/*
This file is part of TALER
Copyright (C) 2014-2021 Taler Systems SA
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.
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
TALER; see the file COPYING. If not, see
*/
/**
* @file lib/exchange_api_deposit.c
* @brief Implementation of the /deposit request of the exchange's HTTP API
* @author Sree Harsha Totakura
* @author Christian Grothoff
*/
#include "platform.h"
#include
#include /* just for HTTP status codes */
#include
#include
#include
#include "taler_json_lib.h"
#include "taler_auditor_service.h"
#include "taler_exchange_service.h"
#include "exchange_api_handle.h"
#include "taler_signatures.h"
#include "exchange_api_curl_defaults.h"
/**
* 1:#AUDITOR_CHANCE is the probability that we report deposits
* to the auditor.
*
* 20==5% of going to auditor. This is possibly still too high, but set
* deliberately this high for testing
*/
#define AUDITOR_CHANCE 20
/**
* @brief A Deposit Handle
*/
struct TALER_EXCHANGE_DepositHandle
{
/**
* The connection to exchange this request handle will use
*/
struct TALER_EXCHANGE_Handle *exchange;
/**
* The url for this request.
*/
char *url;
/**
* Context for #TEH_curl_easy_post(). Keeps the data that must
* persist for Curl to make the upload.
*/
struct TALER_CURL_PostContext ctx;
/**
* Handle for the request.
*/
struct GNUNET_CURL_Job *job;
/**
* Function to call with the result.
*/
TALER_EXCHANGE_DepositResultCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Hash over the contract for which this deposit is made.
*/
struct TALER_PrivateContractHash h_contract_terms GNUNET_PACKED;
/**
* Hash over the wiring information of the merchant.
*/
struct TALER_MerchantWireHash h_wire GNUNET_PACKED;
/**
* Hash over the extension options of the deposit, 0 if there
* were not extension options.
*/
struct TALER_ExtensionContractHash h_extensions GNUNET_PACKED;
/**
* Time when this confirmation was generated / when the exchange received
* the deposit request.
*/
struct GNUNET_TIME_Absolute exchange_timestamp;
/**
* By when does the exchange expect to pay the merchant
* (as per the merchant's request).
*/
struct GNUNET_TIME_Absolute wire_deadline;
/**
* How much time does the @e merchant have to issue a refund
* request? Zero if refunds are not allowed. After this time, the
* coin cannot be refunded. Note that the wire transfer will not be
* performed by the exchange until the refund deadline. This value
* is taken from the original deposit request.
*/
struct GNUNET_TIME_Absolute refund_deadline;
/**
* Amount to be deposited, excluding fee. Calculated from the
* amount with fee and the fee from the deposit request.
*/
struct TALER_Amount amount_without_fee;
/**
* The public key of the coin that was deposited.
*/
struct TALER_CoinSpendPublicKeyP coin_pub;
/**
* The Merchant's public key. Allows the merchant to later refund
* the transaction or to inquire about the wire transfer identifier.
*/
struct TALER_MerchantPublicKeyP merchant_pub;
/**
* Exchange signature, set for #auditor_cb.
*/
struct TALER_ExchangeSignatureP exchange_sig;
/**
* Exchange signing public key, set for #auditor_cb.
*/
struct TALER_ExchangePublicKeyP exchange_pub;
/**
* Value of the /deposit transaction, including fee.
*/
struct TALER_Amount amount_with_fee;
/**
* @brief Public information about the coin's denomination key.
* Note that the "key" field itself has been zero'ed out.
*/
struct TALER_EXCHANGE_DenomPublicKey dki;
/**
* Chance that we will inform the auditor about the deposit
* is 1:n, where the value of this field is "n".
*/
unsigned int auditor_chance;
};
/**
* Function called for each auditor to give us a chance to possibly
* launch a deposit confirmation interaction.
*
* @param cls closure
* @param ah handle to the auditor
* @param auditor_pub public key of the auditor
* @return NULL if no deposit confirmation interaction was launched
*/
static struct TEAH_AuditorInteractionEntry *
auditor_cb (void *cls,
struct TALER_AUDITOR_Handle *ah,
const struct TALER_AuditorPublicKeyP *auditor_pub)
{
struct TALER_EXCHANGE_DepositHandle *dh = cls;
const struct TALER_EXCHANGE_Keys *key_state;
const struct TALER_EXCHANGE_SigningPublicKey *spk;
struct TEAH_AuditorInteractionEntry *aie;
if (0 != GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
dh->auditor_chance))
{
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Not providing deposit confirmation to auditor\n");
return NULL;
}
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Will provide deposit confirmation to auditor `%s'\n",
TALER_B2S (auditor_pub));
key_state = TALER_EXCHANGE_get_keys (dh->exchange);
spk = TALER_EXCHANGE_get_signing_key_info (key_state,
&dh->exchange_pub);
if (NULL == spk)
{
GNUNET_break_op (0);
return NULL;
}
aie = GNUNET_new (struct TEAH_AuditorInteractionEntry);
aie->dch = TALER_AUDITOR_deposit_confirmation (
ah,
&dh->h_wire,
&dh->h_extensions,
&dh->h_contract_terms,
dh->exchange_timestamp,
dh->wire_deadline,
dh->refund_deadline,
&dh->amount_without_fee,
&dh->coin_pub,
&dh->merchant_pub,
&dh->exchange_pub,
&dh->exchange_sig,
&key_state->master_pub,
spk->valid_from,
spk->valid_until,
spk->valid_legal,
&spk->master_sig,
&TEAH_acc_confirmation_cb,
aie);
return aie;
}
/**
* Verify that the signatures on the "403 FORBIDDEN" response from the
* exchange demonstrating customer double-spending are valid.
*
* @param dh deposit handle
* @param json json reply with the signature(s) and transaction history
* @return #GNUNET_OK if the signature(s) is valid, #GNUNET_SYSERR if not
*/
static enum GNUNET_GenericReturnValue
verify_deposit_signature_conflict (
const struct TALER_EXCHANGE_DepositHandle *dh,
const json_t *json)
{
json_t *history;
struct TALER_Amount total;
enum TALER_ErrorCode ec;
struct TALER_DenominationHash h_denom_pub;
memset (&h_denom_pub,
0,
sizeof (h_denom_pub));
history = json_object_get (json,
"history");
if (GNUNET_OK !=
TALER_EXCHANGE_verify_coin_history (&dh->dki,
dh->dki.value.currency,
&dh->coin_pub,
history,
&h_denom_pub,
&total))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
ec = TALER_JSON_get_error_code (json);
switch (ec)
{
case TALER_EC_EXCHANGE_DEPOSIT_INSUFFICIENT_FUNDS:
if (0 >
TALER_amount_add (&total,
&total,
&dh->amount_with_fee))
{
/* clearly not OK if our transaction would have caused
the overflow... */
return GNUNET_OK;
}
if (0 >= TALER_amount_cmp (&total,
&dh->dki.value))
{
/* transaction should have still fit */
GNUNET_break (0);
return GNUNET_SYSERR;
}
/* everything OK, proof of double-spending was provided */
return GNUNET_OK;
case TALER_EC_EXCHANGE_GENERIC_COIN_CONFLICTING_DENOMINATION_KEY:
if (0 != GNUNET_memcmp (&dh->dki.h_key,
&h_denom_pub))
return GNUNET_OK; /* indeed, proof with different denomination key provided */
/* invalid proof provided */
return GNUNET_SYSERR;
default:
/* unexpected error code */
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
}
/**
* Function called when we're done processing the
* HTTP /deposit request.
*
* @param cls the `struct TALER_EXCHANGE_DepositHandle`
* @param response_code HTTP response code, 0 on error
* @param response parsed JSON result, NULL on error
*/
static void
handle_deposit_finished (void *cls,
long response_code,
const void *response)
{
struct TALER_EXCHANGE_DepositHandle *dh = cls;
const json_t *j = response;
struct TALER_EXCHANGE_DepositResult dr = {
.hr.reply = j,
.hr.http_status = (unsigned int) response_code
};
dh->job = NULL;
switch (response_code)
{
case 0:
dr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
break;
case MHD_HTTP_OK:
{
const struct TALER_EXCHANGE_Keys *key_state;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_fixed_auto ("exchange_sig",
&dh->exchange_sig),
GNUNET_JSON_spec_fixed_auto ("exchange_pub",
&dh->exchange_pub),
GNUNET_JSON_spec_mark_optional (
GNUNET_JSON_spec_string ("transaction_base_url",
&dr.details.success.transaction_base_url)),
TALER_JSON_spec_absolute_time ("exchange_timestamp",
&dh->exchange_timestamp),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (j,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
key_state = TALER_EXCHANGE_get_keys (dh->exchange);
if (GNUNET_OK !=
TALER_EXCHANGE_test_signing_key (key_state,
&dh->exchange_pub))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_EXCHANGE_DEPOSIT_INVALID_SIGNATURE_BY_EXCHANGE;
break;
}
if (GNUNET_OK !=
TALER_exchange_deposit_confirm_verify (&dh->h_contract_terms,
&dh->h_wire,
&dh->h_extensions,
dh->exchange_timestamp,
dh->wire_deadline,
dh->refund_deadline,
&dh->amount_without_fee,
&dh->coin_pub,
&dh->merchant_pub,
&dh->exchange_pub,
&dh->exchange_sig))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_EXCHANGE_DEPOSIT_INVALID_SIGNATURE_BY_EXCHANGE;
break;
}
TEAH_get_auditors_for_dc (dh->exchange,
&auditor_cb,
dh);
}
dr.details.success.exchange_sig = &dh->exchange_sig;
dr.details.success.exchange_pub = &dh->exchange_pub;
dr.details.success.deposit_timestamp = dh->exchange_timestamp;
break;
case MHD_HTTP_BAD_REQUEST:
/* This should never happen, either us or the exchange is buggy
(or API version conflict); just pass JSON reply to the application */
dr.hr.ec = TALER_JSON_get_error_code (j);
dr.hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_FORBIDDEN:
dr.hr.ec = TALER_JSON_get_error_code (j);
dr.hr.hint = TALER_JSON_get_error_hint (j);
/* Nothing really to verify, exchange says one of the signatures is
invalid; as we checked them, this should never happen, we
should pass the JSON reply to the application */
break;
case MHD_HTTP_NOT_FOUND:
dr.hr.ec = TALER_JSON_get_error_code (j);
dr.hr.hint = TALER_JSON_get_error_hint (j);
/* Nothing really to verify, this should never
happen, we should pass the JSON reply to the application */
break;
case MHD_HTTP_CONFLICT:
/* Double spending; check signatures on transaction history */
if (GNUNET_OK !=
verify_deposit_signature_conflict (dh,
j))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_EXCHANGE_DEPOSIT_INVALID_SIGNATURE_BY_EXCHANGE;
}
else
{
dr.hr.ec = TALER_JSON_get_error_code (j);
dr.hr.hint = TALER_JSON_get_error_hint (j);
}
break;
case MHD_HTTP_GONE:
/* could happen if denomination was revoked */
/* Note: one might want to check /keys for revocation
signature here, alas tricky in case our /keys
is outdated => left to clients */
dr.hr.ec = TALER_JSON_get_error_code (j);
dr.hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_INTERNAL_SERVER_ERROR:
dr.hr.ec = TALER_JSON_get_error_code (j);
dr.hr.hint = TALER_JSON_get_error_hint (j);
/* Server had an internal issue; we should retry, but this API
leaves this to the application */
break;
default:
/* unexpected response code */
dr.hr.ec = TALER_JSON_get_error_code (j);
dr.hr.hint = TALER_JSON_get_error_hint (j);
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Unexpected response code %u/%d for exchange deposit\n",
(unsigned int) response_code,
dr.hr.ec);
GNUNET_break_op (0);
break;
}
dh->cb (dh->cb_cls,
&dr);
TALER_EXCHANGE_deposit_cancel (dh);
}
/**
* Verify signature information about the deposit.
*
* @param dki public key information
* @param amount the amount to be deposited
* @param h_wire hash of the merchant’s account details
* @param h_contract_terms hash of the contact of the merchant with the customer (further details are never disclosed to the exchange)
* @param coin_pub coin’s public key
* @param denom_sig exchange’s unblinded signature of the coin
* @param denom_pub denomination key with which the coin is signed
* @param denom_pub_hash hash of @a denom_pub
* @param timestamp timestamp when the deposit was finalized
* @param merchant_pub the public key of the merchant (used to identify the merchant for refund requests)
* @param refund_deadline date until which the merchant can issue a refund to the customer via the exchange (can be zero if refunds are not allowed)
* @param coin_sig the signature made with purpose #TALER_SIGNATURE_WALLET_COIN_DEPOSIT made by the customer with the coin’s private key.
* @return #GNUNET_OK if signatures are OK, #GNUNET_SYSERR if not
*/
static enum GNUNET_GenericReturnValue
verify_signatures (const struct TALER_EXCHANGE_DenomPublicKey *dki,
const struct TALER_Amount *amount,
const struct TALER_MerchantWireHash *h_wire,
const struct TALER_PrivateContractHash *h_contract_terms,
const struct TALER_ExtensionContractHash *ech,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
const struct TALER_DenominationSignature *denom_sig,
const struct TALER_DenominationPublicKey *denom_pub,
const struct TALER_DenominationHash *denom_pub_hash,
struct GNUNET_TIME_Absolute timestamp,
const struct TALER_MerchantPublicKeyP *merchant_pub,
struct GNUNET_TIME_Absolute refund_deadline,
const struct TALER_CoinSpendSignatureP *coin_sig)
{
if (GNUNET_OK !=
TALER_wallet_deposit_verify (amount,
&dki->fee_deposit,
h_wire,
h_contract_terms,
ech,
denom_pub_hash,
timestamp,
merchant_pub,
refund_deadline,
coin_pub,
coin_sig))
{
GNUNET_break_op (0);
TALER_LOG_WARNING ("Invalid coin signature on /deposit request!\n");
TALER_LOG_DEBUG ("... amount_with_fee was %s\n",
TALER_amount2s (amount));
TALER_LOG_DEBUG ("... deposit_fee was %s\n",
TALER_amount2s (&dki->fee_deposit));
return GNUNET_SYSERR;
}
/* check coin signature */
{
struct TALER_CoinPublicInfo coin_info = {
.coin_pub = *coin_pub,
.denom_pub_hash = *denom_pub_hash,
.denom_sig = *denom_sig,
.age_commitment_hash = { 0 } /* FIXME-Oec */
};
if (GNUNET_YES !=
TALER_test_coin_valid (&coin_info,
denom_pub))
{
GNUNET_break_op (0);
TALER_LOG_WARNING ("Invalid coin passed for /deposit\n");
return GNUNET_SYSERR;
}
}
/* Check coin does make a contribution */
if (0 < TALER_amount_cmp (&dki->fee_deposit,
amount))
{
GNUNET_break_op (0);
TALER_LOG_WARNING ("Deposit amount smaller than fee\n");
return GNUNET_SYSERR;
}
return GNUNET_OK;
}
struct TALER_EXCHANGE_DepositHandle *
TALER_EXCHANGE_deposit (
struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_Amount *amount,
struct GNUNET_TIME_Absolute wire_deadline,
const char *merchant_payto_uri,
const struct TALER_WireSalt *wire_salt,
const struct TALER_PrivateContractHash *h_contract_terms,
const json_t *extension_details,
const struct TALER_CoinSpendPublicKeyP *coin_pub,
const struct TALER_DenominationSignature *denom_sig,
const struct TALER_DenominationPublicKey *denom_pub,
struct GNUNET_TIME_Absolute timestamp,
const struct TALER_MerchantPublicKeyP *merchant_pub,
struct GNUNET_TIME_Absolute refund_deadline,
const struct TALER_CoinSpendSignatureP *coin_sig,
TALER_EXCHANGE_DepositResultCallback cb,
void *cb_cls,
enum TALER_ErrorCode *ec)
{
const struct TALER_EXCHANGE_Keys *key_state;
const struct TALER_EXCHANGE_DenomPublicKey *dki;
struct TALER_EXCHANGE_DepositHandle *dh;
struct GNUNET_CURL_Context *ctx;
json_t *deposit_obj;
CURL *eh;
struct TALER_MerchantWireHash h_wire;
struct TALER_DenominationHash denom_pub_hash;
struct TALER_Amount amount_without_fee;
struct TALER_ExtensionContractHash ech;
char arg_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2 + 32];
if (NULL != extension_details)
TALER_deposit_extension_hash (extension_details,
&ech);
{
char pub_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2];
char *end;
end = GNUNET_STRINGS_data_to_string (
coin_pub,
sizeof (struct TALER_CoinSpendPublicKeyP),
pub_str,
sizeof (pub_str));
*end = '\0';
GNUNET_snprintf (arg_str,
sizeof (arg_str),
"/coins/%s/deposit",
pub_str);
}
(void) GNUNET_TIME_round_abs (&wire_deadline);
(void) GNUNET_TIME_round_abs (&refund_deadline);
if (refund_deadline.abs_value_us > wire_deadline.abs_value_us)
{
GNUNET_break_op (0);
*ec = TALER_EC_EXCHANGE_DEPOSIT_REFUND_DEADLINE_AFTER_WIRE_DEADLINE;
return NULL;
}
GNUNET_assert (GNUNET_YES ==
TEAH_handle_is_ready (exchange));
/* initialize h_wire */
TALER_merchant_wire_signature_hash (merchant_payto_uri,
wire_salt,
&h_wire);
key_state = TALER_EXCHANGE_get_keys (exchange);
dki = TALER_EXCHANGE_get_denomination_key (key_state,
denom_pub);
if (NULL == dki)
{
*ec = TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN;
GNUNET_break_op (0);
return NULL;
}
if (0 >
TALER_amount_subtract (&amount_without_fee,
amount,
&dki->fee_deposit))
{
*ec = TALER_EC_EXCHANGE_DEPOSIT_FEE_ABOVE_AMOUNT;
GNUNET_break_op (0);
return NULL;
}
TALER_denom_pub_hash (denom_pub,
&denom_pub_hash);
if (GNUNET_OK !=
verify_signatures (dki,
amount,
&h_wire,
h_contract_terms,
(NULL != extension_details)
? &ech
: NULL,
coin_pub,
denom_sig,
denom_pub,
&denom_pub_hash,
timestamp,
merchant_pub,
refund_deadline,
coin_sig))
{
*ec = TALER_EC_EXCHANGE_DEPOSIT_COIN_SIGNATURE_INVALID;
GNUNET_break_op (0);
return NULL;
}
deposit_obj = GNUNET_JSON_PACK (
TALER_JSON_pack_amount ("contribution",
amount),
GNUNET_JSON_pack_string ("merchant_payto_uri",
merchant_payto_uri),
GNUNET_JSON_pack_data_auto ("wire_salt",
wire_salt),
GNUNET_JSON_pack_data_auto ("h_contract_terms",
h_contract_terms),
GNUNET_JSON_pack_data_auto ("denom_pub_hash",
&denom_pub_hash),
TALER_JSON_pack_denom_sig ("ub_sig",
denom_sig),
GNUNET_JSON_pack_time_abs ("timestamp",
timestamp),
GNUNET_JSON_pack_data_auto ("merchant_pub",
merchant_pub),
GNUNET_JSON_pack_allow_null (
GNUNET_JSON_pack_time_abs ("refund_deadline",
refund_deadline)),
GNUNET_JSON_pack_time_abs ("wire_transfer_deadline",
wire_deadline),
GNUNET_JSON_pack_data_auto ("coin_sig",
coin_sig));
dh = GNUNET_new (struct TALER_EXCHANGE_DepositHandle);
dh->auditor_chance = AUDITOR_CHANCE;
dh->exchange = exchange;
dh->cb = cb;
dh->cb_cls = cb_cls;
dh->url = TEAH_path_to_url (exchange,
arg_str);
if (NULL == dh->url)
{
GNUNET_break (0);
*ec = TALER_EC_GENERIC_ALLOCATION_FAILURE;
GNUNET_free (dh);
json_decref (deposit_obj);
return NULL;
}
dh->h_contract_terms = *h_contract_terms;
dh->h_wire = h_wire;
/* dh->h_extensions = ... */
dh->refund_deadline = refund_deadline;
dh->wire_deadline = wire_deadline;
dh->amount_without_fee = amount_without_fee;
dh->coin_pub = *coin_pub;
dh->merchant_pub = *merchant_pub;
dh->amount_with_fee = *amount;
dh->dki = *dki;
memset (&dh->dki.key,
0,
sizeof (dh->dki.key)); /* lifetime not warranted, so better
not copy the contents! */
eh = TALER_EXCHANGE_curl_easy_get_ (dh->url);
if ( (NULL == eh) ||
(GNUNET_OK !=
TALER_curl_easy_post (&dh->ctx,
eh,
deposit_obj)) )
{
*ec = TALER_EC_GENERIC_CURL_ALLOCATION_FAILURE;
GNUNET_break (0);
if (NULL != eh)
curl_easy_cleanup (eh);
json_decref (deposit_obj);
GNUNET_free (dh->url);
GNUNET_free (dh);
return NULL;
}
json_decref (deposit_obj);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"URL for deposit: `%s'\n",
dh->url);
ctx = TEAH_handle_to_context (exchange);
dh->job = GNUNET_CURL_job_add2 (ctx,
eh,
dh->ctx.headers,
&handle_deposit_finished,
dh);
return dh;
}
void
TALER_EXCHANGE_deposit_force_dc (struct TALER_EXCHANGE_DepositHandle *deposit)
{
deposit->auditor_chance = 1;
}
void
TALER_EXCHANGE_deposit_cancel (struct TALER_EXCHANGE_DepositHandle *deposit)
{
if (NULL != deposit->job)
{
GNUNET_CURL_job_cancel (deposit->job);
deposit->job = NULL;
}
GNUNET_free (deposit->url);
TALER_curl_easy_post_finished (&deposit->ctx);
GNUNET_free (deposit);
}
/* end of exchange_api_deposit.c */