tomoyo.c revision 97fb35e413f256ded07b88c73b3d932ec31ea84e 
1/*
2 * security/tomoyo/tomoyo.c
3 *
4 * LSM hooks for TOMOYO Linux.
5 *
6 * Copyright (C) 2005-2010  NTT DATA CORPORATION
7 */
8
9#include <linux/security.h>
10#include "common.h"
11
12static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
13{
14	new->security = NULL;
15	return 0;
16}
17
18static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
19			       gfp_t gfp)
20{
21	struct tomoyo_domain_info *domain = old->security;
22	new->security = domain;
23	if (domain)
24		atomic_inc(&domain->users);
25	return 0;
26}
27
28static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
29{
30	tomoyo_cred_prepare(new, old, 0);
31}
32
33static void tomoyo_cred_free(struct cred *cred)
34{
35	struct tomoyo_domain_info *domain = cred->security;
36	if (domain)
37		atomic_dec(&domain->users);
38}
39
40static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
41{
42	int rc;
43
44	rc = cap_bprm_set_creds(bprm);
45	if (rc)
46		return rc;
47
48	/*
49	 * Do only if this function is called for the first time of an execve
50	 * operation.
51	 */
52	if (bprm->cred_prepared)
53		return 0;
54#ifndef CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER
55	/*
56	 * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
57	 * for the first time.
58	 */
59	if (!tomoyo_policy_loaded)
60		tomoyo_load_policy(bprm->filename);
61#endif
62	/*
63	 * Release reference to "struct tomoyo_domain_info" stored inside
64	 * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
65	 * stored inside "bprm->cred->security" will be acquired later inside
66	 * tomoyo_find_next_domain().
67	 */
68	atomic_dec(&((struct tomoyo_domain_info *)
69		     bprm->cred->security)->users);
70	/*
71	 * Tell tomoyo_bprm_check_security() is called for the first time of an
72	 * execve operation.
73	 */
74	bprm->cred->security = NULL;
75	return 0;
76}
77
78static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
79{
80	struct tomoyo_domain_info *domain = bprm->cred->security;
81
82	/*
83	 * Execute permission is checked against pathname passed to do_execve()
84	 * using current domain.
85	 */
86	if (!domain) {
87		const int idx = tomoyo_read_lock();
88		const int err = tomoyo_find_next_domain(bprm);
89		tomoyo_read_unlock(idx);
90		return err;
91	}
92	/*
93	 * Read permission is checked against interpreters using next domain.
94	 */
95	return tomoyo_check_open_permission(domain, &bprm->file->f_path, O_RDONLY);
96}
97
98static int tomoyo_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
99{
100	struct path path = { mnt, dentry };
101	return tomoyo_path_perm(TOMOYO_TYPE_GETATTR, &path, NULL);
102}
103
104static int tomoyo_path_truncate(struct path *path)
105{
106	return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path, NULL);
107}
108
109static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
110{
111	struct path path = { parent->mnt, dentry };
112	return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path, NULL);
113}
114
115static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
116			     int mode)
117{
118	struct path path = { parent->mnt, dentry };
119	return tomoyo_path_number_perm(TOMOYO_TYPE_MKDIR, &path,
120				       mode & S_IALLUGO);
121}
122
123static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
124{
125	struct path path = { parent->mnt, dentry };
126	return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path, NULL);
127}
128
129static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
130			       const char *old_name)
131{
132	struct path path = { parent->mnt, dentry };
133	return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path, old_name);
134}
135
136static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
137			     int mode, unsigned int dev)
138{
139	struct path path = { parent->mnt, dentry };
140	int type = TOMOYO_TYPE_CREATE;
141	const unsigned int perm = mode & S_IALLUGO;
142
143	switch (mode & S_IFMT) {
144	case S_IFCHR:
145		type = TOMOYO_TYPE_MKCHAR;
146		break;
147	case S_IFBLK:
148		type = TOMOYO_TYPE_MKBLOCK;
149		break;
150	default:
151		goto no_dev;
152	}
153	return tomoyo_mkdev_perm(type, &path, perm, dev);
154 no_dev:
155	switch (mode & S_IFMT) {
156	case S_IFIFO:
157		type = TOMOYO_TYPE_MKFIFO;
158		break;
159	case S_IFSOCK:
160		type = TOMOYO_TYPE_MKSOCK;
161		break;
162	}
163	return tomoyo_path_number_perm(type, &path, perm);
164}
165
166static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
167			    struct dentry *new_dentry)
168{
169	struct path path1 = { new_dir->mnt, old_dentry };
170	struct path path2 = { new_dir->mnt, new_dentry };
171	return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2);
172}
173
174static int tomoyo_path_rename(struct path *old_parent,
175			      struct dentry *old_dentry,
176			      struct path *new_parent,
177			      struct dentry *new_dentry)
178{
179	struct path path1 = { old_parent->mnt, old_dentry };
180	struct path path2 = { new_parent->mnt, new_dentry };
181	return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2);
182}
183
184static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
185			     unsigned long arg)
186{
187	if (!(cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND)))
188		return 0;
189	return tomoyo_check_open_permission(tomoyo_domain(), &file->f_path,
190					    O_WRONLY | (arg & O_APPEND));
191}
192
193static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
194{
195	int flags = f->f_flags;
196	/* Don't check read permission here if called from do_execve(). */
197	if (current->in_execve)
198		return 0;
199	return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
200}
201
202static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
203			     unsigned long arg)
204{
205	return tomoyo_path_number_perm(TOMOYO_TYPE_IOCTL, &file->f_path, cmd);
206}
207
208static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
209			     mode_t mode)
210{
211	struct path path = { mnt, dentry };
212	return tomoyo_path_number_perm(TOMOYO_TYPE_CHMOD, &path,
213				       mode & S_IALLUGO);
214}
215
216static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
217{
218	int error = 0;
219	if (uid != (uid_t) -1)
220		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path, uid);
221	if (!error && gid != (gid_t) -1)
222		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path, gid);
223	return error;
224}
225
226static int tomoyo_path_chroot(struct path *path)
227{
228	return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path, NULL);
229}
230
231static int tomoyo_sb_mount(char *dev_name, struct path *path,
232			   char *type, unsigned long flags, void *data)
233{
234	return tomoyo_mount_permission(dev_name, path, type, flags, data);
235}
236
237static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
238{
239	struct path path = { mnt, mnt->mnt_root };
240	return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path, NULL);
241}
242
243static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
244{
245	return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path);
246}
247
248/*
249 * tomoyo_security_ops is a "struct security_operations" which is used for
250 * registering TOMOYO.
251 */
252static struct security_operations tomoyo_security_ops = {
253	.name                = "tomoyo",
254	.cred_alloc_blank    = tomoyo_cred_alloc_blank,
255	.cred_prepare        = tomoyo_cred_prepare,
256	.cred_transfer	     = tomoyo_cred_transfer,
257	.cred_free           = tomoyo_cred_free,
258	.bprm_set_creds      = tomoyo_bprm_set_creds,
259	.bprm_check_security = tomoyo_bprm_check_security,
260	.file_fcntl          = tomoyo_file_fcntl,
261	.dentry_open         = tomoyo_dentry_open,
262	.path_truncate       = tomoyo_path_truncate,
263	.path_unlink         = tomoyo_path_unlink,
264	.path_mkdir          = tomoyo_path_mkdir,
265	.path_rmdir          = tomoyo_path_rmdir,
266	.path_symlink        = tomoyo_path_symlink,
267	.path_mknod          = tomoyo_path_mknod,
268	.path_link           = tomoyo_path_link,
269	.path_rename         = tomoyo_path_rename,
270	.inode_getattr       = tomoyo_inode_getattr,
271	.file_ioctl          = tomoyo_file_ioctl,
272	.path_chmod          = tomoyo_path_chmod,
273	.path_chown          = tomoyo_path_chown,
274	.path_chroot         = tomoyo_path_chroot,
275	.sb_mount            = tomoyo_sb_mount,
276	.sb_umount           = tomoyo_sb_umount,
277	.sb_pivotroot        = tomoyo_sb_pivotroot,
278};
279
280/* Lock for GC. */
281struct srcu_struct tomoyo_ss;
282
283static int __init tomoyo_init(void)
284{
285	struct cred *cred = (struct cred *) current_cred();
286
287	if (!security_module_enable(&tomoyo_security_ops))
288		return 0;
289	/* register ourselves with the security framework */
290	if (register_security(&tomoyo_security_ops) ||
291	    init_srcu_struct(&tomoyo_ss))
292		panic("Failure registering TOMOYO Linux");
293	printk(KERN_INFO "TOMOYO Linux initialized\n");
294	cred->security = &tomoyo_kernel_domain;
295	tomoyo_mm_init();
296	return 0;
297}
298
299security_initcall(tomoyo_init);
300