Csrf::getGenerator() - Code Metrics - Inspection of "added ReadResponse::continueOnError() option" - oscarotero/psr7-middlewares - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( 1b2d0a...89ea1a )

by Oscar

created 2016-02-23 23:17 UTC

Csrf::getGenerator() A

↳ Parent: Csrf

Complexity

Conditions	1
Paths	1

Size

Total Lines	4
Code Lines	2

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	1

Metric	Value
c	1
b	0
f	1
dl	0
loc	4
rs	10
cc	1
eloc	2
nc	1
nop	1

<?php

namespace Psr7Middlewares\Middleware;

use Psr7Middlewares\Middleware;
use Psr7Middlewares\Utils;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\ResponseInterface;
use InvalidArgumentException;
use RuntimeException;
use ArrayAccess;

/**
 * Middleware for CSRF protection
 * Code inspired from https://github.com/paragonie/anti-csrf.
 */
class Csrf
{
    use Utils\FormTrait;

    const KEY = 'CSRF';
    const KEY_GENERATOR = 'CSRF_GENERATOR';

    /**
     * @var int Max number of CSRF tokens
     */
    private $maxTokens = 100;

    /**
     * @var string field name with the CSRF index
     */
    private $formIndex = '_CSRF_INDEX';

    /**
     * @var string field name with the CSRF token
     */
    private $formToken = '_CSRF_TOKEN';

    /**
     * Returns a callable to generate the inputs.
     *
     * @param ServerRequestInterface $request
     *
     * @return callable|null
     */
    public static function getGenerator(ServerRequestInterface $request)
    {
        return Middleware::getAttribute($request, self::KEY_GENERATOR);
    }

    /**
     * Execute the middleware.
     *
     * @param ServerRequestInterface $request
     * @param ResponseInterface      $response
     * @param callable               $next
     *
     * @return ResponseInterface
     */
    public function __invoke(ServerRequestInterface $request, ResponseInterface $response, callable $next)
    {
        if (!Middleware::hasAttribute($request, FormatNegotiator::KEY)) {
            throw new RuntimeException('Csrf middleware needs FormatNegotiator executed before');
        }

        if (!Middleware::hasAttribute($request, ClientIp::KEY)) {
            throw new RuntimeException('Csrf middleware needs ClientIp executed before');
        }

        if (!Middleware::hasAttribute($request, Middleware::STORAGE_KEY)) {
            throw new RuntimeException('Csrf middleware needs a storage defined');
        }

        if (FormatNegotiator::getFormat($request) !== 'html') {
            return $next($request, $response);
        }

        $storage = Middleware::getAttribute($request, Middleware::STORAGE_KEY);
        $tokens = $storage->get(self::KEY) ?: [];

        if (Utils\Helpers::isPost($request) && !$this->validateRequest($request, $tokens)) {
            return $response->withStatus(403);
        }

        $generator = function ($action) use ($request, &$tokens) {
            return $this->generateTokens($request, $action, $tokens);
        };

        $response = $next($request, $response);

        $response = $this->insertIntoPostForms($response, function ($match) use ($generator) {
            preg_match('/action=["\']?([^"\'\s]+)["\']?/i', $match[0], $matches);

            $action = empty($matches[1]) ? $request->getUri()->getPath() : $matches[1];


            return $match[0].$generator($action);
        });

        $storage->set(self::KEY, $tokens);

        return $response;
    }

    /**
     * Generate and retrieve the tokens.
     * 
     * @param ServerRequestInterface $request
     * @param string                 $lockTo
     * @param array                 $tokens
     *
     * @return string
     */
    private function generateTokens(ServerRequestInterface $request, $lockTo, array &$tokens)
    {
        $index = self::encode(random_bytes(18));
        $token = self::encode(random_bytes(32));

        $tokens[$index] = [
            'created' => intval(date('YmdHis')),
            'uri' => $request->getUri()->getPath(),
            'token' => $token,
            'lockTo' => $lockTo,
        ];

        $this->recycleTokens($tokens);

        $token = self::encode(hash_hmac('sha256', ClientIp::getIp($request), base64_decode($token), true));

        return '<input type="hidden" name="'.$this->formIndex.'" value="'.htmlentities($index, ENT_QUOTES, 'UTF-8').'">'
               .'<input type="hidden" name="'.$this->formToken.'" value="'.htmlentities($token, ENT_QUOTES, 'UTF-8').'">';
    }

    /**
     * Validate the request.
     * 
     * @param ServerRequestInterface $request
     * @param array &$tokens
     *
     * @return bool
     */
    private function validateRequest(ServerRequestInterface $request, array &$tokens)
    {
        $data = $request->getParsedBody();

        if (!isset($data[$this->formIndex]) || !isset($data[$this->formToken])) {
            return false;
        }

        $index = $data[$this->formIndex];
        $token = $data[$this->formToken];

        if (!isset($tokens[$index])) {
            return false;
        }

        $stored = $tokens[$index];
        unset($tokens[$index]);

        $lockTo = $request->getUri()->getPath();

        if (!Utils\Helpers::hashEquals($lockTo, $stored['lockTo'])) {
            return false;
        }

        $expected = self::encode(hash_hmac('sha256', ClientIp::getIp($request), base64_decode($stored['token']), true));

        return Utils\Helpers::hashEquals($token, $expected);
    }

    /**
     * Enforce an upper limit on the number of tokens stored in session state
     * by removing the oldest tokens first.
     * 
     * @param array &$tokens
     */
    private function recycleTokens(array &$tokens)
    {
        if (!$this->maxTokens || count($tokens) <= $this->maxTokens) {
            return;
        }

        uasort($tokens, function ($a, $b) {
            return $a['created'] - $b['created'];
        });

        while (count($tokens) > $this->maxTokens) {
            array_shift($tokens);
        }
    }

    /**
     * Encode string with base64, but strip padding.
     * PHP base64_decode does not croak on that.
     *
     * @param string $value
     *
     * @return string
     */
    private static function encode($value)
    {
        return rtrim(base64_encode($value), '=');
    }
}


1			<?php
2
3			namespace Psr7Middlewares\Middleware;
4
5			use Psr7Middlewares\Middleware;
6			use Psr7Middlewares\Utils;
7			use Psr\Http\Message\ServerRequestInterface;
8			use Psr\Http\Message\ResponseInterface;
9			use InvalidArgumentException;
10			use RuntimeException;
11			use ArrayAccess;
12
13			/**
14			* Middleware for CSRF protection
15			* Code inspired from https://github.com/paragonie/anti-csrf.
16			*/
17			class Csrf
18			{
19			use Utils\FormTrait;
20
21			const KEY = 'CSRF';
22			const KEY_GENERATOR = 'CSRF_GENERATOR';
23
24			/**
25			* @var int Max number of CSRF tokens
26			*/
27			private $maxTokens = 100;
28
29			/**
30			* @var string field name with the CSRF index
31			*/
32			private $formIndex = '_CSRF_INDEX';
33
34			/**
35			* @var string field name with the CSRF token
36			*/
37			private $formToken = '_CSRF_TOKEN';
38
39			/**
40			* Returns a callable to generate the inputs.
41			*
42			* @param ServerRequestInterface $request
43			*
44			* @return callable\|null
45			*/
46			public static function getGenerator(ServerRequestInterface $request)
47			{
48			return Middleware::getAttribute($request, self::KEY_GENERATOR);
49			}
50
51			/**
52			* Execute the middleware.
53			*
54			* @param ServerRequestInterface $request
55			* @param ResponseInterface $response
56			* @param callable $next
57			*
58			* @return ResponseInterface
59			*/
60			public function __invoke(ServerRequestInterface $request, ResponseInterface $response, callable $next)
61			{
62			if (!Middleware::hasAttribute($request, FormatNegotiator::KEY)) {
63			throw new RuntimeException('Csrf middleware needs FormatNegotiator executed before');
64			}
65
66			if (!Middleware::hasAttribute($request, ClientIp::KEY)) {
67			throw new RuntimeException('Csrf middleware needs ClientIp executed before');
68			}
69
70			if (!Middleware::hasAttribute($request, Middleware::STORAGE_KEY)) {
71			throw new RuntimeException('Csrf middleware needs a storage defined');
72			}
73
74			if (FormatNegotiator::getFormat($request) !== 'html') {
75			return $next($request, $response);
76			}
77
78			$storage = Middleware::getAttribute($request, Middleware::STORAGE_KEY);
79			$tokens = $storage->get(self::KEY) ?: [];
80
81			if (Utils\Helpers::isPost($request) && !$this->validateRequest($request, $tokens)) {
82			return $response->withStatus(403);
83			}
84
85			$generator = function ($action) use ($request, &$tokens) {
86			return $this->generateTokens($request, $action, $tokens);
87			};
88
89			$response = $next($request, $response);
90
91			$response = $this->insertIntoPostForms($response, function ($match) use ($generator) {
92			preg_match('/action=["\']?([^"\'\s]+)["\']?/i', $match[0], $matches);
93
94			$action = empty($matches[1]) ? $request->getUri()->getPath() : $matches[1];
			0 ignored issues – show Bug introduced 2016-02-23 23:20 UTC by Report Bug Copy Issue Report The variable `$request` does not exist. Did you forget to declare it? This check marks access to variables or properties that have not been declared yet. While PHP has no explicit notion of declaring a variable, accessing it before a value is assigned to it is most likely a bug. Loading history...
95
96			return $match[0].$generator($action);
97			});
98
99			$storage->set(self::KEY, $tokens);
100
101			return $response;
102			}
103
104			/**
105			* Generate and retrieve the tokens.
106			*
107			* @param ServerRequestInterface $request
108			* @param string $lockTo
109			* @param array $tokens
110			*
111			* @return string
112			*/
113			private function generateTokens(ServerRequestInterface $request, $lockTo, array &$tokens)
114			{
115			$index = self::encode(random_bytes(18));
116			$token = self::encode(random_bytes(32));
117
118			$tokens[$index] = [
119			'created' => intval(date('YmdHis')),
120			'uri' => $request->getUri()->getPath(),
121			'token' => $token,
122			'lockTo' => $lockTo,
123			];
124
125			$this->recycleTokens($tokens);
126
127			$token = self::encode(hash_hmac('sha256', ClientIp::getIp($request), base64_decode($token), true));
128
129			return '<input type="hidden" name="'.$this->formIndex.'" value="'.htmlentities($index, ENT_QUOTES, 'UTF-8').'">'
130			.'<input type="hidden" name="'.$this->formToken.'" value="'.htmlentities($token, ENT_QUOTES, 'UTF-8').'">';
131			}
132
133			/**
134			* Validate the request.
135			*
136			* @param ServerRequestInterface $request
137			* @param array &$tokens
138			*
139			* @return bool
140			*/
141			private function validateRequest(ServerRequestInterface $request, array &$tokens)
142			{
143			$data = $request->getParsedBody();
144
145			if (!isset($data[$this->formIndex]) \|\| !isset($data[$this->formToken])) {
146			return false;
147			}
148
149			$index = $data[$this->formIndex];
150			$token = $data[$this->formToken];
151
152			if (!isset($tokens[$index])) {
153			return false;
154			}
155
156			$stored = $tokens[$index];
157			unset($tokens[$index]);
158
159			$lockTo = $request->getUri()->getPath();
160
161			if (!Utils\Helpers::hashEquals($lockTo, $stored['lockTo'])) {
162			return false;
163			}
164
165			$expected = self::encode(hash_hmac('sha256', ClientIp::getIp($request), base64_decode($stored['token']), true));
166
167			return Utils\Helpers::hashEquals($token, $expected);
168			}
169
170			/**
171			* Enforce an upper limit on the number of tokens stored in session state
172			* by removing the oldest tokens first.
173			*
174			* @param array &$tokens
175			*/
176			private function recycleTokens(array &$tokens)
177			{
178			if (!$this->maxTokens \|\| count($tokens) <= $this->maxTokens) {
179			return;
180			}
181
182			uasort($tokens, function ($a, $b) {
183			return $a['created'] - $b['created'];
184			});
185
186			while (count($tokens) > $this->maxTokens) {
187			array_shift($tokens);
188			}
189			}
190
191			/**
192			* Encode string with base64, but strip padding.
193			* PHP base64_decode does not croak on that.
194			*
195			* @param string $value
196			*
197			* @return string
198			*/
199			private static function encode($value)
200			{
201			return rtrim(base64_encode($value), '=');
202			}
203			}
204

oscarotero / psr7-middlewares

Push — master ( 1b2d0a...89ea1a )

Csrf::getGenerator() A

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