bash_obfus.plx

#!/usr/bin/perl -w
use strict;
use warnings;
use feature ':5.10';

sub print_usage() {
say "$0 is a bash shell script minifier/obfuscator.";
say "It deletes full line comments, whitespaces and tabs, and obfuscates variable names.";
say "Usage:";
say "\t $0 -h \t This help message.";
say "\t $0 -i <input_file> -o <output_file> [-V <new_var_string>] -C -F";
say "\t Where:";
say "\t\t<input_file>\tis the shell script you want to obfuscate";
say "\t\t<output_file>\tis where you want to save the obfuscated script";
say "\t\t<new_var_string>\tis an optional argument that defines what all variables will be changed to.";
say "\t\t\tThe default is 'a', which means all variables will be changed to a0,a1,a2,a3,...";
say "\t\t-C\tis an option to clean out full line comments and blank lines.";
say "\t\t-F\tis an option to flatten out the code (remove indentations)";
exit 0;
}

sub parse_cmd_args {
my $input_file="";
my $output_file="";
my $delete_blanks="";
my $flatten="";
my $new_var="a";
for my $argnum (0 .. $#ARGV) {
if ($ARGV[$argnum] eq "-i") {
$input_file=$ARGV[$argnum+1];
$argnum++;
} elsif ($ARGV[$argnum] eq "-o") {
$output_file=$ARGV[$argnum+1];
$argnum++;
} elsif ($ARGV[$argnum] eq "-h") {
&print_usage();
} elsif ($ARGV[$argnum] eq "-V") {
$new_var=$ARGV[$argnum+1];
$argnum++;
} elsif ($ARGV[$argnum] eq "-C") {
$delete_blanks=1;
} elsif ($ARGV[$argnum] eq "-F") {
$flatten=1;
}
}
if ($input_file eq "" || $output_file eq "") {
say "Input or output file not specified!!";
&print_usage();
}
return ($input_file,$output_file,$new_var,$delete_blanks,$flatten);
}

sub parse_vars_from_file {
my $file_name=shift;
open(my $fh, "<", $file_name) || die "Couldn't open '".$file_name."' for reading because: ".$!;
my %vars=();
while(my $line=<$fh>) {
# First pull var names from declarations
if ($line =~ m/^[ \t]*([a-z]+[a-z0-9_]*)=/) {
$vars{$1}=1;
# Then, from read statements
} elsif (($line =~ m/^[ \t]*read -s ([a-z]+[a-z0-9_]*)/) || ($line =~ m/^[ \t]*read ([a-z]+[a-z0-9_]*)/)) {
$vars{$1}=1;
# Then, from for loops
} elsif ($line =~ m/^[ \t]*for ([a-z]+[a-z0-9_]*) /) {
$vars{$1}=1;
# Then, from array access
} elsif ($line =~ m/^[ \t]*([a-z]+[a-z0-9_]*)\[.+\]=/) {
$vars{$1}=1;
}
}
close $fh;
return keys %vars;
}

sub obfuscate {
my $input_file=shift;
my $output_file=shift;
my $new_var=shift;
my $delete_blanks=shift;
my $flatten=shift;
my @sorted_vars=@_;

open(my $ifh, "<", $input_file) || die "Couldn't open '".$input_file."' for reading because: ".$!;
open(my $ofh, ">", $output_file) || die "Couldn't open '".$output_file."' for writing because: ".$!;
my %var_obfus=();
my $var_index=0;
for my $var (@sorted_vars) {
$var_obfus{$var}=$new_var.$var_index;
$var_index++;
}
my %vars=();
while(my $line=<$ifh>) {
if ($delete_blanks && (($line =~ m/^#[^!].*/) || ($line =~ m/^[ \t]*$/))) {
next;
}
if ($flatten) {
$line =~ s/^[ \t]*//;
}
for my $var (@sorted_vars) {
# Substitute var names in declarations
$line =~ s/^([ \t]*)$var=/$1$var_obfus{$var}=/;
# Then, in read statements
$line =~ s/^([ \t]*read .*)$var/$1$var_obfus{$var}/;
# Then, in for loops
$line =~ s/^([ \t]*for )$var/$1$var_obfus{$var}/;
# Then, in array access
$line =~ s/^([ \t]*)$var(\[.+\]=)/$1$var_obfus{$var}$2/;
# General "$" usage while making sure we're not inside ''
while ($line =~ m/^(([^\']*('[^']*')*[^']*)*)\$$var/) {
$line =~ s/^(([^\']*('[^']*')*[^']*)*)\$$var/$1\$$var_obfus{$var}/;
}
# Only allow a $var to be replaced between '' if they're already inside ""
while ($line =~ m/^([^']*(('[^']*')*("[^"]")*)*"[^"]*)\$$var/) {
$line =~ s/^([^']*(('[^']*')*("[^"]")*)*"[^"]*)\$$var/$1\$$var_obfus{$var}/;
}
# Special case ${var} usage while making sure we're not inside ''
while ($line =~ m/^(([^']*('[^']*')*[^']*)*)\$\{$var/) {
$line =~ s/^(([^']*('[^']*')*[^']*)*)\$\{$var/$1\$\{$var_obfus{$var}/;
}
# Likewise, allow ${var} between '' only if we're already between ""
while ($line =~ m/^([^']*(('[^']*')*("[^"]")*)*"[^"]*)\$\{$var/) {
$line =~ s/^([^']*(('[^']*')*("[^"]")*)*"[^"]*)\$\{$var/$1\$\{$var_obfus{$var}/;
}
}
# Print whatever got through the filters
print $ofh $line
}
close $ifh;
close $ofh;
}

my ($input_file,$output_file,$new_var,$delete_blanks,$flatten)=&parse_cmd_args();
my @parsed_vars=&parse_vars_from_file($input_file);
my @sorted_vars = sort { length($b) <=> length($a) } @parsed_vars;
&obfuscate($input_file,$output_file,$new_var,$delete_blanks,$flatten,@sorted_vars);