Race Example
NetBSD-SA2002-010
A race condition in the pppd program
May be exploited to change the permissions
of an arbitrary file
src/usr.sbin/pppd/pppd/tty.c
if (fchmod(real_ttyfd, tty_mode) != 0) {
/* XXX if devnam is a symlink, this will
change the link */
     chmod(devnam, tty_mode);