1<?php
2
3/*
4 * This file is part of composer/ca-bundle.
5 *
6 * (c) Composer <https://github.com/composer>
7 *
8 * For the full copyright and license information, please view
9 * the LICENSE file that was distributed with this source code.
10 */
11
12namespace Composer\CaBundle;
13
14use Psr\Log\LoggerInterface;
15use Symfony\Component\Process\PhpProcess;
16
17/**
18 * @author Chris Smith <chris@cs278.org>
19 * @author Jordi Boggiano <j.boggiano@seld.be>
20 */
21class CaBundle
22{
23    private static $caPath;
24    private static $caFileValidity = array();
25    private static $useOpensslParse;
26
27    /**
28     * Returns the system CA bundle path, or a path to the bundled one
29     *
30     * This method was adapted from Sslurp.
31     * https://github.com/EvanDotPro/Sslurp
32     *
33     * (c) Evan Coury <me@evancoury.com>
34     *
35     * For the full copyright and license information, please see below:
36     *
37     * Copyright (c) 2013, Evan Coury
38     * All rights reserved.
39     *
40     * Redistribution and use in source and binary forms, with or without modification,
41     * are permitted provided that the following conditions are met:
42     *
43     *     * Redistributions of source code must retain the above copyright notice,
44     *       this list of conditions and the following disclaimer.
45     *
46     *     * Redistributions in binary form must reproduce the above copyright notice,
47     *       this list of conditions and the following disclaimer in the documentation
48     *       and/or other materials provided with the distribution.
49     *
50     * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
51     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
52     * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
53     * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
54     * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
55     * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
56     * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
57     * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
58     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
59     * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
60     *
61     * @param  LoggerInterface $logger optional logger for information about which CA files were loaded
62     * @return string          path to a CA bundle file or directory
63     */
64    public static function getSystemCaRootBundlePath(LoggerInterface $logger = null)
65    {
66        if (self::$caPath !== null) {
67            return self::$caPath;
68        }
69        $caBundlePaths = array();
70
71
72        // If SSL_CERT_FILE env variable points to a valid certificate/bundle, use that.
73        // This mimics how OpenSSL uses the SSL_CERT_FILE env variable.
74        $caBundlePaths[] = getenv('SSL_CERT_FILE');
75
76        // If SSL_CERT_DIR env variable points to a valid certificate/bundle, use that.
77        // This mimics how OpenSSL uses the SSL_CERT_FILE env variable.
78        $caBundlePaths[] = getenv('SSL_CERT_DIR');
79
80        $caBundlePaths[] = ini_get('openssl.cafile');
81        $caBundlePaths[] = ini_get('openssl.capath');
82
83        $otherLocations = array(
84            '/etc/pki/tls/certs/ca-bundle.crt', // Fedora, RHEL, CentOS (ca-certificates package)
85            '/etc/ssl/certs/ca-certificates.crt', // Debian, Ubuntu, Gentoo, Arch Linux (ca-certificates package)
86            '/etc/ssl/ca-bundle.pem', // SUSE, openSUSE (ca-certificates package)
87            '/usr/local/share/certs/ca-root-nss.crt', // FreeBSD (ca_root_nss_package)
88            '/usr/ssl/certs/ca-bundle.crt', // Cygwin
89            '/opt/local/share/curl/curl-ca-bundle.crt', // OS X macports, curl-ca-bundle package
90            '/usr/local/share/curl/curl-ca-bundle.crt', // Default cURL CA bunde path (without --with-ca-bundle option)
91            '/usr/share/ssl/certs/ca-bundle.crt', // Really old RedHat?
92            '/etc/ssl/cert.pem', // OpenBSD
93            '/usr/local/etc/ssl/cert.pem', // FreeBSD 10.x
94            '/usr/local/etc/openssl/cert.pem', // OS X homebrew, openssl package
95        );
96
97        foreach($otherLocations as $location) {
98            $otherLocations[] = dirname($location);
99        }
100
101        $caBundlePaths = array_merge($caBundlePaths, $otherLocations);
102
103        foreach ($caBundlePaths as $caBundle) {
104            if (self::caFileUsable($caBundle, $logger)) {
105                return self::$caPath = $caBundle;
106            }
107
108            if (self::caDirUsable($caBundle)) {
109                return self::$caPath = $caBundle;
110            }
111        }
112
113        return self::$caPath = static::getBundledCaBundlePath(); // Bundled CA file, last resort
114    }
115
116    /**
117     * Returns the path to the bundled CA file
118     *
119     * In case you don't want to trust the user or the system, you can use this directly
120     *
121     * @return string path to a CA bundle file
122     */
123    public static function getBundledCaBundlePath()
124    {
125        $caBundleFile = __DIR__.'/../res/cacert.pem';
126
127        // cURL does not understand 'phar://' paths
128        // see https://github.com/composer/ca-bundle/issues/10
129        if (0 === strpos($caBundleFile, 'phar://')) {
130            file_put_contents(
131                $tempCaBundleFile = tempnam(sys_get_temp_dir(), 'openssl-ca-bundle-'),
132                file_get_contents($caBundleFile)
133            );
134
135            register_shutdown_function(function() use ($tempCaBundleFile) {
136                @unlink($tempCaBundleFile);
137            });
138
139            $caBundleFile = $tempCaBundleFile;
140        }
141
142        return $caBundleFile;
143    }
144
145    /**
146     * Validates a CA file using opensl_x509_parse only if it is safe to use
147     *
148     * @param string          $filename
149     * @param LoggerInterface $logger   optional logger for information about which CA files were loaded
150     *
151     * @return bool
152     */
153    public static function validateCaFile($filename, LoggerInterface $logger = null)
154    {
155        static $warned = false;
156
157        if (isset(self::$caFileValidity[$filename])) {
158            return self::$caFileValidity[$filename];
159        }
160
161        $contents = file_get_contents($filename);
162
163        // assume the CA is valid if php is vulnerable to
164        // https://www.sektioneins.de/advisories/advisory-012013-php-openssl_x509_parse-memory-corruption-vulnerability.html
165        if (!static::isOpensslParseSafe()) {
166            if (!$warned && $logger) {
167                $logger->warning(sprintf(
168                    'Your version of PHP, %s, is affected by CVE-2013-6420 and cannot safely perform certificate validation, we strongly suggest you upgrade.',
169                    PHP_VERSION
170                ));
171                $warned = true;
172            }
173
174            $isValid = !empty($contents);
175        } else {
176            $isValid = (bool) openssl_x509_parse($contents);
177        }
178
179        if ($logger) {
180            $logger->debug('Checked CA file '.realpath($filename).': '.($isValid ? 'valid' : 'invalid'));
181        }
182
183        return self::$caFileValidity[$filename] = $isValid;
184    }
185
186    /**
187     * Test if it is safe to use the PHP function openssl_x509_parse().
188     *
189     * This checks if OpenSSL extensions is vulnerable to remote code execution
190     * via the exploit documented as CVE-2013-6420.
191     *
192     * @return bool
193     */
194    public static function isOpensslParseSafe()
195    {
196        if (null !== self::$useOpensslParse) {
197            return self::$useOpensslParse;
198        }
199
200        if (PHP_VERSION_ID >= 50600) {
201            return self::$useOpensslParse = true;
202        }
203
204        // Vulnerable:
205        // PHP 5.3.0 - PHP 5.3.27
206        // PHP 5.4.0 - PHP 5.4.22
207        // PHP 5.5.0 - PHP 5.5.6
208        if (
209               (PHP_VERSION_ID < 50400 && PHP_VERSION_ID >= 50328)
210            || (PHP_VERSION_ID < 50500 && PHP_VERSION_ID >= 50423)
211            || (PHP_VERSION_ID < 50600 && PHP_VERSION_ID >= 50507)
212        ) {
213            // This version of PHP has the fix for CVE-2013-6420 applied.
214            return self::$useOpensslParse = true;
215        }
216
217        if (defined('PHP_WINDOWS_VERSION_BUILD')) {
218            // Windows is probably insecure in this case.
219            return self::$useOpensslParse = false;
220        }
221
222        $compareDistroVersionPrefix = function ($prefix, $fixedVersion) {
223            $regex = '{^'.preg_quote($prefix).'([0-9]+)$}';
224
225            if (preg_match($regex, PHP_VERSION, $m)) {
226                return ((int) $m[1]) >= $fixedVersion;
227            }
228
229            return false;
230        };
231
232        // Hard coded list of PHP distributions with the fix backported.
233        if (
234            $compareDistroVersionPrefix('5.3.3-7+squeeze', 18) // Debian 6 (Squeeze)
235            || $compareDistroVersionPrefix('5.4.4-14+deb7u', 7) // Debian 7 (Wheezy)
236            || $compareDistroVersionPrefix('5.3.10-1ubuntu3.', 9) // Ubuntu 12.04 (Precise)
237        ) {
238            return self::$useOpensslParse = true;
239        }
240
241        // Symfony Process component is missing so we assume it is unsafe at this point
242        if (!class_exists('Symfony\Component\Process\PhpProcess')) {
243            return self::$useOpensslParse = false;
244        }
245
246        // This is where things get crazy, because distros backport security
247        // fixes the chances are on NIX systems the fix has been applied but
248        // it's not possible to verify that from the PHP version.
249        //
250        // To verify exec a new PHP process and run the issue testcase with
251        // known safe input that replicates the bug.
252
253        // Based on testcase in https://github.com/php/php-src/commit/c1224573c773b6845e83505f717fbf820fc18415
254        // changes in https://github.com/php/php-src/commit/76a7fd893b7d6101300cc656058704a73254d593
255        $cert = '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';
256        $script = <<<'EOT'
257
258error_reporting(-1);
259$info = openssl_x509_parse(base64_decode('%s'));
260var_dump(PHP_VERSION, $info['issuer']['emailAddress'], $info['validFrom_time_t']);
261
262EOT;
263        $script = '<'."?php\n".sprintf($script, $cert);
264
265        try {
266            $process = new PhpProcess($script);
267            $process->mustRun();
268        } catch (\Exception $e) {
269            // In the case of any exceptions just accept it is not possible to
270            // determine the safety of openssl_x509_parse and bail out.
271            return self::$useOpensslParse = false;
272        }
273
274        $output = preg_split('{\r?\n}', trim($process->getOutput()));
275        $errorOutput = trim($process->getErrorOutput());
276
277        if (
278            count($output) === 3
279            && $output[0] === sprintf('string(%d) "%s"', strlen(PHP_VERSION), PHP_VERSION)
280            && $output[1] === 'string(27) "stefan.esser@sektioneins.de"'
281            && $output[2] === 'int(-1)'
282            && preg_match('{openssl_x509_parse\(\): illegal (?:ASN1 data type for|length in) timestamp in - on line \d+}', $errorOutput)
283        ) {
284            // This PHP has the fix backported probably by a distro security team.
285            return self::$useOpensslParse = true;
286        }
287
288        return self::$useOpensslParse = false;
289    }
290
291    /**
292     * Resets the static caches
293     */
294    public static function reset()
295    {
296        self::$caFileValidity = array();
297        self::$caPath = null;
298        self::$useOpensslParse = null;
299    }
300
301    private static function caFileUsable($certFile, LoggerInterface $logger = null)
302    {
303        return $certFile && @is_file($certFile) && @is_readable($certFile) && static::validateCaFile($certFile, $logger);
304    }
305
306    private static function caDirUsable($certDir)
307    {
308        return $certDir && @is_dir($certDir) && @is_readable($certDir) && glob($certDir . '/*');
309    }
310}
311