Sanctum

Content Security Policies for your PHP application.

Sanctum allows you to create and deploy Content Security Policies with ease. Take the guesswork out of this important security feature.

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Installation

composer require decodelabs/sanctum

Usage

Create your definition:

use DecodeLabs\Sanctum\Definition;

class MyCsp extends Definition {

    // These items can be reused in other directives
    const SharedSrc = [
        '@self', // Resolves to 'self'
        '*.myotherdomain.com'
    ];

    // These items create the default-src directive
    const DefaultSrc = [
        '@shared-src', // Import items from SharedSrc
    ];

    // These define script sources
    const ScriptSrc = [
        '@nonce', // Creates a unique nonce to be used in markup
        '@unsafe-inline', // Resolves to 'unsafe-inline'

        '@strict-dynamic',
        '@https',
        '@http'
    ];

    // These define image sources
    const ImgSrc = [
        '@shared', // Import items from SharedSrc
        '@data', // Resolves to data: for data URLs
        '*.myimagecdn.net',
        '!*.myotherdomain.com' // Exclude importing from SharedSrc
    ];


    // Report endpoint
    const ReportUri = 'https://mydomain.com/report';
}

Please see https://content-security-policy.com/ for a full list of directives.

Then in your HTTP handler:

$csp = new MyCsp();

foreach($csp->exportHeaders() as $header => $value) {
    $response->setHeader($header, $value);
}

/*
Reporting-Endpoints => sanctum-csp-report="https://mydomain.com/report"
Content-Security-Policy =>
    default-src 'self' *.myotherdomain.com;
    script-src nonce-98b88fa48f23911d6fc1f5092efb2e36d76423ce4f5d7ef42765a2c2501d57c9' 'unsafe-inline' 'strict-dynamic' https: http:;
    img-src 'self' data: *.myimagecdn.net;
    report-uri https://mydomain.com/report;
    report-to sanctum-csp-report
*/

Hashes

Make use of the hash feature for scripts - see https://content-security-policy.com/hash/ for explanation

/*
HTML:
<script>doSomething();</script>
*/
$script = 'doSomething();'; // Your JS


// Adds sha256-xxx hash to CSP directive
$hash = $csp->hashContent($script, 'script-src');

Archetype loader

Sanctum also provides an optional Archetype loader:

namespace DecodeLabs\Sanctum\Definition;

use DecodeLabs\Sanctum\Definition;

class MyCsp extends Definition {}

$csp = Definition::load('MyCsp');
$csp->exportHeaders();

Archetype will look for implementations in the root namespace (DecodeLabs\Sanctum\Definition) by default. If you want to host your implementations in a different namespace, you should create and register a new Archetype resolver to find them.

Licensing

Sanctum is licensed under the MIT License. See LICENSE for the full license text.