alpine 3.6
access weakness #322


Weakness Breakdown


An access weakness occurs when software does not properly implement permissions that could have unintended consequences if exploited by malicious actors. An example of this weakness is when a default username and password are set by the developer but do not get changed by the system administrator.

Warning code(s):

Ensure that umask is given most restrictive possible setting.

File Name:



The highlighted line of code below is the trigger point of this particular Alpine 3.6 access weakness.

 	if (ret == -1)
		return 0;	/* Failed to unlink existing incorrect node */
	if (ret)
		return 1;	/* Already exists and correct */

	(void) dm_prepare_selinux_context(dm_dir(), S_IFDIR);
	old_umask = umask(DM_DEV_DIR_UMASK);
	ret = dm_create_dir(dm_dir());
	(void) dm_prepare_selinux_context(NULL, 0);

	if (!ret)
		return 0;

	log_verbose("Creating device %s (%u, %u)", control, major, minor);

	(void) dm_prepare_selinux_context(control, S_IFCHR);
	old_umask = umask(DM_CONTROL_NODE_UMASK);
	if (mknod(control, S_IFCHR | S_IRUSR | S_IWUSR,
		  MKDEV((dev_t)major, (dev_t)minor)) < 0)  {
		log_sys_error("mknod", control);
		(void) dm_prepare_selinux_context(NULL, 0);
		return 0;
	(void) dm_prepare_selinux_context(NULL, 0);

	return 1;

 * FIXME Update bitset in long-running process if dm claims new major numbers.
 * If require_module_loaded=0, caller is responsible to check
 * whether _dm_device_major or _dm_bitset is really set. If
 * it's not, it means the module is not loaded.
static int _create_dm_bitset(int require_module_loaded)
	int r;

#ifdef DM_IOCTLS
	if (_dm_bitset || _dm_device_major)
		return 1;

	if (!_uname())
		return 0;

The registered trademark Linux® is used pursuant to a sublicense from the Linux Foundation, the exclusive licensee of Linus Torvalds, owner of the mark on a world­wide basis.