271 lines
8.8 KiB
PHP
271 lines
8.8 KiB
PHP
<?php
|
|
|
|
/*
|
|
* This file is part of the Symfony package.
|
|
*
|
|
* (c) Fabien Potencier <fabien@symfony.com>
|
|
*
|
|
* For the full copyright and license information, please view the LICENSE
|
|
* file that was distributed with this source code.
|
|
*/
|
|
|
|
namespace Symfony\Bundle\WebProfilerBundle\Csp;
|
|
|
|
use Symfony\Component\HttpFoundation\Request;
|
|
use Symfony\Component\HttpFoundation\Response;
|
|
|
|
/**
|
|
* Handles Content-Security-Policy HTTP header for the WebProfiler Bundle.
|
|
*
|
|
* @author Romain Neutron <imprec@gmail.com>
|
|
*
|
|
* @internal
|
|
*/
|
|
class ContentSecurityPolicyHandler
|
|
{
|
|
private $nonceGenerator;
|
|
private $cspDisabled = false;
|
|
|
|
public function __construct(NonceGenerator $nonceGenerator)
|
|
{
|
|
$this->nonceGenerator = $nonceGenerator;
|
|
}
|
|
|
|
/**
|
|
* Returns an array of nonces to be used in Twig templates and Content-Security-Policy headers.
|
|
*
|
|
* Nonce can be provided by;
|
|
* - The request - In case HTML content is fetched via AJAX and inserted in DOM, it must use the same nonce as origin
|
|
* - The response - A call to getNonces() has already been done previously. Same nonce are returned
|
|
* - They are otherwise randomly generated
|
|
*/
|
|
public function getNonces(Request $request, Response $response): array
|
|
{
|
|
if ($request->headers->has('X-SymfonyProfiler-Script-Nonce') && $request->headers->has('X-SymfonyProfiler-Style-Nonce')) {
|
|
return [
|
|
'csp_script_nonce' => $request->headers->get('X-SymfonyProfiler-Script-Nonce'),
|
|
'csp_style_nonce' => $request->headers->get('X-SymfonyProfiler-Style-Nonce'),
|
|
];
|
|
}
|
|
|
|
if ($response->headers->has('X-SymfonyProfiler-Script-Nonce') && $response->headers->has('X-SymfonyProfiler-Style-Nonce')) {
|
|
return [
|
|
'csp_script_nonce' => $response->headers->get('X-SymfonyProfiler-Script-Nonce'),
|
|
'csp_style_nonce' => $response->headers->get('X-SymfonyProfiler-Style-Nonce'),
|
|
];
|
|
}
|
|
|
|
$nonces = [
|
|
'csp_script_nonce' => $this->generateNonce(),
|
|
'csp_style_nonce' => $this->generateNonce(),
|
|
];
|
|
|
|
$response->headers->set('X-SymfonyProfiler-Script-Nonce', $nonces['csp_script_nonce']);
|
|
$response->headers->set('X-SymfonyProfiler-Style-Nonce', $nonces['csp_style_nonce']);
|
|
|
|
return $nonces;
|
|
}
|
|
|
|
/**
|
|
* Disables Content-Security-Policy.
|
|
*
|
|
* All related headers will be removed.
|
|
*/
|
|
public function disableCsp()
|
|
{
|
|
$this->cspDisabled = true;
|
|
}
|
|
|
|
/**
|
|
* Cleanup temporary headers and updates Content-Security-Policy headers.
|
|
*
|
|
* @return array Nonces used by the bundle in Content-Security-Policy header
|
|
*/
|
|
public function updateResponseHeaders(Request $request, Response $response): array
|
|
{
|
|
if ($this->cspDisabled) {
|
|
$this->removeCspHeaders($response);
|
|
|
|
return [];
|
|
}
|
|
|
|
$nonces = $this->getNonces($request, $response);
|
|
$this->cleanHeaders($response);
|
|
$this->updateCspHeaders($response, $nonces);
|
|
|
|
return $nonces;
|
|
}
|
|
|
|
private function cleanHeaders(Response $response)
|
|
{
|
|
$response->headers->remove('X-SymfonyProfiler-Script-Nonce');
|
|
$response->headers->remove('X-SymfonyProfiler-Style-Nonce');
|
|
}
|
|
|
|
private function removeCspHeaders(Response $response)
|
|
{
|
|
$response->headers->remove('X-Content-Security-Policy');
|
|
$response->headers->remove('Content-Security-Policy');
|
|
$response->headers->remove('Content-Security-Policy-Report-Only');
|
|
}
|
|
|
|
/**
|
|
* Updates Content-Security-Policy headers in a response.
|
|
*/
|
|
private function updateCspHeaders(Response $response, array $nonces = []): array
|
|
{
|
|
$nonces = array_replace([
|
|
'csp_script_nonce' => $this->generateNonce(),
|
|
'csp_style_nonce' => $this->generateNonce(),
|
|
], $nonces);
|
|
|
|
$ruleIsSet = false;
|
|
|
|
$headers = $this->getCspHeaders($response);
|
|
|
|
$types = [
|
|
'script-src' => 'csp_script_nonce',
|
|
'script-src-elem' => 'csp_script_nonce',
|
|
'style-src' => 'csp_style_nonce',
|
|
'style-src-elem' => 'csp_style_nonce',
|
|
];
|
|
|
|
foreach ($headers as $header => $directives) {
|
|
foreach ($types as $type => $tokenName) {
|
|
if ($this->authorizesInline($directives, $type)) {
|
|
continue;
|
|
}
|
|
if (!isset($headers[$header][$type])) {
|
|
if (null === $fallback = $this->getDirectiveFallback($directives, $type)) {
|
|
continue;
|
|
}
|
|
|
|
if (['\'none\''] === $fallback) {
|
|
// Fallback came from "default-src: 'none'"
|
|
// 'none' is invalid if it's not the only expression in the source list, so we leave it out
|
|
$fallback = [];
|
|
}
|
|
|
|
$headers[$header][$type] = $fallback;
|
|
}
|
|
$ruleIsSet = true;
|
|
if (!\in_array('\'unsafe-inline\'', $headers[$header][$type], true)) {
|
|
$headers[$header][$type][] = '\'unsafe-inline\'';
|
|
}
|
|
$headers[$header][$type][] = sprintf('\'nonce-%s\'', $nonces[$tokenName]);
|
|
}
|
|
}
|
|
|
|
if (!$ruleIsSet) {
|
|
return $nonces;
|
|
}
|
|
|
|
foreach ($headers as $header => $directives) {
|
|
$response->headers->set($header, $this->generateCspHeader($directives));
|
|
}
|
|
|
|
return $nonces;
|
|
}
|
|
|
|
/**
|
|
* Generates a valid Content-Security-Policy nonce.
|
|
*/
|
|
private function generateNonce(): string
|
|
{
|
|
return $this->nonceGenerator->generate();
|
|
}
|
|
|
|
/**
|
|
* Converts a directive set array into Content-Security-Policy header.
|
|
*/
|
|
private function generateCspHeader(array $directives): string
|
|
{
|
|
return array_reduce(array_keys($directives), function ($res, $name) use ($directives) {
|
|
return ('' !== $res ? $res.'; ' : '').sprintf('%s %s', $name, implode(' ', $directives[$name]));
|
|
}, '');
|
|
}
|
|
|
|
/**
|
|
* Converts a Content-Security-Policy header value into a directive set array.
|
|
*/
|
|
private function parseDirectives(string $header): array
|
|
{
|
|
$directives = [];
|
|
|
|
foreach (explode(';', $header) as $directive) {
|
|
$parts = explode(' ', trim($directive));
|
|
if (\count($parts) < 1) {
|
|
continue;
|
|
}
|
|
$name = array_shift($parts);
|
|
$directives[$name] = $parts;
|
|
}
|
|
|
|
return $directives;
|
|
}
|
|
|
|
/**
|
|
* Detects if the 'unsafe-inline' is prevented for a directive within the directive set.
|
|
*/
|
|
private function authorizesInline(array $directivesSet, string $type): bool
|
|
{
|
|
if (isset($directivesSet[$type])) {
|
|
$directives = $directivesSet[$type];
|
|
} elseif (null === $directives = $this->getDirectiveFallback($directivesSet, $type)) {
|
|
return false;
|
|
}
|
|
|
|
return \in_array('\'unsafe-inline\'', $directives, true) && !$this->hasHashOrNonce($directives);
|
|
}
|
|
|
|
private function hasHashOrNonce(array $directives): bool
|
|
{
|
|
foreach ($directives as $directive) {
|
|
if (!str_ends_with($directive, '\'')) {
|
|
continue;
|
|
}
|
|
if ('\'nonce-' === substr($directive, 0, 7)) {
|
|
return true;
|
|
}
|
|
if (\in_array(substr($directive, 0, 8), ['\'sha256-', '\'sha384-', '\'sha512-'], true)) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
private function getDirectiveFallback(array $directiveSet, string $type)
|
|
{
|
|
if (\in_array($type, ['script-src-elem', 'style-src-elem'], true) || !isset($directiveSet['default-src'])) {
|
|
// Let the browser fallback on it's own
|
|
return null;
|
|
}
|
|
|
|
return $directiveSet['default-src'];
|
|
}
|
|
|
|
/**
|
|
* Retrieves the Content-Security-Policy headers (either X-Content-Security-Policy or Content-Security-Policy) from
|
|
* a response.
|
|
*/
|
|
private function getCspHeaders(Response $response): array
|
|
{
|
|
$headers = [];
|
|
|
|
if ($response->headers->has('Content-Security-Policy')) {
|
|
$headers['Content-Security-Policy'] = $this->parseDirectives($response->headers->get('Content-Security-Policy'));
|
|
}
|
|
|
|
if ($response->headers->has('Content-Security-Policy-Report-Only')) {
|
|
$headers['Content-Security-Policy-Report-Only'] = $this->parseDirectives($response->headers->get('Content-Security-Policy-Report-Only'));
|
|
}
|
|
|
|
if ($response->headers->has('X-Content-Security-Policy')) {
|
|
$headers['X-Content-Security-Policy'] = $this->parseDirectives($response->headers->get('X-Content-Security-Policy'));
|
|
}
|
|
|
|
return $headers;
|
|
}
|
|
}
|