From ade3e8a78ed75746a3ae478195ef510a11de1c49 Mon Sep 17 00:00:00 2001
From: alansyue <b123105@gmail.com>
Date: Thu, 13 Aug 2026 23:49:37 +0800
Subject: [PATCH] fix(security): bind platform credential decryption to aad

---
 .../platform-credential-service.test.ts       | 74 ++++++++++++++++++-
 .../src/platform-credential/service.ts        |  6 +-
 packages/encryption/src/encryption.ts         | 13 +++-
 3 files changed, 87 insertions(+), 6 deletions(-)

diff --git a/packages/business/__tests__/platform-credential-service.test.ts b/packages/business/__tests__/platform-credential-service.test.ts
index 4969cb0f0..35beca249 100644
--- a/packages/business/__tests__/platform-credential-service.test.ts
+++ b/packages/business/__tests__/platform-credential-service.test.ts
@@ -9,13 +9,18 @@ vi.mock("@chatbotx.io/database/client", () => ({
   eq: vi.fn(),
   isNull: vi.fn(),
 }))
+const credentialSchemas = {
+  instagram: { name: "instagram-schema" },
+  messenger: { name: "messenger-schema" },
+}
 vi.mock("@chatbotx.io/database/partials", () => ({
-  credentialEncryptedSchema: {},
+  credentialEncryptedSchema: { parse: vi.fn((value: unknown) => value) },
   credentialPublicSchemas: {},
-  credentialSchemas: {},
+  credentialSchemas,
 }))
 vi.mock("@chatbotx.io/database/schema", () => ({ platformCredentialModel: {} }))
-vi.mock("@chatbotx.io/encryption", () => ({ encryptUtils: {} }))
+const encryptUtils = { decryptObject: vi.fn() }
+vi.mock("@chatbotx.io/encryption", () => ({ encryptUtils }))
 vi.mock("@chatbotx.io/redis", () => ({
   invalidateCacheByTags: vi.fn(async () => undefined),
   withCache: vi.fn(async (_key: string, fn: () => unknown) => fn()),
@@ -39,6 +44,7 @@ beforeEach(() => {
 
 afterEach(() => {
   vi.restoreAllMocks()
+  encryptUtils.decryptObject.mockReset()
 })
 
 describe("resolveForOwner", () => {
@@ -196,3 +202,65 @@ describe("resolvePlatformAppAccessToken", () => {
     ).resolves.toBeUndefined()
   })
 })
+
+describe("_decrypt", () => {
+  test("passes platform aad when decrypting a platform-scoped row", async () => {
+    encryptUtils.decryptObject.mockResolvedValue({ clientId: "client-1" })
+
+    await expect(
+      (platformCredentialService as never)._decrypt({
+        id: "platform-1",
+        userId: null,
+        type: "instagram",
+        livemode: false,
+        value: { encrypted: true },
+        publicConfig: { clientId: "client-1" },
+        createdAt: new Date("2026-08-13T00:00:00.000Z"),
+        updatedAt: new Date("2026-08-13T00:00:00.000Z"),
+      }),
+    ).resolves.toEqual(
+      expect.objectContaining({
+        id: "platform-1",
+        userId: null,
+        type: "instagram",
+        config: { clientId: "client-1" },
+      }),
+    )
+
+    expect(encryptUtils.decryptObject).toHaveBeenCalledWith(
+      { encrypted: true },
+      credentialSchemas.instagram,
+      "platform:instagram:false",
+    )
+  })
+
+  test("passes user aad when decrypting a user-scoped row", async () => {
+    encryptUtils.decryptObject.mockResolvedValue({ clientId: "client-2" })
+
+    await expect(
+      (platformCredentialService as never)._decrypt({
+        id: "user-1",
+        userId: "owner-1",
+        type: "messenger",
+        livemode: true,
+        value: { encrypted: true },
+        publicConfig: { clientId: "client-2" },
+        createdAt: new Date("2026-08-13T00:00:00.000Z"),
+        updatedAt: new Date("2026-08-13T00:00:00.000Z"),
+      }),
+    ).resolves.toEqual(
+      expect.objectContaining({
+        id: "user-1",
+        userId: "owner-1",
+        type: "messenger",
+        config: { clientId: "client-2" },
+      }),
+    )
+
+    expect(encryptUtils.decryptObject).toHaveBeenCalledWith(
+      { encrypted: true },
+      credentialSchemas.messenger,
+      "user:owner-1:messenger:true",
+    )
+  })
+})
diff --git a/packages/business/src/platform-credential/service.ts b/packages/business/src/platform-credential/service.ts
index 380a11b28..de37ad59b 100644
--- a/packages/business/src/platform-credential/service.ts
+++ b/packages/business/src/platform-credential/service.ts
@@ -433,7 +433,11 @@ class PlatformCredentialService extends BaseService {
     const schema = credentialSchemas[row.type] as unknown as z.ZodType<
       CredentialByType[T]
     >
-    const config = await encryptUtils.decryptObject(blob, schema)
+    const aad =
+      row.userId === null
+        ? `platform:${row.type}:${row.livemode}`
+        : `user:${row.userId}:${row.type}:${row.livemode}`
+    const config = await encryptUtils.decryptObject(blob, schema, aad)
     return {
       id: row.id,
       userId: row.userId ?? null,
diff --git a/packages/encryption/src/encryption.ts b/packages/encryption/src/encryption.ts
index 9c4cc58a8..a601e44b4 100644
--- a/packages/encryption/src/encryption.ts
+++ b/packages/encryption/src/encryption.ts
@@ -90,6 +90,15 @@ const encode = (text: string): Uint8Array<ArrayBuffer> =>
 const decode = (bytes: Uint8Array<ArrayBuffer>): string =>
   new TextDecoder().decode(bytes)
 
+const assertMatchingAad = (
+  encryptedAad: string | undefined,
+  providedAad: string | undefined,
+): void => {
+  if (encryptedAad !== providedAad) {
+    throw new Error("AAD mismatch.")
+  }
+}
+
 const buildAlgorithm = (
   iv: Uint8Array<ArrayBuffer>,
   aad?: string,
@@ -128,6 +137,7 @@ export const encryptUtils = {
     aad?: string,
   ): Promise<string> => {
     assertCurrentVersion(encryptedData.v)
+    assertMatchingAad(encryptedData.aad, aad)
     const key = await getKey(encryptedData.kid)
     const iv = hexToBytes(encryptedData.iv)
     // Web Crypto expects ciphertext + tag concatenated as a single buffer
@@ -135,9 +145,8 @@ export const encryptUtils = {
       hexToBytes(encryptedData.text),
       hexToBytes(encryptedData.tag),
     )
-    const resolvedAad = encryptedData.aad ?? aad
     const raw = await crypto.subtle.decrypt(
-      buildAlgorithm(iv, resolvedAad),
+      buildAlgorithm(iv, aad),
       key,
       combined,
     )