227 lines
8.3 KiB
PHP
227 lines
8.3 KiB
PHP
<?php
|
|
|
|
namespace BookStack\Access\Oidc;
|
|
|
|
class OidcIdToken
|
|
{
|
|
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 all possible parts of the id token.
|
|
*
|
|
* @throws OidcInvalidTokenException
|
|
*/
|
|
public function validate(string $clientId): bool
|
|
{
|
|
$this->validateTokenStructure();
|
|
$this->validateTokenSignature();
|
|
$this->validateTokenClaims($clientId);
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Fetch a specific claim from this token.
|
|
* Returns null if it is null or does not exist.
|
|
*
|
|
* @return mixed|null
|
|
*/
|
|
public function getClaim(string $claim)
|
|
{
|
|
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 the claims of the token.
|
|
* As per https://openid.net/specs/openid-connect-basic-1_0.html#IDTokenValidation.
|
|
*
|
|
* @throws OidcInvalidTokenException
|
|
*/
|
|
protected function validateTokenClaims(string $clientId): void
|
|
{
|
|
// 1. The Issuer Identifier for the OpenID Provider (which is typically obtained during Discovery)
|
|
// MUST exactly match the value of the iss (issuer) Claim.
|
|
if (empty($this->payload['iss']) || $this->issuer !== $this->payload['iss']) {
|
|
throw new OidcInvalidTokenException('Missing or non-matching token issuer value');
|
|
}
|
|
|
|
// 2. The Client MUST validate that the aud (audience) Claim contains its client_id value registered
|
|
// at the Issuer identified by the iss (issuer) Claim as an audience. The ID Token MUST be rejected
|
|
// if the ID Token does not list the Client as a valid audience, or if it contains additional
|
|
// audiences not trusted by the Client.
|
|
if (empty($this->payload['aud'])) {
|
|
throw new OidcInvalidTokenException('Missing token audience value');
|
|
}
|
|
|
|
$aud = is_string($this->payload['aud']) ? [$this->payload['aud']] : $this->payload['aud'];
|
|
if (count($aud) !== 1) {
|
|
throw new OidcInvalidTokenException('Token audience value has ' . count($aud) . ' values, Expected 1');
|
|
}
|
|
|
|
if ($aud[0] !== $clientId) {
|
|
throw new OidcInvalidTokenException('Token audience value did not match the expected client_id');
|
|
}
|
|
|
|
// 3. If the ID Token contains multiple audiences, the Client SHOULD verify that an azp Claim is present.
|
|
// NOTE: Addressed by enforcing a count of 1 above.
|
|
|
|
// 4. If an azp (authorized party) Claim is present, the Client SHOULD verify that its client_id
|
|
// is the Claim Value.
|
|
if (isset($this->payload['azp']) && $this->payload['azp'] !== $clientId) {
|
|
throw new OidcInvalidTokenException('Token authorized party exists but does not match the expected client_id');
|
|
}
|
|
|
|
// 5. The current time MUST be before the time represented by the exp Claim
|
|
// (possibly allowing for some small leeway to account for clock skew).
|
|
if (empty($this->payload['exp'])) {
|
|
throw new OidcInvalidTokenException('Missing token expiration time value');
|
|
}
|
|
|
|
$skewSeconds = 120;
|
|
$now = time();
|
|
if ($now >= (intval($this->payload['exp']) + $skewSeconds)) {
|
|
throw new OidcInvalidTokenException('Token has expired');
|
|
}
|
|
|
|
// 6. The iat Claim can be used to reject tokens that were issued too far away from the current time,
|
|
// limiting the amount of time that nonces need to be stored to prevent attacks.
|
|
// The acceptable range is Client specific.
|
|
if (empty($this->payload['iat'])) {
|
|
throw new OidcInvalidTokenException('Missing token issued at time value');
|
|
}
|
|
|
|
$dayAgo = time() - 86400;
|
|
$iat = intval($this->payload['iat']);
|
|
if ($iat > ($now + $skewSeconds) || $iat < $dayAgo) {
|
|
throw new OidcInvalidTokenException('Token issue at time is not recent or is invalid');
|
|
}
|
|
|
|
// 7. If the acr Claim was requested, the Client SHOULD check that the asserted Claim Value is appropriate.
|
|
// The meaning and processing of acr Claim Values is out of scope for this document.
|
|
// NOTE: Not used for our case here. acr is not requested.
|
|
|
|
// 8. When a max_age request is made, the Client SHOULD check the auth_time Claim value and request
|
|
// re-authentication if it determines too much time has elapsed since the last End-User authentication.
|
|
// NOTE: Not used for our case here. A max_age request is not made.
|
|
|
|
// Custom: Ensure the "sub" (Subject) Claim exists and has a value.
|
|
if (empty($this->payload['sub'])) {
|
|
throw new OidcInvalidTokenException('Missing token subject value');
|
|
}
|
|
}
|
|
}
|