Added JS unpacking

[DatL4g]

dean.edwards.name/packer/ is a pretty commonly used Javascript tool to obfuscate code.

This can get pretty frustating when working with script data (since it even messes with strings unlike other obfuscator), so I added a method to unpack that code

[itboy87]

@DatL4g thanks for your contribution. This may be helpful for someone. Could you please kindly add a unit test similar to HtmlParserTest.handlesCdataInScript, but using a packed DataNode and compare the results of both packed and unpacked data?

[DatL4g]

@itboy87 Sorry but I don't quite understand your Testing structure and requested addition.

I've added some DataNodeTest cases to detect packed scripts and resolve them.
Undetected scripts won't change anything and return their data as is.

Can you either elaborate a bit more what kind of test you want or add it yourself?

[itboy87]

@itboy87 Sorry but I don't quite understand your Testing structure and requested addition.

I've added some DataNodeTest cases to detect packed scripts and resolve them.

Undetected scripts won't change anything and return their data as is.

Can you either elaborate a bit more what kind of test you want or add it yourself?

@DatL4g Never mind i will send you test code for it but can you please check my comments for some improvements

[DatL4g]

@itboy87 Do you have anything to review, or which comments do you mean?

Comparing the packed and unpacked result is not really possible as it scales with the data size.

• The getWholeData() method is unchanged, meaning it's not taking longer to get.
• The isPacked field will only return when it's getting called, so the object creation itself has no impact.
• The getUnpackedData() method scales with the data size as mentioned, since the String gets matched with some regular expressions

[itboy87]

@DatL4g sorry i forgot to submit them now you can see them

[itboy87]

@DatL4g please also add this unit test:

        val packedJs = "eval(function(p,a,c,k,e,r){e=String;if(!''.replace(/^/,String)){while(c--)r[c]=k[c]||c;k=[function(e){return r[e]}];e=function(){return'\\\\w+'};c=1};while(c--)if(k[c])p=p.replace(new RegExp('\\\\b'+e(c)+'\\\\b','g'),k[c]);return p}('0.1(\"2 3\")',4,4,'console|log|Hello|World'.split('|'),0,{}))"
        val packedScript = "<script type=\"text/javascript\">$packedJs</script>"
        val unpackedJs = "console.log(\"Hello World\")"
        val doc = Ksoup.parse(packedScript)
        val script = doc.selectFirst("script")!!
        assertEquals(packedScript, script.outerHtml())
        val dataNode = script.childNode(0) as DataNode
        assertEquals(packedJs, dataNode.getWholeData())
        assertEquals(unpackedJs, dataNode.getUnpackedData())

[DatL4g]

@itboy87 Thanks for the hints! Added the changes

[itboy87]

Thanks.

[itboy87]

@DatL4g Do you know how to create a JavaScript packer in Kotlin? I’m thinking of adding a JS packer and unpacker as a utility in the library

[DatL4g]

@itboy87 Sorry I don't.

This unpacker implementation is based on this PHP variant.

Here is a equivalent for packing https://github.com/tholu/php-packer

[itboy87]

Okay thanks