[net-next-2.6.git] / security / tomoyo / tomoyo.c

/*
 * security/tomoyo/tomoyo.c
 *
 * LSM hooks for TOMOYO Linux.
 *
 * Copyright (C) 2005-2009  NTT DATA CORPORATION
 *
 * Version: 2.2.0-pre   2009/02/01
 *
 */

#include <linux/security.h>
#include "common.h"
#include "tomoyo.h"
#include "realpath.h"

static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
			       gfp_t gfp)
{
	/*
	 * Since "struct tomoyo_domain_info *" is a sharable pointer,
	 * we don't need to duplicate.
	 */
	new->security = old->security;
	return 0;
}

static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
{
	/*
	 * Do only if this function is called for the first time of an execve
	 * operation.
	 */
	if (bprm->cred_prepared)
		return 0;
	/*
	 * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
	 * for the first time.
	 */
	if (!tomoyo_policy_loaded)
		tomoyo_load_policy(bprm->filename);
	/*
	 * Tell tomoyo_bprm_check_security() is called for the first time of an
	 * execve operation.
	 */
	bprm->cred->security = NULL;
	return 0;
}

static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
{
	struct tomoyo_domain_info *domain = bprm->cred->security;

	/*
	 * Execute permission is checked against pathname passed to do_execve()
	 * using current domain.
	 */
	if (!domain) {
		struct tomoyo_domain_info *next_domain = NULL;
		int retval = tomoyo_find_next_domain(bprm, &next_domain);

		if (!retval)
			bprm->cred->security = next_domain;
		return retval;
	}
	/*
	 * Read permission is checked against interpreters using next domain.
	 * '1' is the result of open_to_namei_flags(O_RDONLY).
	 */
	return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
}

#ifdef CONFIG_SYSCTL

static int tomoyo_prepend(char **buffer, int *buflen, const char *str)
{
	int namelen = strlen(str);

	if (*buflen < namelen)
		return -ENOMEM;
	*buflen -= namelen;
	*buffer -= namelen;
	memcpy(*buffer, str, namelen);
	return 0;
}

/**
 * tomoyo_sysctl_path - return the realpath of a ctl_table.
 * @table: pointer to "struct ctl_table".
 *
 * Returns realpath(3) of the @table on success.
 * Returns NULL on failure.
 *
 * This function uses tomoyo_alloc(), so the caller must call tomoyo_free()
 * if this function didn't return NULL.
 */
static char *tomoyo_sysctl_path(struct ctl_table *table)
{
	int buflen = TOMOYO_MAX_PATHNAME_LEN;
	char *buf = tomoyo_alloc(buflen);
	char *end = buf + buflen;
	int error = -ENOMEM;

	if (!buf)
		return NULL;

	*--end = '\0';
	buflen--;
	while (table) {
		char buf[32];
		const char *sp = table->procname;

		if (!sp) {
			memset(buf, 0, sizeof(buf));
			snprintf(buf, sizeof(buf) - 1, "=%d=", table->ctl_name);
			sp = buf;
		}
		if (tomoyo_prepend(&end, &buflen, sp) ||
		    tomoyo_prepend(&end, &buflen, "/"))
			goto out;
		table = table->parent;
	}
	if (tomoyo_prepend(&end, &buflen, "/proc/sys"))
		goto out;
	error = tomoyo_encode(buf, end - buf, end);
 out:
	if (!error)
		return buf;
	tomoyo_free(buf);
	return NULL;
}

static int tomoyo_sysctl(struct ctl_table *table, int op)
{
	int error;
	char *name;

	op &= MAY_READ | MAY_WRITE;
	if (!op)
		return 0;
	name = tomoyo_sysctl_path(table);
	if (!name)
		return -ENOMEM;
	error = tomoyo_check_file_perm(tomoyo_domain(), name, op);
	tomoyo_free(name);
	return error;
}
#endif

static int tomoyo_path_truncate(struct path *path, loff_t length,
				unsigned int time_attrs)
{
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_TRUNCATE_ACL,
				       path);
}

static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
{
	struct path path = { parent->mnt, dentry };
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_UNLINK_ACL,
				       &path);
}

static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
			     int mode)
{
	struct path path = { parent->mnt, dentry };
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_MKDIR_ACL,
				       &path);
}

static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
{
	struct path path = { parent->mnt, dentry };
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_RMDIR_ACL,
				       &path);
}

static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
			       const char *old_name)
{
	struct path path = { parent->mnt, dentry };
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_SYMLINK_ACL,
				       &path);
}

static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
			     int mode, unsigned int dev)
{
	struct path path = { parent->mnt, dentry };
	int type = TOMOYO_TYPE_CREATE_ACL;

	switch (mode & S_IFMT) {
	case S_IFCHR:
		type = TOMOYO_TYPE_MKCHAR_ACL;
		break;
	case S_IFBLK:
		type = TOMOYO_TYPE_MKBLOCK_ACL;
		break;
	case S_IFIFO:
		type = TOMOYO_TYPE_MKFIFO_ACL;
		break;
	case S_IFSOCK:
		type = TOMOYO_TYPE_MKSOCK_ACL;
		break;
	}
	return tomoyo_check_1path_perm(tomoyo_domain(),
				       type, &path);
}

static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
			    struct dentry *new_dentry)
{
	struct path path1 = { new_dir->mnt, old_dentry };
	struct path path2 = { new_dir->mnt, new_dentry };
	return tomoyo_check_2path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_LINK_ACL,
				       &path1, &path2);
}

static int tomoyo_path_rename(struct path *old_parent,
			      struct dentry *old_dentry,
			      struct path *new_parent,
			      struct dentry *new_dentry)
{
	struct path path1 = { old_parent->mnt, old_dentry };
	struct path path2 = { new_parent->mnt, new_dentry };
	return tomoyo_check_2path_perm(tomoyo_domain(),
				       TOMOYO_TYPE_RENAME_ACL,
				       &path1, &path2);
}

static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
			     unsigned long arg)
{
	if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
		return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
	return 0;
}

static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
{
	int flags = f->f_flags;

	if ((flags + 1) & O_ACCMODE)
		flags++;
	flags |= f->f_flags & (O_APPEND | O_TRUNC);
	/* Don't check read permission here if called from do_execve(). */
	if (current->in_execve)
		return 0;
	return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
}

static struct security_operations tomoyo_security_ops = {
	.name                = "tomoyo",
	.cred_prepare        = tomoyo_cred_prepare,
	.bprm_set_creds      = tomoyo_bprm_set_creds,
	.bprm_check_security = tomoyo_bprm_check_security,
#ifdef CONFIG_SYSCTL
	.sysctl              = tomoyo_sysctl,
#endif
	.file_fcntl          = tomoyo_file_fcntl,
	.dentry_open         = tomoyo_dentry_open,
	.path_truncate       = tomoyo_path_truncate,
	.path_unlink         = tomoyo_path_unlink,
	.path_mkdir          = tomoyo_path_mkdir,
	.path_rmdir          = tomoyo_path_rmdir,
	.path_symlink        = tomoyo_path_symlink,
	.path_mknod          = tomoyo_path_mknod,
	.path_link           = tomoyo_path_link,
	.path_rename         = tomoyo_path_rename,
};

static int __init tomoyo_init(void)
{
	struct cred *cred = (struct cred *) current_cred();

	if (!security_module_enable(&tomoyo_security_ops))
		return 0;
	/* register ourselves with the security framework */
	if (register_security(&tomoyo_security_ops))
		panic("Failure registering TOMOYO Linux");
	printk(KERN_INFO "TOMOYO Linux initialized\n");
	cred->security = &tomoyo_kernel_domain;
	return 0;
}

security_initcall(tomoyo_init);
Commit	Line	Data
f7433243 KT	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-pre 2009/02/01
	9	*
	10	*/
	11
	12	#include <linux/security.h>
	13	#include "common.h"
	14	#include "tomoyo.h"
	15	#include "realpath.h"
	16
	17	static int tomoyo_cred_prepare(struct cred new, const struct cred old,
	18	gfp_t gfp)
	19	{
	20	/*
	21	* Since "struct tomoyo_domain_info *" is a sharable pointer,
	22	* we don't need to duplicate.
	23	*/
	24	new->security = old->security;
	25	return 0;
	26	}
	27
	28	static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
	29	{
	30	/*
	31	* Do only if this function is called for the first time of an execve
	32	* operation.
	33	*/
	34	if (bprm->cred_prepared)
	35	return 0;
	36	/*
	37	* Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
	38	* for the first time.
	39	*/
	40	if (!tomoyo_policy_loaded)
	41	tomoyo_load_policy(bprm->filename);
	42	/*
	43	* Tell tomoyo_bprm_check_security() is called for the first time of an
	44	* execve operation.
	45	*/
	46	bprm->cred->security = NULL;
	47	return 0;
	48	}
	49
	50	static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
	51	{
	52	struct tomoyo_domain_info *domain = bprm->cred->security;
	53
	54	/*
	55	* Execute permission is checked against pathname passed to do_execve()
	56	* using current domain.
	57	*/
	58	if (!domain) {
	59	struct tomoyo_domain_info *next_domain = NULL;
	60	int retval = tomoyo_find_next_domain(bprm, &next_domain);
	61
	62	if (!retval)
	63	bprm->cred->security = next_domain;
	64	return retval;
65	}
66	/*
67	* Read permission is checked against interpreters using next domain.
68	* '1' is the result of open_to_namei_flags(O_RDONLY).
69	*/
70	return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
71	}
72
73	#ifdef CONFIG_SYSCTL
74
75	static int tomoyo_prepend(char *buffer, int buflen, const char *str)
76	{
77	int namelen = strlen(str);
78
79	if (*buflen < namelen)
80	return -ENOMEM;
81	*buflen -= namelen;
82	*buffer -= namelen;
83	memcpy(*buffer, str, namelen);
84	return 0;
85	}
86
87	/**
88	* tomoyo_sysctl_path - return the realpath of a ctl_table.
89	* @table: pointer to "struct ctl_table".
90	*
91	* Returns realpath(3) of the @table on success.
92	* Returns NULL on failure.
93	*
94	* This function uses tomoyo_alloc(), so the caller must call tomoyo_free()
95	* if this function didn't return NULL.
96	*/
97	static char tomoyo_sysctl_path(struct ctl_table table)
98	{
99	int buflen = TOMOYO_MAX_PATHNAME_LEN;
100	char *buf = tomoyo_alloc(buflen);
101	char *end = buf + buflen;
102	int error = -ENOMEM;
103
104	if (!buf)
105	return NULL;
106
107	*--end = '\0';
108	buflen--;
109	while (table) {
110	char buf[32];
111	const char *sp = table->procname;
112
113	if (!sp) {
114	memset(buf, 0, sizeof(buf));
115	snprintf(buf, sizeof(buf) - 1, "=%d=", table->ctl_name);
116	sp = buf;
117	}
118	if (tomoyo_prepend(&end, &buflen, sp) \|\|
119	tomoyo_prepend(&end, &buflen, "/"))
120	goto out;
121	table = table->parent;
122	}
123	if (tomoyo_prepend(&end, &buflen, "/proc/sys"))
124	goto out;
125	error = tomoyo_encode(buf, end - buf, end);
126	out:
127	if (!error)
128	return buf;
129	tomoyo_free(buf);
130	return NULL;
131	}
132
133	static int tomoyo_sysctl(struct ctl_table *table, int op)
134	{
135	int error;
136	char *name;
137
138	op &= MAY_READ \| MAY_WRITE;
139	if (!op)
140	return 0;
141	name = tomoyo_sysctl_path(table);
142	if (!name)
143	return -ENOMEM;
144	error = tomoyo_check_file_perm(tomoyo_domain(), name, op);
145	tomoyo_free(name);
146	return error;
147	}
148	#endif
149
150	static int tomoyo_path_truncate(struct path *path, loff_t length,
151	unsigned int time_attrs)
152	{
153	return tomoyo_check_1path_perm(tomoyo_domain(),
154	TOMOYO_TYPE_TRUNCATE_ACL,
155	path);
156	}
157
158	static int tomoyo_path_unlink(struct path parent, struct dentry dentry)
159	{
160	struct path path = { parent->mnt, dentry };
161	return tomoyo_check_1path_perm(tomoyo_domain(),
162	TOMOYO_TYPE_UNLINK_ACL,
163	&path);
164	}
165
166	static int tomoyo_path_mkdir(struct path parent, struct dentry dentry,
167	int mode)
168	{
169	struct path path = { parent->mnt, dentry };
170	return tomoyo_check_1path_perm(tomoyo_domain(),
171	TOMOYO_TYPE_MKDIR_ACL,
172	&path);
173	}
174
175	static int tomoyo_path_rmdir(struct path parent, struct dentry dentry)
176	{
177	struct path path = { parent->mnt, dentry };
178	return tomoyo_check_1path_perm(tomoyo_domain(),
179	TOMOYO_TYPE_RMDIR_ACL,
180	&path);
181	}
182
183	static int tomoyo_path_symlink(struct path parent, struct dentry dentry,
184	const char *old_name)
185	{
186	struct path path = { parent->mnt, dentry };
187	return tomoyo_check_1path_perm(tomoyo_domain(),
188	TOMOYO_TYPE_SYMLINK_ACL,
189	&path);
190	}
191
192	static int tomoyo_path_mknod(struct path parent, struct dentry dentry,
193	int mode, unsigned int dev)
194	{
195	struct path path = { parent->mnt, dentry };
196	int type = TOMOYO_TYPE_CREATE_ACL;
197
198	switch (mode & S_IFMT) {
199	case S_IFCHR:
200	type = TOMOYO_TYPE_MKCHAR_ACL;
201	break;
202	case S_IFBLK:
203	type = TOMOYO_TYPE_MKBLOCK_ACL;
204	break;
205	case S_IFIFO:
206	type = TOMOYO_TYPE_MKFIFO_ACL;
207	break;
208	case S_IFSOCK:
209	type = TOMOYO_TYPE_MKSOCK_ACL;
210	break;
211	}
212	return tomoyo_check_1path_perm(tomoyo_domain(),
213	type, &path);
214	}
215
216	static int tomoyo_path_link(struct dentry old_dentry, struct path new_dir,
217	struct dentry *new_dentry)
218	{
219	struct path path1 = { new_dir->mnt, old_dentry };
220	struct path path2 = { new_dir->mnt, new_dentry };
221	return tomoyo_check_2path_perm(tomoyo_domain(),
222	TOMOYO_TYPE_LINK_ACL,
223	&path1, &path2);
224	}
225
226	static int tomoyo_path_rename(struct path *old_parent,
227	struct dentry *old_dentry,
228	struct path *new_parent,
229	struct dentry *new_dentry)
230	{
231	struct path path1 = { old_parent->mnt, old_dentry };
232	struct path path2 = { new_parent->mnt, new_dentry };
233	return tomoyo_check_2path_perm(tomoyo_domain(),
234	TOMOYO_TYPE_RENAME_ACL,
235	&path1, &path2);
236	}
237
238	static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
239	unsigned long arg)
240	{
241	if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
242	return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
243	return 0;
244	}
245
246	static int tomoyo_dentry_open(struct file f, const struct cred cred)
247	{
248	int flags = f->f_flags;
249
250	if ((flags + 1) & O_ACCMODE)
251	flags++;
252	flags \|= f->f_flags & (O_APPEND \| O_TRUNC);
253	/* Don't check read permission here if called from do_execve(). */
254	if (current->in_execve)
255	return 0;
256	return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
257	}
258
259	static struct security_operations tomoyo_security_ops = {
260	.name = "tomoyo",
261	.cred_prepare = tomoyo_cred_prepare,
262	.bprm_set_creds = tomoyo_bprm_set_creds,
263	.bprm_check_security = tomoyo_bprm_check_security,
264	#ifdef CONFIG_SYSCTL
265	.sysctl = tomoyo_sysctl,
266	#endif
267	.file_fcntl = tomoyo_file_fcntl,
268	.dentry_open = tomoyo_dentry_open,
269	.path_truncate = tomoyo_path_truncate,
270	.path_unlink = tomoyo_path_unlink,
271	.path_mkdir = tomoyo_path_mkdir,
272	.path_rmdir = tomoyo_path_rmdir,
273	.path_symlink = tomoyo_path_symlink,
274	.path_mknod = tomoyo_path_mknod,
275	.path_link = tomoyo_path_link,
276	.path_rename = tomoyo_path_rename,
277	};
278
279	static int __init tomoyo_init(void)
280	{
281	struct cred cred = (struct cred ) current_cred();
282
283	if (!security_module_enable(&tomoyo_security_ops))
284	return 0;
285	/* register ourselves with the security framework */
286	if (register_security(&tomoyo_security_ops))
287	panic("Failure registering TOMOYO Linux");
288	printk(KERN_INFO "TOMOYO Linux initialized\n");
289	cred->security = &tomoyo_kernel_domain;
290	return 0;
291	}
292
293	security_initcall(tomoyo_init);