php / php/php-src

PCRE JIT produces wrong result on ~8192-byte strings

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Dieses Issue hat noch niemand übernommen.

Bug Extension: pcre Status: Needs Triage
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Beschreibung

Description

A rather simple anchored pattern produces different results with and without the PCRE JIT when applied to a string just over 8192 characters. The JIT result is wrong.

3v4l.org link

The following code:

<?php

$t = <<<END
(49071,XXXXXXXXXX,XXXXXXXXXX,XXXXXXXXXXXXXXXXXX,XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,0,XXXX,XXXX2XX10X8XXXXXXXXX8XXX02XXXXXX9XXXXXX0XXXX3XXXX8X2XXXXXX7XXXXX,1605115416,XXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX,XXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXX,XXXXX(XXXXXXXXXXXX,XXXXXXX(XXXXX,XXXXXXXXXXXXXX,XXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXX,XXXX(XXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXX,XXXXXXXXXX,XXXXX(XXXXXXXXXXXXXX,XXXX(XXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXX,XXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXXXXXXXXX(XXXX(XXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXX(XXXXXXXXXXX,XXXXXXXXXX(XXXXXXXXXXXXXXXXX,XXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXX(XXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXX(XXXXXXX,XXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXX,XXXX(XXXXXXXXXXXXXXXXXXXXXXXXX,XXXXX(XXXXXXXXXXXXX,XXXX(XXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXX,XXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXX,XXXXXXXXXXX,XXXXXXX(XXXXXXXXXXXXX,XXXXXXXXXXX(XXXXXXXXXXXXXXX,XXXXXXX(XXXXXX,XXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXX(XXXXXXXXXXXXX,XXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXX(XXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXXXXXX,XXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXX,XXXXXXXXXXXX,XXXXXXXX(XXXXXXXX,XXXXXXXXXXX(XXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXX,XXXXXXXXXXXXXX(XXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXX,XXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXXXX,XXXXXXXXXXXXX,XXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXX,XXXXXXXXXX(XXXXXXXXXXX,XXXXXXXXXX(XXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXX,XXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXX,XXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXX,XXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX,XXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX(XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX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END;


$regex = '/\A\((?:[^\\\\\')]|\'(?:[^\'\\\\]|\\\\[\S\s])*?\')*/s';

// test without jit
ini_set("pcre.jit", 0);
echo "length: ", strlen($t), "\n";
echo "match length without pcre.jit: ";
$x = preg_match($regex, $t, $m);
echo ($x ? strlen($m[0]) : "none"), "\n";

// clear PCRE cache
$n = 0;
for ($i = 0; $i < 10000; ++$i) {
    $n += preg_match('/X{' . $i . '}/', $t);
}

// test with jit, should provide same answer
ini_set("pcre.jit", 1);
echo "match length with pcre.jit: ";
$x = preg_match($regex, $t, $m);
echo ($x ? strlen($m[0]) : "none"), "\n";

Resulted in this output:

length: 8220
match length without pcre.jit: 8219
match length with pcre.jit: none

But I expected this output instead:

length: 8220
match length without pcre.jit: 8219
match length with pcre.jit: 8219
PHP Version

PHP 8.0.12 and many others down to 7.3.30

Operating System

Mac OS X, Amazon Linux

Beitragsleitfaden

Beitragsleitfaden öffnen

Erste Schritte

  1. Lies das ganze Issue und danach den Beitragsleitfaden des Projekts.
  2. Schreib ins Issue, dass du es übernimmst — das erspart doppelte Arbeit.
  3. Forke das Repository und arbeite in einem Branch.
  4. Öffne einen Pull Request, der die Issue-Nummer nennt.

Rechercherichtung

Beginnen Sie mit dem bereitgestellten PHP-Reproducer und vergleichen Sie die beiden preg_match-Aufrufe mit deaktiviertem und aktiviertem pcre.jit. Untersuchen Sie den PCRE-JIT-Pfad, der für verankerte Muster bei Zeichenfolgen mit knapp über 8192 Zeichen verantwortlich ist; abgeschlossen ist die Aufgabe, wenn beide Modi einen Treffer der Länge 8219 zurückgeben.

Vom Indexierungsmodell aus dem Issue-Text verfasst.

Bewertung

Tech-Stack
php
Bereich
backend, performance
Issue-Typ
Bug
Schwierigkeit
4/5
Geschätzter Aufwand
3-5 Tage
Aktivitätsstatus
Veraltet
Klarheit
Klar beschrieben
Anfängerfreundlichkeit
35/100

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