merge: shared broker and deployment contracts

.env.example

@@ -10,8 +10,6 @@ POSTGRES_PASSWORD=change-me-postgres-password
 TOKEN_MEDIATING_CLIENT_SECRET=change-me-token-mediating-client-secret
 BFF_CLIENT_SECRET=change-me-bff-client-secret
 EDGE_PROXY_CLIENT_SECRET=change-me-edge-proxy-client-secret
-OAUTH2_PROXY_COOKIE_SECRET=generate-a-base64-encoded-32-byte-secret
-INTERNAL_AUTH_TOKEN=generate-a-long-random-edge-to-backend-token
 MOCK_GOOGLE_BROKER_CLIENT_SECRET=change-me-mock-google-broker-client-secret
 ADMIN_USER_PASSWORD=change-me-admin-user-password
 REGULAR_USER_PASSWORD=change-me-regular-user-password

.gitignore

@@ -4,6 +4,7 @@
 *.iml
 
 backend/target/
+token-mediator/target/
 **/node_modules/
 frontend/dist/
 build/

README.md

@@ -104,21 +104,21 @@ Keycloak을 잠시 중지하고 export한 뒤 자동으로 다시 올립니다.
 runtime export에는 실제 client secret과 credential hash가 포함될 수 있어
 gitignored `build/keycloak-export/`에 권한 `0600`으로만 저장됩니다.
 
-## AP4: oauth2-proxy Edge Forward Auth
+## AP2: Token-Mediating Backend
 
-`develop-keycloak-pattern4`는 oauth2-proxy와 Nginx `auth_request`가
+`develop-keycloak-pattern2`의 Spring confidential client는
-인증을 edge에서 강제하는 패턴입니다.
+`http://localhost:8082`에서 실행됩니다. 브라우저는 로그인 redirect와
+HttpOnly `AP2_SESSION`만 사용하고, authorization code 교환과
+access/refresh token 보관은 backend가 담당합니다.
 
 ```bash
-./scripts/verify-pattern4.sh
+./scripts/verify-pattern2.sh
 ```
 
-첫 feature에서는 oauth2-proxy를 `http://localhost:4180`에 직접 노출해
+`/token/boundary`는 실제 token 값을 반환하지 않고 서버 저장 여부만 보여줍니다.
-OIDC redirect/PKCE/callback과 forwarded-user를 분리 확인합니다. 두 번째
+`/token/access`는 access token과 만료 메타데이터만 `no-store`로 전달하며,
-feature부터 `http://localhost:8088` Nginx가 단일 진입점이며, 내부
+refresh token은 반환하지 않습니다. 브라우저는 이 access token으로
-`auth_request`는 브라우저 요청을 login 302로, API 요청을 JSON 401로
+`http://localhost:8081/api/me`를 직접 호출합니다.
-구분합니다. 최종 feature에서는 backend와 oauth2-proxy의 호스트 노출을
+
-제거하고 Nginx 헤더 덮어쓰기와 내부 토큰 검증으로 spoofing을 막습니다.
+자세한 token 경계와 실험 항목은
-자세한 내용은
+[`docs/ap2-token-boundary.md`](docs/ap2-token-boundary.md)를 참고하세요.
-[`docs/ap4-edge-forward-auth.md`](docs/ap4-edge-forward-auth.md)를
-참고하세요.

backend/src/main/java/com/example/keycloakpattern/AudienceValidator.java

@@ -0,0 +1,29 @@
+package com.example.keycloakpattern;
+
+import org.springframework.security.oauth2.core.OAuth2Error;
+import org.springframework.security.oauth2.core.OAuth2TokenValidator;
+import org.springframework.security.oauth2.core.OAuth2TokenValidatorResult;
+import org.springframework.security.oauth2.jwt.Jwt;
+
+final class AudienceValidator implements OAuth2TokenValidator<Jwt> {
+
+    private static final OAuth2Error MISSING_AUDIENCE = new OAuth2Error(
+        "invalid_token",
+        "The required resource audience is missing",
+        null
+    );
+
+    private final String expectedAudience;
+
+    AudienceValidator(String expectedAudience) {
+        this.expectedAudience = expectedAudience;
+    }
+
+    @Override
+    public OAuth2TokenValidatorResult validate(Jwt jwt) {
+        if (jwt.getAudience().contains(expectedAudience)) {
+            return OAuth2TokenValidatorResult.success();
+        }
+        return OAuth2TokenValidatorResult.failure(MISSING_AUDIENCE);
+    }
+}

backend/src/main/java/com/example/keycloakpattern/EdgeIdentityController.java

@@ -1,59 +0,0 @@
-package com.example.keycloakpattern;
-
-import java.nio.charset.StandardCharsets;
-import java.security.MessageDigest;
-import java.util.LinkedHashMap;
-import java.util.Map;
-
-import jakarta.servlet.http.HttpServletRequest;
-
-import org.springframework.http.ResponseEntity;
-import org.springframework.beans.factory.annotation.Value;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.RestController;
-
-@RestController
-public class EdgeIdentityController {
-
-    private final byte[] internalAuthToken;
-
-    EdgeIdentityController(@Value("${edge.internal-auth-token}") String internalAuthToken) {
-        if (!hasText(internalAuthToken)) {
-            throw new IllegalStateException("edge.internal-auth-token must be configured");
-        }
-        this.internalAuthToken = internalAuthToken.getBytes(StandardCharsets.UTF_8);
-    }
-
-    @GetMapping("/edge/me")
-    ResponseEntity<Map<String, Object>> currentUser(HttpServletRequest request) {
-        String authRequestUser = request.getHeader("X-Auth-Request-User");
-        if (!hasText(authRequestUser) || !hasValidInternalToken(request)) {
-            return ResponseEntity.status(401).body(Map.of(
-                "error",
-                "trusted edge authentication is required"
-            ));
-        }
-
-        Map<String, Object> response = new LinkedHashMap<>();
-        response.put("pattern", "AP4-edge-forward-auth");
-        response.put("user", authRequestUser);
-        response.put("email", request.getHeader("X-Auth-Request-Email"));
-        response.put("identityHeader", "X-Auth-Request-User");
-        return ResponseEntity.ok(response);
-    }
-
-    private boolean hasValidInternalToken(HttpServletRequest request) {
-        String suppliedToken = request.getHeader("X-Internal-Auth-Token");
-        if (!hasText(suppliedToken)) {
-            return false;
-        }
-        return MessageDigest.isEqual(
-            internalAuthToken,
-            suppliedToken.getBytes(StandardCharsets.UTF_8)
-        );
-    }
-
-    private static boolean hasText(String value) {
-        return value != null && !value.isBlank();
-    }
-}

backend/src/main/java/com/example/keycloakpattern/JwtDecoderConfig.java

@@ -0,0 +1,31 @@
+package com.example.keycloakpattern;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.security.oauth2.core.DelegatingOAuth2TokenValidator;
+import org.springframework.security.oauth2.core.OAuth2TokenValidator;
+import org.springframework.security.oauth2.jwt.Jwt;
+import org.springframework.security.oauth2.jwt.JwtDecoder;
+import org.springframework.security.oauth2.jwt.JwtValidators;
+import org.springframework.security.oauth2.jwt.NimbusJwtDecoder;
+
+@Configuration
+public class JwtDecoderConfig {
+
+    @Bean
+    JwtDecoder jwtDecoder(
+        @Value("${spring.security.oauth2.resourceserver.jwt.issuer-uri}") String issuer,
+        @Value("${spring.security.oauth2.resourceserver.jwt.jwk-set-uri}") String jwkSetUri,
+        @Value("${security.expected-audience}") String expectedAudience
+    ) {
+        NimbusJwtDecoder decoder = NimbusJwtDecoder.withJwkSetUri(jwkSetUri).build();
+        OAuth2TokenValidator<Jwt> issuerAndTimestamp =
+            JwtValidators.createDefaultWithIssuer(issuer);
+        OAuth2TokenValidator<Jwt> audience = new AudienceValidator(expectedAudience);
+        decoder.setJwtValidator(
+            new DelegatingOAuth2TokenValidator<>(issuerAndTimestamp, audience)
+        );
+        return decoder;
+    }
+}

backend/src/main/java/com/example/keycloakpattern/SecurityConfig.java

@@ -1,11 +1,16 @@
 package com.example.keycloakpattern;
 
+import java.util.List;
+
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.security.config.Customizer;
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
 import org.springframework.security.config.http.SessionCreationPolicy;
 import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.web.cors.CorsConfiguration;
+import org.springframework.web.cors.CorsConfigurationSource;
+import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
 
 @Configuration
 public class SecurityConfig {
@@ -13,20 +18,28 @@ public class SecurityConfig {
     @Bean
     SecurityFilterChain apiSecurity(HttpSecurity http) throws Exception {
         return http
+            .cors(Customizer.withDefaults())
             .csrf(csrf -> csrf.disable())
             .sessionManagement(session ->
                 session.sessionCreationPolicy(SessionCreationPolicy.STATELESS))
             .authorizeHttpRequests(authorize -> authorize
-                .requestMatchers(
+                .requestMatchers("/actuator/health", "/actuator/health/**", "/api/public")
-                    "/actuator/health",
-                    "/actuator/health/**",
-                    "/api/public",
-                    "/edge/**"
-                )
                 .permitAll()
                 .anyRequest()
                 .authenticated())
             .oauth2ResourceServer(oauth2 -> oauth2.jwt(Customizer.withDefaults()))
             .build();
     }
+
+    @Bean
+    CorsConfigurationSource corsConfigurationSource() {
+        CorsConfiguration configuration = new CorsConfiguration();
+        configuration.setAllowedOrigins(List.of("http://localhost:8082"));
+        configuration.setAllowedMethods(List.of("GET", "OPTIONS"));
+        configuration.setAllowedHeaders(List.of("Authorization", "Content-Type"));
+
+        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
+        source.registerCorsConfiguration("/api/**", configuration);
+        return source;
+    }
 }

backend/src/main/resources/application.yml

@@ -1,9 +1,6 @@
 server:
   port: ${SERVER_PORT:8081}
 
-edge:
-  internal-auth-token: ${EDGE_INTERNAL_AUTH_TOKEN:}
-
 spring:
   application:
     name: keycloak-pattern-api
@@ -14,6 +11,9 @@ spring:
           issuer-uri: ${SPRING_SECURITY_OAUTH2_RESOURCESERVER_JWT_ISSUER_URI:http://localhost:8080/realms/keycloak-patterns}
           jwk-set-uri: ${SPRING_SECURITY_OAUTH2_RESOURCESERVER_JWT_JWK_SET_URI:http://localhost:8080/realms/keycloak-patterns/protocol/openid-connect/certs}
 
+security:
+  expected-audience: ${SECURITY_EXPECTED_AUDIENCE:keycloak-pattern-api}
+
 management:
   endpoint:
     health:

backend/src/test/java/com/example/keycloakpattern/ApiSecurityTest.java

@@ -11,7 +11,7 @@ import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMock
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.test.web.servlet.MockMvc;
 
-@SpringBootTest(properties = "edge.internal-auth-token=test-internal-edge-token")
+@SpringBootTest
 @AutoConfigureMockMvc
 class ApiSecurityTest {
 
@@ -40,36 +40,4 @@ class ApiSecurityTest {
             .andExpect(jsonPath("$.subject").value("test-subject"))
             .andExpect(jsonPath("$.username").value("regular-user"));
     }
-
-    @Test
-    void edgeEndpointRejectsMissingTrustedHeaders() throws Exception {
-        mockMvc.perform(get("/edge/me"))
-            .andExpect(status().isUnauthorized());
-    }
-
-    @Test
-    void edgeEndpointRejectsForgedIdentityWithoutInternalToken() throws Exception {
-        mockMvc.perform(get("/edge/me")
-                .header("X-Auth-Request-User", "spoofed-admin"))
-            .andExpect(status().isUnauthorized());
-    }
-
-    @Test
-    void edgeEndpointRejectsWrongInternalToken() throws Exception {
-        mockMvc.perform(get("/edge/me")
-                .header("X-Auth-Request-User", "spoofed-admin")
-                .header("X-Internal-Auth-Token", "wrong-token"))
-            .andExpect(status().isUnauthorized());
-    }
-
-    @Test
-    void edgeEndpointAcceptsIdentityFromTrustedEdge() throws Exception {
-        mockMvc.perform(get("/edge/me")
-                .header("X-Auth-Request-User", "regular-user")
-                .header("X-Auth-Request-Email", "regular-user@example.test")
-                .header("X-Internal-Auth-Token", "test-internal-edge-token"))
-            .andExpect(status().isOk())
-            .andExpect(jsonPath("$.user").value("regular-user"))
-            .andExpect(jsonPath("$.identityHeader").value("X-Auth-Request-User"));
-    }
 }

backend/src/test/java/com/example/keycloakpattern/AudienceValidatorTest.java

@@ -0,0 +1,49 @@
+package com.example.keycloakpattern;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.time.Instant;
+import java.util.List;
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.security.oauth2.core.OAuth2TokenValidatorResult;
+import org.springframework.security.oauth2.jwt.Jwt;
+
+class AudienceValidatorTest {
+
+    private final AudienceValidator validator =
+        new AudienceValidator("keycloak-pattern-api");
+
+    @Test
+    void acceptsRequiredAudience() {
+        OAuth2TokenValidatorResult result = validator.validate(jwtWithAudience(
+            List.of("account", "keycloak-pattern-api")
+        ));
+
+        assertThat(result.hasErrors()).isFalse();
+    }
+
+    @Test
+    void rejectsForeignAudience() {
+        OAuth2TokenValidatorResult result = validator.validate(jwtWithAudience(
+            List.of("another-resource")
+        ));
+
+        assertThat(result.hasErrors()).isTrue();
+        assertThat(result.getErrors())
+            .extracting(error -> error.getErrorCode())
+            .containsExactly("invalid_token");
+    }
+
+    private Jwt jwtWithAudience(List<String> audience) {
+        Instant now = Instant.now();
+        return new Jwt(
+            "test-token",
+            now,
+            now.plusSeconds(300),
+            Map.of("alg", "none"),
+            Map.of("sub", "test-subject", "aud", audience)
+        );
+    }
+}

docker-compose.yml

@@ -71,9 +71,8 @@ services:
       SERVER_PORT: "8081"
       SPRING_SECURITY_OAUTH2_RESOURCESERVER_JWT_ISSUER_URI: http://localhost:8080/realms/keycloak-patterns
       SPRING_SECURITY_OAUTH2_RESOURCESERVER_JWT_JWK_SET_URI: http://keycloak:8080/realms/keycloak-patterns/protocol/openid-connect/certs
-      EDGE_INTERNAL_AUTH_TOKEN: ${INTERNAL_AUTH_TOKEN:?set INTERNAL_AUTH_TOKEN in .env}
+    ports:
-    expose:
+      - "127.0.0.1:8081:8081"
-      - "8081"
     depends_on:
       keycloak:
         condition: service_healthy
@@ -89,55 +88,25 @@ services:
       - keycloak-net
     restart: unless-stopped
 
-  oauth2-proxy:
+  token-mediator:
-    image: quay.io/oauth2-proxy/oauth2-proxy:v7.15.2
+    build:
-    command:
+      context: ./token-mediator
-      - --http-address=0.0.0.0:4180
-      - --provider=keycloak-oidc
-      - --oidc-issuer-url=http://localhost:8080/realms/keycloak-patterns
-      - --skip-oidc-discovery=true
-      - --login-url=http://localhost:8080/realms/keycloak-patterns/protocol/openid-connect/auth
-      - --redeem-url=http://keycloak:8080/realms/keycloak-patterns/protocol/openid-connect/token
-      - --oidc-jwks-url=http://keycloak:8080/realms/keycloak-patterns/protocol/openid-connect/certs
-      - --profile-url=http://keycloak:8080/realms/keycloak-patterns/protocol/openid-connect/userinfo
-      - --validate-url=http://keycloak:8080/realms/keycloak-patterns/protocol/openid-connect/userinfo
-      - --redirect-url=http://localhost:8088/oauth2/callback
-      - --upstream=http://app:8081
-      - --email-domain=*
-      - --scope=openid profile email
-      - --code-challenge-method=S256
-      - --reverse-proxy=true
-      - --trusted-proxy-ip=172.30.40.10/32
-      - --cookie-name=AP4_SESSION
-      - --cookie-secure=false
-      - --cookie-samesite=lax
-      - --cookie-expire=1h
-      - --session-cookie-minimal=true
-      - --skip-provider-button=true
-      - --set-xauthrequest=true
-      - --pass-user-headers=true
-      - --whitelist-domain=localhost:8088
-      - --whitelist-domain=localhost:8080
     environment:
-      OAUTH2_PROXY_CLIENT_ID: edge-proxy
+      SERVER_PORT: "8082"
-      OAUTH2_PROXY_CLIENT_SECRET: ${EDGE_PROXY_CLIENT_SECRET:?set EDGE_PROXY_CLIENT_SECRET in .env}
+      KEYCLOAK_CLIENT_SECRET: ${TOKEN_MEDIATING_CLIENT_SECRET:?set TOKEN_MEDIATING_CLIENT_SECRET in .env}
-      OAUTH2_PROXY_COOKIE_SECRET: ${OAUTH2_PROXY_COOKIE_SECRET:?set OAUTH2_PROXY_COOKIE_SECRET in .env}
+    ports:
-    expose:
+      - "127.0.0.1:8082:8082"
-      - "4180"
     depends_on:
       keycloak:
         condition: service_healthy
-      app:
-        condition: service_healthy
     healthcheck:
       test:
-        - CMD
+        - CMD-SHELL
-        - /bin/oauth2-proxy
+        - wget -q -O - http://127.0.0.1:8082/actuator/health | grep -q '"status":"UP"'
-        - --version
       interval: 10s
       timeout: 5s
-      retries: 3
+      retries: 12
-      start_period: 5s
+      start_period: 20s
     networks:
       - keycloak-net
     restart: unless-stopped
@@ -145,12 +114,10 @@ services:
   nginx:
     build:
       context: ./frontend
-    environment:
-      INTERNAL_AUTH_TOKEN: ${INTERNAL_AUTH_TOKEN:?set INTERNAL_AUTH_TOKEN in .env}
     ports:
       - "127.0.0.1:${NGINX_PORT:-8088}:80"
     depends_on:
-      oauth2-proxy:
+      app:
         condition: service_healthy
     healthcheck:
       test:
@@ -160,8 +127,7 @@ services:
       timeout: 5s
       retries: 12
     networks:
-      keycloak-net:
+      - keycloak-net
-        ipv4_address: 172.30.40.10
     restart: unless-stopped
 
 volumes:
@@ -171,6 +137,3 @@ volumes:
 networks:
   keycloak-net:
     driver: bridge
-    ipam:
-      config:
-        - subnet: 172.30.40.0/24

docs/ap2-token-boundary.md

@@ -0,0 +1,38 @@
+# AP2 · Token-Mediating Backend
+
+## 책임 경계
+
+1. 브라우저는 Spring backend의 `/oauth2/authorization/keycloak`로 로그인을
+   시작합니다.
+2. Keycloak은 authorization code를 Spring callback으로 전달합니다.
+3. confidential client인 Spring backend가 client secret을 사용해 code를
+   교환하고 access/refresh token을 `OAuth2AuthorizedClientService`에
+   보관합니다.
+4. 브라우저가 `/token/access`를 호출하면 backend는 현재 access token,
+   token type, 만료 시각만 `Cache-Control: no-store`로 반환합니다.
+5. 브라우저는 전달받은 access token을 메모리에서만 사용해 Resource
+   Server를 직접 호출합니다.
+
+refresh token은 브라우저 응답, Web Storage, cookie에 전달되지 않습니다.
+access token이 만료되면 `OAuth2AuthorizedClientManager`가 서버에 보관된
+refresh token으로 갱신한 뒤 새 access token만 전달할 수 있습니다.
+
+## 확인할 보안 속성
+
+- Keycloak client는 `client_secret_basic`을 사용하는 confidential client입니다.
+- Resource Server는 서명, issuer, timestamp와 함께
+  `aud=keycloak-pattern-api`를 검증합니다.
+- CORS는 AP2 UI origin인 `http://localhost:8082`의 `GET`만 허용합니다.
+- access-token 응답에는 `refresh_token` 필드가 없고 `no-store`가 적용됩니다.
+- 브라우저 cookie에는 HttpOnly, SameSite=Lax인 `AP2_SESSION` 식별자만
+  저장됩니다. 실제 OAuth token은 session cookie 안에 들어가지 않습니다.
+
+## 실행
+
+```bash
+./scripts/verify-pattern2.sh
+```
+
+검증은 실제 Keycloak 로그인 후 서버 token 보관 여부, access-only 응답의
+필드 집합과 audience, 브라우저의 직접 Resource Server 호출, Web Storage
+비사용을 확인합니다.

docs/ap4-edge-forward-auth.md

@@ -1,70 +0,0 @@
-# AP4 · oauth2-proxy Edge Forward Auth
-
-## 첫 단계: oauth2-proxy 자체 OIDC 흐름
-
-`feature/keycloak-oauth2-proxy-oidc-flow`에서는 oauth2-proxy를
-`http://localhost:4180`에 직접 노출해 구성 요소를 분리해서 확인합니다.
-
-1. `/edge/me` 미인증 요청이 Keycloak로 redirect됩니다.
-2. oauth2-proxy는 confidential `edge-proxy` client와 PKCE S256을 사용합니다.
-3. callback에서 code/token 교환과 ID/access token 검증은 서버끼리
-   수행합니다.
-4. 브라우저에는 HttpOnly `AP4_SESSION` cookie만 남습니다.
-5. oauth2-proxy가 backend 요청에 `X-Forwarded-User`를 붙여 200을 받습니다.
-
-Keycloak이 발급하는 issuer는 브라우저 기준
-`http://localhost:8080/realms/keycloak-patterns`입니다. 컨테이너 내부의
-`localhost`는 oauth2-proxy 자신이므로 discovery endpoint에 도달할 수
-없습니다. 그래서 이 로컬 Compose 구성은 issuer 검증값은 외부 URL로
-유지하되, login URL은 브라우저용 외부 주소, token/JWKS/userinfo는
-`http://keycloak:8080` 내부 주소로 각각 명시합니다.
-
-HTTP 로컬 시연이라 `cookie-secure=false`를 사용합니다. 운영 HTTPS에서는
-반드시 secure cookie로 되돌려야 합니다.
-
-## 다음 단계의 보안 전제
-
-이 첫 feature의 backend는 전달된 사용자 헤더를 신뢰하며 8081도
-loopback에 publish되어 있습니다. 따라서 로컬에서 직접
-`X-Forwarded-User: spoofed-admin`을 보내면 우회가 재현됩니다. 이후
-Nginx `auth_request` 통합을 거쳐 최종 feature에서 backend no-publish와
-내부 shared-secret 검증을 함께 적용합니다.
-
-## 두 번째 단계: Nginx `auth_request`
-
-`feature/keycloak-nginx-auth-request-integration`부터 외부 진입점은
-`http://localhost:8088` Nginx 하나입니다. oauth2-proxy의 4180 포트는
-Compose 네트워크에만 expose됩니다.
-
-- Nginx의 정확 일치 `location = /oauth2/auth`는 `internal`이라 외부에서
-  직접 호출할 수 없습니다.
-- 인증 서브리퀘스트에는 본문을 보내지 않고 `Content-Length`도
-  비웁니다.
-- 일반 브라우저 요청의 401은 `/oauth2/start` 302로 변환합니다.
-- API 요청 `/api/edge`는 redirect하지 않고 JSON 401을 반환합니다.
-- 인증 성공 시 oauth2-proxy의 `X-Auth-Request-User`와 email만 backend로
-  전달합니다.
-
-Nginx 컨테이너 IP를 전용 Compose subnet에서 고정하고 oauth2-proxy의
-trusted proxy를 그 단일 IP로 제한합니다. 다만 이 단계에서는 backend
-8081이 로컬 호스트에 열려 있어 신뢰 헤더를 직접 위조할 수 있습니다.
-그 재현 조건은 마지막 feature에서 제거합니다.
-
-## 마지막 단계: 신뢰 경계와 헤더 스푸핑 방어
-
-`feature/keycloak-header-spoofing-defense`에서는 신뢰 경계를 실제
-네트워크와 application 양쪽에서 강제합니다.
-
-1. backend 8081과 oauth2-proxy 4180은 host에 publish하지 않습니다.
-   브라우저가 접근 가능한 application 포트는 Nginx 8088뿐입니다.
-2. Nginx는 client가 보낸 `X-Auth-Request-User`, email, 내부 토큰을
-   그대로 전달하지 않고 oauth2-proxy 결과와 server-side 토큰으로
-   항상 덮어씁니다.
-3. backend는 `X-Auth-Request-User`와 `X-Internal-Auth-Token`이 모두
-   유효할 때만 edge identity를 받아들이며 token은 constant-time으로
-   비교합니다.
-
-shared token은 방어 심층화 수단입니다. 운영에서는 Secret Manager나
-orchestrator secret으로 주입하고 주기적으로 교체해야 합니다. 서비스
-간 mTLS 또는 service mesh identity를 사용할 수 있다면 단순 shared
-token보다 강한 workload identity로 대체하는 편이 좋습니다.

docs/edge-forwardauth-google-federation.md

@@ -1,26 +0,0 @@
-# AP4 edge forward-auth with Google federation
-
-Google federation은 AP4의 edge contract를 바꾸지 않는다.
-
-```text
-Browser -> nginx -> oauth2-proxy -> Keycloak -> Google
-Browser <- AP4_SESSION <- oauth2-proxy <- Keycloak
-nginx -> trusted identity headers -> upstream app
-```
-
-oauth2-proxy가 신뢰하는 issuer는 Google이 아니라 Keycloak이다. Google ID
-token은 Keycloak broker 경계 안에서 검증되고, oauth2-proxy는 Keycloak
-authorization code/token과 session cookie만 다룬다. upstream 앱도
-broker 여부와 무관하게 동일한 trusted headers를 받는다.
-
-`verify-edge-google-federation.sh`는 mock Google 로그인, confidential
-server-side token 교환(브라우저에 token 요청 없음), 미검증 broker email 거부,
-Keycloak email verification 완료 후 HttpOnly edge cookie와 brokered
-subject/email header를 실제 컨테이너와 브라우저로 검증한다. minimal session의
-`X-Auth-Request-User`는 표시용 username이 아니라 Keycloak의 안정적인 local
-subject UUID이며, 화면 이름이 필요하면 별도 허용 header를 명시한다.
-
-brokered token/claims가 client-side session cookie의 4KB 한계를 넘지 않도록
-oauth2-proxy에는 `session-cookie-minimal=true`를 적용한다. AP4 upstream은
-token forwarding이 아니라 trusted identity headers만 사용하므로 cookie에
-access/refresh/ID token을 보관할 필요가 없다.

docs/edge-forwardauth-no-google.md

@@ -1,20 +0,0 @@
-# AP4 edge forward-auth: local identity profile
-
-nginx의 `auth_request`가 oauth2-proxy `/oauth2/auth`를 호출하고, 미인증
-브라우저만 Keycloak로 redirect한다. oauth2-proxy는 confidential
-`edge-proxy` client로 code를 교환하며 browser에는 HttpOnly session cookie만
-남긴다.
-
-Google이 없어도 이 경계는 완전히 동작한다. 사용자는 Keycloak local
-credential로 로그인하고 upstream 애플리케이션은 OAuth/OIDC를 몰라도 된다.
-
-보안 경계:
-
-- backend와 oauth2-proxy 포트를 host에 publish하지 않는다.
-- 외부에서 받은 identity header를 nginx가 제거·덮어쓴다.
-- backend는 trusted nginx가 주입하는 별도 internal token도 확인한다.
-- 브라우저가 직접 호출한 `/oauth2/auth`는 공개하지 않는다.
-
-`verify-edge-no-google-profile.sh`는 Compose와 nginx 계약을 검사하고,
-`verify-pattern4.sh`는 실제 local-user 브라우저 흐름과 spoofing 방어를
-검증한다.

e2e/package.json

@@ -4,8 +4,7 @@
   "version": "1.0.0",
   "type": "module",
   "scripts": {
-    "test:pattern4": "node pattern4.mjs",
+    "test:pattern2": "node pattern2.mjs"
-    "test:pattern4-google": "node pattern4-google.mjs"
   },
   "devDependencies": {
     "playwright-core": "1.62.0"

e2e/pattern2.mjs

@@ -0,0 +1,115 @@
+import assert from "node:assert/strict";
+import { chromium } from "playwright-core";
+
+const password = process.env.E2E_PASSWORD;
+assert.ok(password, "E2E_PASSWORD must be set");
+
+async function completeKeycloakLogin(page) {
+  for (let attempt = 1; attempt <= 2; attempt += 1) {
+    await page.locator("#username").fill(
+      process.env.E2E_USERNAME ?? "regular-user",
+    );
+    await page.locator("#password").fill(password);
+    await page.locator("#kc-login").click();
+    await page.waitForLoadState("domcontentloaded");
+
+    if (page.url() === "http://localhost:8082/") {
+      return;
+    }
+    if (attempt === 1) {
+      await page.goto(
+        "http://localhost:8082/oauth2/authorization/keycloak",
+      );
+      await page.waitForURL(/localhost:8080/u);
+    }
+  }
+  throw new Error(`Keycloak login did not return to AP2: ${page.url()}`);
+}
+
+const browser = await chromium.launch({
+  executablePath: process.env.CHROME_BIN ?? "/usr/bin/google-chrome",
+  headless: true,
+  args: ["--no-sandbox"],
+});
+
+try {
+  const context = await browser.newContext();
+  const page = await context.newPage();
+
+  await page.goto("http://localhost:8082");
+  await page.locator("#login").click();
+  await page.waitForURL(/localhost:8080/u);
+  await completeKeycloakLogin(page);
+
+  const boundaryResponsePromise = page.waitForResponse((response) =>
+    response.url().endsWith("/token/boundary"),
+  );
+  await page.locator("#inspect").click();
+  const boundaryResponse = await boundaryResponsePromise;
+  assert.equal(boundaryResponse.status(), 200);
+  const boundary = await boundaryResponse.json();
+
+  assert.equal(boundary.accessTokenStored, true);
+  assert.equal(boundary.refreshTokenStored, true);
+  assert.equal(boundary.browserReceivesRefreshToken, false);
+  assert.equal(JSON.stringify(boundary).includes("refresh_token"), false);
+
+  const accessResponsePromise = page.waitForResponse((response) =>
+    response.url().endsWith("/token/access"),
+  );
+  const resourceResponsePromise = page.waitForResponse(
+    (response) =>
+      response.url() === "http://localhost:8081/api/me" &&
+      response.request().method() === "GET",
+  );
+  await page.locator("#call-api").click();
+
+  const accessResponse = await accessResponsePromise;
+  assert.equal(accessResponse.status(), 200);
+  assert.match(accessResponse.headers()["cache-control"], /no-store/u);
+  const accessHandoff = await accessResponse.json();
+  assert.deepEqual(
+    Object.keys(accessHandoff).sort(),
+    ["access_token", "expires_at", "token_type"],
+  );
+  assert.equal(accessHandoff.token_type, "Bearer");
+  assert.equal(typeof accessHandoff.access_token, "string");
+  assert.ok(accessHandoff.access_token.length > 100);
+  assert.equal(JSON.stringify(accessHandoff).includes("refresh_token"), false);
+
+  const [, payload] = accessHandoff.access_token.split(".");
+  const claims = JSON.parse(
+    Buffer.from(payload, "base64url").toString("utf8"),
+  );
+  const audience = Array.isArray(claims.aud) ? claims.aud : [claims.aud];
+  assert.ok(audience.includes("keycloak-pattern-api"));
+
+  const resourceResponse = await resourceResponsePromise;
+  assert.equal(resourceResponse.status(), 200);
+  const resource = await resourceResponse.json();
+  assert.equal(resource.username, "regular-user");
+  assert.ok(resource.audience.includes("keycloak-pattern-api"));
+  await page.locator("#result").getByText('"resourceApiStatus": 200').waitFor();
+
+  const cookies = await context.cookies("http://localhost:8082/");
+  const sessionCookie = cookies.find((cookie) => cookie.name === "AP2_SESSION");
+  assert.ok(sessionCookie);
+  assert.equal(sessionCookie.httpOnly, true);
+  assert.equal(sessionCookie.sameSite, "Lax");
+
+  const storage = await page.evaluate(() => ({
+    localStorage: Object.values(localStorage),
+    sessionStorage: Object.values(sessionStorage),
+  }));
+  assert.equal(JSON.stringify(storage).includes("refresh_token"), false);
+  assert.equal(
+    JSON.stringify(storage).includes(accessHandoff.access_token),
+    false,
+  );
+
+  console.log(
+    "pattern2 verified: server refresh custody, access-only handoff, direct browser resource call",
+  );
+} finally {
+  await browser.close();
+}

e2e/pattern4-google.mjs

@@ -1,99 +0,0 @@
-import assert from "node:assert/strict";
-import { chromium } from "playwright-core";
-
-const password = process.env.MOCK_GOOGLE_USER_PASSWORD;
-const adminUsername = process.env.KC_BOOTSTRAP_ADMIN_USERNAME;
-const adminPassword = process.env.KC_BOOTSTRAP_ADMIN_PASSWORD;
-assert.ok(password && adminUsername && adminPassword);
-
-async function verifyBrokeredEmail() {
-  const tokenResponse = await fetch(
-    "http://localhost:8080/realms/master/protocol/openid-connect/token",
-    {
-      method: "POST",
-      body: new URLSearchParams({
-        client_id: "admin-cli",
-        grant_type: "password",
-        username: adminUsername,
-        password: adminPassword,
-      }),
-    },
-  );
-  assert.equal(tokenResponse.status, 200);
-  const token = (await tokenResponse.json()).access_token;
-  const headers = { Authorization: `Bearer ${token}` };
-  const usersResponse = await fetch(
-    "http://localhost:8080/admin/realms/keycloak-patterns/users"
-      + "?email=broker-new-user%40example.test&exact=true",
-    { headers },
-  );
-  assert.equal(usersResponse.status, 200);
-  const users = await usersResponse.json();
-  assert.equal(users.length, 1);
-  const userResponse = await fetch(
-    `http://localhost:8080/admin/realms/keycloak-patterns/users/${users[0].id}`,
-    { headers },
-  );
-  const user = await userResponse.json();
-  assert.equal(user.emailVerified, false);
-  const updateResponse = await fetch(
-    `http://localhost:8080/admin/realms/keycloak-patterns/users/${user.id}`,
-    {
-      method: "PUT",
-      headers: { ...headers, "Content-Type": "application/json" },
-      body: JSON.stringify({ ...user, emailVerified: true }),
-    },
-  );
-  assert.equal(updateResponse.status, 204);
-}
-
-const browser = await chromium.launch({
-  executablePath: process.env.CHROME_BIN ?? "/usr/bin/google-chrome",
-  headless: true,
-  args: ["--no-sandbox"],
-});
-
-try {
-  const context = await browser.newContext();
-  const page = await context.newPage();
-  const browserRequests = [];
-  page.on("request", (request) => browserRequests.push(request.url()));
-
-  await page.goto("http://localhost:8088/");
-  await page.waitForURL(/localhost:8080/u);
-  await page.locator('a[href*="/broker/mock-google/login"]').click();
-  await page.waitForURL(/\/realms\/mock-google\//u);
-  await page.locator("#username").fill("mock-new-user");
-  await page.locator("#password").fill(password);
-  await page.locator("#kc-login").click();
-  await page.waitForURL(/\/oauth2\/callback/u);
-  assert.match(await page.locator("body").innerText(), /Internal Server Error/u);
-
-  await verifyBrokeredEmail();
-  await page.goto(
-    "http://localhost:8088/oauth2/start"
-      + "?rd=http%3A%2F%2Flocalhost%3A8088%2F",
-  );
-  await page.waitForURL("http://localhost:8088/");
-
-  const identity = JSON.parse(await page.locator("body").innerText());
-  assert.equal(identity.pattern, "AP4-edge-forward-auth");
-  assert.match(identity.user, /^[0-9a-f-]{36}$/u);
-  assert.equal(identity.email, "broker-new-user@example.test");
-  assert.equal(
-    browserRequests.some((url) =>
-      url.includes("/protocol/openid-connect/token"),
-    ),
-    false,
-  );
-
-  const session = (await context.cookies()).find(
-    (cookie) => cookie.name === "AP4_SESSION",
-  );
-  assert.ok(session?.httpOnly);
-  console.log(
-    "AP4 Google federation verified: unverified email rejected, verified identity -> edge session -> trusted headers",
-  );
-} finally {
-  await browser.close();
-}

e2e/pattern4.mjs

@@ -1,138 +0,0 @@
-import assert from "node:assert/strict";
-import { chromium } from "playwright-core";
-
-const password = process.env.E2E_PASSWORD;
-assert.ok(password, "E2E_PASSWORD must be set");
-
-const edgeBaseUrl = "http://localhost:8088";
-const edgeEntryUrl = `${edgeBaseUrl}/`;
-
-async function completeKeycloakLogin(page) {
-  for (let attempt = 1; attempt <= 2; attempt += 1) {
-    await page.locator("#username").fill(
-      process.env.E2E_USERNAME ?? "regular-user",
-    );
-    await page.locator("#password").fill(password);
-    await page.locator("#kc-login").click();
-    await page.waitForLoadState("domcontentloaded");
-
-    if (page.url() === edgeEntryUrl) {
-      return;
-    }
-    if (attempt === 1) {
-      await page.goto(`${edgeBaseUrl}/oauth2/start?rd=${encodeURIComponent(edgeEntryUrl)}`);
-      await page.waitForURL(/localhost:8080/u);
-    }
-  }
-  throw new Error(`Keycloak login did not return to AP4: ${page.url()}`);
-}
-
-const browser = await chromium.launch({
-  executablePath: process.env.CHROME_BIN ?? "/usr/bin/google-chrome",
-  headless: true,
-  args: ["--no-sandbox"],
-});
-
-try {
-  const context = await browser.newContext();
-  const page = await context.newPage();
-  const browserRequests = [];
-  page.on("request", (request) =>
-    browserRequests.push({ method: request.method(), url: request.url() }),
-  );
-
-  const edgeResponsePromise = page.waitForResponse(
-    (response) =>
-      response.url() === edgeEntryUrl &&
-      response.status() === 302,
-  );
-  const authorizationRequestPromise = page.waitForRequest((request) =>
-    request.url().includes(
-      "/protocol/openid-connect/auth?approval_prompt=",
-    ),
-  );
-  await page.goto(edgeEntryUrl);
-  const unauthenticatedEdgeResponse = await edgeResponsePromise;
-  assert.equal(unauthenticatedEdgeResponse.status(), 302);
-
-  const authorizationRequest = await authorizationRequestPromise;
-  const authorizationUrl = new URL(authorizationRequest.url());
-  assert.equal(authorizationUrl.searchParams.get("client_id"), "edge-proxy");
-  assert.equal(authorizationUrl.searchParams.get("code_challenge_method"), "S256");
-  assert.ok(authorizationUrl.searchParams.get("code_challenge"));
-
-  await page.waitForURL(/localhost:8080/u);
-  await completeKeycloakLogin(page);
-  const edgeIdentity = JSON.parse(await page.locator("body").innerText());
-  assert.equal(edgeIdentity.pattern, "AP4-edge-forward-auth");
-  assert.ok(edgeIdentity.user);
-  assert.equal(edgeIdentity.identityHeader, "X-Auth-Request-User");
-
-  const callbackRequest = browserRequests.find(({ url }) =>
-    url.startsWith(`${edgeBaseUrl}/oauth2/callback?`),
-  );
-  assert.ok(callbackRequest);
-  assert.equal(callbackRequest.method, "GET");
-  assert.equal(
-    browserRequests.some(({ url }) =>
-      url.includes("/protocol/openid-connect/token"),
-    ),
-    false,
-    "the confidential token exchange must be server-to-server",
-  );
-
-  const cookies = await context.cookies(edgeEntryUrl);
-  const sessionCookie = cookies.find((cookie) => cookie.name === "AP4_SESSION");
-  assert.ok(sessionCookie);
-  assert.equal(sessionCookie.httpOnly, true);
-  assert.equal(sessionCookie.sameSite, "Lax");
-  assert.equal(sessionCookie.secure, false);
-
-  const storage = await page.evaluate(() => ({
-    localStorage: Object.values(localStorage),
-    sessionStorage: Object.values(sessionStorage),
-    readableCookies: document.cookie,
-  }));
-  assert.deepEqual(storage.localStorage, []);
-  assert.deepEqual(storage.sessionStorage, []);
-  assert.equal(storage.readableCookies.includes("AP4_SESSION"), false);
-
-  const spoofAttempt = await page.evaluate(async () => {
-    const response = await fetch("/", {
-      headers: {
-        "X-Auth-Request-User": "spoofed-admin",
-        "X-Auth-Request-Email": "spoofed-admin@example.test",
-        "X-Internal-Auth-Token": "attacker-controlled-token",
-      },
-    });
-    return { status: response.status, body: await response.json() };
-  });
-  assert.equal(spoofAttempt.status, 200);
-  assert.equal(spoofAttempt.body.user, edgeIdentity.user);
-  assert.notEqual(spoofAttempt.body.user, "spoofed-admin");
-
-  const externalAuthSubrequest = await fetch(`${edgeBaseUrl}/oauth2/auth`);
-  assert.equal(externalAuthSubrequest.status, 404);
-
-  const apiResponse = await fetch(`${edgeBaseUrl}/api/edge`, {
-    redirect: "manual",
-  });
-  assert.equal(apiResponse.status, 401);
-  assert.equal(apiResponse.headers.get("location"), null);
-
-  await assert.rejects(
-    fetch("http://localhost:4180/ping"),
-    "oauth2-proxy must not be published on the host",
-  );
-
-  await assert.rejects(
-    fetch("http://localhost:8081/edge/me"),
-    "backend must not be published on the host",
-  );
-
-  console.log(
-    "pattern4 hardened edge verified: auth_request, no backend publish, spoofed headers overwritten",
-  );
-} finally {
-  await browser.close();
-}

frontend/Dockerfile

@@ -1,4 +1,4 @@
 FROM nginx:1.29-alpine
 
-COPY default.conf.template /etc/nginx/templates/default.conf.template
+COPY nginx.conf /etc/nginx/conf.d/default.conf
 COPY index.html /usr/share/nginx/html/index.html

frontend/default.conf.template

@@ -1,75 +0,0 @@
-server {
-    listen 80;
-    server_name _;
-
-    large_client_header_buffers 4 16k;
-
-    location = /health {
-        access_log off;
-        default_type text/plain;
-        return 200 "ok\n";
-    }
-
-    location = /oauth2/auth {
-        internal;
-        proxy_pass http://oauth2-proxy:4180;
-        proxy_pass_request_body off;
-        proxy_set_header Content-Length "";
-        proxy_set_header X-Original-URL $scheme://$http_host$request_uri;
-        proxy_set_header X-Real-IP $remote_addr;
-        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-        proxy_set_header X-Forwarded-Host $http_host;
-        proxy_set_header X-Forwarded-Proto $scheme;
-        proxy_set_header X-Forwarded-Uri $request_uri;
-    }
-
-    location /oauth2/ {
-        proxy_pass http://oauth2-proxy:4180;
-        proxy_http_version 1.1;
-        proxy_set_header Host $http_host;
-        proxy_set_header X-Real-IP $remote_addr;
-        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-        proxy_set_header X-Forwarded-Host $http_host;
-        proxy_set_header X-Forwarded-Proto $scheme;
-        proxy_set_header X-Auth-Request-Redirect $scheme://$http_host$request_uri;
-    }
-
-    location = /api/edge {
-        auth_request /oauth2/auth;
-        error_page 401 = @api_unauthorized;
-
-        auth_request_set $auth_user $upstream_http_x_auth_request_user;
-        auth_request_set $auth_email $upstream_http_x_auth_request_email;
-        auth_request_set $auth_cookie $upstream_http_set_cookie;
-        add_header Set-Cookie $auth_cookie always;
-
-        proxy_pass http://app:8081/edge/me;
-        proxy_set_header X-Auth-Request-User $auth_user;
-        proxy_set_header X-Auth-Request-Email $auth_email;
-        proxy_set_header X-Internal-Auth-Token "${INTERNAL_AUTH_TOKEN}";
-    }
-
-    location / {
-        auth_request /oauth2/auth;
-        error_page 401 = @oauth2_signin;
-
-        auth_request_set $auth_user $upstream_http_x_auth_request_user;
-        auth_request_set $auth_email $upstream_http_x_auth_request_email;
-        auth_request_set $auth_cookie $upstream_http_set_cookie;
-        add_header Set-Cookie $auth_cookie always;
-
-        proxy_pass http://app:8081/edge/me;
-        proxy_set_header X-Auth-Request-User $auth_user;
-        proxy_set_header X-Auth-Request-Email $auth_email;
-        proxy_set_header X-Internal-Auth-Token "${INTERNAL_AUTH_TOKEN}";
-    }
-
-    location @oauth2_signin {
-        return 302 $scheme://$http_host/oauth2/start?rd=$scheme://$http_host$request_uri;
-    }
-
-    location @api_unauthorized {
-        default_type application/json;
-        return 401 '{"error":"authentication required"}';
-    }
-}

frontend/nginx.conf

@@ -0,0 +1,26 @@
+server {
+    listen 80;
+    server_name _;
+
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location = /health {
+        access_log off;
+        default_type text/plain;
+        return 200 "ok\n";
+    }
+
+    location /api/ {
+        proxy_pass http://app:8081;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+}

keycloak/import/keycloak-patterns-realm.json

@@ -79,7 +79,22 @@
       ],
       "attributes": {
         "post.logout.redirect.uris": "http://localhost:8082/*"
-      }
+      },
+      "protocolMappers": [
+        {
+          "name": "keycloak-pattern-api-audience",
+          "protocol": "openid-connect",
+          "protocolMapper": "oidc-audience-mapper",
+          "consentRequired": false,
+          "config": {
+            "included.custom.audience": "keycloak-pattern-api",
+            "id.token.claim": "false",
+            "access.token.claim": "true",
+            "userinfo.token.claim": "false",
+            "introspection.token.claim": "true"
+          }
+        }
+      ]
     },
     {
       "clientId": "bff-confidential",
@@ -120,11 +135,10 @@
       "serviceAccountsEnabled": false,
       "frontchannelLogout": true,
       "redirectUris": [
-        "http://localhost:8088/oauth2/callback"
+        "http://localhost:4180/oauth2/callback"
       ],
       "webOrigins": [],
       "attributes": {
-        "pkce.code.challenge.method": "S256",
         "post.logout.redirect.uris": "http://localhost:8088/*"
       }
     }

scripts/verify-edge-google-federation.sh

@@ -1,15 +0,0 @@
-#!/usr/bin/env sh
-set -eu
-
-set -a
-. ./.env
-set +a
-
-docker compose down --volumes --remove-orphans
-docker compose up --build -d --wait
-./scripts/set-first-broker-login-mode.sh secure
-npm --prefix e2e ci
-MOCK_GOOGLE_USER_PASSWORD="$MOCK_GOOGLE_USER_PASSWORD" \
-KC_BOOTSTRAP_ADMIN_USERNAME="$KC_BOOTSTRAP_ADMIN_USERNAME" \
-KC_BOOTSTRAP_ADMIN_PASSWORD="$KC_BOOTSTRAP_ADMIN_PASSWORD" \
-  npm --prefix e2e run test:pattern4-google

scripts/verify-edge-no-google-profile.sh

@@ -1,18 +0,0 @@
-#!/usr/bin/env sh
-set -eu
-
-rendered="$(docker compose config --format json)"
-printf '%s\n' "$rendered" | jq -e '
-  (.services["oauth2-proxy"].command | index("--provider=keycloak-oidc") != null)
-  and
-  (.services["oauth2-proxy"].command | index("--code-challenge-method=S256") != null)
-  and
-  (.services.app.ports == null)
-  and
-  (.services["oauth2-proxy"].ports == null)
-' >/dev/null
-
-rg -Fq 'auth_request /oauth2/auth;' frontend/default.conf.template
-rg -Fq 'proxy_set_header X-Auth-Request-User $auth_user;' \
-  frontend/default.conf.template
-echo "AP4 local-identity edge profile verified"

scripts/verify-pattern2.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env sh
+set -eu
+
+if [ ! -f .env ]; then
+  echo "missing .env; copy .env.example and set development values" >&2
+  exit 1
+fi
+
+set -a
+. ./.env
+set +a
+
+docker compose down --volumes --remove-orphans
+docker compose up --build -d --wait
+
+npm --prefix e2e ci
+E2E_USERNAME=regular-user \
+E2E_PASSWORD="$REGULAR_USER_PASSWORD" \
+  npm --prefix e2e run test:pattern2
+
+echo "AP2 confidential client boundary verified"

scripts/verify-pattern4.sh

@@ -1,41 +0,0 @@
-#!/usr/bin/env sh
-set -eu
-
-if [ ! -f .env ]; then
-  echo "missing .env; copy .env.example and set development values" >&2
-  exit 1
-fi
-
-set -a
-. ./.env
-set +a
-
-docker compose down --volumes --remove-orphans
-docker compose up --build -d --wait
-
-docker compose exec -T nginx nginx -V 2>&1 |
-  grep -q -- '--with-http_auth_request_module'
-docker compose exec -T nginx nginx -T 2>&1 |
-  grep -q 'proxy_pass_request_body off'
-
-app_container_id="$(docker compose ps -q app)"
-published_app_port="$(docker inspect "$app_container_id" \
-  --format '{{with (index .NetworkSettings.Ports "8081/tcp")}}{{json .}}{{end}}')"
-if [ -n "$published_app_port" ]; then
-  echo "backend port 8081 must not be published on the host" >&2
-  exit 1
-fi
-
-if docker compose exec -T nginx wget -q -O /dev/null \
-  --header 'X-Auth-Request-User: spoofed-admin' \
-  http://app:8081/edge/me 2>/dev/null; then
-  echo "backend accepted a forged identity without the internal token" >&2
-  exit 1
-fi
-
-npm --prefix e2e ci
-E2E_USERNAME=regular-user \
-E2E_PASSWORD="$REGULAR_USER_PASSWORD" \
-  npm --prefix e2e run test:pattern4
-
-echo "AP4 hardened Nginx auth_request edge flow verified"

token-mediator/.dockerignore

@@ -0,0 +1 @@
+target/

token-mediator/Dockerfile

@@ -0,0 +1,17 @@
+FROM maven:3.9.11-eclipse-temurin-21-alpine AS build
+
+WORKDIR /workspace
+COPY pom.xml .
+RUN mvn --batch-mode dependency:go-offline
+COPY src src
+RUN mvn --batch-mode verify
+
+FROM eclipse-temurin:21-jre-alpine
+
+RUN addgroup -S spring && adduser -S spring -G spring
+WORKDIR /app
+COPY --from=build /workspace/target/keycloak-token-mediator.jar app.jar
+USER spring:spring
+
+EXPOSE 8082
+ENTRYPOINT ["java", "-jar", "/app/app.jar"]

token-mediator/pom.xml

@@ -0,0 +1,58 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.5.16</version>
+        <relativePath/>
+    </parent>
+
+    <groupId>com.example</groupId>
+    <artifactId>keycloak-token-mediator</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>keycloak-token-mediator</name>
+
+    <properties>
+        <java.version>21</java.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-actuator</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-oauth2-client</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>keycloak-token-mediator</finalName>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+</project>

token-mediator/src/main/java/com/example/keycloakpattern/mediator/AccessTokenController.java

@@ -0,0 +1,56 @@
+package com.example.keycloakpattern.mediator;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.http.CacheControl;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.oauth2.client.OAuth2AuthorizeRequest;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClient;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClientManager;
+import org.springframework.security.oauth2.core.OAuth2AccessToken;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.server.ResponseStatusException;
+
+import static org.springframework.http.HttpStatus.UNAUTHORIZED;
+
+@RestController
+public class AccessTokenController {
+
+    private final OAuth2AuthorizedClientManager authorizedClientManager;
+
+    public AccessTokenController(OAuth2AuthorizedClientManager authorizedClientManager) {
+        this.authorizedClientManager = authorizedClientManager;
+    }
+
+    @GetMapping("/token/access")
+    ResponseEntity<Map<String, Object>> accessToken(Authentication authentication) {
+        OAuth2AuthorizeRequest request = OAuth2AuthorizeRequest
+            .withClientRegistrationId("keycloak")
+            .principal(authentication)
+            .build();
+        OAuth2AuthorizedClient client = authorizedClientManager.authorize(request);
+        if (client == null || client.getAccessToken() == null) {
+            throw new ResponseStatusException(
+                UNAUTHORIZED,
+                "No authorized Keycloak client is available"
+            );
+        }
+
+        OAuth2AccessToken token = client.getAccessToken();
+        Map<String, Object> response = new LinkedHashMap<>();
+        response.put("access_token", token.getTokenValue());
+        response.put("token_type", token.getTokenType().getValue());
+        response.put(
+            "expires_at",
+            token.getExpiresAt() == null ? null : token.getExpiresAt().toString()
+        );
+
+        return ResponseEntity.ok()
+            .cacheControl(CacheControl.noStore())
+            .header("Pragma", "no-cache")
+            .body(response);
+    }
+}

token-mediator/src/main/java/com/example/keycloakpattern/mediator/SecurityConfig.java

@@ -0,0 +1,55 @@
+package com.example.keycloakpattern.mediator;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.oauth2.client.AuthorizedClientServiceOAuth2AuthorizedClientManager;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClientManager;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClientProvider;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClientProviderBuilder;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClientService;
+import org.springframework.security.oauth2.client.registration.ClientRegistrationRepository;
+import org.springframework.security.web.SecurityFilterChain;
+
+@Configuration
+public class SecurityConfig {
+
+    @Bean
+    SecurityFilterChain mediatorSecurity(HttpSecurity http) throws Exception {
+        return http
+            .authorizeHttpRequests(authorize -> authorize
+                .requestMatchers(
+                    "/",
+                    "/index.html",
+                    "/app.js",
+                    "/favicon.ico",
+                    "/actuator/health",
+                    "/actuator/health/**"
+                )
+                .permitAll()
+                .anyRequest()
+                .authenticated())
+            .oauth2Login(oauth2 -> oauth2.defaultSuccessUrl("/", true))
+            .build();
+    }
+
+    @Bean
+    OAuth2AuthorizedClientManager authorizedClientManager(
+        ClientRegistrationRepository clientRegistrationRepository,
+        OAuth2AuthorizedClientService authorizedClientService
+    ) {
+        OAuth2AuthorizedClientProvider authorizedClientProvider =
+            OAuth2AuthorizedClientProviderBuilder.builder()
+                .authorizationCode()
+                .refreshToken()
+                .build();
+
+        AuthorizedClientServiceOAuth2AuthorizedClientManager manager =
+            new AuthorizedClientServiceOAuth2AuthorizedClientManager(
+                clientRegistrationRepository,
+                authorizedClientService
+            );
+        manager.setAuthorizedClientProvider(authorizedClientProvider);
+        return manager;
+    }
+}

token-mediator/src/main/java/com/example/keycloakpattern/mediator/TokenBoundaryController.java

@@ -0,0 +1,44 @@
+package com.example.keycloakpattern.mediator;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.springframework.http.CacheControl;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClient;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClientService;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class TokenBoundaryController {
+
+    private final OAuth2AuthorizedClientService authorizedClientService;
+
+    public TokenBoundaryController(
+        OAuth2AuthorizedClientService authorizedClientService
+    ) {
+        this.authorizedClientService = authorizedClientService;
+    }
+
+    @GetMapping("/token/boundary")
+    ResponseEntity<Map<String, Object>> tokenBoundary(Authentication authentication) {
+        OAuth2AuthorizedClient client = authorizedClientService.loadAuthorizedClient(
+            "keycloak",
+            authentication.getName()
+        );
+
+        Map<String, Object> response = new LinkedHashMap<>();
+        response.put("pattern", "AP2-token-mediating-backend");
+        response.put("principal", authentication.getName());
+        response.put("accessTokenStored", client != null && client.getAccessToken() != null);
+        response.put("refreshTokenStored", client != null && client.getRefreshToken() != null);
+        response.put("browserReceivesRefreshToken", false);
+
+        return ResponseEntity.ok()
+            .cacheControl(CacheControl.noStore())
+            .header("Pragma", "no-cache")
+            .body(response);
+    }
+}

token-mediator/src/main/java/com/example/keycloakpattern/mediator/TokenMediatorApplication.java

@@ -0,0 +1,12 @@
+package com.example.keycloakpattern.mediator;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class TokenMediatorApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(TokenMediatorApplication.class, args);
+    }
+}

token-mediator/src/main/resources/application.yml

@@ -0,0 +1,44 @@
+server:
+  port: ${SERVER_PORT:8082}
+  servlet:
+    session:
+      cookie:
+        name: AP2_SESSION
+        http-only: true
+        same-site: lax
+
+spring:
+  application:
+    name: keycloak-token-mediator
+  security:
+    oauth2:
+      client:
+        registration:
+          keycloak:
+            provider: keycloak
+            client-id: token-mediating-confidential
+            client-secret: ${KEYCLOAK_CLIENT_SECRET}
+            client-authentication-method: client_secret_basic
+            authorization-grant-type: authorization_code
+            redirect-uri: "{baseUrl}/login/oauth2/code/{registrationId}"
+            scope:
+              - openid
+              - profile
+              - email
+        provider:
+          keycloak:
+            authorization-uri: http://localhost:8080/realms/keycloak-patterns/protocol/openid-connect/auth
+            token-uri: http://keycloak:8080/realms/keycloak-patterns/protocol/openid-connect/token
+            jwk-set-uri: http://keycloak:8080/realms/keycloak-patterns/protocol/openid-connect/certs
+            user-info-uri: http://keycloak:8080/realms/keycloak-patterns/protocol/openid-connect/userinfo
+            user-name-attribute: preferred_username
+
+management:
+  endpoint:
+    health:
+      probes:
+        enabled: true
+  endpoints:
+    web:
+      exposure:
+        include: health,info

token-mediator/src/main/resources/static/app.js

@@ -0,0 +1,50 @@
+const result = document.querySelector("#result");
+
+function render(value) {
+  result.textContent = JSON.stringify(value, null, 2);
+}
+
+document.querySelector("#login").addEventListener("click", () => {
+  window.location.assign("/oauth2/authorization/keycloak");
+});
+
+document.querySelector("#inspect").addEventListener("click", async () => {
+  const response = await fetch("/token/boundary", {
+    headers: { Accept: "application/json" },
+  });
+  if (response.redirected || response.status === 401) {
+    window.location.assign("/oauth2/authorization/keycloak");
+    return;
+  }
+  render(await response.json());
+});
+
+document.querySelector("#call-api").addEventListener("click", async () => {
+  const tokenResponse = await fetch("/token/access", {
+    headers: { Accept: "application/json" },
+  });
+  if (tokenResponse.redirected || tokenResponse.status === 401) {
+    window.location.assign("/oauth2/authorization/keycloak");
+    return;
+  }
+  if (!tokenResponse.ok) {
+    render({ tokenEndpointStatus: tokenResponse.status });
+    return;
+  }
+
+  const { access_token: accessToken, expires_at: expiresAt } =
+    await tokenResponse.json();
+  const apiResponse = await fetch("http://localhost:8081/api/me", {
+    headers: {
+      Accept: "application/json",
+      Authorization: `Bearer ${accessToken}`,
+    },
+  });
+  render({
+    accessTokenHeldInMemoryOnly: true,
+    refreshTokenReceived: false,
+    accessTokenExpiresAt: expiresAt,
+    resourceApiStatus: apiResponse.status,
+    resource: await apiResponse.json(),
+  });
+});

token-mediator/src/main/resources/static/index.html

@@ -0,0 +1,30 @@
+<!doctype html>
+<html lang="ko">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>AP2 · Token-Mediating Backend</title>
+  <style>
+    :root { color-scheme: light dark; font-family: system-ui, sans-serif; }
+    body { max-width: 52rem; margin: 6vh auto; padding: 0 1.5rem; line-height: 1.6; }
+    button { margin-right: 0.5rem; padding: 0.6rem 0.9rem; cursor: pointer; }
+    pre { min-height: 8rem; padding: 1rem; border-radius: 0.4rem;
+      background: color-mix(in srgb, CanvasText 9%, Canvas); white-space: pre-wrap; }
+  </style>
+</head>
+<body>
+  <main>
+    <h1>AP2 · Token-Mediating Backend</h1>
+    <p>
+      confidential backend가 authorization code를 token으로 교환합니다.
+      refresh token은 서버의 <code>OAuth2AuthorizedClientService</code>에만
+      보관됩니다.
+    </p>
+    <button id="login" type="button">Keycloak 로그인</button>
+    <button id="inspect" type="button">서버 token 경계 확인</button>
+    <button id="call-api" type="button">access token으로 API 직접 호출</button>
+    <pre id="result" aria-live="polite"></pre>
+  </main>
+  <script type="module" src="/app.js"></script>
+</body>
+</html>

token-mediator/src/test/java/com/example/keycloakpattern/mediator/TokenBoundaryControllerTest.java

@@ -0,0 +1,84 @@
+package com.example.keycloakpattern.mediator;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.oidcLogin;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.header;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import java.time.Instant;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.security.oauth2.client.OAuth2AuthorizeRequest;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClient;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClientManager;
+import org.springframework.security.oauth2.client.OAuth2AuthorizedClientService;
+import org.springframework.security.oauth2.core.OAuth2AccessToken;
+import org.springframework.security.oauth2.core.OAuth2RefreshToken;
+import org.springframework.test.context.bean.override.mockito.MockitoBean;
+import org.springframework.test.web.servlet.MockMvc;
+
+@SpringBootTest(properties = "KEYCLOAK_CLIENT_SECRET=test-only-secret")
+@AutoConfigureMockMvc
+class TokenBoundaryControllerTest {
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @MockitoBean
+    private OAuth2AuthorizedClientService authorizedClientService;
+
+    @MockitoBean
+    private OAuth2AuthorizedClientManager authorizedClientManager;
+
+    @Test
+    void reportsServerSideTokensWithoutReturningTheirValues() throws Exception {
+        OAuth2AuthorizedClient client = mock(OAuth2AuthorizedClient.class);
+        when(client.getAccessToken()).thenReturn(mock(OAuth2AccessToken.class));
+        when(client.getRefreshToken()).thenReturn(mock(OAuth2RefreshToken.class));
+        when(authorizedClientService.loadAuthorizedClient("keycloak", "test-subject"))
+            .thenReturn(client);
+
+        mockMvc.perform(get("/token/boundary").with(oidcLogin()
+                .idToken(token -> token.subject("test-subject"))))
+            .andExpect(status().isOk())
+            .andExpect(header().string("Cache-Control", "no-store"))
+            .andExpect(jsonPath("$.accessTokenStored").value(true))
+            .andExpect(jsonPath("$.refreshTokenStored").value(true))
+            .andExpect(jsonPath("$.browserReceivesRefreshToken").value(false))
+            .andExpect(jsonPath("$.access_token").doesNotExist())
+            .andExpect(jsonPath("$.refresh_token").doesNotExist());
+    }
+
+    @Test
+    void handsOffAccessTokenOnlyAndMarksResponseNoStore() throws Exception {
+        Instant issuedAt = Instant.parse("2026-07-25T00:00:00Z");
+        OAuth2AccessToken accessToken = new OAuth2AccessToken(
+            OAuth2AccessToken.TokenType.BEARER,
+            "test-access-token",
+            issuedAt,
+            issuedAt.plusSeconds(300)
+        );
+        OAuth2AuthorizedClient client = mock(OAuth2AuthorizedClient.class);
+        when(client.getAccessToken()).thenReturn(accessToken);
+        when(authorizedClientManager.authorize(any(OAuth2AuthorizeRequest.class)))
+            .thenReturn(client);
+
+        mockMvc.perform(get("/token/access").with(oidcLogin()
+                .idToken(token -> token.subject("test-subject"))))
+            .andExpect(status().isOk())
+            .andExpect(header().string("Cache-Control", "no-store"))
+            .andExpect(header().string("Pragma", "no-cache"))
+            .andExpect(jsonPath("$.length()").value(3))
+            .andExpect(jsonPath("$.access_token").value("test-access-token"))
+            .andExpect(jsonPath("$.token_type").value("Bearer"))
+            .andExpect(jsonPath("$.expires_at").value("2026-07-25T00:05:00Z"))
+            .andExpect(jsonPath("$.refresh_token").doesNotExist());
+    }
+}