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<?php |
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declare(strict_types=1); |
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/* |
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* This file is part of the Valkyrja Framework package. |
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* |
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* (c) Melech Mizrachi <[email protected]> |
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* |
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* For the full copyright and license information, please view the LICENSE |
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* file that was distributed with this source code. |
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*/ |
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namespace Valkyrja\Http\Message\Header\Security; |
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use Valkyrja\Http\Message\Header\Throwable\Exception\InvalidNameException; |
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use Valkyrja\Http\Message\Header\Throwable\Exception\InvalidValueException; |
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use Valkyrja\Http\Message\Throwable\Exception\InvalidArgumentException; |
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use function in_array; |
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use function ord; |
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use function preg_match; |
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use function sprintf; |
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use function strlen; |
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final class HeaderSecurity |
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{ |
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/** |
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* Private constructor; non-instantiable. |
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* |
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* @codeCoverageIgnore |
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*/ |
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private function __construct() |
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{ |
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} |
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/** |
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* Filter a header value. |
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* Ensures CRLF header injection vectors are filtered. |
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* Per RFC 7230, only VISIBLE ASCII characters, spaces, and horizontal |
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* tabs are allowed in values; header continuations MUST consist of |
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* a single CRLF sequence followed by a space or horizontal tab. |
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* This method filters any values not allowed from the string, and is |
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* lossy. |
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* |
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* @see http://en.wikipedia.org/wiki/HTTP_response_splitting |
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* |
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* @param string $value |
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* |
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* @return string |
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*/ |
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public static function filter(string $value): string |
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{ |
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$length = strlen($value); |
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$string = ''; |
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for ($i = 0; $i < $length; $i++) { |
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$ascii = ord($value[$i]); |
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// Detect continuation sequences |
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if ($ascii === 13) { |
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$lf = ord($value[$i + 1]); |
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$ws = ord($value[$i + 2]); |
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if ($lf === 10 && in_array($ws, [9, 32], true)) { |
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$string .= $value[$i] . $value[$i + 1]; |
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$i++; |
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} |
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continue; |
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} |
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// Non-visible, non-whitespace characters |
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// 9 === horizontal tab |
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// 32-126, 128-254 === visible |
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// 127 === DEL |
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// 255 === null byte |
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if ( |
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($ascii < 32 && $ascii !== 9) |
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|| $ascii === 127 |
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|| $ascii > 254 |
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) { |
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continue; |
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} |
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$string .= $value[$i]; |
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} |
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return $string; |
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} |
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/** |
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* Assert a header value is valid. |
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* |
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* @param string $value |
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* |
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* @throws InvalidArgumentException for invalid values |
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* |
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* @return void |
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*/ |
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public static function assertValid(string $value): void |
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{ |
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if (! self::isValid($value)) { |
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throw new InvalidValueException(sprintf('"%s" is not valid header value', $value)); |
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} |
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} |
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/** |
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* Validate a header value. |
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* Per RFC 7230, only VISIBLE ASCII characters, spaces, and horizontal |
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* tabs are allowed in values; header continuations MUST consist of |
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* a single CRLF sequence followed by a space or horizontal tab. |
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* |
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* @see http://en.wikipedia.org/wiki/HTTP_response_splitting |
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* |
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* @param string $value |
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* |
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* @return bool |
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*/ |
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public static function isValid(string $value): bool |
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{ |
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// Look for: |
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// \n not preceded by \r, OR |
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// \r not followed by \n, OR |
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// \r\n not followed by space or horizontal tab; these are all CRLF attacks |
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if (preg_match("#(?:(?:(?<!\r)\n)|(?:\r(?!\n))|(?:\r\n(?![ \t])))#", $value)) { |
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return false; |
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} |
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// Non-visible, non-whitespace characters |
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// 9 === horizontal tab |
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// 10 === line feed |
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// 13 === carriage return |
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// 32-126, 128-254 === visible |
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// 127 === DEL (disallowed) |
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// 255 === null byte (disallowed) |
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if (preg_match('/[^\x09\x0a\x0d\x20-\x7E\x80-\xFE]/', $value)) { |
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return false; |
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} |
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return true; |
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} |
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/** |
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* Assert whether or not a header name is valid. |
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* |
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* @see http://tools.ietf.org/html/rfc7230#section-3.2 |
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* |
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* @param string $name |
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* |
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* @throws InvalidArgumentException |
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* |
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* @return void |
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*/ |
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public static function assertValidName(string $name): void |
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{ |
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if (! self::isValidName($name)) { |
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throw new InvalidNameException(sprintf('"%s" is not valid header name', $name)); |
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} |
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} |
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public static function isValidName(string $name): bool |
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{ |
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return (bool) preg_match('/^[a-zA-Z0-9\'`#$%&*+.^_|~!-]+$/D', $name); |
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} |
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} |
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valkyrjaio /
valkyrja
