/*
This file is part of GNU Taler
(C) 2019 GNUnet e.V.
GNU Taler is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
GNU Taler; see the file COPYING. If not, see
*/
/**
* Imports.
*/
import {
AbsoluteTime,
Amounts,
canonicalizeBaseUrl,
codecForExchangeKeysJson,
codecForExchangeWireJson,
DenominationPubKey,
Duration,
durationFromSpec,
encodeCrock,
ExchangeAuditor,
ExchangeDenomination,
ExchangeSignKeyJson,
ExchangeWireJson,
hashDenomPub,
LibtoolVersion,
Logger,
NotificationType,
parsePaytoUri,
Recoup,
TalerErrorCode,
TalerErrorDetail,
TalerProtocolDuration,
TalerProtocolTimestamp,
URL,
} from "@gnu-taler/taler-util";
import {
DenominationRecord,
DenominationVerificationStatus,
ExchangeDetailsRecord,
ExchangeRecord,
WalletStoresV1,
WireFee,
WireInfo,
} from "../db.js";
import { TalerError } from "../errors.js";
import { InternalWalletState, TrustInfo } from "../internal-wallet-state.js";
import {
getExpiry,
HttpRequestLibrary,
readSuccessResponseJsonOrThrow,
readSuccessResponseTextOrThrow,
} from "../util/http.js";
import { DbAccess, GetReadOnlyAccess } from "../util/query.js";
import { initRetryInfo, updateRetryInfoTimeout } from "../util/retries.js";
import {
WALLET_CACHE_BREAKER_CLIENT_VERSION,
WALLET_EXCHANGE_PROTOCOL_VERSION,
} from "../versions.js";
import { guardOperationException } from "./common.js";
const logger = new Logger("exchanges.ts");
function denominationRecordFromKeys(
exchangeBaseUrl: string,
exchangeMasterPub: string,
listIssueDate: TalerProtocolTimestamp,
denomIn: ExchangeDenomination,
): DenominationRecord {
let denomPub: DenominationPubKey;
denomPub = denomIn.denom_pub;
const denomPubHash = encodeCrock(hashDenomPub(denomPub));
const d: DenominationRecord = {
denomPub,
denomPubHash,
exchangeBaseUrl,
exchangeMasterPub,
feeDeposit: Amounts.parseOrThrow(denomIn.fee_deposit),
feeRefresh: Amounts.parseOrThrow(denomIn.fee_refresh),
feeRefund: Amounts.parseOrThrow(denomIn.fee_refund),
feeWithdraw: Amounts.parseOrThrow(denomIn.fee_withdraw),
isOffered: true,
isRevoked: false,
masterSig: denomIn.master_sig,
stampExpireDeposit: denomIn.stamp_expire_deposit,
stampExpireLegal: denomIn.stamp_expire_legal,
stampExpireWithdraw: denomIn.stamp_expire_withdraw,
stampStart: denomIn.stamp_start,
verificationStatus: DenominationVerificationStatus.Unverified,
value: Amounts.parseOrThrow(denomIn.value),
listIssueDate,
};
return d;
}
async function handleExchangeUpdateError(
ws: InternalWalletState,
baseUrl: string,
err: TalerErrorDetail,
): Promise {
await ws.db
.mktx((x) => ({ exchanges: x.exchanges }))
.runReadWrite(async (tx) => {
const exchange = await tx.exchanges.get(baseUrl);
if (!exchange) {
return;
}
exchange.retryInfo.retryCounter++;
updateRetryInfoTimeout(exchange.retryInfo);
exchange.lastError = err;
await tx.exchanges.put(exchange);
});
if (err) {
ws.notify({ type: NotificationType.ExchangeOperationError, error: err });
}
}
export function getExchangeRequestTimeout(): Duration {
return Duration.fromSpec({
seconds: 5,
});
}
export interface ExchangeTosDownloadResult {
tosText: string;
tosEtag: string;
tosContentType: string;
}
export async function downloadExchangeWithTermsOfService(
exchangeBaseUrl: string,
http: HttpRequestLibrary,
timeout: Duration,
contentType: string,
): Promise {
const reqUrl = new URL("terms", exchangeBaseUrl);
reqUrl.searchParams.set("cacheBreaker", WALLET_CACHE_BREAKER_CLIENT_VERSION);
const headers = {
Accept: contentType,
};
const resp = await http.get(reqUrl.href, {
headers,
timeout,
});
const tosText = await readSuccessResponseTextOrThrow(resp);
const tosEtag = resp.headers.get("etag") || "unknown";
const tosContentType = resp.headers.get("content-type") || "text/plain";
return { tosText, tosEtag, tosContentType };
}
/**
* Get exchange details from the database.
*/
export async function getExchangeDetails(
tx: GetReadOnlyAccess<{
exchanges: typeof WalletStoresV1.exchanges;
exchangeDetails: typeof WalletStoresV1.exchangeDetails;
}>,
exchangeBaseUrl: string,
): Promise {
const r = await tx.exchanges.get(exchangeBaseUrl);
if (!r) {
return;
}
const dp = r.detailsPointer;
if (!dp) {
return;
}
const { currency, masterPublicKey } = dp;
return await tx.exchangeDetails.get([r.baseUrl, currency, masterPublicKey]);
}
getExchangeDetails.makeContext = (db: DbAccess) =>
db.mktx((x) => ({
exchanges: x.exchanges,
exchangeDetails: x.exchangeDetails,
}));
export async function updateExchangeTermsOfService(
ws: InternalWalletState,
exchangeBaseUrl: string,
tos: ExchangeTosDownloadResult,
): Promise {
await ws.db
.mktx((x) => ({
exchanges: x.exchanges,
exchangeDetails: x.exchangeDetails,
}))
.runReadWrite(async (tx) => {
const d = await getExchangeDetails(tx, exchangeBaseUrl);
if (d) {
d.termsOfServiceText = tos.tosText;
d.termsOfServiceContentType = tos.tosContentType;
d.termsOfServiceLastEtag = tos.tosEtag;
await tx.exchangeDetails.put(d);
}
});
}
export async function acceptExchangeTermsOfService(
ws: InternalWalletState,
exchangeBaseUrl: string,
etag: string | undefined,
): Promise {
await ws.db
.mktx((x) => ({
exchanges: x.exchanges,
exchangeDetails: x.exchangeDetails,
}))
.runReadWrite(async (tx) => {
const d = await getExchangeDetails(tx, exchangeBaseUrl);
if (d) {
d.termsOfServiceAcceptedEtag = etag;
await tx.exchangeDetails.put(d);
}
});
}
async function validateWireInfo(
ws: InternalWalletState,
versionCurrent: number,
wireInfo: ExchangeWireJson,
masterPublicKey: string,
): Promise {
for (const a of wireInfo.accounts) {
logger.trace("validating exchange acct");
let isValid = false;
if (ws.insecureTrustExchange) {
isValid = true;
} else {
const { valid: v } = await ws.cryptoApi.isValidWireAccount({
masterPub: masterPublicKey,
paytoUri: a.payto_uri,
sig: a.master_sig,
versionCurrent,
});
isValid = v;
}
if (!isValid) {
throw Error("exchange acct signature invalid");
}
}
const feesForType: { [wireMethod: string]: WireFee[] } = {};
for (const wireMethod of Object.keys(wireInfo.fees)) {
const feeList: WireFee[] = [];
for (const x of wireInfo.fees[wireMethod]) {
const startStamp = x.start_date;
const endStamp = x.end_date;
const fee: WireFee = {
closingFee: Amounts.parseOrThrow(x.closing_fee),
endStamp,
sig: x.sig,
startStamp,
wireFee: Amounts.parseOrThrow(x.wire_fee),
wadFee: Amounts.parseOrThrow(x.wad_fee),
};
let isValid = false;
if (ws.insecureTrustExchange) {
isValid = true;
} else {
const { valid: v } = await ws.cryptoApi.isValidWireFee({
masterPub: masterPublicKey,
type: wireMethod,
wf: fee,
});
isValid = v;
}
if (!isValid) {
throw Error("exchange wire fee signature invalid");
}
feeList.push(fee);
}
feesForType[wireMethod] = feeList;
}
return {
accounts: wireInfo.accounts,
feesForType,
};
}
export interface ExchangeInfo {
wire: ExchangeWireJson;
keys: ExchangeKeysDownloadResult;
}
export async function downloadExchangeInfo(
exchangeBaseUrl: string,
http: HttpRequestLibrary,
): Promise {
const wireInfo = await downloadExchangeWireInfo(
exchangeBaseUrl,
http,
Duration.getForever(),
);
const keysInfo = await downloadExchangeKeysInfo(
exchangeBaseUrl,
http,
Duration.getForever(),
);
return {
keys: keysInfo,
wire: wireInfo,
};
}
/**
* Fetch wire information for an exchange.
*
* @param exchangeBaseUrl Exchange base URL, assumed to be already normalized.
*/
async function downloadExchangeWireInfo(
exchangeBaseUrl: string,
http: HttpRequestLibrary,
timeout: Duration,
): Promise {
const reqUrl = new URL("wire", exchangeBaseUrl);
reqUrl.searchParams.set("cacheBreaker", WALLET_CACHE_BREAKER_CLIENT_VERSION);
const resp = await http.get(reqUrl.href, {
timeout,
});
const wireInfo = await readSuccessResponseJsonOrThrow(
resp,
codecForExchangeWireJson(),
);
return wireInfo;
}
export async function updateExchangeFromUrl(
ws: InternalWalletState,
baseUrl: string,
acceptedFormat?: string[],
forceNow = false,
): Promise<{
exchange: ExchangeRecord;
exchangeDetails: ExchangeDetailsRecord;
}> {
const onOpErr = (e: TalerErrorDetail): Promise =>
handleExchangeUpdateError(ws, baseUrl, e);
return await guardOperationException(
() => updateExchangeFromUrlImpl(ws, baseUrl, acceptedFormat, forceNow),
onOpErr,
);
}
async function provideExchangeRecord(
ws: InternalWalletState,
baseUrl: string,
now: AbsoluteTime,
): Promise<{
exchange: ExchangeRecord;
exchangeDetails: ExchangeDetailsRecord | undefined;
}> {
return await ws.db
.mktx((x) => ({
exchanges: x.exchanges,
exchangeDetails: x.exchangeDetails,
}))
.runReadWrite(async (tx) => {
let exchange = await tx.exchanges.get(baseUrl);
if (!exchange) {
const r: ExchangeRecord = {
permanent: true,
baseUrl: baseUrl,
retryInfo: initRetryInfo(),
detailsPointer: undefined,
lastUpdate: undefined,
nextUpdate: AbsoluteTime.toTimestamp(now),
nextRefreshCheck: AbsoluteTime.toTimestamp(now),
};
await tx.exchanges.put(r);
exchange = r;
}
const exchangeDetails = await getExchangeDetails(tx, baseUrl);
return { exchange, exchangeDetails };
});
}
interface ExchangeKeysDownloadResult {
masterPublicKey: string;
currency: string;
auditors: ExchangeAuditor[];
currentDenominations: DenominationRecord[];
protocolVersion: string;
signingKeys: ExchangeSignKeyJson[];
reserveClosingDelay: TalerProtocolDuration;
expiry: TalerProtocolTimestamp;
recoup: Recoup[];
listIssueDate: TalerProtocolTimestamp;
}
/**
* Download and validate an exchange's /keys data.
*/
async function downloadExchangeKeysInfo(
baseUrl: string,
http: HttpRequestLibrary,
timeout: Duration,
): Promise {
const keysUrl = new URL("keys", baseUrl);
keysUrl.searchParams.set("cacheBreaker", WALLET_CACHE_BREAKER_CLIENT_VERSION);
const resp = await http.get(keysUrl.href, {
timeout,
});
const exchangeKeysJsonUnchecked = await readSuccessResponseJsonOrThrow(
resp,
codecForExchangeKeysJson(),
);
logger.info("received /keys response");
if (exchangeKeysJsonUnchecked.denoms.length === 0) {
throw TalerError.fromDetail(
TalerErrorCode.WALLET_EXCHANGE_DENOMINATIONS_INSUFFICIENT,
{
exchangeBaseUrl: baseUrl,
},
"exchange doesn't offer any denominations",
);
}
const protocolVersion = exchangeKeysJsonUnchecked.version;
const versionRes = LibtoolVersion.compare(
WALLET_EXCHANGE_PROTOCOL_VERSION,
protocolVersion,
);
if (versionRes?.compatible != true) {
throw TalerError.fromDetail(
TalerErrorCode.WALLET_EXCHANGE_PROTOCOL_VERSION_INCOMPATIBLE,
{
exchangeProtocolVersion: protocolVersion,
walletProtocolVersion: WALLET_EXCHANGE_PROTOCOL_VERSION,
},
"exchange protocol version not compatible with wallet",
);
}
const currency = Amounts.parseOrThrow(
exchangeKeysJsonUnchecked.denoms[0].value,
).currency.toUpperCase();
return {
masterPublicKey: exchangeKeysJsonUnchecked.master_public_key,
currency,
auditors: exchangeKeysJsonUnchecked.auditors,
currentDenominations: exchangeKeysJsonUnchecked.denoms.map((d) =>
denominationRecordFromKeys(
baseUrl,
exchangeKeysJsonUnchecked.master_public_key,
exchangeKeysJsonUnchecked.list_issue_date,
d,
),
),
protocolVersion: exchangeKeysJsonUnchecked.version,
signingKeys: exchangeKeysJsonUnchecked.signkeys,
reserveClosingDelay: exchangeKeysJsonUnchecked.reserve_closing_delay,
expiry: AbsoluteTime.toTimestamp(
getExpiry(resp, {
minDuration: durationFromSpec({ hours: 1 }),
}),
),
recoup: exchangeKeysJsonUnchecked.recoup ?? [],
listIssueDate: exchangeKeysJsonUnchecked.list_issue_date,
};
}
export async function downloadTosFromAcceptedFormat(
ws: InternalWalletState,
baseUrl: string,
timeout: Duration,
acceptedFormat?: string[],
): Promise {
let tosFound: ExchangeTosDownloadResult | undefined;
//Remove this when exchange supports multiple content-type in accept header
if (acceptedFormat)
for (const format of acceptedFormat) {
const resp = await downloadExchangeWithTermsOfService(
baseUrl,
ws.http,
timeout,
format,
);
if (resp.tosContentType === format) {
tosFound = resp;
break;
}
}
if (tosFound !== undefined) return tosFound;
// If none of the specified format was found try text/plain
return await downloadExchangeWithTermsOfService(
baseUrl,
ws.http,
timeout,
"text/plain",
);
}
/**
* Update or add exchange DB entry by fetching the /keys and /wire information.
* Optionally link the reserve entry to the new or existing
* exchange entry in then DB.
*/
async function updateExchangeFromUrlImpl(
ws: InternalWalletState,
baseUrl: string,
acceptedFormat?: string[],
forceNow = false,
): Promise<{
exchange: ExchangeRecord;
exchangeDetails: ExchangeDetailsRecord;
}> {
logger.info(`updating exchange info for ${baseUrl}, forced: ${forceNow}`);
const now = AbsoluteTime.now();
baseUrl = canonicalizeBaseUrl(baseUrl);
const { exchange, exchangeDetails } = await provideExchangeRecord(
ws,
baseUrl,
now,
);
if (
!forceNow &&
exchangeDetails !== undefined &&
!AbsoluteTime.isExpired(AbsoluteTime.fromTimestamp(exchange.nextUpdate))
) {
logger.info("using existing exchange info");
return { exchange, exchangeDetails };
}
logger.info("updating exchange /keys info");
const timeout = getExchangeRequestTimeout();
const keysInfo = await downloadExchangeKeysInfo(baseUrl, ws.http, timeout);
logger.info("updating exchange /wire info");
const wireInfoDownload = await downloadExchangeWireInfo(
baseUrl,
ws.http,
timeout,
);
logger.info("validating exchange /wire info");
const version = LibtoolVersion.parseVersion(keysInfo.protocolVersion);
if (!version) {
// Should have been validated earlier.
throw Error("unexpected invalid version");
}
const wireInfo = await validateWireInfo(
ws,
version.current,
wireInfoDownload,
keysInfo.masterPublicKey,
);
logger.info("finished validating exchange /wire info");
const tosDownload = await downloadTosFromAcceptedFormat(
ws,
baseUrl,
timeout,
acceptedFormat,
);
const tosHasBeenAccepted =
exchangeDetails?.termsOfServiceAcceptedEtag === tosDownload.tosEtag;
let recoupGroupId: string | undefined;
logger.trace("updating exchange info in database");
const updated = await ws.db
.mktx((x) => ({
exchanges: x.exchanges,
exchangeDetails: x.exchangeDetails,
denominations: x.denominations,
coins: x.coins,
refreshGroups: x.refreshGroups,
recoupGroups: x.recoupGroups,
}))
.runReadWrite(async (tx) => {
const r = await tx.exchanges.get(baseUrl);
if (!r) {
logger.warn(`exchange ${baseUrl} no longer present`);
return;
}
let details = await getExchangeDetails(tx, r.baseUrl);
if (details) {
// FIXME: We need to do some consistency checks!
}
// FIXME: validate signing keys and merge with old set
details = {
auditors: keysInfo.auditors,
currency: keysInfo.currency,
masterPublicKey: keysInfo.masterPublicKey,
protocolVersion: keysInfo.protocolVersion,
signingKeys: keysInfo.signingKeys,
reserveClosingDelay: keysInfo.reserveClosingDelay,
exchangeBaseUrl: r.baseUrl,
wireInfo,
termsOfServiceText: tosDownload.tosText,
termsOfServiceAcceptedEtag: tosHasBeenAccepted
? tosDownload.tosEtag
: undefined,
termsOfServiceContentType: tosDownload.tosContentType,
termsOfServiceLastEtag: tosDownload.tosEtag,
termsOfServiceAcceptedTimestamp: TalerProtocolTimestamp.now(),
};
// FIXME: only update if pointer got updated
r.lastError = undefined;
r.retryInfo = initRetryInfo();
r.lastUpdate = TalerProtocolTimestamp.now();
r.nextUpdate = keysInfo.expiry;
// New denominations might be available.
r.nextRefreshCheck = TalerProtocolTimestamp.now();
r.detailsPointer = {
currency: details.currency,
masterPublicKey: details.masterPublicKey,
// FIXME: only change if pointer really changed
updateClock: TalerProtocolTimestamp.now(),
protocolVersionRange: keysInfo.protocolVersion,
};
await tx.exchanges.put(r);
await tx.exchangeDetails.put(details);
logger.info("updating denominations in database");
const currentDenomSet = new Set(
keysInfo.currentDenominations.map((x) => x.denomPubHash),
);
for (const currentDenom of keysInfo.currentDenominations) {
const oldDenom = await tx.denominations.get([
baseUrl,
currentDenom.denomPubHash,
]);
if (oldDenom) {
// FIXME: Do consistency check, report to auditor if necessary.
} else {
await tx.denominations.put(currentDenom);
}
}
// Update list issue date for all denominations,
// and mark non-offered denominations as such.
await tx.denominations.indexes.byExchangeBaseUrl
.iter(r.baseUrl)
.forEachAsync(async (x) => {
if (!currentDenomSet.has(x.denomPubHash)) {
// FIXME: Here, an auditor report should be created, unless
// the denomination is really legally expired.
if (x.isOffered) {
x.isOffered = false;
logger.info(
`setting denomination ${x.denomPubHash} to offered=false`,
);
}
} else {
x.listIssueDate = keysInfo.listIssueDate;
if (!x.isOffered) {
x.isOffered = true;
logger.info(
`setting denomination ${x.denomPubHash} to offered=true`,
);
}
}
await tx.denominations.put(x);
});
logger.trace("done updating denominations in database");
// Handle recoup
const recoupDenomList = keysInfo.recoup;
const newlyRevokedCoinPubs: string[] = [];
logger.trace("recoup list from exchange", recoupDenomList);
for (const recoupInfo of recoupDenomList) {
const oldDenom = await tx.denominations.get([
r.baseUrl,
recoupInfo.h_denom_pub,
]);
if (!oldDenom) {
// We never even knew about the revoked denomination, all good.
continue;
}
if (oldDenom.isRevoked) {
// We already marked the denomination as revoked,
// this implies we revoked all coins
logger.trace("denom already revoked");
continue;
}
logger.info("revoking denom", recoupInfo.h_denom_pub);
oldDenom.isRevoked = true;
await tx.denominations.put(oldDenom);
const affectedCoins = await tx.coins.indexes.byDenomPubHash
.iter(recoupInfo.h_denom_pub)
.toArray();
for (const ac of affectedCoins) {
newlyRevokedCoinPubs.push(ac.coinPub);
}
}
if (newlyRevokedCoinPubs.length != 0) {
logger.info("recouping coins", newlyRevokedCoinPubs);
recoupGroupId = await ws.recoupOps.createRecoupGroup(
ws,
tx,
newlyRevokedCoinPubs,
);
}
return {
exchange: r,
exchangeDetails: details,
};
});
if (recoupGroupId) {
// Asynchronously start recoup. This doesn't need to finish
// for the exchange update to be considered finished.
ws.recoupOps.processRecoupGroup(ws, recoupGroupId).catch((e) => {
logger.error("error while recouping coins:", e);
});
}
if (!updated) {
throw Error("something went wrong with updating the exchange");
}
logger.trace("done updating exchange info in database");
ws.notify({
type: NotificationType.ExchangeAdded,
});
return {
exchange: updated.exchange,
exchangeDetails: updated.exchangeDetails,
};
}
export async function getExchangePaytoUri(
ws: InternalWalletState,
exchangeBaseUrl: string,
supportedTargetTypes: string[],
): Promise {
// We do the update here, since the exchange might not even exist
// yet in our database.
const details = await getExchangeDetails
.makeContext(ws.db)
.runReadOnly(async (tx) => {
return getExchangeDetails(tx, exchangeBaseUrl);
});
const accounts = details?.wireInfo.accounts ?? [];
for (const account of accounts) {
const res = parsePaytoUri(account.payto_uri);
if (!res) {
continue;
}
if (supportedTargetTypes.includes(res.targetType)) {
return account.payto_uri;
}
}
throw Error("no matching exchange account found");
}
/**
* Check if and how an exchange is trusted and/or audited.
*/
export async function getExchangeTrust(
ws: InternalWalletState,
exchangeInfo: ExchangeRecord,
): Promise {
let isTrusted = false;
let isAudited = false;
return await ws.db
.mktx((x) => ({
exchanges: x.exchanges,
exchangeDetails: x.exchangeDetails,
exchangesTrustStore: x.exchangeTrust,
auditorTrust: x.auditorTrust,
}))
.runReadOnly(async (tx) => {
const exchangeDetails = await getExchangeDetails(
tx,
exchangeInfo.baseUrl,
);
if (!exchangeDetails) {
throw Error(`exchange ${exchangeInfo.baseUrl} details not available`);
}
const exchangeTrustRecord =
await tx.exchangesTrustStore.indexes.byExchangeMasterPub.get(
exchangeDetails.masterPublicKey,
);
if (
exchangeTrustRecord &&
exchangeTrustRecord.uids.length > 0 &&
exchangeTrustRecord.currency === exchangeDetails.currency
) {
isTrusted = true;
}
for (const auditor of exchangeDetails.auditors) {
const auditorTrustRecord =
await tx.auditorTrust.indexes.byAuditorPub.get(auditor.auditor_pub);
if (auditorTrustRecord && auditorTrustRecord.uids.length > 0) {
isAudited = true;
break;
}
}
return { isTrusted, isAudited };
});
}