[mirror_ubuntu-bionic-kernel.git] / security / tomoyo / mount.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
2106ccd9 TH	2	/*
	3	* security/tomoyo/mount.c
	4	*
0f2a55d5	5	* Copyright (C) 2005-2011 NTT DATA CORPORATION
2106ccd9 TH	6	*/
	7
	8	#include <linux/slab.h>
	9	#include "common.h"
	10
b5bc60b4 TH	11	/* String table for special mount operations. */
	12	static const char * const tomoyo_mounts[TOMOYO_MAX_SPECIAL_MOUNT] = {
	13	[TOMOYO_MOUNT_BIND] = "--bind",
	14	[TOMOYO_MOUNT_MOVE] = "--move",
	15	[TOMOYO_MOUNT_REMOUNT] = "--remount",
	16	[TOMOYO_MOUNT_MAKE_UNBINDABLE] = "--make-unbindable",
	17	[TOMOYO_MOUNT_MAKE_PRIVATE] = "--make-private",
	18	[TOMOYO_MOUNT_MAKE_SLAVE] = "--make-slave",
	19	[TOMOYO_MOUNT_MAKE_SHARED] = "--make-shared",
	20	};
2106ccd9	21
99a85259 TH	22	/**
	23	* tomoyo_audit_mount_log - Audit mount log.
	24	*
	25	* @r: Pointer to "struct tomoyo_request_info".
	26	*
	27	* Returns 0 on success, negative value otherwise.
	28	*/
	29	static int tomoyo_audit_mount_log(struct tomoyo_request_info *r)
	30	{
eadd99cc	31	return tomoyo_supervisor(r, "file mount %s %s %s 0x%lX\n",
7c75964f	32	r->param.mount.dev->name,
eadd99cc TH	33	r->param.mount.dir->name,
	34	r->param.mount.type->name,
	35	r->param.mount.flags);
99a85259 TH	36	}
99a85259 TH	37
0df7e8b8 TH	38	/**
	39	* tomoyo_check_mount_acl - Check permission for path path path number operation.
	40	*
	41	* @r: Pointer to "struct tomoyo_request_info".
	42	* @ptr: Pointer to "struct tomoyo_acl_info".
	43	*
	44	* Returns true if granted, false otherwise.
	45	*/
484ca79c	46	static bool tomoyo_check_mount_acl(struct tomoyo_request_info *r,
99a85259 TH	47	const struct tomoyo_acl_info *ptr)
	48	{
	49	const struct tomoyo_mount_acl *acl =
	50	container_of(ptr, typeof(*acl), head);
0df7e8b8 TH	51	return tomoyo_compare_number_union(r->param.mount.flags,
	52	&acl->flags) &&
	53	tomoyo_compare_name_union(r->param.mount.type,
	54	&acl->fs_type) &&
	55	tomoyo_compare_name_union(r->param.mount.dir,
	56	&acl->dir_name) &&
99a85259	57	(!r->param.mount.need_dev \|\|
0df7e8b8 TH	58	tomoyo_compare_name_union(r->param.mount.dev,
0df7e8b8 TH	59	&acl->dev_name));
99a85259 TH	60	}
99a85259 TH	61
2106ccd9	62	/**
d795ef9e	63	* tomoyo_mount_acl - Check permission for mount() operation.
2106ccd9 TH	64	*
2106ccd9 TH	65	* @r: Pointer to "struct tomoyo_request_info".
0f2a55d5	66	* @dev_name: Name of device file. Maybe NULL.
2106ccd9 TH	67	* @dir: Pointer to "struct path".
	68	* @type: Name of filesystem type.
	69	* @flags: Mount options.
	70	*
	71	* Returns 0 on success, negative value otherwise.
	72	*
	73	* Caller holds tomoyo_read_lock().
	74	*/
808d4e3c AV	75	static int tomoyo_mount_acl(struct tomoyo_request_info *r,
808d4e3c AV	76	const char *dev_name,
e6641edd	77	const struct path dir, const char type,
b5bc60b4	78	unsigned long flags)
2106ccd9	79	{
97fb35e4	80	struct tomoyo_obj_info obj = { };
2106ccd9	81	struct path path;
2106ccd9 TH	82	struct file_system_type *fstype = NULL;
	83	const char *requested_type = NULL;
	84	const char *requested_dir_name = NULL;
	85	const char *requested_dev_name = NULL;
	86	struct tomoyo_path_info rtype;
	87	struct tomoyo_path_info rdev;
	88	struct tomoyo_path_info rdir;
	89	int need_dev = 0;
	90	int error = -ENOMEM;
97fb35e4	91	r->obj = &obj;
2106ccd9 TH	92
2106ccd9 TH	93	/* Get fstype. */
c8c57e84	94	requested_type = tomoyo_encode(type);
2106ccd9 TH	95	if (!requested_type)
	96	goto out;
	97	rtype.name = requested_type;
	98	tomoyo_fill_path_info(&rtype);
	99
	100	/* Get mount point. */
97fb35e4	101	obj.path2 = *dir;
2106ccd9 TH	102	requested_dir_name = tomoyo_realpath_from_path(dir);
	103	if (!requested_dir_name) {
	104	error = -ENOMEM;
	105	goto out;
	106	}
	107	rdir.name = requested_dir_name;
	108	tomoyo_fill_path_info(&rdir);
	109
	110	/* Compare fs name. */
b5bc60b4	111	if (type == tomoyo_mounts[TOMOYO_MOUNT_REMOUNT]) {
2106ccd9	112	/* dev_name is ignored. */
b5bc60b4 TH	113	} else if (type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE] \|\|
	114	type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE] \|\|
	115	type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE] \|\|
	116	type == tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED]) {
2106ccd9	117	/* dev_name is ignored. */
b5bc60b4 TH	118	} else if (type == tomoyo_mounts[TOMOYO_MOUNT_BIND] \|\|
b5bc60b4 TH	119	type == tomoyo_mounts[TOMOYO_MOUNT_MOVE]) {
2106ccd9 TH	120	need_dev = -1; /* dev_name is a directory */
	121	} else {
	122	fstype = get_fs_type(type);
	123	if (!fstype) {
	124	error = -ENODEV;
	125	goto out;
	126	}
	127	if (fstype->fs_flags & FS_REQUIRES_DEV)
	128	/* dev_name is a block device file. */
	129	need_dev = 1;
	130	}
	131	if (need_dev) {
	132	/* Get mount point or device file. */
4e78c724	133	if (!dev_name \|\| kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
2106ccd9 TH	134	error = -ENOENT;
	135	goto out;
	136	}
97fb35e4	137	obj.path1 = path;
2106ccd9 TH	138	requested_dev_name = tomoyo_realpath_from_path(&path);
	139	if (!requested_dev_name) {
	140	error = -ENOENT;
	141	goto out;
	142	}
	143	} else {
	144	/* Map dev_name to "<NULL>" if no dev_name given. */
	145	if (!dev_name)
	146	dev_name = "<NULL>";
c8c57e84	147	requested_dev_name = tomoyo_encode(dev_name);
2106ccd9 TH	148	if (!requested_dev_name) {
	149	error = -ENOMEM;
	150	goto out;
	151	}
	152	}
	153	rdev.name = requested_dev_name;
	154	tomoyo_fill_path_info(&rdev);
cf6e9a64 TH	155	r->param_type = TOMOYO_TYPE_MOUNT_ACL;
	156	r->param.mount.need_dev = need_dev;
	157	r->param.mount.dev = &rdev;
	158	r->param.mount.dir = &rdir;
	159	r->param.mount.type = &rtype;
	160	r->param.mount.flags = flags;
99a85259 TH	161	do {
	162	tomoyo_check_acl(r, tomoyo_check_mount_acl);
	163	error = tomoyo_audit_mount_log(r);
	164	} while (error == TOMOYO_RETRY_REQUEST);
2106ccd9 TH	165	out:
	166	kfree(requested_dev_name);
	167	kfree(requested_dir_name);
	168	if (fstype)
	169	put_filesystem(fstype);
	170	kfree(requested_type);
97fb35e4 TH	171	/* Drop refcount obtained by kern_path(). */
	172	if (obj.path1.dentry)
	173	path_put(&obj.path1);
2106ccd9 TH	174	return error;
	175	}
	176
2106ccd9 TH	177	/**
	178	* tomoyo_mount_permission - Check permission for mount() operation.
	179	*
0f2a55d5	180	* @dev_name: Name of device file. Maybe NULL.
2106ccd9	181	* @path: Pointer to "struct path".
0f2a55d5	182	* @type: Name of filesystem type. Maybe NULL.
2106ccd9	183	* @flags: Mount options.
0f2a55d5	184	* @data_page: Optional data. Maybe NULL.
2106ccd9 TH	185	*
	186	* Returns 0 on success, negative value otherwise.
	187	*/
e6641edd	188	int tomoyo_mount_permission(const char dev_name, const struct path path,
b5bc60b4 TH	189	const char *type, unsigned long flags,
b5bc60b4 TH	190	void *data_page)
2106ccd9 TH	191	{
	192	struct tomoyo_request_info r;
	193	int error;
	194	int idx;
	195
57c2590f TH	196	if (tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_MOUNT)
57c2590f TH	197	== TOMOYO_CONFIG_DISABLED)
2106ccd9	198	return 0;
d795ef9e TH	199	if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
	200	flags &= ~MS_MGC_MSK;
	201	if (flags & MS_REMOUNT) {
b5bc60b4	202	type = tomoyo_mounts[TOMOYO_MOUNT_REMOUNT];
d795ef9e	203	flags &= ~MS_REMOUNT;
df91e494	204	} else if (flags & MS_BIND) {
b5bc60b4	205	type = tomoyo_mounts[TOMOYO_MOUNT_BIND];
d795ef9e	206	flags &= ~MS_BIND;
df91e494 TH	207	} else if (flags & MS_SHARED) {
	208	if (flags & (MS_PRIVATE \| MS_SLAVE \| MS_UNBINDABLE))
	209	return -EINVAL;
	210	type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SHARED];
	211	flags &= ~MS_SHARED;
	212	} else if (flags & MS_PRIVATE) {
	213	if (flags & (MS_SHARED \| MS_SLAVE \| MS_UNBINDABLE))
	214	return -EINVAL;
b5bc60b4	215	type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_PRIVATE];
d795ef9e	216	flags &= ~MS_PRIVATE;
df91e494 TH	217	} else if (flags & MS_SLAVE) {
	218	if (flags & (MS_SHARED \| MS_PRIVATE \| MS_UNBINDABLE))
	219	return -EINVAL;
b5bc60b4	220	type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_SLAVE];
d795ef9e	221	flags &= ~MS_SLAVE;
df91e494 TH	222	} else if (flags & MS_UNBINDABLE) {
	223	if (flags & (MS_SHARED \| MS_PRIVATE \| MS_SLAVE))
	224	return -EINVAL;
	225	type = tomoyo_mounts[TOMOYO_MOUNT_MAKE_UNBINDABLE];
	226	flags &= ~MS_UNBINDABLE;
	227	} else if (flags & MS_MOVE) {
	228	type = tomoyo_mounts[TOMOYO_MOUNT_MOVE];
	229	flags &= ~MS_MOVE;
d795ef9e	230	}
2106ccd9 TH	231	if (!type)
	232	type = "<NULL>";
	233	idx = tomoyo_read_lock();
	234	error = tomoyo_mount_acl(&r, dev_name, path, type, flags);
	235	tomoyo_read_unlock(idx);
	236	return error;
	237	}