#!/usr/bin/env perl
#
# Author : Dennis Eriksen <d@ennis.no>
# File : makepass.pl
# Created : 2023-07-27
# License : BSD-3-Clause
#
# Copyright (c) 2018-2023 Dennis Eriksen • d@ennis.no
use strict;
use warnings;
use v5.10.0;
use Getopt::Std;
use constant {
MAX => 255, # max length of passwords
RANGE_MAX => 42, # max length when using random length
RANGE_MIN => 8, # min length when using random length
PASS_WORDS => 8, # number of words in passphrases
LOWER => 'abcdefghijklmnopqrstuvwxyz',
UPPER => 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
DIGIT => '0123456789',
OTHER => '!$%&#/()=?+-_,.;:<>[]{}|@*',
};
my @lower = split //, LOWER;
my @upper = split //, UPPER;
my @digit = split //, DIGIT;
my @other = split //, OTHER;
my @alpha = ( @lower, @upper );
my @alnum = ( @alpha, @digit );
my @every = ( @alnum, @other );
my $length = $ENV{'MAKEPASS_LENGTH'} // 0;
my $number = $ENV{'MAKEPASS_NUMBER'} // 10;
my $printlen = 0;
my @normal =
$ENV{'MAKEPASS_NORMAL'}
? split //, $ENV{'MAKEPASS_NORMAL'}
: ( @alnum, '-', '_' );
my @special =
$ENV{'MAKEPASS_SPECIAL'}
? split //, $ENV{'MAKEPASS_SPECIAL'}
: (@every);
my $wordlist = $ENV{'MAKEPASS_WORDLIST'} || '/usr/share/dict/words';
my $col_width;
my $col_num;
# Get screen width so we can print in pretty columns
# TODO: Native perl. Possible solutions:
# - Term::ReadKey
# - not a builtin module. Needs installing everywhere.
# - builtin module ioctl and posix-call `TIOCGWINSZ`.
# - does not work on all systemd. I.e. OpenBSD.
my $xwidth = `tput cols` || 80;
chomp($xwidth); # remove \n at end of line
#
# Main function! Go magic!
#
sub main {
#
# Getopts
#
getopts('hl:n:p');
our ( $opt_h, $opt_l, $opt_n, $opt_p );
# -h = help
help() if ($opt_h);
# -l NUM = length of passwords
# I know this check is unnecessary because we check $LENGTH below, but
# I still want it.
die "-l takes a number between 0 and " . MAX
if ( $opt_l && !int_in_range( $opt_l, 0, MAX ) );
$length = $ARGV[0] // $opt_l // $length;
# -n NUM = number of passwords
die "-n takes a number between 0 and " . MAX
if ( $opt_n && !int_in_range( $opt_n, 1, MAX ) );
$number = $opt_n // $number;
# -p = print length of passwords
$printlen = 1 if $opt_p;
#
# Some errorhandling
#
die "only one argument" if ( scalar(@ARGV) > 1 );
die "length must be a number between 0 and " . MAX
unless ( int_in_range( $length, 0, MAX ) );
die "number-argument must be between 1 and " . MAX
unless ( int_in_range( $number, 1, MAX ) );
#
# Some other stuff
#
# Seed rand() with bits from /dev/random. Because.
open( my $random, '<:raw', '/dev/random' ) or die $!;
read( $random, my $bytes, 8 ) and close($random);
# See https://perldoc.perl.org/functions/pack
srand( unpack( "L", $bytes ) );
$printlen = $length < 100 ? 2 : 3 if $printlen;
$col_width = ( $length ? $length : RANGE_MAX ) + 2;
$col_num =
int( $xwidth / ( $col_width + ( $printlen ? $printlen + 1 : 0 ) ) ) || 1;
#
# Print passwords
#
print_columns( "Normal passwords", $number, @normal );
print "\n";
print_columns( "Passwords with special characters",
int( $number / 3 * 2 + 1 ), @special );
#
# Print Passphrases
#
# But only if we can read the wordlist
if ( -r $wordlist ) {
print "\n";
say "Passphrases:";
open( FILE, "<", $wordlist ) or die("Can't open file");
chomp( my @wordlist = <FILE> ) and close(FILE);
say passphrase( \@wordlist ) foreach ( 1 .. int( $number / 2 ) );
}
}
#
# Print in random strings in columns
#
#sub print_columns ( $title, $num, @chars ) {
sub print_columns {
say "@_";
my $title = shift(@_);
my $num = shift(@_);
my @chars = @_;
my @strings;
push( @strings, randstring(@chars) ) foreach ( 1 .. $num );
say "$title:";
for my $i ( 1 .. $num ) {
printf "%0${printlen}i ", length( $strings[ $i - 1 ] ) if ($printlen);
printf "%-${col_width}s", $strings[ $i - 1 ];
print "\n"
if ( $i % $col_num == 0 || ( $i == $num && $i % $col_num > 0 ) );
}
}
#
# Function to create random string
#
#sub randstring (@chars) {
sub randstring {
my @chars = @_;
my $str;
my $len = $length || int( rand( RANGE_MAX - RANGE_MIN ) + RANGE_MIN );
@chars = @normal if !@chars;
$str .= $alpha[ rand @alpha ];
$str .= $chars[ rand @chars ] foreach ( 1 .. $len - 2 );
$str .= $alnum[ rand @alnum ] if ( $len >= 2 );
return $str;
}
#
# Return passphrases
#
#sub passphrase ($arrh) {
sub passphrase { # Use array-handle to avoid copying large array around
my $arrh = shift(@_);
my @indexes;
push( @indexes, rand( @{$arrh} ) ) foreach ( 1 .. PASS_WORDS );
( my $str = join( '-', @{$arrh}[@indexes] ) ) =~ tr/A-Za-z0-9_-//cd;
return $str;
}
#
# Check if int and in range
#
#sub int_in_range ( $num, $min, $max ) {
sub int_in_range {
my $num = shift(@_);
my $min = shift(@_);
my $max = shift(@_);
return ( $num =~ /^[[:digit:]]+$/ && $min <= $num && $num <= $max ) ? 1 : 0;
}
#
# Help function
#
sub help {
my $str='NAME
makepass - create several random passwords
SYNOPSIS
makepass [OPTIONS] [NUM]
If a NUM is provided, passwords will be NUM characters long.
By default `makepass` will output passwords from the three following classes:
- Normal passwords - random strings with letters (both lower and upper
case), numbers, and dashes and underscores.
- Passwords with special characters - random strings generated from lower
and upper case letters, numbers, and the following characters:
!#$%&/()=?+-_,.;:<>[]{}|@*
- Passphrases - if we find a dictionary, a series of eight random words
from the dictionary, separated by dashes. The number of words can not be
changed, but you do not have to use all of them. Use as mane as you want.
The first character will always be alphabetic, and the last will always be
alphanumeric.
DESCRIPTION
makepass has the following options:
-h
output this help-text
-l
length of passwords. See MAKEPASS_LENGTH below
-n
number of passwords. See MAKEPASS_NUMBER below
-p
print length of number
ENVIRONMENT
makepass examines the following environmental variables.
MAKEPASS_LENGTH
Specifies the length of passwords. Valid values are 0-255. If 0, a
random value between 8 and 42 will be used for each password. -l
overrides this environmental variable, and the argument NUM overrides
that again. So `MAKEPASS_LENGTH=10 makepass -l 12 14` will give
passwords that are 14 characters long, even though both -l and
MAKEPASS_LENGTH also specifies a length.
MAKEPASS_NUMBER
The number of passwords to generate. This formula is used to determine
how many passwords from each group should be generated:
- (n) normal passwords
- (n / 3 * 2 + 1) special passwords
- (n / 2) passphrases
Where n is 10 by default. Valid values for n are 1-255. Floating-poing
math is not used, so results may vary.
MAKEPASS_PRINTLEN
If 1, print length of all passwords. If 0, don\'t.
MAKEPASS_NORMAL
String of characters from which to generate "normal" passwords.
Defaults to:
abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_
MAKEPASS_SPECIAL
String of characters from which to generate passwords with special
characters. Defaults to the same characters as in MAKEPASS_NORMAL, plus
these:
!#$%&/()=?+-_,.;:<>[]{}|@*
MAKEPASS_WORDLIST
Specifies the dictionary we find words for passphrases in. If this is
unset or empty, we try "/usr/share/dict/words". If that file does not
exist, no passphrases will be provided.
NOTES
This scripts makes use of rand() - a perl function that returns a
pseudo-random number. It is not cryptographically secure. We initially
seed the random number generator with a random 32bit integer generated from
/dev/random. This should provide enough randomnes to generate sufficiently
secure passwords.
AUTHOR
Dennis Eriksen <https://dnns.no>';
print "$str\n";
exit(0);
}
# Call with & so it gets the same arguments as root. (@_)
&main;
