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fix: Throw exception on invalid base64 #576

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fix: Throw exception on invalid base64 #576

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340e4a6
fix: Throw exception on invalid base64
Oinkling Aug 8, 2024
86ebae1
urlsafeB64Decode will fail on any invalid input
Oinkling Apr 28, 2025
7908d58
Tests for urlsafeB64Decode
Oinkling Apr 28, 2025
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29 changes: 24 additions & 5 deletions src/JWT.php
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Original file line number Diff line number Diff line change
Expand Up @@ -109,14 +109,22 @@ public static function decode(
throw new UnexpectedValueException('Wrong number of segments');
}
list($headb64, $bodyb64, $cryptob64) = $tks;
$headerRaw = static::urlsafeB64Decode($headb64);
try {
$headerRaw = static::urlsafeB64Decode($headb64);
} catch (InvalidArgumentException $e) {
throw new UnexpectedValueException('Unable to decode header');
}
if (null === ($header = static::jsonDecode($headerRaw))) {
throw new UnexpectedValueException('Invalid header encoding');
}
if ($headers !== null) {
$headers = $header;
}
$payloadRaw = static::urlsafeB64Decode($bodyb64);
try {
$payloadRaw = static::urlsafeB64Decode($bodyb64);
} catch (InvalidArgumentException $e) {
throw new UnexpectedValueException('Unable to decode payload');
}
if (null === ($payload = static::jsonDecode($payloadRaw))) {
throw new UnexpectedValueException('Invalid claims encoding');
}
Expand All @@ -127,7 +135,11 @@ public static function decode(
if (!$payload instanceof stdClass) {
throw new UnexpectedValueException('Payload must be a JSON object');
}
$sig = static::urlsafeB64Decode($cryptob64);
try {
$sig = static::urlsafeB64Decode($cryptob64);
} catch (InvalidArgumentException $e) {
throw new UnexpectedValueException('Unable to decode signature');
}
if (empty($header->alg)) {
throw new UnexpectedValueException('Empty algorithm');
}
Expand Down Expand Up @@ -411,11 +423,18 @@ public static function jsonEncode(array $input): string
*
* @return string A decoded string
*
* @throws InvalidArgumentException invalid base64 characters
* @throws InvalidArgumentException invalid base64URL characters
*/
public static function urlsafeB64Decode(string $input): string
{
return \base64_decode(self::convertBase64UrlToBase64($input));
if (strpbrk($input, '+/=') !== false) {
throw new InvalidArgumentException('Input is not valid Base64URL');
}
$result = \base64_decode(self::convertBase64UrlToBase64($input), true);
if ($result === false) {
throw new InvalidArgumentException('Input is not valid Base64URL');
}
return $result;
}

/**
Expand Down
19 changes: 19 additions & 0 deletions tests/JWTTest.php
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,25 @@ public function testMalformedJsonThrowsException()
JWT::jsonDecode('this is not valid JSON string');
}

public function testBase64UrlDecode()
{
$decoded = JWT::urlsafeB64Decode('VGVzdCB3aXRoIGEgbWludXM-');
$expected = 'Test with a minus>';
$this->assertSame($expected, $decoded);
}

public function testMalformedBase64Url()
{
$this->expectException(InvalidArgumentException::class);
JWT::urlsafeB64Decode('VGVzdCB3aXR&oIGEgbWludXM-');
}

public function testMalformedBase64UrlButValidBase64()
{
$this->expectException(InvalidArgumentException::class);
JWT::urlsafeB64Decode('VGVzdCB3aXRoIGEgc2xhc2g/');
}

public function testExpiredToken()
{
$this->expectException(ExpiredException::class);
Expand Down