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PHPのDOMDocumentがバイナリセーフよりさらに脆いものだった件

php

結論から言うと、DOMDocumentは、「改行」「タブ」「キャリッジリターン」以外のコントロールコードが入っていると、それ以降の文字列を無視してしまう。

ちなみに、バイナリセーフでないと叩かれているereg系はヌルバイトだけを切ってしまう。

なんという脆さ・・・。

検証スクリプト

<?php
$html=<<<EOF
<html>
<head>
  <meta http-equiv="Content-Language" content="ja">
  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
  <meta name="GENERATOR" content="Microsoft FrontPage 6.0">
  <meta name="ProgId" content="FrontPage.Editor.Document">
  <title>ASCII Control Code</title>
  <meta name="Microsoft Border" content="b, default">
</head>
<body>
  <h1>Control Code List</h1>
  <div>test document include control code  %s at the point of after control code</div>
</body>
</html>
EOF;

echo "# DOMDocument\n";
checkCtrlCode('parse_domdocument');
echo "\n# str_replace\n";
checkCtrlCode('string_replace');
echo "\n# ereg_replace\n";
checkCtrlCode('not_binary_safe');

function parse_domdocument($html, $cc)
{
    $dom = new DOMDocument();
    $html = sprintf($html, $cc);
    @$dom->loadHTML($html);
    return $dom->saveHTML()."\n------\n";
}

function string_replace($html, $cc)
{
    $html = sprintf($html, $cc);
    $html = str_replace('%s', $cc, $html);
    return $html."\n------\n";
}

function not_binary_safe($html, $cc)
{
    $html = sprintf($html, $cc);
    $html = ereg_replace("%s", $cc, $html);
    return $html."\n------\n";
}


function hex2bin($hex_str)
{
        return pack("H*" , $hex_str);
}

function checkCtrlCode($callback)
{
    global $html;
    
    $ctrl_code = array(
        "00" => 'NULl(ヌル)',
        "01" => 'Start Of Heading(ヘッダ開始)',
        "02" => 'Start of TeXt(テキスト開始)',
        "03" => 'End of TeXt(テキスト終了)',
        "04" => 'End Of Transmission(転送終了)',
        "05" => 'ENQuiry(問合せ)',
        "06" => 'ACKnowledge(肯定応答)',
        "07" => 'BELl(ベル)',
        "08" => 'Back Space(後退)',
        "09" => 'Horizontal Tabulation(水平タブ)',
        "0A" => 'Line Feed(改行)',
        "0B" => 'Vertical Tabulation(垂直タブ)',
        "0C" => 'Form Feed(改ページ)',
        "0D" => 'Carriage Return(復帰)',
        "0E" => 'Shift Out(シフトアウト)',
        "0F" => 'Shift In(シフトイン)',
        "10" => 'Data Link Escape(伝送制御拡張)',
        "11" => 'Device Control 1(装置制御1)',
        "12" => 'Device Control 2(装置制御2)',
        "13" => 'Device Control 3(装置制御3)',
        "14" => 'Device Control 4(装置制御4)',
        "15" => 'Negative AcKnowledge(否定応答)',
        "16" => 'SYNchronous idle(同期信号)',
        "17" => 'End of Transmission Block(転送ブロック終了)',
        "18" => 'CANcel(取消)',
        "19" => 'End of Medium(媒体終端)',
        "1A" => 'SUBstitute(置換)',
        "1B" => 'ESCape(拡張)',
        "1C" => 'File Separator(ファイル分離)',
        "1D" => 'Group Separator(グループ分離)',
        "1E" => 'Record Separator(レコード分離)',
        "1F" => 'Unit Separator(ユニット分離)',
        );

    $code_array = array();
    foreach ($ctrl_code as $code=>$name){
        $r = $callback($html, hex2bin($code));
        if (strpos($r, 'at the point of after control code') !== false){
            printf("[%s]\n", $name);
        }
    }
}

実行結果

[tohokuaiki@php5 work]$ php control_code.php
# DOMDocument
[Horizontal Tabulation(水平タブ)]
[Line Feed(改行)]
[Carriage Return(復帰)]


# str_replace
[NULl(ヌル)]
[Start Of Heading(ヘッダ開始)]
[Start of TeXt(テキスト開始)]
[End of TeXt(テキスト終了)]
[End Of Transmission(転送終了)]
[ENQuiry(問合せ)]
[ACKnowledge(肯定応答)]
[BELl(ベル)]
[Back Space(後退)]
[Horizontal Tabulation(水平タブ)]
[Line Feed(改行)]
[Vertical Tabulation(垂直タブ)]
[Form Feed(改ページ)]
[Carriage Return(復帰)]
[Shift Out(シフトアウト)]
[Shift In(シフトイン)]
[Data Link Escape(伝送制御拡張)]
[Device Control 1(装置制御1)]
[Device Control 2(装置制御2)]
[Device Control 3(装置制御3)]
[Device Control 4(装置制御4)]
[Negative AcKnowledge(否定応答)]
[SYNchronous idle(同期信号)]
[End of Transmission Block(転送ブロック終了)]
[CANcel(取消)]
[End of Medium(媒体終端)]
[SUBstitute(置換)]
[ESCape(拡張)]
[File Separator(ファイル分離)]
[Group Separator(グループ分離)]
[Record Separator(レコード分離)]
[Unit Separator(ユニット分離)]


# ereg_replace
[Start Of Heading(ヘッダ開始)]
[Start of TeXt(テキスト開始)]
[End of TeXt(テキスト終了)]
[End Of Transmission(転送終了)]
[ENQuiry(問合せ)]
[ACKnowledge(肯定応答)]
[BELl(ベル)]
[Back Space(後退)]
[Horizontal Tabulation(水平タブ)]
[Line Feed(改行)]
[Vertical Tabulation(垂直タブ)]
[Form Feed(改ページ)]
[Carriage Return(復帰)]
[Shift Out(シフトアウト)]
[Shift In(シフトイン)]
[Data Link Escape(伝送制御拡張)]
[Device Control 1(装置制御1)]
[Device Control 2(装置制御2)]
[Device Control 3(装置制御3)]
[Device Control 4(装置制御4)]
[Negative AcKnowledge(否定応答)]
[SYNchronous idle(同期信号)]
[End of Transmission Block(転送ブロック終了)]
[CANcel(取消)]
[End of Medium(媒体終端)]
[SUBstitute(置換)]
[ESCape(拡張)]
[File Separator(ファイル分離)]
[Group Separator(グループ分離)]
[Record Separator(レコード分離)]
[Unit Separator(ユニット分離)]