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Stdlib: preg_* /u rejects invalid UTF-8 subjects (#17503) #17512

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Merged
PurHur merged 1 commit into from
Jul 9, 2026
Merged

Stdlib: preg_* /u rejects invalid UTF-8 subjects (#17503) #17512

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28 changes: 25 additions & 3 deletions ext/standard/VmPreg.php
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Original file line number Diff line number Diff line change
Expand Up @@ -325,8 +325,19 @@ private static function pregReplaceArrayPatterns(
}
$elemCount = 0;
$replaced = self::pregReplaceArrayPatterns($pattern, $replacements, $item, $limit, $elemCount);
if (false === $replaced || null === $replaced) {
return $replaced;
if (false === $replaced) {
return false;
}
if (null === $replaced) {
if (StdlibConstants::PREG_BAD_UTF8_ERROR === self::lastError()) {
if (null !== $count) {
$count = $totalCount;
}

return $out;
}

return null;
}
$out[$key] = $replaced;
$totalCount += $elemCount;
Expand All @@ -348,9 +359,20 @@ private static function pregReplaceArrayPatterns(
$stepCount = 0;
$step = VmPregNative::pregReplace($pat, $repl, $result, $limit, $stepCount);
self::syncLastErrorFromNative();
if (false === $step || null === $step) {
if (false === $step) {
return false;
}
if (null === $step) {
if (StdlibConstants::PREG_BAD_UTF8_ERROR === self::lastError()) {
if (null !== $count) {
$count = $totalCount;
}

return $result;
}

return null;
}
$result = $step;
$totalCount += $stepCount;
}
Expand Down
5 changes: 4 additions & 1 deletion ext/standard/VmPregPattern.php
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,9 @@
*/
final class VmPregPattern
{
/** PCRE2_UTF — PHP /u pattern modifier (ext/pcre/php_pcre.c). */
public const PCRE2_UTF = 0x00080000;

/**
* Zend ext/pcre/php_pcre.c delimiter/compile failure text (issue #12083).
*/
Expand Down Expand Up @@ -124,7 +127,7 @@ public static function parsePhpPattern(string $pattern): ?array
'A' => 0x80000000,
'D' => 0x00000010,
'U' => 0x00040000,
'u' => 0x00080000,
'u' => self::PCRE2_UTF,
default => 0,
};
}
Expand Down
82 changes: 68 additions & 14 deletions ext/standard/VmPregPure.php
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Original file line number Diff line number Diff line change
Expand Up @@ -38,17 +38,19 @@ public static function pregMatch(
return false;
}
[$regex, $opts] = $parsed;
$compiled = self::compile($pattern);
if (null === $compiled) {
return false;
}

$normalizedOffset = self::normalizeMatchSubjectOffset($offset, \strlen($subject));
if (false === $normalizedOffset) {
self::$lastError = StdlibConstants::PREG_INTERNAL_ERROR;

return false;
}
if (!self::ensureUtf8SubjectForOpts($subject, $opts, $normalizedOffset)) {
return false;
}
$compiled = self::compile($pattern);
if (null === $compiled) {
return false;
}

$ovector = self::engineMatch(
$compiled['ast'],
Expand Down Expand Up @@ -100,18 +102,20 @@ public static function pregMatchAll(
return false;
}
[$regex, $opts] = $parsed;
$compiled = self::compile($pattern);
if (null === $compiled) {
return false;
}

$subjectLen = \strlen($subject);
$normalizedOffset = self::normalizeMatchSubjectOffset($offset, $subjectLen);
if (false === $normalizedOffset) {
self::$lastError = StdlibConstants::PREG_INTERNAL_ERROR;

return false;
}
if (!self::ensureUtf8SubjectForOpts($subject, $opts, $normalizedOffset)) {
return false;
}
$compiled = self::compile($pattern);
if (null === $compiled) {
return false;
}

$start = $normalizedOffset;
$count = 0;
Expand Down Expand Up @@ -185,8 +189,19 @@ public static function pregReplace(
}
$elemCount = 0;
$replaced = self::pregReplaceString($pattern, $replacement, $item, $limit, $elemCount);
if (false === $replaced || null === $replaced) {
return $replaced;
if (false === $replaced) {
return false;
}
if (null === $replaced) {
if (StdlibConstants::PREG_BAD_UTF8_ERROR === self::$lastError) {
if (null !== $count) {
$count = $totalCount;
}

return $out;
}

return null;
}
$out[$key] = $replaced;
$totalCount += $elemCount;
Expand Down Expand Up @@ -214,14 +229,21 @@ public static function pregSplit(string $pattern, string $subject, int $limit =
}
[$regex, $opts] = $parsed;
if ('' === $regex) {
if (!self::ensureUtf8SubjectForOpts($subject, $opts, 0)) {
return false;
}

return self::pregSplitEmptyPattern(
$subject,
$limit,
$flags,
0 !== ($opts & 0x00080000)
0 !== ($opts & VmPregPattern::PCRE2_UTF)
);
}

if (!self::ensureUtf8SubjectForOpts($subject, $opts, 0)) {
return false;
}
$compiled = self::compile($pattern);
if (null === $compiled) {
return false;
Expand Down Expand Up @@ -325,7 +347,7 @@ private static function splitAdvanceUnit(string $subject, int $byteOffset, int $
if ($byteOffset >= \strlen($subject)) {
return 0;
}
if (0 !== ($opts & 0x00080000)) {
if (0 !== ($opts & VmPregPattern::PCRE2_UTF)) {
$charIndex = 0;
$pos = 0;
$charLen = VmString::utf8CharLength($subject);
Expand Down Expand Up @@ -407,6 +429,9 @@ private static function pregReplaceString(
$emptyParsed = PregEmptyPatternReplace::parseEmptyPattern($pattern);
if (null !== $emptyParsed) {
[, $opts] = $emptyParsed;
if (!self::ensureUtf8SubjectForOpts($subject, $opts, 0)) {
return null;
}
self::$lastError = 0;
$replacements = 0;
$result = PregEmptyPatternReplace::replace(
Expand All @@ -430,6 +455,9 @@ private static function pregReplaceString(
return null;
}
[$regex, $opts] = $parsed;
if (!self::ensureUtf8SubjectForOpts($subject, $opts, 0)) {
return null;
}
$compiled = self::compile($pattern);
if (null === $compiled) {
self::$lastError = 1;
Expand Down Expand Up @@ -550,6 +578,32 @@ private static function normalizeMatchSubjectOffset(int $offset, int $subjectLen
return $offset;
}

/**
* php-src ext/pcre/php_pcre.c — reject malformed UTF-8 subjects when /u is set.
*/
private static function ensureUtf8SubjectForOpts(string $subject, int $opts, int $offset): bool
{
if (0 === ($opts & VmPregPattern::PCRE2_UTF)) {
return true;
}
if (!VmString::isValidUtf8($subject)) {
self::$lastError = StdlibConstants::PREG_BAD_UTF8_ERROR;

return false;
}
$subjectLen = \strlen($subject);
if ($offset > 0 && $offset < $subjectLen) {
$byte = \ord($subject[$offset]);
if (($byte & 0xC0) === 0x80) {
self::$lastError = StdlibConstants::PREG_BAD_UTF8_OFFSET_ERROR;

return false;
}
}

return true;
}

/**
* @param list<int> $ovector
* @param array<string, int> $groupNameToIndex
Expand Down
3 changes: 3 additions & 0 deletions ext/standard/preg_grep.php
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Expand Up @@ -56,6 +56,9 @@ public function execute(Frame $frame): void
self::rejectNonStringHaystackValue($value);
$match = VmPreg::pregMatch($pattern, $value->toString());
if (false === $match) {
if (StdlibConstants::PREG_BAD_UTF8_ERROR === VmPreg::lastError()) {
continue;
}
if (null !== $frame->returnVar) {
$frame->returnVar->bool(false);
}
Expand Down
32 changes: 32 additions & 0 deletions test/compliance/cases/pcre/preg_utf8_invalid_subject.phpt
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@@ -0,0 +1,32 @@
--TEST--
pcre preg_* /u modifier rejects invalid UTF-8 subject (#17503, ext/pcre/php_pcre.c)
--FILE--
<?php
$bad = "\xFF";

preg_match('//u', $bad, $m, 0, 0);
echo preg_match('//u', $bad) === false ? 'match_fail' : 'match_ok', "\n";
echo preg_last_error(), "\n";

preg_split('//u', $bad);
echo preg_split('//u', $bad) === false ? 'split_fail' : 'split_ok', "\n";
echo preg_last_error(), "\n";

preg_replace('//u', 'x', $bad);
echo preg_replace('//u', 'x', $bad) === null ? 'replace_null' : 'replace_ok', "\n";
echo preg_last_error(), "\n";

var_export(preg_grep('//u', ['a', $bad]));
echo "\n";
echo preg_last_error(), "\n";
--EXPECT--
match_fail
4
split_fail
4
replace_null
4
array (
0 => 'a',
)
4
11 changes: 11 additions & 0 deletions test/repro/maintainer_gap_preg_match_invalid_utf8.php
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@@ -0,0 +1,11 @@
<?php

declare(strict_types=1);

/** Issue #17503 — preg_match(/u) on invalid UTF-8 (ext/pcre/php_pcre.c). */
$bad = "\xFF";

var_export(preg_match('//u', $bad));
echo "\n";
var_export(preg_last_error());
echo "\n";
11 changes: 11 additions & 0 deletions test/repro/maintainer_gap_preg_split_invalid_utf8.php
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@@ -0,0 +1,11 @@
<?php

declare(strict_types=1);

/** Issue #17503 — preg_split(/u) on invalid UTF-8 (ext/pcre/php_pcre.c). */
$bad = "\xFF";

var_export(preg_split('//u', $bad));
echo "\n";
var_export(preg_last_error());
echo "\n";
45 changes: 45 additions & 0 deletions test/unit/VmPregUtf8SubjectTest.php
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@@ -0,0 +1,45 @@
<?php

declare(strict_types=1);

namespace PHPCompiler\Test\Unit;

use PHPCompiler\ext\standard\PregJitHelper;
use PHPCompiler\ext\standard\StdlibConstants;
use PHPCompiler\ext\standard\VmPregNative;
use PHPCompiler\ext\standard\VmPregPure;
use PHPUnit\Framework\TestCase;

/** preg_* /u rejects malformed UTF-8 subjects (#17503, ext/pcre/php_pcre.c). */
final class VmPregUtf8SubjectTest extends TestCase
{
private const BAD = "\xFF";

public function testPregMatchInvalidUtf8SetsBadUtf8Error(): void
{
VmPregPure::setLastError(0);
$this->assertFalse(VmPregPure::pregMatch('//u', self::BAD));
$this->assertSame(StdlibConstants::PREG_BAD_UTF8_ERROR, VmPregPure::lastError());
}

public function testPregSplitInvalidUtf8SetsBadUtf8Error(): void
{
VmPregPure::setLastError(0);
$this->assertFalse(VmPregPure::pregSplit('//u', self::BAD));
$this->assertSame(StdlibConstants::PREG_BAD_UTF8_ERROR, VmPregPure::lastError());
}

public function testPregReplaceInvalidUtf8ReturnsNull(): void
{
VmPregPure::setLastError(0);
$this->assertNull(VmPregPure::pregReplace('//u', 'x', self::BAD));
$this->assertSame(StdlibConstants::PREG_BAD_UTF8_ERROR, VmPregPure::lastError());
}

public function testJitHelperPropagatesBadUtf8Error(): void
{
VmPregNative::setLastError(0);
$this->assertSame(-1, PregJitHelper::matchArgv('//u', self::BAD));
$this->assertSame(StdlibConstants::PREG_BAD_UTF8_ERROR, PregJitHelper::lastError());
}
}