Content Security Protocol: LAMP-flavored CSP header for Content-Security-Policy

cspheader.php

<?php

  /**
   * @author Dave LaRonde
   * @author Lucas Larson
   * @link   https://gist.github.com/phpdave/24d879514e7411047267
   */

  // Content Security Protocol (CSP) works only in modern browsers Chrome ≥25,
  // Firefox ≥23, Safari ≥7
  $headerCSP = "Content-Security-Policy: "

               . // XMLHttpRequest (AJAX request), WebSocket, or EventSource
               "connect-src 'self' *.google-analytics.com *.doubleclick.net;"

               . // default policy for loading HTML elements
               "default-src 'self' *.example.com *.google-analytics.com *.googletagmanager.com googletagmanager.com *.google.com;"

               . // allow parent framing – this one blocks clickjacking and
                 // UI redress
               "frame-ancestors 'self';"

               . // valid sources for frames
               "frame-src 'self'"

               . // valid src domains for media via HTML audio and
                 // video elements
               "media-src 'self' *.example.com;"

               . // valid src domains for object, embed, and applet elements
               "object-src 'none';"

               . // a URL that will get raw JSON data in post that lets you
                 // know what was violated and blocked
                 // sign up for your own at report-uri.com
                 // hat tip Matt Ferderer https://dev.to/mattferderer/what-is-csp-why--how-to-add-it-to-your-website-28df
               "report-uri https://example.report-uri.com/r/d/csp/reportOnly;"

               . // report-to, which is deprecating report-uri
               "Report-To: {'group':'default','max_age':31536000,'endpoints':[{'url':'https://example.report-uri.com/a/d/g'}],'include_subdomains':true};"

               . // The Network Error Logging (NEL) spec defines a mechanism for collecting client-side network errors from an origin
               "NEL: {'report_to':'default','max_age':31536000,'include_subdomains':true};"

               . // allows JavaScript from self, jQuery and Google Analytics;
                 // inline allows inline JavaScript
               "script-src 'self' 'unsafe-inline' 'unsafe-eval' *.example.com *.jquery.com *.google-analytics.com *.googletagmanager.com;"

               . // allows CSS from self and inline allows inline CSS
               "style-src 'self' 'unsafe-inline' *.example.com *.cloudflare.com *.jsdelivr.net *.googleapis.com;"

               . // allows fonts from self and jsdelivr.net for Computer Modern!
               "font-src 'self' 'unsafe-inline' *.example.com *.jsdelivr.net;";


  // Sends the header in the HTTP response to instruct the browser how it
  // should handle content and what is whitelisted. It’s up to the browser to
  // follow the policy which each browser has varying support
  // $contentSecurityPolicy → $headerCSP via @hobbyman https://git.io/fjtmU
  header($headerCSP);


  // X-Frame-Options was never officially created – its X- prefix indicates
  // it’s non-standard – but most browsers support it to block iframing
  header('X-Frame-Options: SAMEORIGIN');

httpd.conf

# This can also be done in a .htaccess file depending on your server set
# determines where you decide to set it
Header unset Content-Security-Policy

# Add the entire CSP key value pairs that you want below is just default-src
Header add Content-Security-Policy "default-src 'self'"

# This opens support to older browsers that support
# X-Content-Security-Policy but not Content-Security-Policy
Header unset X-Content-Security-Policy
Header add X-Content-Security-Policy "default-src 'self'"

# This opens support to older browsers that support X-WebKit-CSP
# but not Content-Security-Policy
Header unset X-WebKit-CSP
Header add X-WebKit-CSP "default-src 'self'"

#These headers are also helpful in increasing security
Header set X-Content-Type-Options "nosniff"
Header set X-XSS-Protection "1; mode=block"
Header set X-Frame-Options "DENY"
Header set Strict-Transport-Security "max-age=31557600; includeSubDomains"

violationReportForCSP.php

<?php
  /**
   * This isn’t working and neither was the original: https://git.io/fjtZ9
   * Matt Ferderer referred me to an excellent replacement: https://report-uri.com
   */

  // $requestContent and $data replace $HTTP_RAW_POST_DATA via @naitsirch git.io/fjtqx
  /*
  $requestContent = file_get_contents("php://input");
  $data           = json_decode($requestContent, TRUE);
  $to             = '[email protected]';
  $subject        = 'CSP Violations';
  $message        = "Following violations occurred:<br/><br/>";
  if ($document_uri != "") {
    $message .= "<b>Document URI:</b> " . $data['csp-report']['document-uri'] . "<br/><br/>";
  }
  if ($referrer != "") {
    $message .= "<b>Referrer:</b> " . $data['csp-report']['referrer'] . "<br/><br/>";
  }
  if ($blocked_uri != "") {
    $message .= "<b>Blocked URI:</b> " . $data['csp-report']['blocked-uri'] . "<br/><br/>";
  }
  if ($violated_directive != "") {
    $message .= "<b>Violated Directive:</b> " . $data['csp-report']['violated-directive'] . "<br/><br/>";
  }
  if ($original_policy != "") {
    $message .= "<b>Original Policy:</b> " . $data['csp-report']['original-policy'] . "<br/><br/>";
  }
  */


  // To send HTML mail, the Content-Type header must be set
  /*
  $headers = 'MIME-Version: 1.0' . "\r\n";
  $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
  $headers .= 'From: Example Website <[email protected]>' . "\r\n";
  */

  // Mail it
  /*
  mail($to, $subject, $message, $headers);
  */