[linux.git] / security / tomoyo / mount.c

/*
 * security/tomoyo/mount.c
 *
 * Copyright (C) 2005-2011  NTT DATA CORPORATION
 */

#include <linux/slab.h>
#include "common.h"

/* String table for special mount operations. */
static const char * const tomoyo_mounts[TOMOYO_MAX_SPECIAL_MOUNT] = {
	[TOMOYO_MOUNT_BIND]            = "--bind",
	[TOMOYO_MOUNT_MOVE]            = "--move",
	[TOMOYO_MOUNT_REMOUNT]         = "--remount",
	[TOMOYO_MOUNT_MAKE_UNBINDABLE] = "--make-unbindable",
	[TOMOYO_MOUNT_MAKE_PRIVATE]    = "--make-private",
	[TOMOYO_MOUNT_MAKE_SLAVE]      = "--make-slave",
	[TOMOYO_MOUNT_MAKE_SHARED]     = "--make-shared",
};

/**
 * tomoyo_audit_mount_log - Audit mount log.
 *
 * @r: Pointer to "struct tomoyo_request_info".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int tomoyo_audit_mount_log(struct tomoyo_request_info *r)
{
	return tomoyo_supervisor(r, "file mount %s %s %s 0x%lX\n",
				 r->param.mount.dev->name,
				 r->param.mount.dir->name,
				 r->param.mount.type->name,
				 r->param.mount.flags);
}

/**
 * tomoyo_check_mount_acl - Check permission for path path path number operation.
 *
 * @r:   Pointer to "struct tomoyo_request_info".
 * @ptr: Pointer to "struct tomoyo_acl_info".
 *
 * Returns true if granted, false otherwise.
 */
static bool tomoyo_check_mount_acl(struct tomoyo_request_info *r,
				   const struct tomoyo_acl_info *ptr)
{
	const struct tomoyo_mount_acl *acl =
		container_of(ptr, typeof(*acl), head);
	return tomoyo_compare_number_union(r->param.mount.flags,
					   &acl->flags) &&
		tomoyo_compare_name_union(r->param.mount.type,
					  &acl->fs_type) &&
		tomoyo_compare_name_union(r->param.mount.dir,
					  &acl->dir_name) &&
		(!r->param.mount.need_dev ||
		 tomoyo_compare_name_union(r->param.mount.dev,
					   &acl->dev_name));
}

/**
 * tomoyo_mount_acl - Check permission for mount() operation.
 *
 * @r:        Pointer to "struct tomoyo_request_info".
 * @dev_name: Name of device file. Maybe NULL.
 * @dir:      Pointer to "struct path".
 * @type:     Name of filesystem type.
 * @flags:    Mount options.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_mount_acl(struct tomoyo_request_info *r,
			    const char *dev_name,
			    const struct path *dir, const char *type,
			    unsigned long flags)
{
	struct tomoyo_obj_info obj = { };
	struct path path;
	struct file_system_type *fstype = NULL;
	const char *requested_type = NULL;
	const char *requested_dir_name = NULL;
	const char *requested_dev_name = NULL;
	struct tomoyo_path_info rtype;
	struct tomoyo_path_info rdev;
	struct tomoyo_path_info rdir;
	int need_dev = 0;
	int error = -ENOMEM;
	r->obj = &obj;

	/* Get fstype. */
	requested_type = tomoyo_encode(type);
	if (!requested_type)
		goto out;
	rtype.name = requested_type;
	tomoyo_fill_path_info(&rtype);

	/* Get mount point. */
	obj.path2 = *dir;
	requested_dir_name = tomoyo_realpath_from_path(dir);
	if (!requested_dir_name) {
		error = -ENOMEM;
		goto out;
	}
	rdir.name = requested_dir_name;
	tomoyo_fill_path_info(&rdir);

	/* Compare fs name. */
	if (type == tomoyo_mounts[TOMOYO_MOUNT_REMOUNT]) {
		/* dev_name is ignored. */
	} else if (type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE] ||
		   type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE] ||
		   type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE] ||
		   type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED]) {
		/* dev_name is ignored. */
	} else if (type == tomoyo_mounts[TOMOYO_MOUNT_BIND] ||
		   type == tomoyo_mounts[TOMOYO_MOUNT_MOVE]) {
		need_dev = -1; /* dev_name is a directory */
	} else {
		fstype = get_fs_type(type);
		if (!fstype) {
			error = -ENODEV;
			goto out;
		}
		if (fstype->fs_flags & FS_REQUIRES_DEV)
			/* dev_name is a block device file. */
			need_dev = 1;
	}
	if (need_dev) {
		/* Get mount point or device file. */
		if (!dev_name || kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
			error = -ENOENT;
			goto out;
		}
		obj.path1 = path;
		requested_dev_name = tomoyo_realpath_from_path(&path);
		if (!requested_dev_name) {
			error = -ENOENT;
			goto out;
		}
	} else {
		/* Map dev_name to "<NULL>" if no dev_name given. */
		if (!dev_name)
			dev_name = "<NULL>";
		requested_dev_name = tomoyo_encode(dev_name);
		if (!requested_dev_name) {
			error = -ENOMEM;
			goto out;
		}
	}
	rdev.name = requested_dev_name;
	tomoyo_fill_path_info(&rdev);
	r->param_type = TOMOYO_TYPE_MOUNT_ACL;
	r->param.mount.need_dev = need_dev;
	r->param.mount.dev = &rdev;
	r->param.mount.dir = &rdir;
	r->param.mount.type = &rtype;
	r->param.mount.flags = flags;
	do {
		tomoyo_check_acl(r, tomoyo_check_mount_acl);
		error = tomoyo_audit_mount_log(r);
	} while (error == TOMOYO_RETRY_REQUEST);
 out:
	kfree(requested_dev_name);
	kfree(requested_dir_name);
	if (fstype)
		put_filesystem(fstype);
	kfree(requested_type);
	/* Drop refcount obtained by kern_path(). */
	if (obj.path1.dentry)
		path_put(&obj.path1);
	return error;
}

/**
 * tomoyo_mount_permission - Check permission for mount() operation.
 *
 * @dev_name:  Name of device file. Maybe NULL.
 * @path:      Pointer to "struct path".
 * @type:      Name of filesystem type. Maybe NULL.
 * @flags:     Mount options.
 * @data_page: Optional data. Maybe NULL.
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_mount_permission(const char *dev_name, const struct path *path,
			    const char *type, unsigned long flags,
			    void *data_page)
{
	struct tomoyo_request_info r;
	int error;
	int idx;

	if (tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_MOUNT)
	    == TOMOYO_CONFIG_DISABLED)
		return 0;
	if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
		flags &= ~MS_MGC_MSK;
	if (flags & MS_REMOUNT) {
		type = tomoyo_mounts[TOMOYO_MOUNT_REMOUNT];
		flags &= ~MS_REMOUNT;
	} else if (flags & MS_BIND) {
		type = tomoyo_mounts[TOMOYO_MOUNT_BIND];
		flags &= ~MS_BIND;
	} else if (flags & MS_SHARED) {
		if (flags & (MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
			return -EINVAL;
		type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED];
		flags &= ~MS_SHARED;
	} else if (flags & MS_PRIVATE) {
		if (flags & (MS_SHARED | MS_SLAVE | MS_UNBINDABLE))
			return -EINVAL;
		type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE];
		flags &= ~MS_PRIVATE;
	} else if (flags & MS_SLAVE) {
		if (flags & (MS_SHARED | MS_PRIVATE | MS_UNBINDABLE))
			return -EINVAL;
		type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE];
		flags &= ~MS_SLAVE;
	} else if (flags & MS_UNBINDABLE) {
		if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE))
			return -EINVAL;
		type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE];
		flags &= ~MS_UNBINDABLE;
	} else if (flags & MS_MOVE) {
		type = tomoyo_mounts[TOMOYO_MOUNT_MOVE];
		flags &= ~MS_MOVE;
	}
	if (!type)
		type = "<NULL>";
	idx = tomoyo_read_lock();
	error = tomoyo_mount_acl(&r, dev_name, path, type, flags);
	tomoyo_read_unlock(idx);
	return error;
}
Commit	Line	Data
2106ccd9 TH	1	/*
	2	* security/tomoyo/mount.c
	3	*
0f2a55d5	4	* Copyright (C) 2005-2011 NTT DATA CORPORATION
2106ccd9 TH	5	*/
	6
	7	#include <linux/slab.h>
	8	#include "common.h"
	9
b5bc60b4 TH	10	/* String table for special mount operations. */
	11	static const char * const tomoyo_mounts[TOMOYO_MAX_SPECIAL_MOUNT] = {
	12	[TOMOYO_MOUNT_BIND] = "--bind",
	13	[TOMOYO_MOUNT_MOVE] = "--move",
	14	[TOMOYO_MOUNT_REMOUNT] = "--remount",
	15	[TOMOYO_MOUNT_MAKE_UNBINDABLE] = "--make-unbindable",
	16	[TOMOYO_MOUNT_MAKE_PRIVATE] = "--make-private",
	17	[TOMOYO_MOUNT_MAKE_SLAVE] = "--make-slave",
	18	[TOMOYO_MOUNT_MAKE_SHARED] = "--make-shared",
	19	};
2106ccd9	20
99a85259 TH	21	/**
	22	* tomoyo_audit_mount_log - Audit mount log.
	23	*
	24	* @r: Pointer to "struct tomoyo_request_info".
	25	*
	26	* Returns 0 on success, negative value otherwise.
	27	*/
	28	static int tomoyo_audit_mount_log(struct tomoyo_request_info *r)
	29	{
eadd99cc	30	return tomoyo_supervisor(r, "file mount %s %s %s 0x%lX\n",
7c75964f	31	r->param.mount.dev->name,
eadd99cc TH	32	r->param.mount.dir->name,
	33	r->param.mount.type->name,
	34	r->param.mount.flags);
99a85259 TH	35	}
99a85259 TH	36
0df7e8b8 TH	37	/**
	38	* tomoyo_check_mount_acl - Check permission for path path path number operation.
	39	*
	40	* @r: Pointer to "struct tomoyo_request_info".
	41	* @ptr: Pointer to "struct tomoyo_acl_info".
	42	*
	43	* Returns true if granted, false otherwise.
	44	*/
484ca79c	45	static bool tomoyo_check_mount_acl(struct tomoyo_request_info *r,
99a85259 TH	46	const struct tomoyo_acl_info *ptr)
	47	{
	48	const struct tomoyo_mount_acl *acl =
	49	container_of(ptr, typeof(*acl), head);
0df7e8b8 TH	50	return tomoyo_compare_number_union(r->param.mount.flags,
	51	&acl->flags) &&
	52	tomoyo_compare_name_union(r->param.mount.type,
	53	&acl->fs_type) &&
	54	tomoyo_compare_name_union(r->param.mount.dir,
	55	&acl->dir_name) &&
99a85259	56	(!r->param.mount.need_dev \|\|
0df7e8b8 TH	57	tomoyo_compare_name_union(r->param.mount.dev,
0df7e8b8 TH	58	&acl->dev_name));
99a85259 TH	59	}
99a85259 TH	60
2106ccd9	61	/**
d795ef9e	62	* tomoyo_mount_acl - Check permission for mount() operation.
2106ccd9 TH	63	*
2106ccd9 TH	64	* @r: Pointer to "struct tomoyo_request_info".
0f2a55d5	65	* @dev_name: Name of device file. Maybe NULL.
2106ccd9 TH	66	* @dir: Pointer to "struct path".
	67	* @type: Name of filesystem type.
	68	* @flags: Mount options.
	69	*
	70	* Returns 0 on success, negative value otherwise.
	71	*
	72	* Caller holds tomoyo_read_lock().
	73	*/
808d4e3c AV	74	static int tomoyo_mount_acl(struct tomoyo_request_info *r,
808d4e3c AV	75	const char *dev_name,
e6641edd	76	const struct path dir, const char type,
b5bc60b4	77	unsigned long flags)
2106ccd9	78	{
97fb35e4	79	struct tomoyo_obj_info obj = { };
2106ccd9	80	struct path path;
2106ccd9 TH	81	struct file_system_type *fstype = NULL;
	82	const char *requested_type = NULL;
	83	const char *requested_dir_name = NULL;
	84	const char *requested_dev_name = NULL;
	85	struct tomoyo_path_info rtype;
	86	struct tomoyo_path_info rdev;
	87	struct tomoyo_path_info rdir;
	88	int need_dev = 0;
	89	int error = -ENOMEM;
97fb35e4	90	r->obj = &obj;
2106ccd9 TH	91
2106ccd9 TH	92	/* Get fstype. */
c8c57e84	93	requested_type = tomoyo_encode(type);
2106ccd9 TH	94	if (!requested_type)
	95	goto out;
	96	rtype.name = requested_type;
	97	tomoyo_fill_path_info(&rtype);
	98
	99	/* Get mount point. */
97fb35e4	100	obj.path2 = *dir;
2106ccd9 TH	101	requested_dir_name = tomoyo_realpath_from_path(dir);
	102	if (!requested_dir_name) {
	103	error = -ENOMEM;
	104	goto out;
	105	}
	106	rdir.name = requested_dir_name;
	107	tomoyo_fill_path_info(&rdir);
	108
	109	/* Compare fs name. */
b5bc60b4	110	if (type == tomoyo_mounts[TOMOYO_MOUNT_REMOUNT]) {
2106ccd9	111	/* dev_name is ignored. */
b5bc60b4 TH	112	} else if (type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE] \|\|
	113	type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE] \|\|
	114	type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE] \|\|
	115	type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED]) {
2106ccd9	116	/* dev_name is ignored. */
b5bc60b4 TH	117	} else if (type == tomoyo_mounts[TOMOYO_MOUNT_BIND] \|\|
b5bc60b4 TH	118	type == tomoyo_mounts[TOMOYO_MOUNT_MOVE]) {
2106ccd9 TH	119	need_dev = -1; /* dev_name is a directory */
	120	} else {
	121	fstype = get_fs_type(type);
	122	if (!fstype) {
	123	error = -ENODEV;
	124	goto out;
	125	}
	126	if (fstype->fs_flags & FS_REQUIRES_DEV)
	127	/* dev_name is a block device file. */
	128	need_dev = 1;
	129	}
	130	if (need_dev) {
	131	/* Get mount point or device file. */
4e78c724	132	if (!dev_name \|\| kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
2106ccd9 TH	133	error = -ENOENT;
	134	goto out;
	135	}
97fb35e4	136	obj.path1 = path;
2106ccd9 TH	137	requested_dev_name = tomoyo_realpath_from_path(&path);
	138	if (!requested_dev_name) {
	139	error = -ENOENT;
	140	goto out;
	141	}
	142	} else {
	143	/* Map dev_name to "<NULL>" if no dev_name given. */
	144	if (!dev_name)
	145	dev_name = "<NULL>";
c8c57e84	146	requested_dev_name = tomoyo_encode(dev_name);
2106ccd9 TH	147	if (!requested_dev_name) {
	148	error = -ENOMEM;
	149	goto out;
	150	}
	151	}
	152	rdev.name = requested_dev_name;
	153	tomoyo_fill_path_info(&rdev);
cf6e9a64 TH	154	r->param_type = TOMOYO_TYPE_MOUNT_ACL;
	155	r->param.mount.need_dev = need_dev;
	156	r->param.mount.dev = &rdev;
	157	r->param.mount.dir = &rdir;
	158	r->param.mount.type = &rtype;
	159	r->param.mount.flags = flags;
99a85259 TH	160	do {
	161	tomoyo_check_acl(r, tomoyo_check_mount_acl);
	162	error = tomoyo_audit_mount_log(r);
	163	} while (error == TOMOYO_RETRY_REQUEST);
2106ccd9 TH	164	out:
	165	kfree(requested_dev_name);
	166	kfree(requested_dir_name);
	167	if (fstype)
	168	put_filesystem(fstype);
	169	kfree(requested_type);
97fb35e4 TH	170	/* Drop refcount obtained by kern_path(). */
	171	if (obj.path1.dentry)
	172	path_put(&obj.path1);
2106ccd9 TH	173	return error;
	174	}
	175
2106ccd9 TH	176	/**
	177	* tomoyo_mount_permission - Check permission for mount() operation.
	178	*
0f2a55d5	179	* @dev_name: Name of device file. Maybe NULL.
2106ccd9	180	* @path: Pointer to "struct path".
0f2a55d5	181	* @type: Name of filesystem type. Maybe NULL.
2106ccd9	182	* @flags: Mount options.
0f2a55d5	183	* @data_page: Optional data. Maybe NULL.
2106ccd9 TH	184	*
	185	* Returns 0 on success, negative value otherwise.
	186	*/
e6641edd	187	int tomoyo_mount_permission(const char dev_name, const struct path path,
b5bc60b4 TH	188	const char *type, unsigned long flags,
b5bc60b4 TH	189	void *data_page)
2106ccd9 TH	190	{
	191	struct tomoyo_request_info r;
	192	int error;
	193	int idx;
	194
57c2590f TH	195	if (tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_MOUNT)
57c2590f TH	196	== TOMOYO_CONFIG_DISABLED)
2106ccd9	197	return 0;
d795ef9e TH	198	if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
	199	flags &= ~MS_MGC_MSK;
	200	if (flags & MS_REMOUNT) {
b5bc60b4	201	type = tomoyo_mounts[TOMOYO_MOUNT_REMOUNT];
d795ef9e	202	flags &= ~MS_REMOUNT;
df91e494	203	} else if (flags & MS_BIND) {
b5bc60b4	204	type = tomoyo_mounts[TOMOYO_MOUNT_BIND];
d795ef9e	205	flags &= ~MS_BIND;
df91e494 TH	206	} else if (flags & MS_SHARED) {
	207	if (flags & (MS_PRIVATE \| MS_SLAVE \| MS_UNBINDABLE))
	208	return -EINVAL;
	209	type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED];
	210	flags &= ~MS_SHARED;
	211	} else if (flags & MS_PRIVATE) {
	212	if (flags & (MS_SHARED \| MS_SLAVE \| MS_UNBINDABLE))
	213	return -EINVAL;
b5bc60b4	214	type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE];
d795ef9e	215	flags &= ~MS_PRIVATE;
df91e494 TH	216	} else if (flags & MS_SLAVE) {
	217	if (flags & (MS_SHARED \| MS_PRIVATE \| MS_UNBINDABLE))
	218	return -EINVAL;
b5bc60b4	219	type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE];
d795ef9e	220	flags &= ~MS_SLAVE;
df91e494 TH	221	} else if (flags & MS_UNBINDABLE) {
	222	if (flags & (MS_SHARED \| MS_PRIVATE \| MS_SLAVE))
	223	return -EINVAL;
	224	type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE];
	225	flags &= ~MS_UNBINDABLE;
	226	} else if (flags & MS_MOVE) {
	227	type = tomoyo_mounts[TOMOYO_MOUNT_MOVE];
	228	flags &= ~MS_MOVE;
d795ef9e	229	}
2106ccd9 TH	230	if (!type)
	231	type = "<NULL>";
	232	idx = tomoyo_read_lock();
	233	error = tomoyo_mount_acl(&r, dev_name, path, type, flags);
	234	tomoyo_read_unlock(idx);
	235	return error;
	236	}