/*
* 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_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)
{
const char *dev = r->param.mount.dev->name;
const char *dir = r->param.mount.dir->name;
const char *type = r->param.mount.type->name;
const unsigned long flags = r->param.mount.flags;
if (r->granted)
return 0;
if (!strcmp(type, TOMOYO_MOUNT_REMOUNT_KEYWORD))
tomoyo_warn_log(r, "mount -o remount %s 0x%lX", dir, flags);
else if (!strcmp(type, TOMOYO_MOUNT_BIND_KEYWORD)
|| !strcmp(type, TOMOYO_MOUNT_MOVE_KEYWORD))
tomoyo_warn_log(r, "mount %s %s %s 0x%lX", type, dev, dir,
flags);
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))
tomoyo_warn_log(r, "mount %s %s 0x%lX", type, dir, flags);
else
tomoyo_warn_log(r, "mount -t %s %s %s 0x%lX", type, dev, dir,
flags);
return tomoyo_supervisor(r,
TOMOYO_KEYWORD_ALLOW_MOUNT "%s %s %s 0x%lX\n",
tomoyo_pattern(r->param.mount.dev),
tomoyo_pattern(r->param.mount.dir), type,
flags);
}
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.
* @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)
{
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;
/* 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);
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);
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 ((flags & MS_MGC_MSK) == MS_MGC_VAL)
flags &= ~MS_MGC_MSK;
if (flags & MS_REMOUNT) {
type = TOMOYO_MOUNT_REMOUNT_KEYWORD;
flags &= ~MS_REMOUNT;
}
if (flags & MS_MOVE) {
type = TOMOYO_MOUNT_MOVE_KEYWORD;
flags &= ~MS_MOVE;
}
if (flags & MS_BIND) {
type = TOMOYO_MOUNT_BIND_KEYWORD;
flags &= ~MS_BIND;
}
if (flags & MS_UNBINDABLE) {
type = TOMOYO_MOUNT_MAKE_UNBINDABLE_KEYWORD;
flags &= ~MS_UNBINDABLE;
}
if (flags & MS_PRIVATE) {
type = TOMOYO_MOUNT_MAKE_PRIVATE_KEYWORD;
flags &= ~MS_PRIVATE;
}
if (flags & MS_SLAVE) {
type = TOMOYO_MOUNT_MAKE_SLAVE_KEYWORD;
flags &= ~MS_SLAVE;
}
if (flags & MS_SHARED) {
type = TOMOYO_MOUNT_MAKE_SHARED_KEYWORD;
flags &= ~MS_SHARED;
}
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_same_acl_head(&p1->head, &p2->head) &&
tomoyo_same_name_union(&p1->dev_name, &p2->dev_name) &&
tomoyo_same_name_union(&p1->dir_name, &p2->dir_name) &&
tomoyo_same_name_union(&p1->fs_type, &p2->fs_type) &&
tomoyo_same_number_union(&p1->flags, &p2->flags);
}
/**
* tomoyo_write_mount - 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(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;
}
