	.cred_alloc_blank    = tomoyo_cred_alloc_blank,
510	.cred_prepare        = tomoyo_cred_prepare,
511	.cred_transfer	     = tomoyo_cred_transfer,
512	.cred_free           = tomoyo_cred_free,
513	.bprm_set_creds      = tomoyo_bprm_set_creds,
514	.bprm_check_security = tomoyo_bprm_check_security,
515	.file_fcntl          = tomoyo_file_fcntl,
516	.dentry_open         = tomoyo_dentry_open,
517	.path_truncate       = tomoyo_path_truncate,
518	.path_unlink         = tomoyo_path_unlink,
519	.path_mkdir          = tomoyo_path_mkdir,
520	.path_rmdir          = tomoyo_path_rmdir,
521	.path_symlink        = tomoyo_path_symlink,
522	.path_mknod          = tomoyo_path_mknod,
523	.path_link           = tomoyo_path_link,
524	.path_rename         = tomoyo_path_rename,
525	.inode_getattr       = tomoyo_inode_getattr,
526	.file_ioctl          = tomoyo_file_ioctl,
527	.path_chmod          = tomoyo_path_chmod,
528	.path_chown          = tomoyo_path_chown,
529	.path_chroot         = tomoyo_path_chroot,
530	.sb_mount            = tomoyo_sb_mount,
531	.sb_umount           = tomoyo_sb_umount,
532	.sb_pivotroot        = tomoyo_sb_pivotroot,
533	.socket_bind         = tomoyo_socket_bind,
534	.socket_connect      = tomoyo_socket_connect,
535	.socket_listen       = tomoyo_socket_listen,
536	.socket_sendmsg      = tomoyo_socket_sendmsg,
537};
538
539/* Lock for GC. */
540struct srcu_struct tomoyo_ss;
541
542/**
543 * tomoyo_init - Register TOMOYO Linux as a LSM module.
544 *
545 * Returns 0.
546 */
547static int __init tomoyo_init(void)
548{
549	struct cred *cred = (struct cred *) current_cred();
550
551	if (!security_module_enable(&tomoyo_security_ops))
552		return 0;
553	/* register ourselves with the security framework */
554	if (register_security(&tomoyo_security_ops) ||
555	    init_srcu_struct(&tomoyo_ss))
556		panic("Failure registering TOMOYO Linux");
557	printk(KERN_INFO "TOMOYO Linux initialized\n");
558	cred->security = &tomoyo_kernel_domain;
559	tomoyo_mm_init();
560	return 0;
561}
562
563security_initcall(tomoyo_init);
564