tomoyo.c revision 76bb0895d038be7bcdb6ccfcd2dd7deb30371d6b 
1/*
2 * security/tomoyo/tomoyo.c
3 *
4 * LSM hooks for TOMOYO Linux.
5 *
6 * Copyright (C) 2005-2009  NTT DATA CORPORATION
7 *
8 * Version: 2.2.0   2009/04/01
9 *
10 */
11
12#include <linux/security.h>
13#include "common.h"
14
15static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
16{
17	new->security = NULL;
18	return 0;
19}
20
21static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
22			       gfp_t gfp)
23{
24	/*
25	 * Since "struct tomoyo_domain_info *" is a sharable pointer,
26	 * we don't need to duplicate.
27	 */
28	new->security = old->security;
29	return 0;
30}
31
32static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
33{
34	/*
35	 * Since "struct tomoyo_domain_info *" is a sharable pointer,
36	 * we don't need to duplicate.
37	 */
38	new->security = old->security;
39}
40
41static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
42{
43	int rc;
44
45	rc = cap_bprm_set_creds(bprm);
46	if (rc)
47		return rc;
48
49	/*
50	 * Do only if this function is called for the first time of an execve
51	 * operation.
52	 */
53	if (bprm->cred_prepared)
54		return 0;
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	/*
62	 * Tell tomoyo_bprm_check_security() is called for the first time of an
63	 * execve operation.
64	 */
65	bprm->cred->security = NULL;
66	return 0;
67}
68
69static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
70{
71	struct tomoyo_domain_info *domain = bprm->cred->security;
72
73	/*
74	 * Execute permission is checked against pathname passed to do_execve()
75	 * using current domain.
76	 */
77	if (!domain) {
78		/*
79		 * We will need to protect whole execve() operation when GC
80		 * starts kfree()ing "struct tomoyo_domain_info" because
81		 * bprm->cred->security points to "struct tomoyo_domain_info"
82		 * but "struct tomoyo_domain_info" does not have a refcounter.
83		 */
84		const int idx = tomoyo_read_lock();
85		const int err = tomoyo_find_next_domain(bprm);
86		tomoyo_read_unlock(idx);
87		return err;
88	}
89	/*
90	 * Read permission is checked against interpreters using next domain.
91	 * '1' is the result of open_to_namei_flags(O_RDONLY).
92	 */
93	return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
94}
95
96static int tomoyo_path_truncate(struct path *path, loff_t length,
97				unsigned int time_attrs)
98{
99	return tomoyo_check_1path_perm(tomoyo_domain(),
100				       TOMOYO_TYPE_TRUNCATE_ACL,
101				       path);
102}
103
104static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
105{
106	struct path path = { parent->mnt, dentry };
107	return tomoyo_check_1path_perm(tomoyo_domain(),
108				       TOMOYO_TYPE_UNLINK_ACL,
109				       &path);
110}
111
112static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
113			     int mode)
114{
115	struct path path = { parent->mnt, dentry };
116	return tomoyo_check_1path_perm(tomoyo_domain(),
117				       TOMOYO_TYPE_MKDIR_ACL,
118				       &path);
119}
120
121static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
122{
123	struct path path = { parent->mnt, dentry };
124	return tomoyo_check_1path_perm(tomoyo_domain(),
125				       TOMOYO_TYPE_RMDIR_ACL,
126				       &path);
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_check_1path_perm(tomoyo_domain(),
134				       TOMOYO_TYPE_SYMLINK_ACL,
135				       &path);
136}
137
138static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
139			     int mode, unsigned int dev)
140{
141	struct path path = { parent->mnt, dentry };
142	int type = TOMOYO_TYPE_CREATE_ACL;
143
144	switch (mode & S_IFMT) {
145	case S_IFCHR:
146		type = TOMOYO_TYPE_MKCHAR_ACL;
147		break;
148	case S_IFBLK:
149		type = TOMOYO_TYPE_MKBLOCK_ACL;
150		break;
151	case S_IFIFO:
152		type = TOMOYO_TYPE_MKFIFO_ACL;
153		break;
154	case S_IFSOCK:
155		type = TOMOYO_TYPE_MKSOCK_ACL;
156		break;
157	}
158	return tomoyo_check_1path_perm(tomoyo_domain(),
159				       type, &path);
160}
161
162static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
163			    struct dentry *new_dentry)
164{
165	struct path path1 = { new_dir->mnt, old_dentry };
166	struct path path2 = { new_dir->mnt, new_dentry };
167	return tomoyo_check_2path_perm(tomoyo_domain(),
168				       TOMOYO_TYPE_LINK_ACL,
169				       &path1, &path2);
170}
171
172static int tomoyo_path_rename(struct path *old_parent,
173			      struct dentry *old_dentry,
174			      struct path *new_parent,
175			      struct dentry *new_dentry)
176{
177	struct path path1 = { old_parent->mnt, old_dentry };
178	struct path path2 = { new_parent->mnt, new_dentry };
179	return tomoyo_check_2path_perm(tomoyo_domain(),
180				       TOMOYO_TYPE_RENAME_ACL,
181				       &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 tomoyo_check_rewrite_permission(tomoyo_domain(), file);
189	return 0;
190}
191
192static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
193{
194	int flags = f->f_flags;
195
196	if ((flags + 1) & O_ACCMODE)
197		flags++;
198	flags |= f->f_flags & (O_APPEND | O_TRUNC);
199	/* Don't check read permission here if called from do_execve(). */
200	if (current->in_execve)
201		return 0;
202	return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
203}
204
205static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
206			     unsigned long arg)
207{
208	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_IOCTL_ACL,
209				       &file->f_path);
210}
211
212static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
213			     mode_t mode)
214{
215	struct path path = { mnt, dentry };
216	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_CHMOD_ACL,
217				       &path);
218}
219
220static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
221{
222	int error = 0;
223	if (uid != (uid_t) -1)
224		error = tomoyo_check_1path_perm(tomoyo_domain(),
225						TOMOYO_TYPE_CHOWN_ACL, path);
226	if (!error && gid != (gid_t) -1)
227		error = tomoyo_check_1path_perm(tomoyo_domain(),
228						TOMOYO_TYPE_CHGRP_ACL, path);
229	return error;
230}
231
232static int tomoyo_path_chroot(struct path *path)
233{
234	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_CHROOT_ACL,
235				       path);
236}
237
238static int tomoyo_sb_mount(char *dev_name, struct path *path,
239			   char *type, unsigned long flags, void *data)
240{
241	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_MOUNT_ACL,
242				       path);
243}
244
245static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
246{
247	struct path path = { mnt, mnt->mnt_root };
248	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_UMOUNT_ACL,
249				       &path);
250}
251
252static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
253{
254	return tomoyo_check_2path_perm(tomoyo_domain(),
255				       TOMOYO_TYPE_PIVOT_ROOT_ACL,
256				       new_path, old_path);
257}
258
259/*
260 * tomoyo_security_ops is a "struct security_operations" which is used for
261 * registering TOMOYO.
262 */
263static struct security_operations tomoyo_security_ops = {
264	.name                = "tomoyo",
265	.cred_alloc_blank    = tomoyo_cred_alloc_blank,
266	.cred_prepare        = tomoyo_cred_prepare,
267	.cred_transfer	     = tomoyo_cred_transfer,
268	.bprm_set_creds      = tomoyo_bprm_set_creds,
269	.bprm_check_security = tomoyo_bprm_check_security,
270	.file_fcntl          = tomoyo_file_fcntl,
271	.dentry_open         = tomoyo_dentry_open,
272	.path_truncate       = tomoyo_path_truncate,
273	.path_unlink         = tomoyo_path_unlink,
274	.path_mkdir          = tomoyo_path_mkdir,
275	.path_rmdir          = tomoyo_path_rmdir,
276	.path_symlink        = tomoyo_path_symlink,
277	.path_mknod          = tomoyo_path_mknod,
278	.path_link           = tomoyo_path_link,
279	.path_rename         = tomoyo_path_rename,
280	.file_ioctl          = tomoyo_file_ioctl,
281	.path_chmod          = tomoyo_path_chmod,
282	.path_chown          = tomoyo_path_chown,
283	.path_chroot         = tomoyo_path_chroot,
284	.sb_mount            = tomoyo_sb_mount,
285	.sb_umount           = tomoyo_sb_umount,
286	.sb_pivotroot        = tomoyo_sb_pivotroot,
287};
288
289/* Lock for GC. */
290struct srcu_struct tomoyo_ss;
291
292static int __init tomoyo_init(void)
293{
294	struct cred *cred = (struct cred *) current_cred();
295
296	if (!security_module_enable(&tomoyo_security_ops))
297		return 0;
298	/* register ourselves with the security framework */
299	if (register_security(&tomoyo_security_ops) ||
300	    init_srcu_struct(&tomoyo_ss))
301		panic("Failure registering TOMOYO Linux");
302	printk(KERN_INFO "TOMOYO Linux initialized\n");
303	cred->security = &tomoyo_kernel_domain;
304	tomoyo_realpath_init();
305	return 0;
306}
307
308security_initcall(tomoyo_init);
309