<?php
/**
* Transforms for Jetpack Waf
*
* @package automattic/jetpack-waf
*/
namespace Automattic\Jetpack\Waf;
/**
* Waf_Transforms class
*/
class Waf_Transforms {
/**
* Decode a Base64-encoded string.
*
* @param string $value value to be decoded.
* @return string
*/
public function base64_decode( $value ) {
return base64_decode( $value );
}
/**
* Remove all characters that might escape a command line command
*
* @see https://github.com/SpiderLabs/ModSecurity/wiki/Reference-Manual-%28v2.x%29#cmdLine
* @param string $value value to be escaped.
* @return string
*/
public function cmd_line( $value ) {
return strtolower(
preg_replace(
'/\s+/',
' ',
str_replace(
array( ',', ';' ),
' ',
preg_replace(
'/\s+(?=[\/\(])/',
'',
str_replace(
array( '^', "'", '"', '\\' ),
'',
$value
)
)
)
)
);
}
/**
* Decode a SQL hex string.
*
* @example 414243 decodes to "ABC"
* @param string $value value to be decoded.
* @return string
*/
public function sql_hex_decode( $value ) {
return preg_replace_callback(
'/0x[a-f0-9]+/i',
function ( $matches ) {
$str = substr( $matches[0], 2 );
if ( 0 !== strlen( $str ) % 2 ) {
$str = '0' . $str;
}
return hex2bin( $str );
},
$value
);
}
/**
* Encode a string using Base64 encoding.
*
* @param string $value value to be decoded.
* @return string
*/
public function base64_encode( $value ) {
return base64_encode( $value );
}
/**
* Convert all whitespace characters to a space and remove any repeated spaces.
*
* @param string $value value to be converted.
* @return string
*/
public function compress_whitespace( $value ) {
return preg_replace( '/\s+/', ' ', $value );
}
/**
* Encode string (possibly containing binary characters) by replacing each input byte with two hexadecimal characters.
*
* @param string $value value to be encoded.
* @return string
*/
public function hex_encode( $value ) {
return bin2hex( $value );
}
/**
* Decode string that was previously encoded by hexEncode()
*
* @param string $value value to be decoded.
* @return string
*/
public function hex_decode( $value ) {
return pack( 'H*', $value );
}
/**
* Decode the characters encoded as HTML entities.
*
* @param mixed $value value do be decoded.
* @return string
*/
public function html_entity_decode( $value ) {
return html_entity_decode( $value );
}
/**
* Return the length of the input string.
*
* @param string $value input string.
* @return int
*/
public function length( $value ) {
return strlen( $value );
}
/**
* Convert all characters to lowercase.
*
* @param string $value string to be converted.
* @return string
*/
public function lowercase( $value ) {
return strtolower( $value );
}
/**
* Calculate an md5 hash for the given data
*
* @param mixed $value value to be hashed.
* @return string
*/
public function md5( $value ) {
return md5( $value, true );
}
/**
* Removes multiple slashes, directory self-references, and directory back-references (except when at the beginning of the input) from input string.
*
* @param string $value value to be normalized.
* @return string
*/
public function normalize_path( $value ) {
$parts = explode(
'/',
// replace any duplicate slashes with a single one.
preg_replace( '~/{2,}~', '/', $value )
);
$i = 0;
while ( isset( $parts[ $i ] ) ) {
switch ( $parts[ $i ] ) {
// If this folder is a self-reference, remove it.
case '..':
// If this folder is a backreference, remove it unless we're already at the root.
if ( isset( $parts[ $i - 1 ] ) && ! in_array( $parts[ $i - 1 ], array( '', '..' ), true ) ) {
array_splice( $parts, $i - 1, 2 );
$i--;
continue 2;
}
break;
case '.':
array_splice( $parts, $i, 1 );
continue 2;
}
$i++;
}
return implode( '/', $parts );
}
/**
* Convert backslash characters to forward slashes, and then normalize using `normalizePath`
*
* @param string $value to be normalized.
* @return string
*/
public function normalize_path_win( $value ) {
return $this->normalize_path( str_replace( '\\', '/', $value ) );
}
/**
* Removes all NUL bytes from input.
*
* @param string $value value to be filtered.
* @return string
*/
public function remove_nulls( $value ) {
return str_replace( "\x0", '', $value );
}
/**
* Remove all whitespace characters from input.
*
* @param string $value value to be filtered.
* @return string
*/
public function remove_whitespace( $value ) {
return preg_replace( '/\s/', '', $value );
}
/**
* Replaces each occurrence of a C-style comment (/ * ... * /) with a single space.
* Unterminated comments will also be replaced with a space. However, a standalone termination of a comment (* /) will not be acted upon.
*
* @param string $value value to be filtered.
* @return string
*/
public function replace_comments( $value ) {
$value = preg_replace( '~/\*.*?\*/|/\*.*?$~Ds', ' ', $value );
return explode( '/*', $value, 2 )[0];
}
/**
* Removes common comments chars (/ *, * /, --, #).
*
* @param string $value value to be filtered.
* @return string
*/
public function remove_comments_char( $value ) {
return preg_replace( '~/*|*/|--|#|//~', '', $value );
}
/**
* Replaces each NUL byte in input with a space.
*
* @param string $value value to be filtered.
* @return string
*/
public function replace_nulls( $value ) {
return str_replace( "\x0", ' ', $value );
}
/**
* Decode a URL-encoded input string.
*
* @param string $value value to be decoded.
* @return string
*/
public function url_decode( $value ) {
return urldecode( $value );
}
/**
* Decode a URL-encoded input string.
*
* @param string $value value to be decoded.
* @return string
*/
public function url_decode_uni( $value ) {
error_log( 'JETPACKWAF TRANSFORM NOT IMPLEMENTED: urlDecodeUni' );
return $value;
}
/**
* Decode a json encoded input string.
*
* @param string $value value to be decoded.
* @return string
*/
public function js_decode( $value ) {
error_log( 'JETPACKWAF TRANSFORM NOT IMPLEMENTED: jsDecode' );
return $value;
}
/**
* Convert all characters to uppercase.
*
* @param string $value value to be encoded.
* @return string
*/
public function uppercase( $value ) {
return strtoupper( $value );
}
/**
* Calculate a SHA1 hash from the input string.
*
* @param mixed $value value to be hashed.
* @return string
*/
public function sha1( $value ) {
return sha1( $value, true );
}
/**
* Remove whitespace from the left side of the input string.
*
* @param string $value value to be trimmed.
* @return string
*/
public function trim_left( $value ) {
return ltrim( $value );
}
/**
* Remove whitespace from the right side of the input string.
*
* @param string $value value to be trimmed.
* @return string
*/
public function trim_right( $value ) {
return rtrim( $value );
}
/**
* Remove whitespace from both sides of the input string.
*
* @param string $value value to be trimmed.
* @return string
*/
public function trim( $value ) {
return trim( $value );
}
/**
* Convert utf-8 characters to unicode characters
*
* @param string $value value to be encoded.
* @return string
*/
public function utf8_to_unicode( $value ) {
return preg_replace( '/\\\u(?=[a-f0-9]{4})/', '%u', substr( json_encode( $value ), 1, -1 ) );
}
}