alpine 3.6
access weakness #386


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.

dev_lock (const char *devname)
	const char * p;
	char device[MAXPATHLEN+1];
	char lock[MAXPATHLEN+1];
	char lock0[MAXPATHLEN+1];
	char lock1[MAXPATHLEN+1];
	char lock2[MAXPATHLEN+1];
	struct stat statbuf;
	pid_t pid, pid2, our_pid;
	FILE *fd = 0;

	if ( env_var_debug == -1 ) {
		char *value;
		if ( value=getenv( _env_var ) )
			env_var_debug = liblockdev_debug = atoi( value);
		signal( SIGUSR1, _dl_sig_handler);
		signal( SIGUSR2, _dl_sig_handler);
#endif /* DEBUG */
	_debug( 3, "dev_lock(%s)\n", devname);
	if (oldmask == -1 )
		oldmask = umask( 002);	/* apply o-w to files created */
	if ( ! (p=_dl_check_devname( devname)) )
	strcpy( device, DEV_PATH);
	strcat( device, p);	/* now device has a copy of the pathname */
	_debug( 2, "dev_lock() device = %s\n", device);

	/* check the device name for existence and retrieve the major
	 * and minor numbers
	if ( stat( device, &statbuf) == -1 ) {
	if ( access( device, W_OK ) == -1 ) {

	/* now get our own pid */
	our_pid = dev_getpid();
	_debug( 2, "dev_lock() our own pid = %d\n", (int)our_pid);

	/* We will use this algorithm:
	 * first we build a file using the pid in the name (garanteed to
	 * be unique), then we try to link to the lockname (atomic
	 * operation which doesn't overwrite existing files). If we
	 * succeed then we link it to the other lockname. Only when both 

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