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Fix memory-safety crash on invalid UTF-8 variable names #602

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Merged
GrahamCampbell merged 3 commits into from
Aug 24, 2026
Merged

Fix memory-safety crash on invalid UTF-8 variable names #602

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aea163f
Validate variable names with the u modifier instead of the (*UTF8) verb
GrahamCampbell Aug 24, 2026
bcbfb0e
Add tests pinning invalid UTF-8 name rejection
GrahamCampbell Aug 24, 2026
1c2769e
Strip the export prefix and name quotes with byte operations
GrahamCampbell Aug 24, 2026
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14 changes: 7 additions & 7 deletions src/Parser/EntryParser.php
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Original file line number Diff line number Diff line change
Expand Up @@ -96,12 +96,12 @@ private static function splitStringIntoParts(string $line)
*/
private static function parseName(string $name)
{
if (Str::substr($name, 0, 6) === 'export' && \ctype_space(Str::substr($name, 6, 1))) {
$name = \ltrim(Str::substr($name, 6), " \t\n\r\v\f");
if (\strlen($name) > 6 && \substr($name, 0, 6) === 'export' && \ctype_space($name[6])) {
$name = \ltrim(\substr($name, 6), " \t\n\r\v\f");
}

if (self::isQuotedName($name)) {
$name = Str::substr($name, 1, -1);
$name = \substr($name, 1, -1);
}

if (!self::isValidName($name)) {
Expand All @@ -120,12 +120,12 @@ private static function parseName(string $name)
*/
private static function isQuotedName(string $name)
{
if (Str::len($name) < 3) {
if (\strlen($name) < 3) {
return false;
}

$first = Str::substr($name, 0, 1);
$last = Str::substr($name, -1, 1);
$first = $name[0];
$last = $name[\strlen($name) - 1];

return ($first === '"' && $last === '"') || ($first === '\'' && $last === '\'');
}
Expand All @@ -143,7 +143,7 @@ private static function isValidName(string $name)
return true;
}

return Regex::matches('~(*UTF8)\A[\p{Ll}\p{Lu}\p{M}\p{N}_.]+\z~', $name)->success()->getOrElse(false);
return Regex::matches('~\A[\p{Ll}\p{Lu}\p{M}\p{N}_.]+\z~u', $name)->success()->getOrElse(false);
}

/**
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36 changes: 36 additions & 0 deletions tests/Dotenv/Parser/EntryParserTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -157,6 +157,42 @@ public function testParseInvalidName()
$this->checkErrorResult($result, 'Encountered an invalid name at [FOO_ASD!].');
}

public function testParseInvalidUtf8Name()
{
$result = EntryParser::parse("\xC3=1");
$this->checkErrorResult($result, "Encountered an invalid name at [\xC3].");
}

public function testParseTruncatedUtf8Name()
{
$result = EntryParser::parse("A\xE2\x82=1");
$this->checkErrorResult($result, "Encountered an invalid name at [A\xE2\x82].");
}

public function testParseUtf16ByteOrderMarkName()
{
$result = EntryParser::parse("\xFF\xFE=1");
$this->checkErrorResult($result, "Encountered an invalid name at [\xFF\xFE].");
}

public function testParseNameWithSubstituteCharacterConfigured()
{
if (\PHP_VERSION_ID < 80302 || !\extension_loaded('mbstring')) {
self::markTestSkipped('Requires the native mbstring substitution behaviour of PHP 8.3.2.');
}

$previous = \mb_substitute_character();
\mb_substitute_character(0x41);

$quoted = EntryParser::parse("\"\xC3\"=evil");
$exported = EntryParser::parse("export \xC3=evil");

\mb_substitute_character($previous);

$this->checkErrorResult($quoted, "Encountered an invalid name at [\xC3].");
$this->checkErrorResult($exported, "Encountered an invalid name at [\xC3].");
}

public function testParserEscapingDouble()
{
$result = EntryParser::parse('FOO_BAD="iiiiviiiixiiiiviiii\\a"');
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8 changes: 8 additions & 0 deletions tests/Dotenv/Parser/ParserTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -63,6 +63,14 @@ public function testParseInvalidName()
(new Parser())->parse('FOO_ASD!=BAZ');
}

public function testParseInvalidUtf8Name()
{
$this->expectException(InvalidFileException::class);
$this->expectExceptionMessage("Failed to parse dotenv file. Encountered an invalid name at [\xC3].");

(new Parser())->parse("\xC3=1");
}

/**
* @param \Dotenv\Parser\Entry $entry
* @param string $name
Expand Down
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