adding global fee info from exchange

5 files changed, 103 insertions, 2 deletions

diff --git a/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts b/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts
index bfc48d961..98bb6c9cb 100644
--- a/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts
+++ b/packages/taler-wallet-core/src/crypto/cryptoImplementation.ts
@@ -51,6 +51,7 @@ import {
   encryptContractForMerge,
   ExchangeProtocolVersion,
   getRandomBytes,
+  GlobalFees,
   hash,
   HashCodeString,
   hashCoinEv,
@@ -74,6 +75,7 @@ import {
   rsaVerify,
   setupTipPlanchet,
   stringToBytes,
+  TalerProtocolDuration,
   TalerProtocolTimestamp,
   TalerSignaturePurpose,
   UnblindedSignature,
@@ -142,6 +144,10 @@ export interface TalerCryptoInterface {
 
   isValidWireFee(req: WireFeeValidationRequest): Promise<ValidationResult>;
 
+  isValidGlobalFees(
+    req: GlobalFeesValidationRequest,
+  ): Promise<ValidationResult>;
+
   isValidDenom(req: DenominationValidationRequest): Promise<ValidationResult>;
 
   isValidWireAccount(
@@ -152,7 +158,7 @@ export interface TalerCryptoInterface {
     req: ContractTermsValidationRequest,
   ): Promise<ValidationResult>;
 
-  createEddsaKeypair(req: {}): Promise<EddsaKeypair>;
+  createEddsaKeypair(req: unknown): Promise<EddsaKeypair>;
 
   eddsaGetPublic(req: EddsaGetPublicRequest): Promise<EddsaGetPublicResponse>;
 
@@ -283,12 +289,17 @@ export const nullCrypto: TalerCryptoInterface = {
   ): Promise<ValidationResult> {
     throw new Error("Function not implemented.");
   },
+  isValidGlobalFees: function (
+    req: GlobalFeesValidationRequest,
+  ): Promise<ValidationResult> {
+    throw new Error("Function not implemented.");
+  },
   isValidContractTermsSignature: function (
     req: ContractTermsValidationRequest,
   ): Promise<ValidationResult> {
     throw new Error("Function not implemented.");
   },
-  createEddsaKeypair: function (req: {}): Promise<EddsaKeypair> {
+  createEddsaKeypair: function (req: unknown): Promise<EddsaKeypair> {
     throw new Error("Function not implemented.");
   },
   eddsaGetPublic: function (req: EddsaGetPublicRequest): Promise<EddsaKeypair> {
@@ -484,6 +495,11 @@ export interface WireFeeValidationRequest {
   masterPub: string;
 }
 
+export interface GlobalFeesValidationRequest {
+  gf: GlobalFees;
+  masterPub: string;
+}
+
 export interface DenominationValidationRequest {
   denom: DenominationRecord;
   masterPub: string;
@@ -888,6 +904,30 @@ export const nativeCryptoR: TalerCryptoInterfaceR = {
   },
 
   /**
+   * Check if a global fee is correctly signed.
+   */
+  async isValidGlobalFees(
+    tci: TalerCryptoInterfaceR,
+    req: GlobalFeesValidationRequest,
+  ): Promise<ValidationResult> {
+    const { gf, masterPub } = req;
+    const p = buildSigPS(TalerSignaturePurpose.GLOBAL_FEES)
+      .put(timestampRoundedToBuffer(gf.start_date))
+      .put(timestampRoundedToBuffer(gf.end_date))
+      .put(durationRoundedToBuffer(gf.purse_timeout))
+      .put(durationRoundedToBuffer(gf.account_kyc_timeout))
+      .put(durationRoundedToBuffer(gf.history_expiration))
+      .put(amountToBuffer(Amounts.parseOrThrow(gf.history_fee)))
+      .put(amountToBuffer(Amounts.parseOrThrow(gf.kyc_fee)))
+      .put(amountToBuffer(Amounts.parseOrThrow(gf.account_fee)))
+      .put(amountToBuffer(Amounts.parseOrThrow(gf.purse_fee)))
+      .put(bufferForUint32(gf.purse_account_limit))
+      .build();
+    const sig = decodeCrock(gf.master_sig);
+    const pub = decodeCrock(masterPub);
+    return { valid: eddsaVerify(p, sig, pub) };
+  },
+  /**
    * Check if the signature of a denomination is valid.
    */
   async isValidDenom(
@@ -1630,6 +1670,24 @@ function timestampRoundedToBuffer(ts: TalerProtocolTimestamp): Uint8Array {
   return new Uint8Array(b);
 }
 
+function durationRoundedToBuffer(ts: TalerProtocolDuration): Uint8Array {
+  const b = new ArrayBuffer(8);
+  const v = new DataView(b);
+  // The buffer we sign over represents the timestamp in microseconds.
+  if (typeof v.setBigUint64 !== "undefined") {
+    const s = BigInt(ts.d_us);
+    v.setBigUint64(0, s);
+  } else {
+    const s = ts.d_us === "forever" ? bigint.zero : bigint(ts.d_us);
+    const arr = s.toArray(2 ** 8).value;
+    let offset = 8 - arr.length;
+    for (let i = 0; i < arr.length; i++) {
+      v.setUint8(offset++, arr[i]);
+    }
+  }
+  return new Uint8Array(b);
+}
+
 export interface EddsaSignRequest {
   msg: string;
   priv: string;
diff --git a/packages/taler-wallet-core/src/db.ts b/packages/taler-wallet-core/src/db.ts
index ec11f4d47..e266275c1 100644
--- a/packages/taler-wallet-core/src/db.ts
+++ b/packages/taler-wallet-core/src/db.ts
@@ -45,6 +45,7 @@ import {
   Location,
   WireInfo,
   DenominationInfo,
+  GlobalFees,
 } from "@gnu-taler/taler-util";
 import { RetryInfo, RetryTags } from "./util/retries.js";
 import { Event, IDBDatabase } from "@gnu-taler/idb-bridge";
@@ -425,6 +426,10 @@ export interface ExchangeDetailsRecord {
   reserveClosingDelay: TalerProtocolDuration;
 
   /**
+   * Fees for exchange services
+   */
+  globalFees: GlobalFees[];
+  /**
    * Signing keys we got from the exchange, can also contain
    * older signing keys that are not returned by /keys anymore.
    *
diff --git a/packages/taler-wallet-core/src/operations/backup/export.ts b/packages/taler-wallet-core/src/operations/backup/export.ts
index 2e2a1c4b4..f611a2380 100644
--- a/packages/taler-wallet-core/src/operations/backup/export.ts
+++ b/packages/taler-wallet-core/src/operations/backup/export.ts
@@ -345,6 +345,7 @@ export async function exportBackup(
             stamp_expire: x.stamp_expire,
             stamp_start: x.stamp_start,
           })),
+          global_fees: ex.globalFees,
           tos_accepted_etag: ex.termsOfServiceAcceptedEtag,
           tos_accepted_timestamp: ex.termsOfServiceAcceptedTimestamp,
           denominations:
diff --git a/packages/taler-wallet-core/src/operations/backup/import.ts b/packages/taler-wallet-core/src/operations/backup/import.ts
index 3ee3680fe..ee8cb6f6c 100644
--- a/packages/taler-wallet-core/src/operations/backup/import.ts
+++ b/packages/taler-wallet-core/src/operations/backup/import.ts
@@ -405,6 +405,7 @@ export async function importBackup(
             masterPublicKey: backupExchangeDetails.master_public_key,
             protocolVersion: backupExchangeDetails.protocol_version,
             reserveClosingDelay: backupExchangeDetails.reserve_closing_delay,
+            globalFees: backupExchangeDetails.global_fees,
             signingKeys: backupExchangeDetails.signing_keys.map((x) => ({
               key: x.key,
               master_sig: x.master_sig,
diff --git a/packages/taler-wallet-core/src/operations/exchanges.ts b/packages/taler-wallet-core/src/operations/exchanges.ts
index 9a6c72577..a26c14fcc 100644
--- a/packages/taler-wallet-core/src/operations/exchanges.ts
+++ b/packages/taler-wallet-core/src/operations/exchanges.ts
@@ -32,6 +32,7 @@ import {
   ExchangeDenomination,
   ExchangeSignKeyJson,
   ExchangeWireJson,
+  GlobalFees,
   hashDenomPub,
   j2s,
   LibtoolVersion,
@@ -269,6 +270,32 @@ async function validateWireInfo(
   };
 }
 
+async function validateGlobalFees(
+  ws: InternalWalletState,
+  fees: GlobalFees[],
+  masterPub: string,
+): Promise<GlobalFees[]> {
+  for (const gf of fees) {
+    logger.trace("validating exchange global fees");
+    let isValid = false;
+    if (ws.insecureTrustExchange) {
+      isValid = true;
+    } else {
+      const { valid: v } = await ws.cryptoApi.isValidGlobalFees({
+        masterPub,
+        gf,
+      });
+      isValid = v;
+    }
+
+    if (!isValid) {
+      throw Error("exchange global fees signature invalid: " + gf.master_sig);
+    }
+  }
+
+  return fees;
+}
+
 export interface ExchangeInfo {
   wire: ExchangeWireJson;
   keys: ExchangeKeysDownloadResult;
@@ -359,6 +386,7 @@ interface ExchangeKeysDownloadResult {
   expiry: TalerProtocolTimestamp;
   recoup: Recoup[];
   listIssueDate: TalerProtocolTimestamp;
+  globalFees: GlobalFees[];
 }
 
 /**
@@ -432,6 +460,7 @@ async function downloadExchangeKeysInfo(
     ),
     recoup: exchangeKeysJsonUnchecked.recoup ?? [],
     listIssueDate: exchangeKeysJsonUnchecked.list_issue_date,
+    globalFees: exchangeKeysJsonUnchecked.global_fees,
   };
 }
 
@@ -552,6 +581,12 @@ export async function updateExchangeFromUrlHandler(
     keysInfo.masterPublicKey,
   );
 
+  const globalFees = await validateGlobalFees(
+    ws,
+    keysInfo.globalFees,
+    keysInfo.masterPublicKey,
+  );
+
   logger.info("finished validating exchange /wire info");
 
   const tosDownload = await downloadTosFromAcceptedFormat(
@@ -594,6 +629,7 @@ export async function updateExchangeFromUrlHandler(
         protocolVersion: keysInfo.protocolVersion,
         signingKeys: keysInfo.signingKeys,
         reserveClosingDelay: keysInfo.reserveClosingDelay,
+        globalFees,
         exchangeBaseUrl: r.baseUrl,
         wireInfo,
         termsOfServiceText: tosDownload.tosText,