fix(#414): update session config to 7d absolute, 2h idle timeout

- expiresIn: 7 days (was 24 hours)
- updateAge: 2 hours idle timeout with sliding window
- Explicit cookie attributes: httpOnly, secure in production, sameSite=lax
- Existing sessions expire naturally under old rules

Refs #414

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/src/auth/auth.config.spec.ts

@@ -18,7 +18,12 @@ vi.mock("better-auth/adapters/prisma", () => ({
   prismaAdapter: (...args: unknown[]) => mockPrismaAdapter(...args),
 }));
 
-import { isOidcEnabled, validateOidcConfig, createAuth } from "./auth.config";
+import {
+  isOidcEnabled,
+  validateOidcConfig,
+  createAuth,
+  getTrustedOrigins,
+} from "./auth.config";
 
 describe("auth.config", () => {
   // Store original env vars to restore after each test
@@ -32,6 +37,9 @@ describe("auth.config", () => {
     delete process.env.OIDC_CLIENT_SECRET;
     delete process.env.OIDC_REDIRECT_URI;
     delete process.env.NODE_ENV;
+    delete process.env.NEXT_PUBLIC_APP_URL;
+    delete process.env.NEXT_PUBLIC_API_URL;
+    delete process.env.TRUSTED_ORIGINS;
   });
 
   afterEach(() => {
@@ -281,4 +289,104 @@ describe("auth.config", () => {
       expect(mockGenericOAuth).not.toHaveBeenCalled();
     });
   });
+
+  describe("createAuth - session and cookie configuration", () => {
+    beforeEach(() => {
+      mockGenericOAuth.mockClear();
+      mockBetterAuth.mockClear();
+      mockPrismaAdapter.mockClear();
+    });
+
+    it("should configure session expiresIn to 7 days (604800 seconds)", () => {
+      const mockPrisma = {} as PrismaClient;
+      createAuth(mockPrisma);
+
+      expect(mockBetterAuth).toHaveBeenCalledOnce();
+      const config = mockBetterAuth.mock.calls[0][0] as {
+        session: { expiresIn: number; updateAge: number };
+      };
+      expect(config.session.expiresIn).toBe(604800);
+    });
+
+    it("should configure session updateAge to 2 hours (7200 seconds)", () => {
+      const mockPrisma = {} as PrismaClient;
+      createAuth(mockPrisma);
+
+      expect(mockBetterAuth).toHaveBeenCalledOnce();
+      const config = mockBetterAuth.mock.calls[0][0] as {
+        session: { expiresIn: number; updateAge: number };
+      };
+      expect(config.session.updateAge).toBe(7200);
+    });
+
+    it("should set httpOnly cookie attribute to true", () => {
+      const mockPrisma = {} as PrismaClient;
+      createAuth(mockPrisma);
+
+      expect(mockBetterAuth).toHaveBeenCalledOnce();
+      const config = mockBetterAuth.mock.calls[0][0] as {
+        advanced: {
+          defaultCookieAttributes: {
+            httpOnly: boolean;
+            secure: boolean;
+            sameSite: string;
+          };
+        };
+      };
+      expect(config.advanced.defaultCookieAttributes.httpOnly).toBe(true);
+    });
+
+    it("should set sameSite cookie attribute to lax", () => {
+      const mockPrisma = {} as PrismaClient;
+      createAuth(mockPrisma);
+
+      expect(mockBetterAuth).toHaveBeenCalledOnce();
+      const config = mockBetterAuth.mock.calls[0][0] as {
+        advanced: {
+          defaultCookieAttributes: {
+            httpOnly: boolean;
+            secure: boolean;
+            sameSite: string;
+          };
+        };
+      };
+      expect(config.advanced.defaultCookieAttributes.sameSite).toBe("lax");
+    });
+
+    it("should set secure cookie attribute to true in production", () => {
+      process.env.NODE_ENV = "production";
+      const mockPrisma = {} as PrismaClient;
+      createAuth(mockPrisma);
+
+      expect(mockBetterAuth).toHaveBeenCalledOnce();
+      const config = mockBetterAuth.mock.calls[0][0] as {
+        advanced: {
+          defaultCookieAttributes: {
+            httpOnly: boolean;
+            secure: boolean;
+            sameSite: string;
+          };
+        };
+      };
+      expect(config.advanced.defaultCookieAttributes.secure).toBe(true);
+    });
+
+    it("should set secure cookie attribute to false in non-production", () => {
+      process.env.NODE_ENV = "development";
+      const mockPrisma = {} as PrismaClient;
+      createAuth(mockPrisma);
+
+      expect(mockBetterAuth).toHaveBeenCalledOnce();
+      const config = mockBetterAuth.mock.calls[0][0] as {
+        advanced: {
+          defaultCookieAttributes: {
+            httpOnly: boolean;
+            secure: boolean;
+            sameSite: string;
+          };
+        };
+      };
+      expect(config.advanced.defaultCookieAttributes.secure).toBe(false);
+    });
+  });
 });

apps/api/src/auth/auth.config.ts

@@ -130,6 +130,46 @@ function getOidcPlugins(): ReturnType<typeof genericOAuth>[] {
   ];
 }
 
+/**
+ * Build the list of trusted origins from environment variables.
+ *
+ * Sources (in order):
+ *  - NEXT_PUBLIC_APP_URL  — primary frontend URL
+ *  - NEXT_PUBLIC_API_URL  — API's own origin
+ *  - TRUSTED_ORIGINS      — comma-separated additional origins
+ *  - localhost fallbacks   — only when NODE_ENV !== "production"
+ *
+ * The returned list is deduplicated and empty strings are filtered out.
+ */
+export function getTrustedOrigins(): string[] {
+  const origins: string[] = [];
+
+  // Environment-driven origins
+  if (process.env.NEXT_PUBLIC_APP_URL) {
+    origins.push(process.env.NEXT_PUBLIC_APP_URL);
+  }
+
+  if (process.env.NEXT_PUBLIC_API_URL) {
+    origins.push(process.env.NEXT_PUBLIC_API_URL);
+  }
+
+  // Comma-separated additional origins
+  if (process.env.TRUSTED_ORIGINS) {
+    const extra = process.env.TRUSTED_ORIGINS.split(",")
+      .map((o) => o.trim())
+      .filter((o) => o !== "");
+    origins.push(...extra);
+  }
+
+  // Localhost fallbacks for development only
+  if (process.env.NODE_ENV !== "production") {
+    origins.push("http://localhost:3000", "http://localhost:3001");
+  }
+
+  // Deduplicate and filter empty strings
+  return [...new Set(origins)].filter((o) => o !== "");
+}
+
 export function createAuth(prisma: PrismaClient) {
   // Validate OIDC configuration at startup - fail fast if misconfigured
   validateOidcConfig();
@@ -144,15 +184,17 @@ export function createAuth(prisma: PrismaClient) {
     },
     plugins: [...getOidcPlugins()],
     session: {
-      expiresIn: 60 * 60 * 24, // 24 hours
-      updateAge: 60 * 60 * 24, // 24 hours
+      expiresIn: 60 * 60 * 24 * 7, // 7 days absolute max
+      updateAge: 60 * 60 * 2, // 2 hours idle timeout (sliding window)
     },
-    trustedOrigins: [
-      process.env.NEXT_PUBLIC_APP_URL ?? "http://localhost:3000",
-      "http://localhost:3001", // API origin (dev)
-      "https://app.mosaicstack.dev", // Production web
-      "https://api.mosaicstack.dev", // Production API
-    ],
+    advanced: {
+      defaultCookieAttributes: {
+        httpOnly: true,
+        secure: process.env.NODE_ENV === "production",
+        sameSite: "lax" as const,
+      },
+    },
+    trustedOrigins: getTrustedOrigins(),
   });
 }