OIDC Userinfo: Added JWT signed response support

Not yet tested, nor checked all response validations.

app/Access/Oidc/OidcIdToken.php

@@ -2,58 +2,8 @@
 
 namespace BookStack\Access\Oidc;
 
-class OidcIdToken implements ProvidesClaims
+class OidcIdToken extends 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 all possible parts of the id token.
      *
@@ -61,89 +11,12 @@ class OidcIdToken implements ProvidesClaims
      */
     public function validate(string $clientId): bool
     {
-        $this->validateTokenStructure();
+        parent::validateCommonClaims();
-        $this->validateTokenSignature();
         $this->validateTokenClaims($clientId);
 
         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, $this->signature)) {
-                return;
-            }
-        }
-
-        throw new OidcInvalidTokenException('Token signature could not be validated using the provided keys');
-    }
-
     /**
      * Validate the claims of the token.
      * As per https://openid.net/specs/openid-connect-basic-1_0.html#IDTokenValidation.
@@ -154,27 +27,18 @@ class OidcIdToken implements ProvidesClaims
     {
         // 1. The Issuer Identifier for the OpenID Provider (which is typically obtained during Discovery)
         // MUST exactly match the value of the iss (issuer) Claim.
-        if (empty($this->payload['iss']) || $this->issuer !== $this->payload['iss']) {
+        // Already done in parent.
-            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'])) {
+        // Partially done in parent.
-            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.
 

app/Access/Oidc/OidcJwtWithClaims.php

@@ -0,0 +1,174 @@
+<?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');
+        }
+    }
+}

app/Access/Oidc/OidcService.php

@@ -246,7 +246,11 @@ class OidcService
         if (!$userDetails->isFullyPopulated($this->shouldSyncGroups()) && !empty($settings->userinfoEndpoint)) {
             $provider = $this->getProvider($settings);
             $request = $provider->getAuthenticatedRequest('GET', $settings->userinfoEndpoint, $accessToken->getToken());
-            $response = new OidcUserinfoResponse($provider->getResponse($request));
+            $response = new OidcUserinfoResponse(
+                $provider->getResponse($request),
+                $settings->issuer,
+                $settings->keys,
+            );
 
             try {
                 $response->validate($idToken->getClaim('sub'));

app/Access/Oidc/OidcUserinfoResponse.php

@@ -7,14 +7,20 @@ use Psr\Http\Message\ResponseInterface;
 class OidcUserinfoResponse implements ProvidesClaims
 {
     protected array $claims = [];
+    protected ?OidcJwtWithClaims $jwt = null;
 
-    public function __construct(ResponseInterface $response)
+    public function __construct(ResponseInterface $response, string $issuer, array $keys)
     {
-        if ($response->getHeader('Content-Type')[0] === 'application/json') {
+        $contentType = $response->getHeader('Content-Type')[0];
+        if ($contentType === 'application/json') {
             $this->claims = json_decode($response->getBody()->getContents(), true);
         }
 
-        // TODO - Support JWTs
+        if ($contentType === 'application/jwt') {
+            $this->jwt = new OidcJwtWithClaims($response->getBody()->getContents(), $issuer, $keys);
+            $this->claims = $this->jwt->getAllClaims();
+        }
+
         // TODO - Response validation (5.3.4):
             // TODO - Verify that the OP that responded was the intended OP through a TLS server certificate check, per RFC 6125 [RFC6125].
             // TODO - If the Client has provided a userinfo_encrypted_response_alg parameter during Registration, decrypt the UserInfo Response using the keys specified during Registration.
@@ -26,6 +32,10 @@ class OidcUserinfoResponse implements ProvidesClaims
      */
     public function validate(string $idTokenSub): bool
     {
+        if (!is_null($this->jwt)) {
+            $this->jwt->validateCommonClaims();
+        }
+
         $sub = $this->getClaim('sub');
 
         // Spec: v1.0 5.3.2: The sub (subject) Claim MUST always be returned in the UserInfo Response.