Request 서명 시스템 삭제

보안에 큰 도움이 되지 않는다고 판단하여 삭제하였습니다. 판단 근거는 다음과 같습니다.

1. Web Crypto API는 HTTPS 환경에서만 사용할 수 있음
2. 프론트엔드와 백엔드가 하나의 서버에서 제공되므로, 리버스 프록시에 의한 중간자 공격을 받지 않는가에 대한 직관적인 검증이 불가능함
3. 신뢰할 수 없는 리버스 프록시는 애초에 사용하지 않는 것이 맞음

다만 MEK에 대한 서명 등은 그대로 유지됩니다.

src/lib/hooks/callApi.ts

@@ -1,5 +1,3 @@
-import { signRequestBody } from "$lib/modules/crypto";
-
 export const refreshToken = async (fetchInternal = fetch) => {
   return await fetchInternal("/api/auth/refreshToken", { method: "POST" });
 };
@@ -35,20 +33,3 @@ export const callPostApi = async <T>(
     fetchInternal,
   );
 };
-
-export const callSignedPostApi = async <T>(
-  input: RequestInfo,
-  payload: T,
-  signKey: CryptoKey,
-  fetchInternal?: typeof fetch,
-) => {
-  return await callApi(
-    input,
-    {
-      method: "POST",
-      headers: { "Content-Type": "application/json" },
-      body: await signRequestBody(payload, signKey),
-    },
-    fetchInternal,
-  );
-};

src/lib/modules/crypto/rsa.ts

@@ -122,15 +122,6 @@ export const verifySignature = async (
   );
 };
 
-export const signRequestBody = async <T>(requestBody: T, signKey: CryptoKey) => {
-  const dataBuffer = new TextEncoder().encode(JSON.stringify(requestBody));
-  const signature = await signMessage(dataBuffer, signKey);
-  return JSON.stringify({
-    data: requestBody,
-    signature: encodeToBase64(signature),
-  });
-};
-
 export const signMasterKeyWrapped = async (
   masterKeyVersion: number,
   masterKeyWrapped: string,

src/lib/server/modules/crypto.ts

@@ -1,8 +1,5 @@
-import { error } from "@sveltejs/kit";
 import { constants, randomBytes, createPublicKey, publicEncrypt, verify } from "crypto";
 import { promisify } from "util";
-import { z } from "zod";
-import { getClient } from "$lib/server/db/client";
 
 const makePubKeyToPem = (pubKey: string) =>
   `-----BEGIN PUBLIC KEY-----\n${pubKey}\n-----END PUBLIC KEY-----`;
@@ -37,31 +34,3 @@ export const generateChallenge = async (length: number, encPubKey: string) => {
   const challenge = encryptAsymmetric(answer, encPubKey);
   return { answer, challenge };
 };
-
-export const parseSignedRequest = async <T extends z.ZodTypeAny>(
-  clientId: number,
-  data: unknown,
-  schema: T,
-) => {
-  const zodRes = z
-    .object({
-      data: schema,
-      signature: z.string().base64().nonempty(),
-    })
-    .safeParse(data);
-  if (!zodRes.success) error(400, "Invalid request body");
-
-  const { data: parsedData, signature } = zodRes.data;
-  if (!parsedData) error(500, "Invalid request body");
-
-  const client = await getClient(clientId);
-  if (!client) {
-    error(500, "Invalid access token");
-  } else if (
-    !verifySignature(Buffer.from(JSON.stringify(parsedData)), signature, client.sigPubKey)
-  ) {
-    error(400, "Invalid signature");
-  }
-
-  return parsedData;
-};

src/lib/server/schemas/file.ts

@@ -20,7 +20,6 @@ export const fileUploadRequest = z.object({
   parentId: z.union([z.enum(["root"]), z.number().int().positive()]),
   mekVersion: z.number().int().positive(),
   dek: z.string().base64().nonempty(),
-  contentHash: z.string().base64().nonempty(),
   contentIv: z.string().base64().nonempty(),
   name: z.string().base64().nonempty(),
   nameIv: z.string().base64().nonempty(),

src/lib/server/services/file.ts

@@ -1,5 +1,4 @@
 import { error } from "@sveltejs/kit";
-import { createHash } from "crypto";
 import { createReadStream, createWriteStream, ReadStream, WriteStream } from "fs";
 import { mkdir, stat, unlink } from "fs/promises";
 import { dirname } from "path";
@@ -106,7 +105,6 @@ const safeUnlink = async (path: string) => {
 export const uploadFile = async (
   params: Omit<NewFileParams, "path">,
   encContentStream: ReadableStream<Uint8Array>,
-  encContentHash: string,
 ) => {
   const activeMekVersion = await getActiveMekVersion(params.userId);
   if (activeMekVersion === null) {
@@ -116,32 +114,12 @@ export const uploadFile = async (
   }
 
   const path = `${env.libraryPath}/${params.userId}/${uuidv4()}`;
-  const hash = createHash("sha256");
-
   await mkdir(dirname(path), { recursive: true });
 
   try {
-    const hashStream = new TransformStream<Uint8Array, Uint8Array>({
-      transform: (chunk, controller) => {
-        hash.update(chunk);
-        controller.enqueue(chunk);
-      },
-    });
-    const fileStream = convertToWritableStream(
-      createWriteStream(path, { flags: "wx", mode: 0o600 }),
+    await encContentStream.pipeTo(
+      convertToWritableStream(createWriteStream(path, { flags: "wx", mode: 0o600 })),
     );
-    await encContentStream.pipeThrough(hashStream).pipeTo(fileStream);
-  } catch (e) {
-    await safeUnlink(path);
-    throw e;
-  }
-
-  if (hash.digest("base64") !== encContentHash) {
-    await safeUnlink(path);
-    error(400, "Invalid content hash");
-  }
-
-  try {
     await registerNewFile({
       ...params,
       path,

src/routes/(fullscreen)/key/export/service.ts

@@ -1,4 +1,4 @@
-import { callSignedPostApi } from "$lib/hooks";
+import { callPostApi } from "$lib/hooks";
 import { storeClientKey } from "$lib/indexedDB";
 import { signMasterKeyWrapped } from "$lib/modules/crypto";
 import type { InitialMasterKeyRegisterRequest } from "$lib/server/schemas";
@@ -46,13 +46,9 @@ export const requestInitialMasterKeyRegistration = async (
   masterKeyWrapped: string,
   signKey: CryptoKey,
 ) => {
-  const res = await callSignedPostApi<InitialMasterKeyRegisterRequest>(
-    "/api/mek/register/initial",
-    {
-      mek: masterKeyWrapped,
-      mekSig: await signMasterKeyWrapped(1, masterKeyWrapped, signKey),
-    },
-    signKey,
-  );
+  const res = await callPostApi<InitialMasterKeyRegisterRequest>("/api/mek/register/initial", {
+    mek: masterKeyWrapped,
+    mekSig: await signMasterKeyWrapped(1, masterKeyWrapped, signKey),
+  });
   return res.ok || res.status === 409;
 };

src/routes/(main)/directory/[[id]]/+page.svelte

@@ -10,7 +10,7 @@
   import { goto } from "$app/navigation";
   import { TopBar } from "$lib/components";
   import { FloatingButton } from "$lib/components/buttons";
-  import { clientKeyStore, masterKeyStore } from "$lib/stores";
+  import { masterKeyStore } from "$lib/stores";
   import CreateBottomSheet from "./CreateBottomSheet.svelte";
   import CreateDirectoryModal from "./CreateDirectoryModal.svelte";
   import DeleteDirectoryEntryModal from "./DeleteDirectoryEntryModal.svelte";
@@ -81,12 +81,7 @@
   });
 
   const createDirectory = async (name: string) => {
-    await requestDirectroyCreation(
-      name,
-      data.id,
-      $masterKeyStore?.get(1)!,
-      $clientKeyStore?.signKey!,
-    );
+    await requestDirectroyCreation(name, data.id, $masterKeyStore?.get(1)!);
     isCreateDirectoryModalOpen = false;
   };
 
@@ -94,7 +89,7 @@
     const file = fileInput?.files?.[0];
     if (!file) return;
 
-    requestFileUpload(file, data.id, $masterKeyStore?.get(1)!, $clientKeyStore?.signKey!);
+    requestFileUpload(file, data.id, $masterKeyStore?.get(1)!);
   };
 </script>
 

src/routes/(main)/directory/[[id]]/service.ts

@@ -1,4 +1,4 @@
-import { callSignedPostApi } from "$lib/hooks";
+import { callPostApi } from "$lib/hooks";
 import {
   encodeToBase64,
   generateDataKey,
@@ -7,8 +7,6 @@ import {
   encryptData,
   encryptString,
   decryptString,
-  digestMessage,
-  signRequestBody,
 } from "$lib/modules/crypto";
 import type {
   DirectroyInfoResponse,
@@ -33,49 +31,38 @@ export const requestDirectroyCreation = async (
   name: string,
   parentId: "root" | number,
   masterKey: MasterKey,
-  signKey: CryptoKey,
 ) => {
   const { dataKey } = await generateDataKey();
   const nameEncrypted = await encryptData(new TextEncoder().encode(name), dataKey);
-  return await callSignedPostApi<DirectoryCreateRequest>(
-    "/api/directory/create",
-    {
-      parentId,
-      mekVersion: masterKey.version,
-      dek: await wrapDataKey(dataKey, masterKey.key),
-      name: encodeToBase64(nameEncrypted.ciphertext),
-      nameIv: nameEncrypted.iv,
-    },
-    signKey,
-  );
+  return await callPostApi<DirectoryCreateRequest>("/api/directory/create", {
+    parentId,
+    mekVersion: masterKey.version,
+    dek: await wrapDataKey(dataKey, masterKey.key),
+    name: encodeToBase64(nameEncrypted.ciphertext),
+    nameIv: nameEncrypted.iv,
+  });
 };
 
 export const requestFileUpload = async (
   file: File,
   parentId: "root" | number,
   masterKey: MasterKey,
-  signKey: CryptoKey,
 ) => {
   const { dataKey } = await generateDataKey();
   const fileEncrypted = await encryptData(await file.arrayBuffer(), dataKey);
-  const fileEncryptedHash = await digestMessage(fileEncrypted.ciphertext);
   const nameEncrypted = await encryptString(file.name, dataKey);
 
   const form = new FormData();
   form.set(
     "metadata",
-    await signRequestBody<FileUploadRequest>(
-      {
-        parentId,
-        mekVersion: masterKey.version,
-        dek: await wrapDataKey(dataKey, masterKey.key),
-        contentHash: encodeToBase64(fileEncryptedHash),
-        contentIv: fileEncrypted.iv,
-        name: nameEncrypted.ciphertext,
-        nameIv: nameEncrypted.iv,
-      },
-      signKey,
-    ),
+    JSON.stringify({
+      parentId,
+      mekVersion: masterKey.version,
+      dek: await wrapDataKey(dataKey, masterKey.key),
+      contentIv: fileEncrypted.iv,
+      name: nameEncrypted.ciphertext,
+      nameIv: nameEncrypted.iv,
+    } satisfies FileUploadRequest),
   );
   form.set("content", new Blob([fileEncrypted.ciphertext]));
 

src/routes/api/directory/[id]/rename/+server.ts

@@ -1,26 +1,24 @@
 import { error, text } from "@sveltejs/kit";
 import { z } from "zod";
 import { authorize } from "$lib/server/modules/auth";
-import { parseSignedRequest } from "$lib/server/modules/crypto";
 import { directoryRenameRequest } from "$lib/server/schemas";
 import { renameDirectory } from "$lib/server/services/directory";
 import type { RequestHandler } from "./$types";
 
 export const POST: RequestHandler = async ({ request, cookies, params }) => {
-  const { userId, clientId } = await authorize(cookies, "activeClient");
+  const { userId } = await authorize(cookies, "activeClient");
 
-  const zodRes = z
+  const paramsZodRes = z
     .object({
       id: z.coerce.number().int().positive(),
     })
     .safeParse(params);
-  if (!zodRes.success) error(400, "Invalid path parameters");
-  const { id } = zodRes.data;
-  const { name, nameIv } = await parseSignedRequest(
-    clientId,
-    await request.json(),
-    directoryRenameRequest,
-  );
+  if (!paramsZodRes.success) error(400, "Invalid path parameters");
+  const { id } = paramsZodRes.data;
+
+  const bodyZodRes = directoryRenameRequest.safeParse(await request.json());
+  if (!bodyZodRes.success) error(400, "Invalid request body");
+  const { name, nameIv } = bodyZodRes.data;
 
   await renameDirectory(userId, id, name, nameIv);
   return text("Directory renamed", { headers: { "Content-Type": "text/plain" } });

src/routes/api/directory/create/+server.ts

@@ -1,17 +1,15 @@
-import { text } from "@sveltejs/kit";
+import { error, text } from "@sveltejs/kit";
 import { authorize } from "$lib/server/modules/auth";
-import { parseSignedRequest } from "$lib/server/modules/crypto";
 import { directoryCreateRequest } from "$lib/server/schemas";
 import { createDirectory } from "$lib/server/services/directory";
 import type { RequestHandler } from "./$types";
 
 export const POST: RequestHandler = async ({ request, cookies }) => {
-  const { userId, clientId } = await authorize(cookies, "activeClient");
-  const { parentId, mekVersion, dek, name, nameIv } = await parseSignedRequest(
-    clientId,
-    await request.json(),
-    directoryCreateRequest,
-  );
+  const { userId } = await authorize(cookies, "activeClient");
+
+  const zodRes = directoryCreateRequest.safeParse(await request.json());
+  if (!zodRes.success) error(400, "Invalid request body");
+  const { parentId, mekVersion, dek, name, nameIv } = zodRes.data;
 
   await createDirectory({
     userId,

src/routes/api/file/[id]/rename/+server.ts

@@ -1,26 +1,24 @@
 import { error, text } from "@sveltejs/kit";
 import { z } from "zod";
 import { authorize } from "$lib/server/modules/auth";
-import { parseSignedRequest } from "$lib/server/modules/crypto";
 import { fileRenameRequest } from "$lib/server/schemas";
 import { renameFile } from "$lib/server/services/file";
 import type { RequestHandler } from "./$types";
 
 export const POST: RequestHandler = async ({ request, cookies, params }) => {
-  const { userId, clientId } = await authorize(cookies, "activeClient");
+  const { userId } = await authorize(cookies, "activeClient");
 
-  const zodRes = z
+  const paramsZodRes = z
     .object({
       id: z.coerce.number().int().positive(),
     })
     .safeParse(params);
-  if (!zodRes.success) error(400, "Invalid path parameters");
-  const { id } = zodRes.data;
-  const { name, nameIv } = await parseSignedRequest(
-    clientId,
-    await request.json(),
-    fileRenameRequest,
-  );
+  if (!paramsZodRes.success) error(400, "Invalid path parameters");
+  const { id } = paramsZodRes.data;
+
+  const bodyZodRes = fileRenameRequest.safeParse(await request.json());
+  if (!bodyZodRes.success) error(400, "Invalid request body");
+  const { name, nameIv } = bodyZodRes.data;
 
   await renameFile(userId, id, name, nameIv);
   return text("File renamed", { headers: { "Content-Type": "text/plain" } });

src/routes/api/file/upload/+server.ts

@@ -1,27 +1,23 @@
 import { error, text } from "@sveltejs/kit";
 import { authorize } from "$lib/server/modules/auth";
-import { parseSignedRequest } from "$lib/server/modules/crypto";
 import { fileUploadRequest } from "$lib/server/schemas";
 import { uploadFile } from "$lib/server/services/file";
 import type { RequestHandler } from "./$types";
 
 export const POST: RequestHandler = async ({ request, cookies }) => {
-  const { userId, clientId } = await authorize(cookies, "activeClient");
+  const { userId } = await authorize(cookies, "activeClient");
 
   const form = await request.formData();
-
   const metadata = form.get("metadata");
-  if (!metadata || typeof metadata !== "string") {
-    error(400, "Invalid request body");
-  }
-  const { parentId, mekVersion, dek, contentHash, contentIv, name, nameIv } =
-    await parseSignedRequest(clientId, JSON.parse(metadata), fileUploadRequest);
-
   const content = form.get("content");
-  if (!content || !(content instanceof File)) {
+  if (typeof metadata !== "string" || !(content instanceof File)) {
     error(400, "Invalid request body");
   }
 
+  const zodRes = fileUploadRequest.safeParse(JSON.parse(metadata));
+  if (!zodRes.success) error(400, "Invalid request body");
+  const { parentId, mekVersion, dek, contentIv, name, nameIv } = zodRes.data;
+
   await uploadFile(
     {
       userId,
@@ -33,7 +29,6 @@ export const POST: RequestHandler = async ({ request, cookies }) => {
       encNameIv: nameIv,
     },
     content.stream(),
-    contentHash,
   );
   return text("File uploaded", { headers: { "Content-Type": "text/plain" } });
 };

src/routes/api/mek/register/initial/+server.ts

@@ -1,6 +1,5 @@
 import { error, text } from "@sveltejs/kit";
 import { authenticate } from "$lib/server/modules/auth";
-import { parseSignedRequest } from "$lib/server/modules/crypto";
 import { initialMasterKeyRegisterRequest } from "$lib/server/schemas";
 import { registerInitialActiveMek } from "$lib/server/services/mek";
 import type { RequestHandler } from "./$types";
@@ -11,11 +10,9 @@ export const POST: RequestHandler = async ({ request, cookies }) => {
     error(403, "Forbidden");
   }
 
-  const { mek, mekSig } = await parseSignedRequest(
-    clientId,
-    await request.json(),
-    initialMasterKeyRegisterRequest,
-  );
+  const zodRes = initialMasterKeyRegisterRequest.safeParse(await request.json());
+  if (!zodRes.success) error(400, "Invalid request body");
+  const { mek, mekSig } = zodRes.data;
 
   await registerInitialActiveMek(userId, clientId, mek, mekSig);
   return text("MEK registered", { headers: { "Content-Type": "text/plain" } });