Saying Thanks – Open Source Appreciation

Wow, it has been a really long time since I’ve posted here. Most of my writing has ended up in articles of php[architect] or over on I wanted to jump back into the blog though and talk about something inspired by a post over on the Symfony blog about giving thanks.

Normally the Thanksgiving holiday is more associated with sharing what you’re thankful for in your life. However, the Christmas holiday comes at a perfect time to look back over the past year and think about everything you’re thankful for and how your life has changed, hopefully for the better. In the Symfony blog post they share a Composer plugin – Thanks – that makes it simple to show your appreciation to those packages you’re currently using in your applications. It sends stars to the projects (the ones you haven’t already starred naturally) as a token of appreciation. This is a great first step to showing how much you appreciate the work the maintainers have done but there’s also other ways to show that you support them and that they’re doing a great job. Here’s a few other suggestions:

  • Find their email (often in the repo’s file) and send them a quick note telling them how much you enjoy using the library and how important it is to your application.
  • Write a blog post about the package and how you use it to share with others. Maintainers always enjoy seeing how their work is used and maybe even get ideas for future features and fixes.
  • Send out a Tweet about the project, telling them how much you appreciate the work they do.
  • Support them on Patreon if they have a page on there with a recurring donation. This allows them to spend more time focusing on the project and making it better for everyone.
  • Open an issue on the project’s Github/Bitbucket repository with a quick “Thanks” to everyone involved.

These are just a few ideas to get you started, of course. There’s plenty of other ways that you can support and thank the authors and maintainers of your favorite packages. Get creative and think of your own but this is the perfect time of year to do it and let those developers know their work is appreciated!


Protecting your application with PropAuth (Property-based Policy evaluation)

Library: PropAuth (Property-based policy evaluation)

I’ve been working on a library for a while now that kind of distills down some of the ideas of property-based authorization (like XACML) and makes it a bit more accessible to the average developer. Property-based evaluation can be a little tricky to get your head around if you’re used to the usual RBAC world. Let me introduce it briefly.

Property-based evaluation is more or less what it sounds like: a system checks the properties of an object (or objects) and looks for different kinds of matches. That much is pretty simple but then you get into the “policies” aspect. This is where the real power comes in. With policies you can define the pass/fail requirements for the checks against an object and see if there’s a good enough match. With something like XACML it gets pretty complicated as it defines policies with XML documents (and we all know how “simple” XML is). There’s all sorts of different combining algorithms for the results like “first wins” or “all must match”. These can, of course, be nested and combined themselves leading to pretty complex policies and a mess if you’re not careful.

So, back to PropAuth now. In the work that I’ve been doing I’ve only really seen the need for a more streamlined version of this kind of evaluation. Some of the overall flexibility that XACML provides hasn’t been included in PropAuth, but I haven’t found much of a need for that so far anyway (like nested policies). The PropAuth library provides some of the basic property evaluation handling and policy creation I think could replace a lot of the mish-mash of role-based access control functionality out there and make for much more reusable code.

First off, to install just use Composer:

composer require psecio/propauth

And here’s a simple example of a policy evaluation:

require_once 'vendor/autoload.php';

$enforcer = new \Psecio\PropAuth\Enforcer();
$myUser = (object)[
    'username' => 'ccornutt'

$myPolicy = new \Psecio\PropAuth\Policy();

echo 'Result: '.var_export($enforcer->evaluate($myUser, $myPolicy), true);

Here’s a quick summary of what’s happening here: the Enforcer object is the “frontend” that handles most of the work. You pass in a subject for the evaluation and the policy to evaluate against. In this case I’ve used the “hasUsername” check to look at the “username” property on the object and check to see if it matches the “ccornutt” value. The “evaluate” method is then called and a true/false result is returned…in this case true as our “myUser” object has a matching username.

This only scratches the surface of what the PropAuth library can do but it gives you an idea of how the evaluations are set up.

There’s also a simplified interface you can use with the same library to perform an authentication of a user with a system that uses bcrypted passwords (like with the password hashing API):

require_once 'vendor/autoload.php';

$password = $_POST['password'];

$myUser = (object)[
    'username' => 'ccornutt',
    'password' => password_hash('test1234', PASSWORD_DEFAULT)

$gate = new \Psecio\PropAuth\Gateway($myUser);
$subject = $gate->authenticate($password);

If the password matches, you’ll be given an authenticated version of the “subject” back from the “authenticate” call. If not, you’ll get a false back on failure. Naturally, since this is all powered by the same library, you can also throw in policy checks too (warning: a bit more complicated example here):

require_once 'vendor/autoload.php';

$password = $_POST['password'];

$myUser = (object)[
    'username' => 'ccornutt',
    'password' => password_hash('test1234', PASSWORD_DEFAULT),
    'groups' => ['group1']

$policy = Policy::instance()->hasGroups(['group1', 'group2'], Policy::ANY);
$context = new Context([
    'policies' => PolicySet::instance()->add('policy1', $policy)

$gate = new Gateway($myUser, $context);
if ($gate->authenticate($password) !== false && $gate->can('policy1')) {
    echo "They're authenticated and they have one of the required groups in the policy!";


There’s a lot more going on here with a Policy Set and some of the “instance” calls but it’s all explained in the PropAuth documentation. I’d be interested in your feedback on the library and if you think it might be useful in your apps.

I’ve also put together a Provider for Laravel 5 applications that makes it simpler to incorporate the checks into both the controllers and your Blade templates, evaluating the policies directly.

There’s also a bit more detailed tutorial on using PropAuth over on the site with more information.

Custom Callbacks with Invoke

In putting the Invoke library to use I noticed something. While I could tell it to check for groups and permissions on the current user and limit HTTP methods on the request, there were more complex things I needed to check that weren’t part of these defaults. Now, I could just extend invoke to include match types for everything I needed (injecting a custom match class based on my needs) but I wanted something a bit more generic that I could use to call my own logic and return the pass/fail result.

So, I added in the “object.callback” match type that allows you to call a static method in your own code and perform the evaluation yourself. Here’s how it works. Say you have this configuration in your routes.yml file:

  protected: on
  callback: \App\MyUser::test

This tells Invoke that when the user requests the /foo URL, the protection should kick in. It then goes into the checks portion of the process. This sees the special callback option and looks the class and method to call. In this case, we’ve told it to try calling the test method \App\MyUser. This class needs to be autoloadable so that Invoke can directly call it and its static method. Yep, that’s right – it needs to be a static method but you’ll be provided with everything about the request in the incoming $data variable. Here’s what the method should look like:

public static function test(\Psecio\Invoke\Data $data)
  /* perform your evaluation here and return a boolean */

In the $data variable there, you’ll have access to the context of the application via some object properties:

  • user: The current InvokeUser instance (ideally where your user lies too)
  • resource: The resource that was requested (includes access to the requested URI)
  • route: This is the route match from Invoke’s configuration the current request matches. This contains the route regex match, the configuration options and any additional parameters passed along

For example, say you needed to get the parameters from the request to do further evaluation. You could fetch them through $data->resource->getParams() and get the associative array back.

Adding these callbacks makes the Invoke system a lot more flexible and allows you to create those custom match types without having to have whole other classes just to perform your checks.

Laravel Route Protection with Invoke

I started on a tool a while back to “scratch an itch” in a personal project to make it easier to protect endpoints based on the requested URL. The Invoke library makes it possible to detect the route requested and ensure a set of criteria are met to be sure a user can access a resource. This isn’t anything new or revolutionary, but it is something I couldn’t find separate and effectively decoupled from other tools. It’s loosely based on how Symfony (v1) does it’s route protection, right down to the .yaml file that it uses for configuration. In my case, I was using it in a Slim framework-based application to evaluate the current user to see if they had the required groups and permissions.

More recently, though, I’ve been messing with Laravel and since they’ve been putting a heavy emphasis on middleware, I thought I’d see how tough an integration might be. I wanted to use Invoke to check my Laravel user to see if they met my requirements. Fortunately, it turned out to be super easy.

Here’s how I did it – hopefully it can be useful for you. I’ll provide one caveat though: Laravel’s default auth handling only sets up users, not groups/permissions, so you’ll need a way to manage those but that’s outside the scope of this. You’ll see how it integrates in a bit.

First off, we need to get Invoke installed via Composer:

composer require psecio/invoke

Once that’s installed, we need to set up our middleware. This will go in with the rest of the default middleware in the app/Http/Middleware folder in your application. Create a file called InvokeMiddleware.php with this code:


namespace App\Http\Middleware;

use Closure;
use Illuminate\Support\Facades\Auth as Auth;

class InvokeMiddleware
     * Handle an incoming request and validate against Invoke rules
     * @param \Illuminate\Http\Request $request
     * @param \Closure  $next
     * @return mixed
    public function handle($request, Closure $next)
        $en = new \Psecio\Invoke\Enforcer(app_path().'/../config/routes.yml');
        $user = Auth::user();

        $allowed = $en->isAuthorized(
            new \App\InvokeUser($user),
            new \Psecio\Invoke\Resource($request->path())

        if ($allowed !== true) {
            return response('Unauthorized.', 401);

        return $next($request);

You’ll see there’s a reference to an InvokeUser class in there. Let’s make that next. In app/InvokeUser.php put this code:


namespace App;

class InvokeUser implements \Psecio\Invoke\UserInterface
	private $user;

	public function __construct($user)
		$this->user = $user;

	public function getGroups()
		// This is where you fetch groups
		return [];

	public function getPermissions()
		// This is where you fetch permissions
		return [];

	public function isAuthed()
		return ($this->user !== null);


Then, to turn it on, edit your app/Http/Kernel.php class and add this to the list of $middleware:


Viola, you’re set to go using Invoke. Now, the next step is to define your rules. You’ll notice in the middleware above we’re loading the config/routes.yml configuration file for our rules. Let’s make one of those with a super simple example. In app/config/routes.yml put:

  protected: on

This configuration is telling Invoke that, when you hit the base URL of your application (“/”) it’s protected. This means that it requires a logged in user. If you’ve just added this to your application and try to load the main page without a user, you’ll be given the unhappy “Forbidden” message instead of your lovely site. It’s the check in InvokeUser::isAuthed that evaluates for this, checking to see if the user is null (no valid logged in user).

That’s it…it’s a pretty simple integration to get just get bare minimum up and running. If you’re interested in how to add group and permission checking to this, forge ahead and keep reading.

So we have our basic yaml configuration file with protection turned on. Say we wanted to add in group and permission checks too. I’ve already talked some about this kind of handling in a different post but I’ve more recently simplified it even more, no longer requiring extra classes in the mix.

Let’s start by changing our configuration file to tell Invoke that we want to be sure the user is in the “admin” group and has a permission of “delete_user” to access the /admin/user/delete resource:

  protected: on
  groups: [admin]
  permissions: [delete_user]

When you fire off the page request for that URL, Invoke will try to call the InvokeUser::getGroups and InvokeUser::getPermissions methods to return the user’s current permission set. Before it required you to use classes that implemented the InvokeGroup and InvokePermission interfaces for each group/permission. I streamlined this since it’s really only evaluating string matches and allowed those methods to either return a set of objects or of strings. Let’s update the InvokeUser class to hard-code in some groups/permissions for return:


namespace App;

class InvokeUser implements \Psecio\Invoke\UserInterface
        /** ...more code... */

	public function getGroups()
		return ['admin','froods'];

	public function getPermissions()
		return ['delete_user','view_user','update_user'];
        /** ...more code... */

Ideally you’d be fetching these groups and permissions from some role-based access control system (maybe, say Gatekeeper) and returning real values. These hard-coded values will work for now.

Since the user has all the requirements, Invoke is happy and they’re able to move along and delete all the users they want.

I’ve tried to keep the class as simple as possible to use and I’m definitely open to suggestions. There’s a few additions I’d though about including adding HTTP method matching (different rules for POST than GET) and other match types than just groups and permissions. Let me know if you’d like to see something else included in Invoke – I’d love to chat!

Why Drupal’s Bug Bounty is Important

The Drupal project has just announced a bug bounty program where they’re offering sums between $50-1000 USD for anyone who finds and reports a security issue with Drupal 8:

Drupal 8 is nearing release, and with all the big architectural changes it brings, we want to ensure D8 upholds the same level of security as our previous releases. That’s where you come in!

The security team is using monies from the D8 Accelerate fund to pay for valid security issues found in Drupal 8, from now until August 31, 2015 (open to extension). This program is open for participation by anyone.

One thing to note, they’re only looking for Drupal 8 issues here, not problems in past editions (I’m sure they’d still appreciate them being reported though). There’s some stipulations they list where the vulnerability doesn’t count including someone with Administer level access and several other very specific kinds of issues. I’m assuming they’ve already run some pretty extensive testing on those, though, otherwise they would’ve been included in the list of allowed vulnerabilities.

A mention of the bug bounty was posted over on the /r/php subreddit earlier and there’s already some good feedback about it. There’s two points that I want to touch on as to why Drupal announcing this bounty is a major and important thing for the entire PHP community, not just Drupal.

First off, it sends a message to the wider world of developers that it’s time to take (PHP) security seriously. PHP’s had a less than stellar reputation when it comes to security. Fortunately it seems like things are getting better and more developers are working towards building secure applications. Security is a hot topic everywhere, not just in development communities and it’s starting to rub off on PHP devs. This bold move from the Drupal organization takes that up to the next level. It’s essentially telling everyone that uses Drupal or has any kind of contact with it, that they’re taking the security of their systems seriously and are “putting their money where their mouth is” to encourage as much participation as possible.

Bold moves like this are what get people’s attention too, even people not in the PHP community. Bug bounties have become a pretty common place thing in the security world, for software and hardware alike. By posting this bounty Drupal has shown that they (and vicariously PHP) are ready to move up and join with the security community as a whole to make their software more secure. Not only does this look good for Drupal but it looks good for PHP too, elevating the status of the language back to a “major contender” in the security circles.

Second, it helps pave the way for other projects to do the same. Most PHP projects tend to be smaller, not only in size but in complexity. There’s only a handful that most PHP developers can immediately list that are larger and have really stood the test of time. Keep in mind, I’m not talking about corporate applications or services here. I’m talking about PHP-based applications like Drupal, WordPress or Joomla that can be used as a platform to build other things. For the most part, their PHP brethren trend more towards the smaller side. Some of the most popular packages on Packagist are smaller libraries and frameworks, not applications as a whole.

There are some larger projects, though. Frameworks like the Zend Framework and Symfony have put their own emphasis on security, having internal groups or just contributors handling the vulnerability discovery and disclosure. Drupal has done things similarly in the past, but with the posting of this bounty, they’ve set a precedent for other projects to follow. It’s an unfortunate fact but in the Real World, time spent on a project (that’s not for work) falls into two categories:

  1. You do it for passion, either because the project is “yours” and you want to see it thrive or
  2. You do it because you’ll get something back out of it, either financial or in terms of much needed features

Bug bounties, pretty obviously, fall into that second category. Being able to pay out that financial compensation for work done bug hunting could be enough to tip people over from the “eh, I could” mentality to the “that’s worth my time” world. Don’t get me wrong, I’m not saying that developers are only interested in the money…far from it. I’m only saying that bounties like this gather more attention and show that the project believes in itself enough to have people commit time, either free or for work, to hunting down bugs.

I do want to touch on a third (bonus!) point too, while I have you here. While bounties like this are good for projects that have a budget, it sort of rules it out for those smaller projects where it’s just a one person team (or just a few people). In general these kinds of projects have little to no budget associated with them and don’t have spare cash on hand to pay out for bugs found or fixed. Unfortunately, there’s not too much in the way of options on this one. I’ve seen differing opinions on the payout amounts too. Some people think that the payout should relate to the severity of the bug, but the project just may not be able to afford that. People could feel slighted by the low compensation for their time which could in turn reflect poorly on the project overall. It’s a tough line…

There is one option out there that might be a good fit for your smaller project, though. The site has integrated an interesting concept of a “fundraiser” for open source projects. The idea is that a project could raise the finds in a Kickstarter-like fashion and use it to pay out bounties (or really however they might see fit). While it’s a good idea in theory, smaller projects that don’t have much exposure are still going to have a hard time raising any funds to make the bounties a realistic thing.

I don’t have a good answer here, unfortunately. I think with so much of the PHP world turing to smaller packages, it’s a tough problem to figure out. I’m all ears if you can think of any other options or even services that might help. I’d love to help make bug bounties a more wide-spread thing in the PHP world. I feel like, done correctly, they can only help to make the PHP ecosystem a better, more secure place.

Gatekeeper & Policies

I’ve been working on a system for a while now, inspired by the work that was done on the Sentry project, to provide a role-based access control system that was not only more well-maintained but also built on the foundation they provided to add in some new features. My “little project” Gatekeeper has really grown over time and (I think) really evolved into something that’s quite useful.

With this progression in mind, I’ve recently added another new feature that sits on top of the permissions and groups system that allows you to create reusable policies. Policies are a common concept when it comes to access control. They can make performing complex operations a lot simpler and, in the case of how it’s implemented here, make it much more reusable across the entire system (or multiple systems). Checking user permissions and groups is a relatively simple operation if you’re just doing one or two checks. You’d end up with something like this:

use \Psecio\Gatekeeper\Gatekeeper as g;

$user = g::findUserById(1);
if ($user->inGroup("group1") && $user->hasPermission("perm1")) {
    echo "Good to go!";


In this case, the check is relatively simple but there’s one think that any DRY code advocate could tell you – this exact check would need to be reproduced throughout the entire application exactly as stated to ensure the evaluation is the same. Even worse, if the requirements changed you’d have to work across the entire application and replace all instances with the new logic.

This is where policies can come in very handy. With the functionality that Gatekeeper includes, they’re dead simple to use too. The key is in their use of the Symfony Expression Language component. This language allows you to define text strings that represent logic and allow for more complex and self-contained evaluation. Enough talk, let’s see how we can use these policies to perform the same check as above.

// First we'll make the policy - this only needs to be done once
    'name' => 'admin-test1',
    'expression' => '"group1" in user.groups.getName() and "perm1" in user.permissions.getName()',
    'description' => 'See if a user has "permission1" and is in "group1"'

// Now, we need to evaluate the user against the policy
if (Gatekeeper::evaluatePolicy('admin-test1', $user) === true) {
    echo 'They have the permission! Rock on!';


It’s a little more verbose than the previous example, but you can see how it would fetch the permissions and groups for the user and check it against the set of names. In this case the getName function is a magic method that filters the collection and returns a set of the name property values as an array. This way it can be used with the incheck. Once the policy is in place, then any time you need to perform that evaluation, all you need to do is call the evaluatePolicy method with the information and it will always execute the same logic making it super portable and DRY.

I also mentioned how it helps with changing requirements. All you’d need to do here is change the policy contents (the expression string) and all of the code already in place will now evaluate with that new logic with no code changes required. Easy, huh?

I hope this functionality will be useful if you’re a Gatekeeper user or, if you’re not, may give you a reason to check it out. I’m also interested to hear if you think this might make for a good stand-alone component, abstracted out from the Gatekeeper system. It’s integrated right now because of the known model/relationship structure but it’s not hard to pull it out and make it abstract enough to use for other systems.

PHP, Security & PSR-9/PSR-10

Late yesterday afternoon the PSR-9 and PSR-10 drafts were moved into master on the php-fig/standards repository, moving them along to the next step and to get the wider perspective of the main PHP-FIG group’s opinions on it.

What are PSR-9 and PSR-10, you ask? Here’s a brief summary so far:

At the end of last year (2014) Lukas Smith made a proposal to the PHP-FIG group for a standard that would make reporting security issues with PHP projects and libraries a much more structured thing. The general idea is that a standardized document (or documents?) in a project’s repository would provide information about current and past security issues in a well-defined structure that could have some automated tooling around it. Much discussion was had around what the proposal actually entailed and how it would integrate with the goals of the PHP-FIG process. As work progressed on it, a few others besides Lukas came on-board to help flesh out the standard and work out the kinks, including myself.

It wasn’t long before we realized that, while having a standardized method for reporting vulnerabilities was good there also needed to be a way to discover this documentation for a given project (more than just a “look for this file” kind of thing). So, the original PSR-9 was split, giving us the security advisory reporting standard (PSR-9) and the security disclosure workflow (PSR-10) to make discovery of the reports easier. Both PSRs have received the votes needed for entrance and consideration and, as I mentioned, work is moving forward on them in the wider PHP-FIG group.

So, what are the standards? Well, I’m not going to just copy and paste from the documents (you can find those here if you’re interested) but I will give a quick overview of what they contain and their goals.

Note: these standards are by no means complete so this information is a bit subject to change. I just wanted to share their current state though.


The main goal of the PSR-9 standard is to provide structure around the documentation a project provides to the wider community around security vulnerabilities that have been found (and fixed) and those that are still pending. The idea is that any given user could look at the document and have a security-centric view into where the project currently stands. Right now, with the exception of those participating in the security-advisories database, most projects make it a bit of a run around to try to figure out what issues have come up and what problems have been fixed. Sometimes it’s reported in the Changelog, other times it’s in the mailing lists and other times you just have to know what to search for in the project’s issue tracker to get the list. This PSR-9 aims to eliminate a lot of this hassle and give a single source for the information.

The security-advisories database has provided a great start around this same kind of information but with PSR-9 the burden of reporting this information falls on the project, not a single source. We’re not aiming to replace that database by any means, though. We just want to empower the projects to share the information in a vetted, well-defined way. The PSR-9 proposal provides a lot more context around the security issues too.

This information includes:

  • An entry for each vulnerability that includes a short summary, published date, link to more information and a unique reference ID
  • CWE and/or CVE information, if possible (not all vulnerabilities are reported as CVEs)
  • What versions the issue affects
  • Current status of the issue
  • A description of the remediation if resolved
  • A low/medium/high severity rating based on the impact to the project’s users

We discussed the versioning of this resource (multiple files) so new vulnerabilities could be added and a “history” of sorts could be tracked over time but nixed that idea in favor of a single file that would just evolve over time. A lot of this vulnerability metadata is similar to information currently reported by other projects, so it’s not too far of a stretch to see this dropped into a structured, easy to find document. Speaking of which, this brings me to the next proposal…


Where PSR-9 is about the structured vulnerability list, PSR-10 is about the discovery of said document. As we worked through the original PSR-9 ideas, we found that reporting the vulnerabilities was one thing and having a structured way to access the documentation was another. One is more about the concrete thing, the document, and the other is more around process.

The PSR-10 proposal isn’t quite as fleshed out at the moment, but there are a few main points that give us a starting place:

  • The document that represents the data for a project’s PSR-9 disclosure should live somewhere the project can directly reference it, such as the project’s website or other documentation page. This is the ideal place as it removes ambiguity around which version of the document is the “master”.
  • Projects may opt to have the source in their version control system with the caveat that it should be publicly facing (not require a checkout) and that the “master” branch should be visibly documented.
  • Projects would be allowed to split up the information by the version number of the release but, as this can get much more confusing quickly, it would need to be well documented

We discussed just having the document in the version controlled repository of the project, but this leads to other issues including the definition of which branch is the “master” for the document and how to deal with private repositories (remember, the goal is public disclosure). Ultimately is was worked out that a public-facing resource was the best option. One suggestion includes a custom “link” tag with a relation value of “php-vuln-disclosures” to help with automated discovery.

We’re all excited about these two standards moving forward and look forward to the feedback the wider PHP-FIG group can provide around them. Things will be developing a bit more quickly now (it was slow going mainly because of holidays and other personal issues around the end of the year) and our hopes are that these two standards can evolve and be worked out as soon as possible.

Keep an eye on the proposals as they evolve. I’d love to get any feedback on them or suggestions based on your own experiences that would help make things even better.