Forum Discussion

lbertacco's avatar
lbertacco
Icon for Nimbostratus rankNimbostratus
Apr 04, 2017

deflate/inflate data in an irule

I'd like to decode a SAML request from an iRule. The reason is that I'd like to synthesize a SAML response when the user has no valid session. The problem is that the SAML request, passed as an url parameter, is deflated and b64 encoded. B64decoding it is easy but I can't find how to decompress the deflated data. TCL v4.6 would include the zlib package which has a "zlib inflate" command, but big-ip up to v13 only has tcl4.5 and I can't find any way to inflate data. Is there any way to "load" the zlib package or use some other mechanism to inflate data in an irule?

 

application delivery
iRules
LTM
  • JoshBecigneul's avatar
    JoshBecigneul
    Icon for MVP rankMVP
    Apr 04, 2017

    Can you provide an example of the SAML request?

     

    Are you using Access Policy Manager to receive the SAML request?

     

  • cjunior's avatar
    cjunior
    Icon for Nacreous rankNacreous
    Apr 04, 2017

    Hi, I don't know your exactly goal to the SAML, but maybe you can do the deflate/inflate with the zlib library from node.js with iRule LX. In the example below, I just created a workspace, plugin then an iRule and it has worked (at least on my lab :).

    I hope it helps!

    My iRule LX scenario hierarchy: 

    ilx_plugin   
    ilx_workspace    
        ilx_extension    
            index.js    
        rules    
            ilx_rule

    index.js

    'use strict'
var f5 = require('f5-nodejs');
var zlib = require('zlib');

var ilx = new f5.ILXServer();

ilx.addMethod('deflate_b64', function(req, res) {
    var zip64 = zlib.deflateSync(req.params()[0]).toString('base64');
    res.reply(zip64);
});

ilx.addMethod('inflate_b64', function(req, res) {
    var unzip = zlib.inflateSync(new Buffer(req.params()[0], 'base64')).toString();
    res.reply(unzip);
});

ilx.listen();

    ilx_rule 

    when HTTP_REQUEST {
    set handle [ILX::init "ilx_plugin" "ilx_extension"]
    set b64response [ILX::call $handle "deflate_b64" "My string to deflate and base64 encoding"]
    log local0. "Deflate response: $b64response"

    set response [ILX::call $handle "inflate_b64" $b64response]
    log local0. "Inflate response: $response"
}

    Result: 

    Apr  4 12:32:01 bigiplab info tmm2[19039]: Rule /Common/ilx_plugin/ilx_rule : Deflate response: eJzzrVQoLinKzEtXKMlXSElNy0ksSVVIzEtRSEosTjUzUUjNS85PAUoDACY7DlU=
Apr  4 12:32:01 bigiplab info tmm2[19039]: Rule /Common/ilx_plugin/ilx_rule : Inflate response: My string to deflate and base64 encoding