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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\Utilities |
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6 */ |
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7 |
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8 namespace WpOrg\Requests; |
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9 |
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10 use WpOrg\Requests\Exception\InvalidArgument; |
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11 use WpOrg\Requests\Utility\InputValidator; |
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12 |
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13 /** |
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14 * SSL utilities for Requests |
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15 * |
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16 * Collection of utilities for working with and verifying SSL certificates. |
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17 * |
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18 * @package Requests\Utilities |
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19 */ |
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20 final class Ssl { |
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21 /** |
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22 * Verify the certificate against common name and subject alternative names |
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23 * |
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24 * Unfortunately, PHP doesn't check the certificate against the alternative |
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25 * names, leading things like 'https://www.github.com/' to be invalid. |
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26 * |
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27 * @link https://tools.ietf.org/html/rfc2818#section-3.1 RFC2818, Section 3.1 |
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28 * |
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29 * @param string|Stringable $host Host name to verify against |
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30 * @param array $cert Certificate data from openssl_x509_parse() |
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31 * @return bool |
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32 * @throws \WpOrg\Requests\Exception\InvalidArgument When the passed $host argument is not a string or a stringable object. |
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33 * @throws \WpOrg\Requests\Exception\InvalidArgument When the passed $cert argument is not an array or array accessible. |
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34 */ |
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35 public static function verify_certificate($host, $cert) { |
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36 if (InputValidator::is_string_or_stringable($host) === false) { |
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37 throw InvalidArgument::create(1, '$host', 'string|Stringable', gettype($host)); |
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38 } |
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39 |
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40 if (InputValidator::has_array_access($cert) === false) { |
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41 throw InvalidArgument::create(2, '$cert', 'array|ArrayAccess', gettype($cert)); |
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42 } |
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43 |
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44 $has_dns_alt = false; |
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45 |
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46 // Check the subjectAltName |
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47 if (!empty($cert['extensions']['subjectAltName'])) { |
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48 $altnames = explode(',', $cert['extensions']['subjectAltName']); |
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49 foreach ($altnames as $altname) { |
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50 $altname = trim($altname); |
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51 if (strpos($altname, 'DNS:') !== 0) { |
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52 continue; |
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53 } |
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54 |
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55 $has_dns_alt = true; |
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56 |
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57 // Strip the 'DNS:' prefix and trim whitespace |
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58 $altname = trim(substr($altname, 4)); |
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59 |
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60 // Check for a match |
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61 if (self::match_domain($host, $altname) === true) { |
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62 return true; |
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63 } |
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64 } |
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65 |
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66 if ($has_dns_alt === true) { |
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67 return false; |
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68 } |
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69 } |
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70 |
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71 // Fall back to checking the common name if we didn't get any dNSName |
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72 // alt names, as per RFC2818 |
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73 if (!empty($cert['subject']['CN'])) { |
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74 // Check for a match |
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75 return (self::match_domain($host, $cert['subject']['CN']) === true); |
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76 } |
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77 |
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78 return false; |
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79 } |
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80 |
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81 /** |
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82 * Verify that a reference name is valid |
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83 * |
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84 * Verifies a dNSName for HTTPS usage, (almost) as per Firefox's rules: |
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85 * - Wildcards can only occur in a name with more than 3 components |
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86 * - Wildcards can only occur as the last character in the first |
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87 * component |
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88 * - Wildcards may be preceded by additional characters |
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89 * |
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90 * We modify these rules to be a bit stricter and only allow the wildcard |
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91 * character to be the full first component; that is, with the exclusion of |
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92 * the third rule. |
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93 * |
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94 * @param string|Stringable $reference Reference dNSName |
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95 * @return boolean Is the name valid? |
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96 * @throws \WpOrg\Requests\Exception\InvalidArgument When the passed argument is not a string or a stringable object. |
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97 */ |
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98 public static function verify_reference_name($reference) { |
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99 if (InputValidator::is_string_or_stringable($reference) === false) { |
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100 throw InvalidArgument::create(1, '$reference', 'string|Stringable', gettype($reference)); |
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101 } |
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102 |
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103 if ($reference === '') { |
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104 return false; |
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105 } |
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106 |
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107 if (preg_match('`\s`', $reference) > 0) { |
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108 // Whitespace detected. This can never be a dNSName. |
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109 return false; |
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110 } |
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111 |
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112 $parts = explode('.', $reference); |
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113 if ($parts !== array_filter($parts)) { |
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114 // DNSName cannot contain two dots next to each other. |
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115 return false; |
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116 } |
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117 |
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118 // Check the first part of the name |
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119 $first = array_shift($parts); |
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120 |
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121 if (strpos($first, '*') !== false) { |
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122 // Check that the wildcard is the full part |
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123 if ($first !== '*') { |
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124 return false; |
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125 } |
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126 |
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127 // Check that we have at least 3 components (including first) |
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128 if (count($parts) < 2) { |
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129 return false; |
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130 } |
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131 } |
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132 |
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133 // Check the remaining parts |
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134 foreach ($parts as $part) { |
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135 if (strpos($part, '*') !== false) { |
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136 return false; |
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137 } |
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138 } |
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139 |
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140 // Nothing found, verified! |
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141 return true; |
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142 } |
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143 |
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144 /** |
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145 * Match a hostname against a dNSName reference |
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146 * |
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147 * @param string|Stringable $host Requested host |
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148 * @param string|Stringable $reference dNSName to match against |
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149 * @return boolean Does the domain match? |
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150 * @throws \WpOrg\Requests\Exception\InvalidArgument When either of the passed arguments is not a string or a stringable object. |
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151 */ |
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152 public static function match_domain($host, $reference) { |
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153 if (InputValidator::is_string_or_stringable($host) === false) { |
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154 throw InvalidArgument::create(1, '$host', 'string|Stringable', gettype($host)); |
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155 } |
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156 |
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157 // Check if the reference is blocklisted first |
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158 if (self::verify_reference_name($reference) !== true) { |
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159 return false; |
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160 } |
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161 |
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162 // Check for a direct match |
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163 if ((string) $host === (string) $reference) { |
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164 return true; |
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165 } |
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166 |
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167 // Calculate the valid wildcard match if the host is not an IP address |
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168 // Also validates that the host has 3 parts or more, as per Firefox's ruleset, |
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169 // as a wildcard reference is only allowed with 3 parts or more, so the |
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170 // comparison will never match if host doesn't contain 3 parts or more as well. |
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171 if (ip2long($host) === false) { |
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172 $parts = explode('.', $host); |
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173 $parts[0] = '*'; |
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174 $wildcard = implode('.', $parts); |
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175 if ($wildcard === (string) $reference) { |
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176 return true; |
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177 } |
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178 } |
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179 |
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180 return false; |
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181 } |
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182 } |