From: utzoo!decvax!harpo!duke!trt
Newsgroups: net.games.emp
Title: Re: sri-unix.1410: redirection to file
Article-I.D.: duke.2136
Posted: Thu May 13 12:30:33 1982
Received: Fri May 14 03:47:14 1982


Opening a restricted file as the SUID, then reverting to the RUID
is still a security hole if the open file descriptor
is available to a RUID-specifiable program (e.g. a shell escape).
Steve Bellovin long ago pointed out that:
	fd = open(SECRETFILE, 2);
	if (fd < 0)
		could not open...
	ioctl(fd, FIOCLEX, NULL);
is a wise way to open such files.
	Tom Truscott