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1 <?php |
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2 /** |
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3 * SSL utilities for Requests |
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4 * |
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5 * @package Requests |
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6 * @subpackage Utilities |
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7 */ |
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8 |
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9 /** |
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10 * SSL utilities for Requests |
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11 * |
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12 * Collection of utilities for working with and verifying SSL certificates. |
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13 * |
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14 * @package Requests |
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15 * @subpackage Utilities |
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16 */ |
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17 class Requests_SSL { |
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18 /** |
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19 * Verify the certificate against common name and subject alternative names |
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20 * |
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21 * Unfortunately, PHP doesn't check the certificate against the alternative |
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22 * names, leading things like 'https://www.github.com/' to be invalid. |
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23 * Instead |
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24 * |
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25 * @see https://tools.ietf.org/html/rfc2818#section-3.1 RFC2818, Section 3.1 |
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26 * |
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27 * @throws Requests_Exception On not obtaining a match for the host (`fsockopen.ssl.no_match`) |
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28 * @param string $host Host name to verify against |
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29 * @param array $cert Certificate data from openssl_x509_parse() |
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30 * @return bool |
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31 */ |
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32 public static function verify_certificate($host, $cert) { |
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33 // Calculate the valid wildcard match if the host is not an IP address |
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34 $parts = explode('.', $host); |
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35 if (ip2long($host) === false) { |
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36 $parts[0] = '*'; |
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37 } |
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38 $wildcard = implode('.', $parts); |
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39 |
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40 $has_dns_alt = false; |
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41 |
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42 // Check the subjectAltName |
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43 if (!empty($cert['extensions']) && !empty($cert['extensions']['subjectAltName'])) { |
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44 $altnames = explode(',', $cert['extensions']['subjectAltName']); |
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45 foreach ($altnames as $altname) { |
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46 $altname = trim($altname); |
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47 if (strpos($altname, 'DNS:') !== 0) { |
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48 continue; |
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49 } |
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50 |
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51 $has_dns_alt = true; |
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52 |
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53 // Strip the 'DNS:' prefix and trim whitespace |
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54 $altname = trim(substr($altname, 4)); |
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55 |
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56 // Check for a match |
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57 if (self::match_domain($host, $altname) === true) { |
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58 return true; |
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59 } |
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60 } |
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61 } |
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62 |
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63 // Fall back to checking the common name if we didn't get any dNSName |
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64 // alt names, as per RFC2818 |
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65 if (!$has_dns_alt && !empty($cert['subject']['CN'])) { |
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66 // Check for a match |
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67 if (self::match_domain($host, $cert['subject']['CN']) === true) { |
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68 return true; |
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69 } |
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70 } |
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71 |
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72 return false; |
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73 } |
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74 |
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75 /** |
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76 * Verify that a reference name is valid |
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77 * |
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78 * Verifies a dNSName for HTTPS usage, (almost) as per Firefox's rules: |
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79 * - Wildcards can only occur in a name with more than 3 components |
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80 * - Wildcards can only occur as the last character in the first |
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81 * component |
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82 * - Wildcards may be preceded by additional characters |
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83 * |
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84 * We modify these rules to be a bit stricter and only allow the wildcard |
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85 * character to be the full first component; that is, with the exclusion of |
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86 * the third rule. |
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87 * |
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88 * @param string $reference Reference dNSName |
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89 * @return boolean Is the name valid? |
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90 */ |
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91 public static function verify_reference_name($reference) { |
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92 $parts = explode('.', $reference); |
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93 |
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94 // Check the first part of the name |
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95 $first = array_shift($parts); |
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96 |
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97 if (strpos($first, '*') !== false) { |
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98 // Check that the wildcard is the full part |
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99 if ($first !== '*') { |
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100 return false; |
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101 } |
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102 |
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103 // Check that we have at least 3 components (including first) |
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104 if (count($parts) < 2) { |
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105 return false; |
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106 } |
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107 } |
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108 |
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109 // Check the remaining parts |
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110 foreach ($parts as $part) { |
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111 if (strpos($part, '*') !== false) { |
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112 return false; |
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113 } |
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114 } |
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115 |
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116 // Nothing found, verified! |
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117 return true; |
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118 } |
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119 |
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120 /** |
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121 * Match a hostname against a dNSName reference |
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122 * |
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123 * @param string $host Requested host |
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124 * @param string $reference dNSName to match against |
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125 * @return boolean Does the domain match? |
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126 */ |
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127 public static function match_domain($host, $reference) { |
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128 // Check if the reference is blacklisted first |
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129 if (self::verify_reference_name($reference) !== true) { |
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130 return false; |
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131 } |
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132 |
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133 // Check for a direct match |
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134 if ($host === $reference) { |
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135 return true; |
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136 } |
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137 |
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138 // Calculate the valid wildcard match if the host is not an IP address |
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139 // Also validates that the host has 3 parts or more, as per Firefox's |
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140 // ruleset. |
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141 if (ip2long($host) === false) { |
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142 $parts = explode('.', $host); |
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143 $parts[0] = '*'; |
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144 $wildcard = implode('.', $parts); |
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145 if ($wildcard === $reference) { |
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146 return true; |
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147 } |
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148 } |
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149 |
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150 return false; |
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151 } |
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152 } |