Ugly Password Script (#4)

* Ugly Password Script

Generates a randomly generated long ugly password.  Uses /dev/random to ensure reliable entropy.  Could be used to password protect Submitty system accounts.

* Fix Comment

/sample_bin/ugly_password.pl

Fix comment style line 23

* Ugly Password Fix

sample_bin/ugly_password.pl

Bugfix/refactor to disqualify certain printable chars that could confuse psql or possibly cli.

* Ugly Password Comment Update

sample_bin/ugly_password.pl

Some comments didn't make it to last commit.

* Ugly Password Script
Changes to be committed:
modified:   sample_bin/ugly_password.pl

Author: pbailie

sample_bin/ugly_password.pl

@@ -0,0 +1,36 @@
+#!/usr/bin/env perl
+
+# File: ugly_password.pl
+# Date: August 7, 2018
+# Author: Peter Bailie
+#
+# This will output to STDOUT a randomly generated ugly password using the
+# printable ASCII character range of 33 - 126.  Passwords are based on
+# /dev/random to ensure reliable pseudo-random entropy.
+#
+# /dev/random is blocking, so there may be a (possibly lengthy) delay in
+# output when the seed pool needs to be refreshed.
+
+use strict;
+use warnings;
+use autodie;
+
+my $PW_LENGTH = 32;  # length of the ugly password in characters.
+my ($fh, $byte, $val, $output);
+
+open $fh, '<:raw', '/dev/random';
+$output = "";  # password output
+while (length $output < $PW_LENGTH) {
+	# Read a random byte and scale it to range 33 - 126.
+	read $fh, $byte, 1;
+	$val = (unpack 'C', $byte) % 94 + 33;
+
+	# Single quote, double quote, and backtick chars are disqualified.
+	# Prevents some edge cases for copy/pasting ugly passwords to psql or cli.
+	if ($val != 34 && $val != 39 && $val != 96) {
+		# Character qualifies, append it to password.
+		$output .= chr $val;
+	}
+}
+close $fh;
+print STDOUT $output . "\n";