From 458777c5a2e66187cc3a8ac3e4a7557114886a4e Mon Sep 17 00:00:00 2001
From: Florian Dold <florian@dold.me>
Date: Wed, 6 Jan 2021 17:06:19 +0100
Subject: [PATCH] fix tipping planchet derivation

---
 .../src/crypto/talerCrypto.ts                 |  4 ---
 .../crypto/workers/cryptoImplementation.ts    |  6 ++---
 .../taler-wallet-core/src/operations/tip.ts   | 27 ++++++++++++-------
 3 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/packages/taler-wallet-core/src/crypto/talerCrypto.ts b/packages/taler-wallet-core/src/crypto/talerCrypto.ts
index d28f11174..381896858 100644
--- a/packages/taler-wallet-core/src/crypto/talerCrypto.ts
+++ b/packages/taler-wallet-core/src/crypto/talerCrypto.ts
@@ -340,10 +340,6 @@ export function createEcdheKeyPair(): EcdheKeyPair {
   return { ecdhePriv, ecdhePub };
 }
 
-export function createBlindingKeySecret(): Uint8Array {
-  return nacl.randomBytes(32);
-}
-
 export function hash(d: Uint8Array): Uint8Array {
   return nacl.hash(d);
 }
diff --git a/packages/taler-wallet-core/src/crypto/workers/cryptoImplementation.ts b/packages/taler-wallet-core/src/crypto/workers/cryptoImplementation.ts
index fc8b53eb7..9b703e2c8 100644
--- a/packages/taler-wallet-core/src/crypto/workers/cryptoImplementation.ts
+++ b/packages/taler-wallet-core/src/crypto/workers/cryptoImplementation.ts
@@ -48,7 +48,6 @@ import {
   encodeCrock,
   decodeCrock,
   createEddsaKeyPair,
-  createBlindingKeySecret,
   hash,
   rsaBlind,
   eddsaVerify,
@@ -199,12 +198,11 @@ export class CryptoImplementation {
   createTipPlanchet(req: DeriveTipRequest): DerivedTipPlanchet {
     const fc = setupTipPlanchet(decodeCrock(req.secretSeed), req.planchetIndex);
     const denomPub = decodeCrock(req.denomPub);
-    const blindingFactor = createBlindingKeySecret();
     const coinPubHash = hash(fc.coinPub);
-    const ev = rsaBlind(coinPubHash, blindingFactor, denomPub);
+    const ev = rsaBlind(coinPubHash, fc.bks, denomPub);
 
     const tipPlanchet: DerivedTipPlanchet = {
-      blindingKey: encodeCrock(blindingFactor),
+      blindingKey: encodeCrock(fc.bks),
       coinEv: encodeCrock(ev),
       coinEvHash: encodeCrock(hash(ev)),
       coinPriv: encodeCrock(fc.coinPriv),
diff --git a/packages/taler-wallet-core/src/operations/tip.ts b/packages/taler-wallet-core/src/operations/tip.ts
index f683999bc..68b5a2ad0 100644
--- a/packages/taler-wallet-core/src/operations/tip.ts
+++ b/packages/taler-wallet-core/src/operations/tip.ts
@@ -52,7 +52,7 @@ import { checkDbInvariant, checkLogicInvariant } from "../util/invariants";
 import { TalerErrorCode } from "../TalerErrorCode";
 import { initRetryInfo, updateRetryInfoTimeout } from "../util/retries";
 import { j2s } from "../util/helpers";
-import { DerivedTipPlanchet } from '../types/cryptoTypes';
+import { DerivedTipPlanchet } from "../types/cryptoTypes";
 
 const logger = new Logger("operations/tip.ts");
 
@@ -95,11 +95,11 @@ export async function prepareTip(
 
     const walletTipId = encodeCrock(getRandomBytes(32));
     await updateWithdrawalDenoms(ws, tipPickupStatus.exchange_url);
-    const denoms = await getPossibleWithdrawalDenoms(ws, tipPickupStatus.exchange_url);
-    const selectedDenoms = await selectWithdrawalDenominations(
-      amount,
-      denoms
+    const denoms = await getPossibleWithdrawalDenoms(
+      ws,
+      tipPickupStatus.exchange_url,
     );
+    const selectedDenoms = selectWithdrawalDenominations(amount, denoms);
 
     const secretSeed = encodeCrock(getRandomBytes(64));
 
@@ -213,7 +213,7 @@ async function processTipImpl(
   const planchets: DerivedTipPlanchet[] = [];
   // Planchets in the form that the merchant expects
   const planchetsDetail: TipPlanchetDetail[] = [];
-  const denomForPlanchet: { [index: number]: DenominationRecord} = [];
+  const denomForPlanchet: { [index: number]: DenominationRecord } = [];
 
   for (const dh of denomsForWithdraw.selectedDenoms) {
     const denom = await ws.db.get(Stores.denominations, [
@@ -222,11 +222,14 @@ async function processTipImpl(
     ]);
     checkDbInvariant(!!denom, "denomination should be in database");
     for (let i = 0; i < dh.count; i++) {
-      const p = await ws.cryptoApi.createTipPlanchet({
+      const deriveReq = {
         denomPub: denom.denomPub,
         planchetIndex: planchets.length,
         secretSeed: tipRecord.secretSeed,
-      });
+      };
+      logger.trace(`deriving tip planchet: ${j2s(deriveReq)}`)
+      const p = await ws.cryptoApi.createTipPlanchet(deriveReq);
+      logger.trace(`derive result: ${j2s(p)}`);
       denomForPlanchet[planchets.length] = denom;
       planchets.push(p);
       planchetsDetail.push({
@@ -242,14 +245,18 @@ async function processTipImpl(
   );
 
   const req = { planchets: planchetsDetail };
+  logger.trace(`sending tip request: ${j2s(req)}`);
   const merchantResp = await ws.http.postJson(tipStatusUrl.href, req);
 
+  logger.trace(`got tip response, status ${merchantResp.status}`);
+
   // Hide transient errors.
   if (
     tipRecord.retryInfo.retryCounter < 5 &&
-    merchantResp.status >= 500 &&
-    merchantResp.status <= 599
+    ((merchantResp.status >= 500 && merchantResp.status <= 599) ||
+      merchantResp.status === 424)
   ) {
+    logger.trace(`got transient tip error`);
     const err = makeErrorDetails(
       TalerErrorCode.WALLET_UNEXPECTED_REQUEST_ERROR,
       "tip pickup failed (transient)",