/*
* security/tomoyo/mount.c
*
* Copyright (C) 2005-2010 NTT DATA CORPORATION
*/
#include <linux/slab.h>
#include "common.h"
/* Keywords for mount restrictions. */
/* Allow to call 'mount --bind /source_dir /dest_dir' */
#define TOMOYO_MOUNT_BIND_KEYWORD "--bind"
/* Allow to call 'mount --move /old_dir /new_dir ' */
#define TOMOYO_MOUNT_MOVE_KEYWORD "--move"
/* Allow to call 'mount -o remount /dir ' */
#define TOMOYO_MOUNT_REMOUNT_KEYWORD "--remount"
/* Allow to call 'mount --make-unbindable /dir' */
#define TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD "--make-unbindable"
/* Allow to call 'mount --make-private /dir' */
#define TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD "--make-private"
/* Allow to call 'mount --make-slave /dir' */
#define TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD "--make-slave"
/* Allow to call 'mount --make-shared /dir' */
#define TOMOYO_MOUNT_MAKE_SHARED_KEYWORD "--make-shared"
/**
* tomoyo_mount_acl2 - Check permission for mount() operation.
*
* @r: Pointer to "struct tomoyo_request_info".
* @dev_name: Name of device file.
* @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_acl2(struct tomoyo_request_info *r, char *dev_name,
struct path *dir, char *type, unsigned long flags)
{
struct path path;
struct tomoyo_acl_info *ptr;
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;
/* Get fstype. */
requested_type = tomoyo_encode(type);
if (!requested_type)
goto out;
rtype.name = requested_type;
tomoyo_fill_path_info(&rtype);
/* Get mount point. */
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 (!strcmp(type, TOMOYO_MOUNT_REMOUNT_KEYWORD)) {
/* dev_name is ignored. */
} else if (!strcmp(type, TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD) ||
!strcmp(type, TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD) ||
!strcmp(type, TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD) ||
!strcmp(type, TOMOYO_MOUNT_MAKE_SHARED_KEYWORD)) {
/* dev_name is ignored. */
} else if (!strcmp(type, TOMOYO_MOUNT_BIND_KEYWORD) ||
!strcmp(type, TOMOYO_MOUNT_MOVE_KEYWORD)) {
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 (kern_path(dev_name, LOOKUP_FOLLOW, &path)) {
error = -ENOENT;
goto out;
}
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);
list_for_each_entry_rcu(ptr, &r->domain->acl_info_list, list) {
struct tomoyo_mount_acl *acl;
if (ptr->is_deleted || ptr->type != TOMOYO_TYPE_MOUNT_ACL)
continue;
acl = container_of(ptr, struct tomoyo_mount_acl, head);
if (!tomoyo_compare_number_union(flags, &acl->flags) ||
!tomoyo_compare_name_union(&rtype, &acl->fs_type) ||
!tomoyo_compare_name_union(&rdir, &acl->dir_name) ||
(need_dev &&
!tomoyo_compare_name_union(&rdev, &acl->dev_name)))
continue;
error = 0;
break;
}
if (error)
error = tomoyo_supervisor(r, TOMOYO_KEYWORD_ALLOW_MOUNT
"%s %s %s 0x%lX\n",
tomoyo_file_pattern(&rdev),
tomoyo_file_pattern(&rdir),
requested_type, flags);
out:
kfree(requested_dev_name);
kfree(requested_dir_name);
if (fstype)
put_filesystem(fstype);
kfree(requested_type);
return error;
}
/**
* tomoyo_mount_acl - Check permission for mount() operation.
*
* @r: Pointer to "struct tomoyo_request_info".
* @dev_name: Name of device file.
* @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, char *dev_name,
struct path *dir, char *type, unsigned long flags)
{
int error;
error = -EPERM;
if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
flags &= ~MS_MGC_MSK;
switch (flags & (MS_REMOUNT | MS_MOVE | MS_BIND)) {
case MS_REMOUNT:
case MS_MOVE:
case MS_BIND:
case 0:
break;
default:
printk(KERN_WARNING "ERROR: "
"%s%s%sare given for single mount operation.\n",
flags & MS_REMOUNT ? "'remount' " : "",
flags & MS_MOVE ? "'move' " : "",
flags & MS_BIND ? "'bind' " : "");
return -EINVAL;
}
switch (flags & (MS_UNBINDABLE | MS_PRIVATE | MS_SLAVE | MS_SHARED)) {
case MS_UNBINDABLE:
case MS_PRIVATE:
case MS_SLAVE:
case MS_SHARED:
case 0:
break;
default:
printk(KERN_WARNING "ERROR: "
"%s%s%s%sare given for single mount operation.\n",
flags & MS_UNBINDABLE ? "'unbindable' " : "",
flags & MS_PRIVATE ? "'private' " : "",
flags & MS_SLAVE ? "'slave' " : "",
flags & MS_SHARED ? "'shared' " : "");
return -EINVAL;
}
if (flags & MS_REMOUNT)
error = tomoyo_mount_acl(r, dev_name, dir,
TOMOYO_MOUNT_REMOUNT_KEYWORD,
flags & ~MS_REMOUNT);
else if (flags & MS_MOVE)
error = tomoyo_mount_acl(r, dev_name, dir,
TOMOYO_MOUNT_MOVE_KEYWORD,
flags & ~MS_MOVE);
else if (flags & MS_BIND)
error = tomoyo_mount_acl(r, dev_name, dir,
TOMOYO_MOUNT_BIND_KEYWORD,
flags & ~MS_BIND);
else if (flags & MS_UNBINDABLE)
error = tomoyo_mount_acl(r, dev_name, dir,
TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD,
flags & ~MS_UNBINDABLE);
else if (flags & MS_PRIVATE)
error = tomoyo_mount_acl(r, dev_name, dir,
TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD,
flags & ~MS_PRIVATE);
else if (flags & MS_SLAVE)
error = tomoyo_mount_acl(r, dev_name, dir,
TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD,
flags & ~MS_SLAVE);
else if (flags & MS_SHARED)
error = tomoyo_mount_acl(r, dev_name, dir,
TOMOYO_MOUNT_MAKE_SHARED_KEYWORD,
flags & ~MS_SHARED);
else
do {
error = tomoyo_mount_acl2(r, dev_name, dir, type,
flags);
} while (error == TOMOYO_RETRY_REQUEST);
if (r->mode != TOMOYO_CONFIG_ENFORCING)
error = 0;
return error;
}
/**
* tomoyo_mount_permission - Check permission for mount() operation.
*
* @dev_name: Name of device file.
* @path: Pointer to "struct path".
* @type: Name of filesystem type. May be NULL.
* @flags: Mount options.
* @data_page: Optional data. May be NULL.
*
* Returns 0 on success, negative value otherwise.
*/
int tomoyo_mount_permission(char *dev_name, struct path *path, 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 (!type)
type = "<NULL>";
idx = tomoyo_read_lock();
error = tomoyo_mount_acl(&r, dev_name, path, type, flags);
tomoyo_read_unlock(idx);
return error;
}
static bool tomoyo_same_mount_acl(const struct tomoyo_acl_info *a,
const struct tomoyo_acl_info *b)
{
const struct tomoyo_mount_acl *p1 = container_of(a, typeof(*p1), head);
const struct tomoyo_mount_acl *p2 = container_of(b, typeof(*p2), head);
return tomoyo_is_same_acl_head(&p1->head, &p2->head) &&
tomoyo_is_same_name_union(&p1->dev_name, &p2->dev_name) &&
tomoyo_is_same_name_union(&p1->dir_name, &p2->dir_name) &&
tomoyo_is_same_name_union(&p1->fs_type, &p2->fs_type) &&
tomoyo_is_same_number_union(&p1->flags, &p2->flags);
}
/**
* tomoyo_write_mount_policy - Write "struct tomoyo_mount_acl" list.
*
* @data: String to parse.
* @domain: Pointer to "struct tomoyo_domain_info".
* @is_delete: True if it is a delete request.
*
* Returns 0 on success, negative value otherwise.
*
* Caller holds tomoyo_read_lock().
*/
int tomoyo_write_mount_policy(char *data, struct tomoyo_domain_info *domain,
const bool is_delete)
{
struct tomoyo_mount_acl e = { .head.type = TOMOYO_TYPE_MOUNT_ACL };
int error = is_delete ? -ENOENT : -ENOMEM;
char *w[4];
if (!tomoyo_tokenize(data, w, sizeof(w)) || !w[3][0])
return -EINVAL;
if (!tomoyo_parse_name_union(w[0], &e.dev_name) ||
!tomoyo_parse_name_union(w[1], &e.dir_name) ||
!tomoyo_parse_name_union(w[2], &e.fs_type) ||
!tomoyo_parse_number_union(w[3], &e.flags))
goto out;
error = tomoyo_update_domain(&e.head, sizeof(e), is_delete, domain,
tomoyo_same_mount_acl, NULL);
out:
tomoyo_put_name_union(&e.dev_name);
tomoyo_put_name_union(&e.dir_name);
tomoyo_put_name_union(&e.fs_type);
tomoyo_put_number_union(&e.flags);
return error;
}
