클라이언트 등록시 검증키도 등록하도록 변경 (WiP)

src/lib/server/db/client.ts

@@ -1,10 +1,21 @@
-import { and, eq, gt, lte } from "drizzle-orm";
+import { and, or, eq, gt, lte, count } from "drizzle-orm";
 import db from "./drizzle";
 import { client, userClient, userClientChallenge } from "./schema";
 
-export const createClient = async (pubKey: string, userId: number) => {
+export const createClient = async (encPubKey: string, sigPubKey: string, userId: number) => {
   return await db.transaction(async (tx) => {
-    const insertRes = await tx.insert(client).values({ pubKey }).returning({ id: client.id });
+    const clients = await tx
+      .select()
+      .from(client)
+      .where(or(eq(client.encPubKey, sigPubKey), eq(client.sigPubKey, encPubKey)));
+    if (clients.length > 0) {
+      throw new Error("Already used public key(s)");
+    }
+
+    const insertRes = await tx
+      .insert(client)
+      .values({ encPubKey, sigPubKey })
+      .returning({ id: client.id });
     const { id: clientId } = insertRes[0]!;
     await tx.insert(userClient).values({ userId, clientId });
 
@@ -12,11 +23,28 @@ export const createClient = async (pubKey: string, userId: number) => {
   });
 };
 
-export const getClientByPubKey = async (pubKey: string) => {
-  const clients = await db.select().from(client).where(eq(client.pubKey, pubKey)).execute();
+export const getClient = async (clientId: number) => {
+  const clients = await db.select().from(client).where(eq(client.id, clientId)).execute();
   return clients[0] ?? null;
 };
 
+export const getClientByPubKeys = async (encPubKey: string, sigPubKey: string) => {
+  const clients = await db
+    .select()
+    .from(client)
+    .where(and(eq(client.encPubKey, encPubKey), eq(client.sigPubKey, sigPubKey)))
+    .execute();
+  return clients[0] ?? null;
+};
+
+export const countClientByPubKey = async (pubKey: string) => {
+  const clients = await db
+    .select({ count: count() })
+    .from(client)
+    .where(or(eq(client.encPubKey, pubKey), eq(client.encPubKey, pubKey)));
+  return clients[0]?.count ?? 0;
+};
+
 export const createUserClient = async (userId: number, clientId: number) => {
   await db.insert(userClient).values({ userId, clientId }).execute();
 };

src/lib/server/db/schema/client.ts

@@ -1,10 +1,17 @@
-import { sqliteTable, text, integer, primaryKey } from "drizzle-orm/sqlite-core";
+import { sqliteTable, text, integer, primaryKey, unique } from "drizzle-orm/sqlite-core";
 import { user } from "./user";
 
-export const client = sqliteTable("client", {
-  id: integer("id").primaryKey(),
-  pubKey: text("public_key").notNull().unique(), // Base64
-});
+export const client = sqliteTable(
+  "client",
+  {
+    id: integer("id").primaryKey(),
+    encPubKey: text("encryption_public_key").notNull().unique(), // Base64
+    sigPubKey: text("signature_public_key").notNull().unique(), // Base64
+  },
+  (t) => ({
+    unq: unique().on(t.encPubKey, t.sigPubKey),
+  }),
+);
 
 export const userClient = sqliteTable(
   "user_client",

src/lib/server/modules/crypto.ts

@@ -0,0 +1,34 @@
+import { constants, randomBytes, createPublicKey, publicEncrypt, verify } from "crypto";
+import { promisify } from "util";
+
+export const generateRandomBytes = async (length: number) => {
+  return await promisify(randomBytes)(length);
+};
+
+const makePubKeyPem = (pubKey: string) =>
+  `-----BEGIN PUBLIC KEY-----\n${pubKey}\n-----END PUBLIC KEY-----`;
+
+export const verifyPubKey = (pubKey: string) => {
+  const pubKeyPem = makePubKeyPem(pubKey);
+  const pubKeyObject = createPublicKey(pubKeyPem);
+  return (
+    pubKeyObject.asymmetricKeyType === "rsa" &&
+    pubKeyObject.asymmetricKeyDetails?.modulusLength === 4096
+  );
+};
+
+export const encryptAsymmetric = (data: Buffer, encPubKey: string) => {
+  return publicEncrypt({ key: makePubKeyPem(encPubKey), oaepHash: "sha256" }, data);
+};
+
+export const verifySignature = (data: string, signature: string, sigPubKey: string) => {
+  return verify(
+    "rsa-sha256",
+    Buffer.from(data, "base64"),
+    {
+      key: makePubKeyPem(sigPubKey),
+      padding: constants.RSA_PKCS1_PSS_PADDING,
+    },
+    Buffer.from(signature, "base64"),
+  );
+};

src/lib/server/services/client.ts

@@ -1,17 +1,23 @@
 import { error } from "@sveltejs/kit";
-import { randomBytes, publicEncrypt, createPublicKey } from "crypto";
 import ms from "ms";
-import { promisify } from "util";
 import {
   createClient,
-  getClientByPubKey,
+  getClient,
+  getClientByPubKeys,
+  countClientByPubKey,
   createUserClient,
   getAllUserClients,
   getUserClient,
+  setUserClientStateToPending,
   createUserClientChallenge,
   getUserClientChallenge,
-  setUserClientStateToPending,
 } from "$lib/server/db/client";
+import {
+  generateRandomBytes,
+  verifyPubKey,
+  encryptAsymmetric,
+  verifySignature,
+} from "$lib/server/modules/crypto";
 import { isInitialMekNeeded } from "$lib/server/modules/mek";
 import env from "$lib/server/loadenv";
 
@@ -28,42 +34,53 @@ export const getUserClientList = async (userId: number) => {
 const expiresIn = ms(env.challenge.pubKeyExp);
 const expiresAt = () => new Date(Date.now() + expiresIn);
 
-const generateChallenge = async (userId: number, ip: string, clientId: number, pubKey: string) => {
-  const answer = await promisify(randomBytes)(32);
+const generateChallenge = async (
+  userId: number,
+  ip: string,
+  clientId: number,
+  encPubKey: string,
+) => {
+  const answer = await generateRandomBytes(32);
   const answerBase64 = answer.toString("base64");
   await createUserClientChallenge(userId, clientId, answerBase64, ip, expiresAt());
 
-  const pubKeyPem = `-----BEGIN PUBLIC KEY-----\n${pubKey}\n-----END PUBLIC KEY-----`;
-  const challenge = publicEncrypt({ key: pubKeyPem, oaepHash: "sha256" }, answer);
+  const challenge = encryptAsymmetric(answer, encPubKey);
   return challenge.toString("base64");
 };
 
-export const registerUserClient = async (userId: number, ip: string, pubKey: string) => {
-  const client = await getClientByPubKey(pubKey);
+export const registerUserClient = async (
+  userId: number,
+  ip: string,
+  encPubKey: string,
+  sigPubKey: string,
+) => {
   let clientId;
 
+  const client = await getClientByPubKeys(encPubKey, sigPubKey);
   if (client) {
     const userClient = await getUserClient(userId, client.id);
     if (userClient) {
-      error(409, "Public key already registered");
+      error(409, "Client already registered");
     }
 
     await createUserClient(userId, client.id);
     clientId = client.id;
   } else {
-    const pubKeyPem = `-----BEGIN PUBLIC KEY-----\n${pubKey}\n-----END PUBLIC KEY-----`;
-    const pubKeyObject = createPublicKey(pubKeyPem);
-    if (
-      pubKeyObject.asymmetricKeyType !== "rsa" ||
-      pubKeyObject.asymmetricKeyDetails?.modulusLength !== 4096
+    if (!verifyPubKey(encPubKey) || !verifyPubKey(sigPubKey)) {
+      error(400, "Invalid public key(s)");
+    } else if (encPubKey === sigPubKey) {
+      error(400, "Public keys must be different");
+    } else if (
+      (await countClientByPubKey(encPubKey)) > 0 ||
+      (await countClientByPubKey(sigPubKey)) > 0
     ) {
-      error(400, "Invalid public key");
+      error(409, "Public key(s) already registered");
     }
 
-    clientId = await createClient(pubKey, userId);
+    clientId = await createClient(encPubKey, sigPubKey, userId);
   }
 
-  return await generateChallenge(userId, ip, clientId, pubKey);
+  return { challenge: await generateChallenge(userId, ip, clientId, encPubKey) };
 };
 
 export const getUserClientStatus = async (userId: number, clientId: number) => {
@@ -78,7 +95,12 @@ export const getUserClientStatus = async (userId: number, clientId: number) => {
   };
 };
 
-export const verifyUserClient = async (userId: number, ip: string, answer: string) => {
+export const verifyUserClient = async (
+  userId: number,
+  ip: string,
+  answer: string,
+  sigAnswer: string,
+) => {
   const challenge = await getUserClientChallenge(answer, ip);
   if (!challenge) {
     error(401, "Invalid challenge answer");
@@ -86,5 +108,12 @@ export const verifyUserClient = async (userId: number, ip: string, answer: strin
     error(403, "Forbidden");
   }
 
+  const client = await getClient(challenge.clientId);
+  if (!client) {
+    error(500, "Invalid challenge answer");
+  } else if (!verifySignature(answer, sigAnswer, client.sigPubKey)) {
+    error(401, "Invalid challenge answer signature");
+  }
+
   await setUserClientStateToPending(userId, challenge.clientId);
 };

src/routes/api/client/register/+server.ts

@@ -12,12 +12,18 @@ export const POST: RequestHandler = async ({ request, cookies, getClientAddress
 
   const zodRes = z
     .object({
-      pubKey: z.string().base64().nonempty(),
+      encPubKey: z.string().base64().nonempty(),
+      sigPubKey: z.string().base64().nonempty(),
     })
     .safeParse(await request.json());
   if (!zodRes.success) error(400, "Invalid request body");
-  const { pubKey } = zodRes.data;
+  const { encPubKey, sigPubKey } = zodRes.data;
 
-  const challenge = await registerUserClient(userId, getClientAddress(), pubKey.trim());
+  const { challenge } = await registerUserClient(
+    userId,
+    getClientAddress(),
+    encPubKey.trim(),
+    sigPubKey.trim(),
+  );
   return json({ challenge });
 };

src/routes/api/client/verify/+server.ts

@@ -13,11 +13,12 @@ export const POST: RequestHandler = async ({ request, cookies, getClientAddress
   const zodRes = z
     .object({
       answer: z.string().base64().nonempty(),
+      sigAnswer: z.string().base64().nonempty(),
     })
     .safeParse(await request.json());
   if (!zodRes.success) error(400, "Invalid request body");
-  const { answer } = zodRes.data;
+  const { answer, sigAnswer } = zodRes.data;
 
-  await verifyUserClient(userId, getClientAddress(), answer.trim());
+  await verifyUserClient(userId, getClientAddress(), answer.trim(), sigAnswer.trim());
   return text("Client verified", { headers: { "Content-Type": "text/plain" } });
 };