tomoyo.c revision ea0d3ab239fba48d6e998b19c28d78f765963007 
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	/*
55	 * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
56	 * for the first time.
57	 */
58	if (!tomoyo_policy_loaded)
59		tomoyo_load_policy(bprm->filename);
60	/*
61	 * Release reference to "struct tomoyo_domain_info" stored inside
62	 * "bprm->cred->security". New reference to "struct tomoyo_domain_info"
63	 * stored inside "bprm->cred->security" will be acquired later inside
64	 * tomoyo_find_next_domain().
65	 */
66	atomic_dec(&((struct tomoyo_domain_info *)
67		     bprm->cred->security)->users);
68	/*
69	 * Tell tomoyo_bprm_check_security() is called for the first time of an
70	 * execve operation.
71	 */
72	bprm->cred->security = NULL;
73	return 0;
74}
75
76static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
77{
78	struct tomoyo_domain_info *domain = bprm->cred->security;
79
80	/*
81	 * Execute permission is checked against pathname passed to do_execve()
82	 * using current domain.
83	 */
84	if (!domain) {
85		const int idx = tomoyo_read_lock();
86		const int err = tomoyo_find_next_domain(bprm);
87		tomoyo_read_unlock(idx);
88		return err;
89	}
90	/*
91	 * Read permission is checked against interpreters using next domain.
92	 */
93	return tomoyo_check_open_permission(domain, &bprm->file->f_path, O_RDONLY);
94}
95
96static int tomoyo_path_truncate(struct path *path)
97{
98	return tomoyo_path_perm(TOMOYO_TYPE_TRUNCATE, path);
99}
100
101static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
102{
103	struct path path = { parent->mnt, dentry };
104	return tomoyo_path_perm(TOMOYO_TYPE_UNLINK, &path);
105}
106
107static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
108			     int mode)
109{
110	struct path path = { parent->mnt, dentry };
111	return tomoyo_path_number_perm(TOMOYO_TYPE_MKDIR, &path,
112				       mode & S_IALLUGO);
113}
114
115static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
116{
117	struct path path = { parent->mnt, dentry };
118	return tomoyo_path_perm(TOMOYO_TYPE_RMDIR, &path);
119}
120
121static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
122			       const char *old_name)
123{
124	struct path path = { parent->mnt, dentry };
125	return tomoyo_path_perm(TOMOYO_TYPE_SYMLINK, &path);
126}
127
128static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
129			     int mode, unsigned int dev)
130{
131	struct path path = { parent->mnt, dentry };
132	int type = TOMOYO_TYPE_CREATE;
133	const unsigned int perm = mode & S_IALLUGO;
134
135	switch (mode & S_IFMT) {
136	case S_IFCHR:
137		type = TOMOYO_TYPE_MKCHAR;
138		break;
139	case S_IFBLK:
140		type = TOMOYO_TYPE_MKBLOCK;
141		break;
142	default:
143		goto no_dev;
144	}
145	return tomoyo_path_number3_perm(type, &path, perm, dev);
146 no_dev:
147	switch (mode & S_IFMT) {
148	case S_IFIFO:
149		type = TOMOYO_TYPE_MKFIFO;
150		break;
151	case S_IFSOCK:
152		type = TOMOYO_TYPE_MKSOCK;
153		break;
154	}
155	return tomoyo_path_number_perm(type, &path, perm);
156}
157
158static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
159			    struct dentry *new_dentry)
160{
161	struct path path1 = { new_dir->mnt, old_dentry };
162	struct path path2 = { new_dir->mnt, new_dentry };
163	return tomoyo_path2_perm(TOMOYO_TYPE_LINK, &path1, &path2);
164}
165
166static int tomoyo_path_rename(struct path *old_parent,
167			      struct dentry *old_dentry,
168			      struct path *new_parent,
169			      struct dentry *new_dentry)
170{
171	struct path path1 = { old_parent->mnt, old_dentry };
172	struct path path2 = { new_parent->mnt, new_dentry };
173	return tomoyo_path2_perm(TOMOYO_TYPE_RENAME, &path1, &path2);
174}
175
176static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
177			     unsigned long arg)
178{
179	if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
180		return tomoyo_path_perm(TOMOYO_TYPE_REWRITE, &file->f_path);
181	return 0;
182}
183
184static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
185{
186	int flags = f->f_flags;
187	/* Don't check read permission here if called from do_execve(). */
188	if (current->in_execve)
189		return 0;
190	return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
191}
192
193static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
194			     unsigned long arg)
195{
196	return tomoyo_path_number_perm(TOMOYO_TYPE_IOCTL, &file->f_path, cmd);
197}
198
199static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
200			     mode_t mode)
201{
202	struct path path = { mnt, dentry };
203	return tomoyo_path_number_perm(TOMOYO_TYPE_CHMOD, &path,
204				       mode & S_IALLUGO);
205}
206
207static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
208{
209	int error = 0;
210	if (uid != (uid_t) -1)
211		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHOWN, path, uid);
212	if (!error && gid != (gid_t) -1)
213		error = tomoyo_path_number_perm(TOMOYO_TYPE_CHGRP, path, gid);
214	return error;
215}
216
217static int tomoyo_path_chroot(struct path *path)
218{
219	return tomoyo_path_perm(TOMOYO_TYPE_CHROOT, path);
220}
221
222static int tomoyo_sb_mount(char *dev_name, struct path *path,
223			   char *type, unsigned long flags, void *data)
224{
225	return tomoyo_mount_permission(dev_name, path, type, flags, data);
226}
227
228static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
229{
230	struct path path = { mnt, mnt->mnt_root };
231	return tomoyo_path_perm(TOMOYO_TYPE_UMOUNT, &path);
232}
233
234static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
235{
236	return tomoyo_path2_perm(TOMOYO_TYPE_PIVOT_ROOT, new_path, old_path);
237}
238
239/*
240 * tomoyo_security_ops is a "struct security_operations" which is used for
241 * registering TOMOYO.
242 */
243static struct security_operations tomoyo_security_ops = {
244	.name                = "tomoyo",
245	.cred_alloc_blank    = tomoyo_cred_alloc_blank,
246	.cred_prepare        = tomoyo_cred_prepare,
247	.cred_transfer	     = tomoyo_cred_transfer,
248	.cred_free           = tomoyo_cred_free,
249	.bprm_set_creds      = tomoyo_bprm_set_creds,
250	.bprm_check_security = tomoyo_bprm_check_security,
251	.file_fcntl          = tomoyo_file_fcntl,
252	.dentry_open         = tomoyo_dentry_open,
253	.path_truncate       = tomoyo_path_truncate,
254	.path_unlink         = tomoyo_path_unlink,
255	.path_mkdir          = tomoyo_path_mkdir,
256	.path_rmdir          = tomoyo_path_rmdir,
257	.path_symlink        = tomoyo_path_symlink,
258	.path_mknod          = tomoyo_path_mknod,
259	.path_link           = tomoyo_path_link,
260	.path_rename         = tomoyo_path_rename,
261	.file_ioctl          = tomoyo_file_ioctl,
262	.path_chmod          = tomoyo_path_chmod,
263	.path_chown          = tomoyo_path_chown,
264	.path_chroot         = tomoyo_path_chroot,
265	.sb_mount            = tomoyo_sb_mount,
266	.sb_umount           = tomoyo_sb_umount,
267	.sb_pivotroot        = tomoyo_sb_pivotroot,
268};
269
270/* Lock for GC. */
271struct srcu_struct tomoyo_ss;
272
273static int __init tomoyo_init(void)
274{
275	struct cred *cred = (struct cred *) current_cred();
276
277	if (!security_module_enable(&tomoyo_security_ops))
278		return 0;
279	/* register ourselves with the security framework */
280	if (register_security(&tomoyo_security_ops) ||
281	    init_srcu_struct(&tomoyo_ss))
282		panic("Failure registering TOMOYO Linux");
283	printk(KERN_INFO "TOMOYO Linux initialized\n");
284	cred->security = &tomoyo_kernel_domain;
285	tomoyo_mm_init();
286	return 0;
287}
288
289security_initcall(tomoyo_init);
290