BookStack/app/Access/Oidc/OidcJwtWithClaims.php
Dan Brown b18cee3dc4
OIDC Userinfo: Added JWT signed response support
Not yet tested, nor checked all response validations.
2024-04-19 14:12:27 +01:00

175 lines
5.7 KiB
PHP

<?php
namespace BookStack\Access\Oidc;
class OidcJwtWithClaims implements ProvidesClaims
{
protected array $header;
protected array $payload;
protected string $signature;
protected string $issuer;
protected array $tokenParts = [];
/**
* @var array[]|string[]
*/
protected array $keys;
public function __construct(string $token, string $issuer, array $keys)
{
$this->keys = $keys;
$this->issuer = $issuer;
$this->parse($token);
}
/**
* Parse the token content into its components.
*/
protected function parse(string $token): void
{
$this->tokenParts = explode('.', $token);
$this->header = $this->parseEncodedTokenPart($this->tokenParts[0]);
$this->payload = $this->parseEncodedTokenPart($this->tokenParts[1] ?? '');
$this->signature = $this->base64UrlDecode($this->tokenParts[2] ?? '') ?: '';
}
/**
* Parse a Base64-JSON encoded token part.
* Returns the data as a key-value array or empty array upon error.
*/
protected function parseEncodedTokenPart(string $part): array
{
$json = $this->base64UrlDecode($part) ?: '{}';
$decoded = json_decode($json, true);
return is_array($decoded) ? $decoded : [];
}
/**
* Base64URL decode. Needs some character conversions to be compatible
* with PHP's default base64 handling.
*/
protected function base64UrlDecode(string $encoded): string
{
return base64_decode(strtr($encoded, '-_', '+/'));
}
/**
* Validate common parts of OIDC JWT tokens.
*
* @throws OidcInvalidTokenException
*/
protected function validateCommonTokenDetails(): bool
{
$this->validateTokenStructure();
$this->validateTokenSignature();
$this->validateCommonClaims();
return true;
}
/**
* Fetch a specific claim from this token.
* Returns null if it is null or does not exist.
*/
public function getClaim(string $claim): mixed
{
return $this->payload[$claim] ?? null;
}
/**
* Get all returned claims within the token.
*/
public function getAllClaims(): array
{
return $this->payload;
}
/**
* Replace the existing claim data of this token with that provided.
*/
public function replaceClaims(array $claims): void
{
$this->payload = $claims;
}
/**
* Validate the structure of the given token and ensure we have the required pieces.
* As per https://datatracker.ietf.org/doc/html/rfc7519#section-7.2.
*
* @throws OidcInvalidTokenException
*/
protected function validateTokenStructure(): void
{
foreach (['header', 'payload'] as $prop) {
if (empty($this->$prop) || !is_array($this->$prop)) {
throw new OidcInvalidTokenException("Could not parse out a valid {$prop} within the provided token");
}
}
if (empty($this->signature) || !is_string($this->signature)) {
throw new OidcInvalidTokenException('Could not parse out a valid signature within the provided token');
}
}
/**
* Validate the signature of the given token and ensure it validates against the provided key.
*
* @throws OidcInvalidTokenException
*/
protected function validateTokenSignature(): void
{
if ($this->header['alg'] !== 'RS256') {
throw new OidcInvalidTokenException("Only RS256 signature validation is supported. Token reports using {$this->header['alg']}");
}
$parsedKeys = array_map(function ($key) {
try {
return new OidcJwtSigningKey($key);
} catch (OidcInvalidKeyException $e) {
throw new OidcInvalidTokenException('Failed to read signing key with error: ' . $e->getMessage());
}
}, $this->keys);
$parsedKeys = array_filter($parsedKeys);
$contentToSign = $this->tokenParts[0] . '.' . $this->tokenParts[1];
/** @var OidcJwtSigningKey $parsedKey */
foreach ($parsedKeys as $parsedKey) {
if ($parsedKey->verify($contentToSign, $this->signature)) {
return;
}
}
throw new OidcInvalidTokenException('Token signature could not be validated using the provided keys');
}
/**
* Validate common claims for OIDC JWT tokens.
* As per https://openid.net/specs/openid-connect-basic-1_0.html#IDTokenValidation
* and https://openid.net/specs/openid-connect-core-1_0.html#UserInfoResponse
*
* @throws OidcInvalidTokenException
*/
public function validateCommonClaims(): void
{
// 1. The Issuer Identifier for the OpenID Provider (which is typically obtained during Discovery)
// MUST exactly match the value of the iss (issuer) Claim.
if (empty($this->payload['iss']) || $this->issuer !== $this->payload['iss']) {
throw new OidcInvalidTokenException('Missing or non-matching token issuer value');
}
// 2. The Client MUST validate that the aud (audience) Claim contains its client_id value registered
// at the Issuer identified by the iss (issuer) Claim as an audience. The ID Token MUST be rejected
// if the ID Token does not list the Client as a valid audience.
if (empty($this->payload['aud'])) {
throw new OidcInvalidTokenException('Missing token audience value');
}
$aud = is_string($this->payload['aud']) ? [$this->payload['aud']] : $this->payload['aud'];
if (!in_array($this->payload['aud'], $aud, true)) {
throw new OidcInvalidTokenException('Token audience value did not match the expected client_id');
}
}
}