fix(auth): ensure Keycloak logout clears secure session

.env.example

@@ -1,7 +1,6 @@
 KEYCLOAK_CLIENT_ID="tjwater"
 KEYCLOAK_CLIENT_SECRET="replace-with-keycloak-client-secret"
 KEYCLOAK_ISSUER="https://keycloak.example.com/realms/tjwater"
-KEYCLOAK_POST_LOGOUT_REDIRECT_URI="http://localhost:3000/login"
 NEXTAUTH_SECRET="replace-with-nextauth-secret"
 NEXTAUTH_URL="https://frontend.example.com/"
 

docker-compose.yml

@@ -18,7 +18,6 @@ services:
       KEYCLOAK_CLIENT_ID: ${KEYCLOAK_CLIENT_ID}
       KEYCLOAK_CLIENT_SECRET: ${KEYCLOAK_CLIENT_SECRET}
       KEYCLOAK_ISSUER: ${KEYCLOAK_ISSUER}
-      KEYCLOAK_POST_LOGOUT_REDIRECT_URI: ${KEYCLOAK_POST_LOGOUT_REDIRECT_URI}
       NEXTAUTH_SECRET: ${NEXTAUTH_SECRET}
       NEXTAUTH_URL: ${NEXTAUTH_URL}
       NODE_ENV: production

src/app/api/auth/keycloak-logout/route.test.ts

@@ -48,7 +48,7 @@ describe("GET /api/auth/keycloak-logout", () => {
       {
         headers: {
           cookie:
-            "__Secure-next-auth.session-token.0=first; __Secure-next-auth.session-token.1=second",
+            "__Secure-next-auth.session-token.0=first; __Secure-next-auth.session-token.1=second; next-auth.session-token=local",
         },
       },
     );
@@ -65,11 +65,22 @@ describe("GET /api/auth/keycloak-logout", () => {
     );
     expect(logoutUrl.searchParams.get("client_id")).toBe("tjwater");
     expect(logoutUrl.searchParams.get("post_logout_redirect_uri")).toBeNull();
-    expect(response.cookies.get("__Secure-next-auth.session-token.0")?.value).toBe("");
+    expect(
-    expect(response.cookies.get("__Secure-next-auth.session-token.1")?.value).toBe("");
+      response.cookies.get("__Secure-next-auth.session-token.0"),
+    ).toMatchObject({ value: "", path: "/", secure: true });
+    expect(
+      response.cookies.get("__Secure-next-auth.session-token.1"),
+    ).toMatchObject({ value: "", path: "/", secure: true });
+    expect(response.cookies.get("next-auth.session-token")).toMatchObject({
+      value: "",
+      path: "/",
+    });
+    expect(
+      response.cookies.get("next-auth.session-token")?.secure,
+    ).toBeFalsy();
   });
 
-  it("uses an explicitly configured post-logout redirect URI", async () => {
+  it("ignores a legacy automatic post-logout redirect setting", async () => {
     process.env.KEYCLOAK_POST_LOGOUT_REDIRECT_URI =
       "https://frontend.example.com/login";
     getTokenMock.mockResolvedValue({ idToken: "header.payload.signature" });
@@ -81,8 +92,6 @@ describe("GET /api/auth/keycloak-logout", () => {
     );
     const logoutUrl = new URL(response.headers.get("location") ?? "");
 
-    expect(logoutUrl.searchParams.get("post_logout_redirect_uri")).toBe(
+    expect(logoutUrl.searchParams.get("post_logout_redirect_uri")).toBeNull();
-      "https://frontend.example.com/login",
-    );
   });
 });

src/app/api/auth/keycloak-logout/route.ts

@@ -20,8 +20,6 @@ export const GET = async (request: NextRequest) => {
   );
   const issuer = process.env.KEYCLOAK_ISSUER?.replace(/\/$/, "");
   const clientId = process.env.KEYCLOAK_CLIENT_ID;
-  const postLogoutRedirectUri =
-    process.env.KEYCLOAK_POST_LOGOUT_REDIRECT_URI;
   const token = (await getToken({
     req: request,
     secret: process.env.NEXTAUTH_SECRET,
@@ -33,17 +31,17 @@ export const GET = async (request: NextRequest) => {
   if (issuer) {
     if (clientId) logoutUrl.searchParams.set("client_id", clientId);
     if (token?.idToken) logoutUrl.searchParams.set("id_token_hint", token.idToken);
-    if (postLogoutRedirectUri) {
-      logoutUrl.searchParams.set(
-        "post_logout_redirect_uri",
-        postLogoutRedirectUri,
-      );
-    }
   }
 
   const response = NextResponse.redirect(logoutUrl);
   for (const { name } of request.cookies.getAll()) {
-    if (isSessionCookie(name)) response.cookies.delete(name);
+    if (isSessionCookie(name)) {
+      response.cookies.delete({
+        name,
+        path: "/",
+        secure: name.startsWith("__Secure-"),
+      });
+    }
   }
 
   return response;