eval()'d code error

[cursed]

Error:

Warning: fgets(): supplied argument is not a valid stream resource in /user/public_html/decode/unlock.php(49) : eval()'d code on line 1

Warning: fgets(): supplied argument is not a valid stream resource in /user/public_html/decode/unlock.php(49) : eval()'d code on line 1

Warning: fgets(): supplied argument is not a valid stream resource in /user/public_html/decode/unlock.php(49) : eval()'d code on line 1


Code:

<?php

$input = file_get_contents( $filename = 'index.php');
if (ereg(
"[$]([^=]+)=[_][_]FILE[_][_][;]"
. "[$]([^=]+)=[_][_]LINE[_][_][;]"
. "[$]([^=]+)[=]([0-9]+)[;]"
. "eval.*(base64_decode.['][^']*['].)", $input, $x)) {
// first pass
$ifilename = $x[1];
$ilinenum
= $x[2];
$ioffset
= $x[3];
$offset
= $x[4];
$decoder
= $x[5];
// get the decoder
$decoder = eval("return $decoder;");
// decipher the decoder
ereg("[$]([^=]+)[=].*[$]([^=]+)=.base64",$decoder,$x);
$ihandle = $x[1];
$iout
= $x[2];
$decoder = str_replace($iout
,'output'
,$decoder);
$decoder = str_replace($ihandle
,'handle'
,$decoder);
$decoder = str_replace($ilinenum ,'line'
,$decoder);
$decoder = str_replace($ifilename,'filename',$decoder);
// the decoder is our slave!
$decoder = str_replace('eval($output);','return $output;',$decoder);
$decoder = '$line=2;'.$decoder;
// sandbox
$next
= eval($decoder);
// remove expiration time
$next = ereg_replace("^if[^;]+;",'',$next);
// some more deciphering
ereg('^[$]([^=]+)=',$next,$x);
$next = str_replace($ihandle,
'handle',
$next);
$next = str_replace($ifilename,'filename',$next);
$next = str_replace($x[1]
,
'output',
$next);
$next = str_replace($ioffset,
'offset',
$next);
// the decoder is our slave, again!
$next = str_replace('eval($output)','return $output',$next);
// final pass
$code = eval($next);
// finish
echo '<','?php',$code,'?','>',"\n";
} else die("Failed. No base64_decode anymore.\n");
?>

what am i doing wrong?

[Twey]

I think the question is more, "what are you doing?"

Print the strings before passing them to eval() to see what you're really evaluating.

[mburt]

Yes. If the string type isn't a number/integer/float etc, it won't work.

I think the question is more, "what are you doing?"

Heh... I find that quite funny.

Back to the question...
In javascript a simple way to see what type of variable your testing, is to use the typeof construct. It outputs the type, so in PHP all I would assume to do is to echo it or something to see what - as Twey mentioned - your are trying to evaluate.

[Twey]

No, it's definitely a string, but there's some interpolation going on with data from an external file, so what s/he's evaluating might not be what s/he thinks s/he is.

Nevertheless, this looks to be a completely pointless venture overall, as so many things using eval() are. It's certainly not possible to give a definitive answer without the contents of that file.

[mburt]

file_get_contents outputs html: using this on a .php file won't output the php. In Firefox the php code shows up like this (devistating if databse info is shown):

<?php
...
?>

[cursed]

nevermind, my hosting made that problem.

The script is suppose to decode a type of Base64 code if anyone was wondering.