+<?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');
+ }
+ }
+}
projects / bookstack / commitdiff