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(const struct path *path)
148{
149	return tomoyo_path_perm(TOMOYO_TYPE_GETATTR, path, NULL);
150}
151
152/**
153 * tomoyo_path_truncate - Target for security_path_truncate().
154 *
155 * @path: Pointer to "struct path".
156 *
157 * Returns 0 on success, negative value otherwise.
158 */
159static int tomoyo_path_truncate(struct path *path)
160{
161	return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path, NULL);
162}
163
164/**
165 * tomoyo_path_unlink - Target for security_path_unlink().
166 *
167 * @parent: Pointer to "struct path".
168 * @dentry: Pointer to "struct dentry".
169 *
170 * Returns 0 on success, negative value otherwise.
171 */
172static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
173{
174	struct path path = { parent->mnt, dentry };
175	return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path, NULL);
176}
177
178/**
179 * tomoyo_path_mkdir - Target for security_path_mkdir().
180 *
181 * @parent: Pointer to "struct path".
182 * @dentry: Pointer to "struct dentry".
183 * @mode:   DAC permission mode.
184 *
185 * Returns 0 on success, negative value otherwise.
186 */
187static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
188			     umode_t mode)
189{
190	struct path path = { parent->mnt, dentry };
191	return tomoyo_path_number_perm(TOMOYO_TYPE_MKDIR, &path,
192				       mode & S_IALLUGO);
193}
194
195/**
196 * tomoyo_path_rmdir - Target for security_path_rmdir().
197 *
198 * @parent: Pointer to "struct path".
199 * @dentry: Pointer to "struct dentry".
200 *
201 * Returns 0 on success, negative value otherwise.
202 */
203static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
204{
205	struct path path = { parent->mnt, dentry };
206	return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path, NULL);
207}
208
209/**
210 * tomoyo_path_symlink - Target for security_path_symlink().
211 *
212 * @parent:   Pointer to "struct path".
213 * @dentry:   Pointer to "struct dentry".
214 * @old_name: Symlink's content.
215 *
216 * Returns 0 on success, negative value otherwise.
217 */
218static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
219			       const char *old_name)
220{
221	struct path path = { parent->mnt, dentry };
222	return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path, old_name);
223}
224
225/**
226 * tomoyo_path_mknod - Target for security_path_mknod().
227 *
228 * @parent: Pointer to "struct path".
229 * @dentry: Pointer to "struct dentry".
230 * @mode:   DAC permission mode.
231 * @dev:    Device attributes.
232 *
233 * Returns 0 on success, negative value otherwise.
234 */
235static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
236			     umode_t mode, unsigned int dev)
237{
238	struct path path = { parent->mnt, dentry };
239	int type = TOMOYO_TYPE_CREATE;
240	const unsigned int perm = mode & S_IALLUGO;
241
242	switch (mode & S_IFMT) {
243	case S_IFCHR:
244		type = TOMOYO_TYPE_MKCHAR;
245		break;
246	case S_IFBLK:
247		type = TOMOYO_TYPE_MKBLOCK;
248		break;
249	default:
250		goto no_dev;
251	}
252	return tomoyo_mkdev_perm(type, &path, perm, dev);
253 no_dev:
254	switch (mode & S_IFMT) {
255	case S_IFIFO:
256		type = TOMOYO_TYPE_MKFIFO;
257		break;
258	case S_IFSOCK:
259		type = TOMOYO_TYPE_MKSOCK;
260		break;
261	}
262	return tomoyo_path_number_perm(type, &path, perm);
263}
264
265/**
266 * tomoyo_path_link - Target for security_path_link().
267 *
268 * @old_dentry: Pointer to "struct dentry".
269 * @new_dir:    Pointer to "struct path".
270 * @new_dentry: Pointer to "struct dentry".
271 *
272 * Returns 0 on success, negative value otherwise.
273 */
274static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
275			    struct dentry *new_dentry)
276{
277	struct path path1 = { new_dir->mnt, old_dentry };
278	struct path path2 = { new_dir->mnt, new_dentry };
279	return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2);
280}
281
282/**
283 * tomoyo_path_rename - Target for security_path_rename().
284 *
285 * @old_parent: Pointer to "struct path".
286 * @old_dentry: Pointer to "struct dentry".
287 * @new_parent: Pointer to "struct path".
288 * @new_dentry: Pointer to "struct dentry".
289 *
290 * Returns 0 on success, negative value otherwise.
291 */
292static int tomoyo_path_rename(struct path *old_parent,
293			      struct dentry *old_dentry,
294			      struct path *new_parent,
295			      struct dentry *new_dentry)
296{
297	struct path path1 = { old_parent->mnt, old_dentry };
298	struct path path2 = { new_parent->mnt, new_dentry };
299	return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2);
300}
301
302/**
303 * tomoyo_file_fcntl - Target for security_file_fcntl().
304 *
305 * @file: Pointer to "struct file".
306 * @cmd:  Command for fcntl().
307 * @arg:  Argument for @cmd.
308 *
309 * Returns 0 on success, negative value otherwise.
310 */
311static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
312			     unsigned long arg)
313{
314	if (!(cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND)))
315		return 0;
316	return tomoyo_check_open_permission(tomoyo_domain(), &file->f_path,
317					    O_WRONLY | (arg & O_APPEND));
318}
319
320/**
321 * tomoyo_file_open - Target for security_file_open().
322 *
323 * @f:    Pointer to "struct file".
324 * @cred: Pointer to "struct cred".
325 *
326 * Returns 0 on success, negative value otherwise.
327 */
328static int tomoyo_file_open(struct file *f, const struct cred *cred)
329{
330	int flags = f->f_flags;
331	/* Don't check read permission here if called from do_execve(). */
332	if (current->in_execve)
333		return 0;
334	return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
335}
336
337/**
338 * tomoyo_file_ioctl - Target for security_file_ioctl().
339 *
340 * @file: Pointer to "struct file".
341 * @cmd:  Command for ioctl().
342 * @arg:  Argument for @cmd.
343 *
344 * Returns 0 on success, negative value otherwise.
345 */
346static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
347			     unsigned long arg)
348{
349	return tomoyo_path_number_perm(TOMOYO_TYPE_IOCTL, &file->f_path, cmd);
350}
351
352/**
353 * tomoyo_path_chmod - Target for security_path_chmod().
354 *
355 * @path: Pointer to "struct path".
356 * @mode: DAC permission mode.
357 *
358 * Returns 0 on success, negative value otherwise.
359 */
360static int tomoyo_path_chmod(struct path *path, umode_t mode)
361{
362	return tomoyo_path_number_perm(TOMOYO_TYPE_CHMOD, path,
363				       mode & S_IALLUGO);
364}
365
366/**
367 * tomoyo_path_chown - Target for security_path_chown().
368 *
369 * @path: Pointer to "struct path".
370 * @uid:  Owner ID.
371 * @gid:  Group ID.
372 *
373 * Returns 0 on success, negative value otherwise.
374 */
375static int tomoyo_path_chown(struct path *path, kuid_t uid, kgid_t gid)
376{
377	int error = 0;
378	if (uid_valid(uid))
379		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path,
380						from_kuid(&init_user_ns, uid));
381	if (!error && gid_valid(gid))
382		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path,
383						from_kgid(&init_user_ns, gid));
384	return error;
385}
386
387/**
388 * tomoyo_path_chroot - Target for security_path_chroot().
389 *
390 * @path: Pointer to "struct path".
391 *
392 * Returns 0 on success, negative value otherwise.
393 */
394static int tomoyo_path_chroot(struct path *path)
395{
396	return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path, NULL);
397}
398
399/**
400 * tomoyo_sb_mount - Target for security_sb_mount().
401 *
402 * @dev_name: Name of device file. Maybe NULL.
403 * @path:     Pointer to "struct path".
404 * @type:     Name of filesystem type. Maybe NULL.
405 * @flags:    Mount options.
406 * @data:     Optional data. Maybe NULL.
407 *
408 * Returns 0 on success, negative value otherwise.
409 */
410static int tomoyo_sb_mount(const char *dev_name, struct path *path,
411			   const char *type, unsigned long flags, void *data)
412{
413	return tomoyo_mount_permission(dev_name, path, type, flags, data);
414}
415
416/**
417 * tomoyo_sb_umount - Target for security_sb_umount().
418 *
419 * @mnt:   Pointer to "struct vfsmount".
420 * @flags: Unmount options.
421 *
422 * Returns 0 on success, negative value otherwise.
423 */
424static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
425{
426	struct path path = { mnt, mnt->mnt_root };
427	return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path, NULL);
428}
429
430/**
431 * tomoyo_sb_pivotroot - Target for security_sb_pivotroot().
432 *
433 * @old_path: Pointer to "struct path".
434 * @new_path: Pointer to "struct path".
435 *
436 * Returns 0 on success, negative value otherwise.
437 */
438static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
439{
440	return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path);
441}
442
443/**
444 * tomoyo_socket_listen - Check permission for listen().
445 *
446 * @sock:    Pointer to "struct socket".
447 * @backlog: Backlog parameter.
448 *
449 * Returns 0 on success, negative value otherwise.
450 */
451static int tomoyo_socket_listen(struct socket *sock, int backlog)
452{
453	return tomoyo_socket_listen_permission(sock);
454}
455
456/**
457 * tomoyo_socket_connect - Check permission for connect().
458 *
459 * @sock:     Pointer to "struct socket".
460 * @addr:     Pointer to "struct sockaddr".
461 * @addr_len: Size of @addr.
462 *
463 * Returns 0 on success, negative value otherwise.
464 */
465static int tomoyo_socket_connect(struct socket *sock, struct sockaddr *addr,
466				 int addr_len)
467{
468	return tomoyo_socket_connect_permission(sock, addr, addr_len);
469}
470
471/**
472 * tomoyo_socket_bind - Check permission for bind().
473 *
474 * @sock:     Pointer to "struct socket".
475 * @addr:     Pointer to "struct sockaddr".
476 * @addr_len: Size of @addr.
477 *
478 * Returns 0 on success, negative value otherwise.
479 */
480static int tomoyo_socket_bind(struct socket *sock, struct sockaddr *addr,
481			      int addr_len)
482{
483	return tomoyo_socket_bind_permission(sock, addr, addr_len);
484}
485
486/**
487 * tomoyo_socket_sendmsg - Check permission for sendmsg().
488 *
489 * @sock: Pointer to "struct socket".
490 * @msg:  Pointer to "struct msghdr".
491 * @size: Size of message.
492 *
493 * Returns 0 on success, negative value otherwise.
494 */
495static int tomoyo_socket_sendmsg(struct socket *sock, struct msghdr *msg,
496				 int size)
497{
498	return tomoyo_socket_sendmsg_permission(sock, msg, size);
499}
500
501/*
502 * tomoyo_security_ops is a "struct security_operations" which is used for
503 * registering TOMOYO.
504 */
505static struct security_operations tomoyo_security_ops = {
506	.name                = "tomoyo",
507	.cred_alloc_blank    = tomoyo_cred_alloc_blank,
508	.cred_prepare        = tomoyo_cred_prepare,
509	.cred_transfer	     = tomoyo_cred_transfer,
510	.cred_free           = tomoyo_cred_free,
511	.bprm_set_creds      = tomoyo_bprm_set_creds,
512	.bprm_check_security = tomoyo_bprm_check_security,
513	.file_fcntl          = tomoyo_file_fcntl,
514	.file_open           = tomoyo_file_open,
515	.path_truncate       = tomoyo_path_truncate,
516	.path_unlink         = tomoyo_path_unlink,
517	.path_mkdir          = tomoyo_path_mkdir,
518	.path_rmdir          = tomoyo_path_rmdir,
519	.path_symlink        = tomoyo_path_symlink,
520	.path_mknod          = tomoyo_path_mknod,
521	.path_link           = tomoyo_path_link,
522	.path_rename         = tomoyo_path_rename,
523	.inode_getattr       = tomoyo_inode_getattr,
524	.file_ioctl          = tomoyo_file_ioctl,
525	.path_chmod          = tomoyo_path_chmod,
526	.path_chown          = tomoyo_path_chown,
527	.path_chroot         = tomoyo_path_chroot,
528	.sb_mount            = tomoyo_sb_mount,
529	.sb_umount           = tomoyo_sb_umount,
530	.sb_pivotroot        = tomoyo_sb_pivotroot,
531	.socket_bind         = tomoyo_socket_bind,
532	.socket_connect      = tomoyo_socket_connect,
533	.socket_listen       = tomoyo_socket_listen,
534	.socket_sendmsg      = tomoyo_socket_sendmsg,
535};
536
537/* Lock for GC. */
538DEFINE_SRCU(tomoyo_ss);
539
540/**
541 * tomoyo_init - Register TOMOYO Linux as a LSM module.
542 *
543 * Returns 0.
544 */
545static int __init tomoyo_init(void)
546{
547	struct cred *cred = (struct cred *) current_cred();
548
549	if (!security_module_enable(&tomoyo_security_ops))
550		return 0;
551	/* register ourselves with the security framework */
552	if (register_security(&tomoyo_security_ops))
553		panic("Failure registering TOMOYO Linux");
554	printk(KERN_INFO "TOMOYO Linux initialized\n");
555	cred->security = &tomoyo_kernel_domain;
556	tomoyo_mm_init();
557	return 0;
558}
559
560security_initcall(tomoyo_init);
561