tomoyo.c revision 937bf6133b21b16965f75223085f4314ae32b8eb 
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#include "tomoyo.h"
15#include "realpath.h"
16
17static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
18{
19	new->security = NULL;
20	return 0;
21}
22
23static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
24			       gfp_t gfp)
25{
26	/*
27	 * Since "struct tomoyo_domain_info *" is a sharable pointer,
28	 * we don't need to duplicate.
29	 */
30	new->security = old->security;
31	return 0;
32}
33
34static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
35{
36	/*
37	 * Since "struct tomoyo_domain_info *" is a sharable pointer,
38	 * we don't need to duplicate.
39	 */
40	new->security = old->security;
41}
42
43static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
44{
45	int rc;
46
47	rc = cap_bprm_set_creds(bprm);
48	if (rc)
49		return rc;
50
51	/*
52	 * Do only if this function is called for the first time of an execve
53	 * operation.
54	 */
55	if (bprm->cred_prepared)
56		return 0;
57	/*
58	 * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
59	 * for the first time.
60	 */
61	if (!tomoyo_policy_loaded)
62		tomoyo_load_policy(bprm->filename);
63	/*
64	 * Tell tomoyo_bprm_check_security() is called for the first time of an
65	 * execve operation.
66	 */
67	bprm->cred->security = NULL;
68	return 0;
69}
70
71static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
72{
73	struct tomoyo_domain_info *domain = bprm->cred->security;
74
75	/*
76	 * Execute permission is checked against pathname passed to do_execve()
77	 * using current domain.
78	 */
79	if (!domain)
80		return tomoyo_find_next_domain(bprm);
81	/*
82	 * Read permission is checked against interpreters using next domain.
83	 * '1' is the result of open_to_namei_flags(O_RDONLY).
84	 */
85	return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
86}
87
88#ifdef CONFIG_SYSCTL
89
90static int tomoyo_prepend(char **buffer, int *buflen, const char *str)
91{
92	int namelen = strlen(str);
93
94	if (*buflen < namelen)
95		return -ENOMEM;
96	*buflen -= namelen;
97	*buffer -= namelen;
98	memcpy(*buffer, str, namelen);
99	return 0;
100}
101
102/**
103 * tomoyo_sysctl_path - return the realpath of a ctl_table.
104 * @table: pointer to "struct ctl_table".
105 *
106 * Returns realpath(3) of the @table on success.
107 * Returns NULL on failure.
108 *
109 * This function uses tomoyo_alloc(), so the caller must call tomoyo_free()
110 * if this function didn't return NULL.
111 */
112static char *tomoyo_sysctl_path(struct ctl_table *table)
113{
114	int buflen = TOMOYO_MAX_PATHNAME_LEN;
115	char *buf = tomoyo_alloc(buflen);
116	char *end = buf + buflen;
117	int error = -ENOMEM;
118
119	if (!buf)
120		return NULL;
121
122	*--end = '\0';
123	buflen--;
124	while (table) {
125		char num[32];
126		const char *sp = table->procname;
127
128		if (!sp) {
129			memset(num, 0, sizeof(num));
130			snprintf(num, sizeof(num) - 1, "=%d=", table->ctl_name);
131			sp = num;
132		}
133		if (tomoyo_prepend(&end, &buflen, sp) ||
134		    tomoyo_prepend(&end, &buflen, "/"))
135			goto out;
136		table = table->parent;
137	}
138	if (tomoyo_prepend(&end, &buflen, "/proc/sys"))
139		goto out;
140	error = tomoyo_encode(buf, end - buf, end);
141 out:
142	if (!error)
143		return buf;
144	tomoyo_free(buf);
145	return NULL;
146}
147
148static int tomoyo_sysctl(struct ctl_table *table, int op)
149{
150	int error;
151	char *name;
152
153	op &= MAY_READ | MAY_WRITE;
154	if (!op)
155		return 0;
156	name = tomoyo_sysctl_path(table);
157	if (!name)
158		return -ENOMEM;
159	error = tomoyo_check_file_perm(tomoyo_domain(), name, op);
160	tomoyo_free(name);
161	return error;
162}
163#endif
164
165static int tomoyo_path_truncate(struct path *path, loff_t length,
166				unsigned int time_attrs)
167{
168	return tomoyo_check_1path_perm(tomoyo_domain(),
169				       TOMOYO_TYPE_TRUNCATE_ACL,
170				       path);
171}
172
173static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
174{
175	struct path path = { parent->mnt, dentry };
176	return tomoyo_check_1path_perm(tomoyo_domain(),
177				       TOMOYO_TYPE_UNLINK_ACL,
178				       &path);
179}
180
181static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
182			     int mode)
183{
184	struct path path = { parent->mnt, dentry };
185	return tomoyo_check_1path_perm(tomoyo_domain(),
186				       TOMOYO_TYPE_MKDIR_ACL,
187				       &path);
188}
189
190static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
191{
192	struct path path = { parent->mnt, dentry };
193	return tomoyo_check_1path_perm(tomoyo_domain(),
194				       TOMOYO_TYPE_RMDIR_ACL,
195				       &path);
196}
197
198static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
199			       const char *old_name)
200{
201	struct path path = { parent->mnt, dentry };
202	return tomoyo_check_1path_perm(tomoyo_domain(),
203				       TOMOYO_TYPE_SYMLINK_ACL,
204				       &path);
205}
206
207static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
208			     int mode, unsigned int dev)
209{
210	struct path path = { parent->mnt, dentry };
211	int type = TOMOYO_TYPE_CREATE_ACL;
212
213	switch (mode & S_IFMT) {
214	case S_IFCHR:
215		type = TOMOYO_TYPE_MKCHAR_ACL;
216		break;
217	case S_IFBLK:
218		type = TOMOYO_TYPE_MKBLOCK_ACL;
219		break;
220	case S_IFIFO:
221		type = TOMOYO_TYPE_MKFIFO_ACL;
222		break;
223	case S_IFSOCK:
224		type = TOMOYO_TYPE_MKSOCK_ACL;
225		break;
226	}
227	return tomoyo_check_1path_perm(tomoyo_domain(),
228				       type, &path);
229}
230
231static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
232			    struct dentry *new_dentry)
233{
234	struct path path1 = { new_dir->mnt, old_dentry };
235	struct path path2 = { new_dir->mnt, new_dentry };
236	return tomoyo_check_2path_perm(tomoyo_domain(),
237				       TOMOYO_TYPE_LINK_ACL,
238				       &path1, &path2);
239}
240
241static int tomoyo_path_rename(struct path *old_parent,
242			      struct dentry *old_dentry,
243			      struct path *new_parent,
244			      struct dentry *new_dentry)
245{
246	struct path path1 = { old_parent->mnt, old_dentry };
247	struct path path2 = { new_parent->mnt, new_dentry };
248	return tomoyo_check_2path_perm(tomoyo_domain(),
249				       TOMOYO_TYPE_RENAME_ACL,
250				       &path1, &path2);
251}
252
253static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
254			     unsigned long arg)
255{
256	if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
257		return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
258	return 0;
259}
260
261static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
262{
263	int flags = f->f_flags;
264
265	if ((flags + 1) & O_ACCMODE)
266		flags++;
267	flags |= f->f_flags & (O_APPEND | O_TRUNC);
268	/* Don't check read permission here if called from do_execve(). */
269	if (current->in_execve)
270		return 0;
271	return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
272}
273
274static int tomoyo_file_ioctl(struct file *file, unsigned int cmd,
275			     unsigned long arg)
276{
277	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_IOCTL_ACL,
278				       &file->f_path);
279}
280
281static int tomoyo_path_chmod(struct dentry *dentry, struct vfsmount *mnt,
282			     mode_t mode)
283{
284	struct path path = { mnt, dentry };
285	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_CHMOD_ACL,
286				       &path);
287}
288
289static int tomoyo_path_chown(struct path *path, uid_t uid, gid_t gid)
290{
291	int error = 0;
292	if (uid != (uid_t) -1)
293		error = tomoyo_check_1path_perm(tomoyo_domain(),
294						TOMOYO_TYPE_CHOWN_ACL, path);
295	if (!error && gid != (gid_t) -1)
296		error = tomoyo_check_1path_perm(tomoyo_domain(),
297						TOMOYO_TYPE_CHGRP_ACL, path);
298	return error;
299}
300
301static int tomoyo_path_chroot(struct path *path)
302{
303	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_CHROOT_ACL,
304				       path);
305}
306
307static int tomoyo_sb_mount(char *dev_name, struct path *path,
308			   char *type, unsigned long flags, void *data)
309{
310	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_MOUNT_ACL,
311				       path);
312}
313
314static int tomoyo_sb_umount(struct vfsmount *mnt, int flags)
315{
316	struct path path = { mnt, mnt->mnt_root };
317	return tomoyo_check_1path_perm(tomoyo_domain(), TOMOYO_TYPE_UMOUNT_ACL,
318				       &path);
319}
320
321static int tomoyo_sb_pivotroot(struct path *old_path, struct path *new_path)
322{
323	return tomoyo_check_2path_perm(tomoyo_domain(),
324				       TOMOYO_TYPE_PIVOT_ROOT_ACL,
325				       new_path, old_path);
326}
327
328/*
329 * tomoyo_security_ops is a "struct security_operations" which is used for
330 * registering TOMOYO.
331 */
332static struct security_operations tomoyo_security_ops = {
333	.name                = "tomoyo",
334	.cred_alloc_blank    = tomoyo_cred_alloc_blank,
335	.cred_prepare        = tomoyo_cred_prepare,
336	.cred_transfer	     = tomoyo_cred_transfer,
337	.bprm_set_creds      = tomoyo_bprm_set_creds,
338	.bprm_check_security = tomoyo_bprm_check_security,
339#ifdef CONFIG_SYSCTL
340	.sysctl              = tomoyo_sysctl,
341#endif
342	.file_fcntl          = tomoyo_file_fcntl,
343	.dentry_open         = tomoyo_dentry_open,
344	.path_truncate       = tomoyo_path_truncate,
345	.path_unlink         = tomoyo_path_unlink,
346	.path_mkdir          = tomoyo_path_mkdir,
347	.path_rmdir          = tomoyo_path_rmdir,
348	.path_symlink        = tomoyo_path_symlink,
349	.path_mknod          = tomoyo_path_mknod,
350	.path_link           = tomoyo_path_link,
351	.path_rename         = tomoyo_path_rename,
352	.file_ioctl          = tomoyo_file_ioctl,
353	.path_chmod          = tomoyo_path_chmod,
354	.path_chown          = tomoyo_path_chown,
355	.path_chroot         = tomoyo_path_chroot,
356	.sb_mount            = tomoyo_sb_mount,
357	.sb_umount           = tomoyo_sb_umount,
358	.sb_pivotroot        = tomoyo_sb_pivotroot,
359};
360
361static int __init tomoyo_init(void)
362{
363	struct cred *cred = (struct cred *) current_cred();
364
365	if (!security_module_enable(&tomoyo_security_ops))
366		return 0;
367	/* register ourselves with the security framework */
368	if (register_security(&tomoyo_security_ops))
369		panic("Failure registering TOMOYO Linux");
370	printk(KERN_INFO "TOMOYO Linux initialized\n");
371	cred->security = &tomoyo_kernel_domain;
372	tomoyo_realpath_init();
373	return 0;
374}
375
376security_initcall(tomoyo_init);
377