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exchange/src/lib/exchange_api_purse_deposit.c

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/*
This file is part of TALER
Copyright (C) 2022 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
<http://www.gnu.org/licenses/>
*/
/**
* @file lib/exchange_api_purse_deposit.c
* @brief Implementation of the client to create a purse with
* an initial set of deposits (and a contract)
* @author Christian Grothoff
*/
#include "platform.h"
#include <jansson.h>
#include <microhttpd.h> /* just for HTTP status codes */
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_json_lib.h"
#include "taler_exchange_service.h"
#include "exchange_api_common.h"
#include "exchange_api_handle.h"
#include "taler_signatures.h"
#include "exchange_api_curl_defaults.h"
/**
* Information we track per coin.
*/
struct Coin
{
/**
* Coin's public key.
*/
struct TALER_CoinSpendPublicKeyP coin_pub;
/**
* Signature made with the coin.
*/
struct TALER_CoinSpendSignatureP coin_sig;
/**
* Coin's denomination.
*/
struct TALER_DenominationHashP h_denom_pub;
/**
* Age restriction hash for the coin.
*/
struct TALER_AgeCommitmentHash ahac;
/**
* How much did we say the coin contributed.
*/
struct TALER_Amount contribution;
};
/**
* @brief A purse create with deposit handle
*/
struct TALER_EXCHANGE_PurseDepositHandle
{
/**
* The connection to exchange this request handle will use
*/
struct TALER_EXCHANGE_Handle *exchange;
/**
* The url for this request.
*/
char *url;
/**
* The base url of the exchange we are talking to.
*/
char *base_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_PurseDepositCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Public key of the purse.
*/
struct TALER_PurseContractPublicKeyP purse_pub;
/**
* Array of @e num_deposits coins we are depositing.
*/
struct Coin *coins;
/**
* Number of coins we are depositing.
*/
unsigned int num_deposits;
};
/**
* Function called when we're done processing the
* HTTP /purses/$PID/deposit request.
*
* @param cls the `struct TALER_EXCHANGE_PurseDepositHandle`
* @param response_code HTTP response code, 0 on error
* @param response parsed JSON result, NULL on error
*/
static void
handle_purse_deposit_finished (void *cls,
long response_code,
const void *response)
{
struct TALER_EXCHANGE_PurseDepositHandle *pch = cls;
const json_t *j = response;
struct TALER_EXCHANGE_PurseDepositResponse dr = {
.hr.reply = j,
.hr.http_status = (unsigned int) response_code
};
const struct TALER_EXCHANGE_Keys *keys;
pch->job = NULL;
keys = TALER_EXCHANGE_get_keys (pch->exchange);
switch (response_code)
{
case 0:
dr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
break;
case MHD_HTTP_OK:
{
struct GNUNET_TIME_Timestamp etime;
struct TALER_ExchangeSignatureP exchange_sig;
struct TALER_ExchangePublicKeyP exchange_pub;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_fixed_auto ("exchange_sig",
&exchange_sig),
GNUNET_JSON_spec_fixed_auto ("exchange_pub",
&exchange_pub),
GNUNET_JSON_spec_fixed_auto ("h_contract_terms",
&dr.details.success.h_contract_terms),
GNUNET_JSON_spec_timestamp ("exchange_timestamp",
&etime),
GNUNET_JSON_spec_timestamp ("purse_expiration",
&dr.details.success.purse_expiration),
TALER_JSON_spec_amount ("total_deposited",
keys->currency,
&dr.details.success.total_deposited),
TALER_JSON_spec_amount ("purse_value_after_fees",
keys->currency,
&dr.details.success.purse_value_after_fees),
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;
}
if (GNUNET_OK !=
TALER_EXCHANGE_test_signing_key (keys,
&exchange_pub))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_EXCHANGE_PURSE_DEPOSIT_EXCHANGE_SIGNATURE_INVALID;
break;
}
if (GNUNET_OK !=
TALER_exchange_online_purse_created_verify (
etime,
dr.details.success.purse_expiration,
&dr.details.success.purse_value_after_fees,
&dr.details.success.total_deposited,
&pch->purse_pub,
&dr.details.success.h_contract_terms,
&exchange_pub,
&exchange_sig))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_EXCHANGE_PURSE_DEPOSIT_EXCHANGE_SIGNATURE_INVALID;
break;
}
}
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);
break;
case MHD_HTTP_FORBIDDEN:
dr.hr.ec = TALER_JSON_get_error_code (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);
/* Nothing really to verify, this should never
happen, we should pass the JSON reply to the application */
break;
case MHD_HTTP_CONFLICT:
dr.hr.ec = TALER_JSON_get_error_code (j);
switch (dr.hr.ec)
{
case TALER_EC_EXCHANGE_PURSE_DEPOSIT_CONFLICTING_META_DATA:
{
struct TALER_CoinSpendPublicKeyP coin_pub;
struct TALER_CoinSpendSignatureP coin_sig;
struct TALER_DenominationHashP h_denom_pub;
struct TALER_AgeCommitmentHash phac;
bool found = false;
if (GNUNET_OK !=
TALER_EXCHANGE_check_purse_coin_conflict_ (
&pch->purse_pub,
pch->base_url,
j,
&h_denom_pub,
&phac,
&coin_pub,
&coin_sig))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
for (unsigned int i = 0; i<pch->num_deposits; i++)
{
struct Coin *coin = &pch->coins[i];
if (0 != GNUNET_memcmp (&coin_pub,
&coin->coin_pub))
continue;
if (0 !=
GNUNET_memcmp (&coin->h_denom_pub,
&h_denom_pub))
{
found = true;
break;
}
if (0 !=
GNUNET_memcmp (&coin->ahac,
&phac))
{
found = true;
break;
}
if (0 == GNUNET_memcmp (&coin_sig,
&coin->coin_sig))
{
/* identical signature => not a conflict */
continue;
}
found = true;
break;
}
if (! found)
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
/* meta data conflict is real! */
break;
}
case TALER_EC_EXCHANGE_GENERIC_INSUFFICIENT_FUNDS:
{
struct TALER_CoinSpendPublicKeyP coin_pub;
struct TALER_Amount remaining;
bool found = false;
const struct Coin *my_coin;
if (GNUNET_OK !=
TALER_EXCHANGE_check_coin_amount_conflict_ (
keys,
j,
&coin_pub,
&remaining))
{
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
for (unsigned int i = 0; i<pch->num_deposits; i++)
{
if (0 == GNUNET_memcmp (&coin_pub,
&pch->coins[i].coin_pub))
{
found = true;
my_coin = &pch->coins[i];
break;
}
}
if (! found)
{
/* proof is about a coin we did not even deposit */
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
if (1 == TALER_amount_cmp (&remaining,
&my_coin->contribution))
{
/* transaction should have still fit */
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
if (GNUNET_OK !=
TALER_EXCHANGE_check_coin_signature_conflict_ (
j,
&my_coin->coin_sig))
{
/* THIS transaction must not be in the conflicting history */
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
/* everything OK, proof of double-spending was provided */
break;
}
case TALER_EC_EXCHANGE_GENERIC_COIN_CONFLICTING_DENOMINATION_KEY:
{
struct TALER_CoinSpendPublicKeyP coin_pub;
struct TALER_Amount remaining;
bool found = false;
const struct Coin *my_coin;
if (GNUNET_OK !=
TALER_EXCHANGE_check_coin_amount_conflict_ (
keys,
j,
&coin_pub,
&remaining))
{
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
for (unsigned int i = 0; i<pch->num_deposits; i++)
{
if (0 == GNUNET_memcmp (&coin_pub,
&pch->coins[i].coin_pub))
{
found = true;
my_coin = &pch->coins[i];
break;
}
}
if (! found)
{
/* proof is about a coin we did not even deposit */
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
if (GNUNET_OK !=
TALER_EXCHANGE_check_coin_denomination_conflict_ (
j,
&my_coin->h_denom_pub))
{
/* no conflicting denomination detected */
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
/* everything OK, proof of conflicting denomination was provided */
break;
}
default:
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
} /* ec switch */
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);
break;
case MHD_HTTP_INTERNAL_SERVER_ERROR:
dr.hr.ec = TALER_JSON_get_error_code (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);
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;
}
if (TALER_EC_NONE == dr.hr.ec)
dr.hr.hint = NULL;
else
dr.hr.hint = TALER_ErrorCode_get_hint (dr.hr.ec);
pch->cb (pch->cb_cls,
&dr);
TALER_EXCHANGE_purse_deposit_cancel (pch);
}
struct TALER_EXCHANGE_PurseDepositHandle *
TALER_EXCHANGE_purse_deposit (
struct TALER_EXCHANGE_Handle *exchange,
const char *purse_exchange_url,
const struct TALER_PurseContractPublicKeyP *purse_pub,
uint8_t min_age,
unsigned int num_deposits,
const struct TALER_EXCHANGE_PurseDeposit *deposits,
TALER_EXCHANGE_PurseDepositCallback cb,
void *cb_cls)
{
struct TALER_EXCHANGE_PurseDepositHandle *pch;
struct GNUNET_CURL_Context *ctx;
json_t *create_obj;
json_t *deposit_arr;
CURL *eh;
char arg_str[sizeof (pch->purse_pub) * 2 + 32];
if (0 == num_deposits)
{
GNUNET_break (0);
return NULL;
}
GNUNET_assert (GNUNET_YES ==
TEAH_handle_is_ready (exchange));
pch = GNUNET_new (struct TALER_EXCHANGE_PurseDepositHandle);
pch->purse_pub = *purse_pub;
pch->exchange = exchange;
pch->cb = cb;
pch->cb_cls = cb_cls;
{
char pub_str[sizeof (pch->purse_pub) * 2];
char *end;
end = GNUNET_STRINGS_data_to_string (
&pch->purse_pub,
sizeof (pch->purse_pub),
pub_str,
sizeof (pub_str));
*end = '\0';
GNUNET_snprintf (arg_str,
sizeof (arg_str),
"/purses/%s/deposit",
pub_str);
}
pch->url = TEAH_path_to_url (exchange,
arg_str);
if (NULL == pch->url)
{
GNUNET_break (0);
GNUNET_free (pch);
return NULL;
}
deposit_arr = json_array ();
GNUNET_assert (NULL != deposit_arr);
pch->base_url = TEAH_path_to_url (exchange,
"/");
pch->num_deposits = num_deposits;
pch->coins = GNUNET_new_array (num_deposits,
struct Coin);
for (unsigned int i = 0; i<num_deposits; i++)
{
const struct TALER_EXCHANGE_PurseDeposit *deposit = &deposits[i];
const struct TALER_AgeCommitmentProof *acp = deposit->age_commitment_proof;
struct Coin *coin = &pch->coins[i];
json_t *jdeposit;
struct TALER_AgeCommitmentHash *achp = NULL;
struct TALER_AgeAttestation attest;
struct TALER_AgeAttestation *attestp = NULL;
if (NULL != acp)
{
TALER_age_commitment_hash (&acp->commitment,
&coin->ahac);
achp = &coin->ahac;
if (GNUNET_OK !=
TALER_age_commitment_attest (acp,
min_age,
&attest))
{
GNUNET_break (0);
json_decref (deposit_arr);
GNUNET_free (pch->base_url);
GNUNET_free (pch->coins);
GNUNET_free (pch);
return NULL;
}
attestp = &attest;
}
GNUNET_CRYPTO_eddsa_key_get_public (&deposit->coin_priv.eddsa_priv,
&coin->coin_pub.eddsa_pub);
coin->h_denom_pub = deposit->h_denom_pub;
coin->contribution = deposit->amount;
TALER_wallet_purse_deposit_sign (
pch->base_url,
&pch->purse_pub,
&deposit->amount,
&coin->h_denom_pub,
&coin->ahac,
&deposit->coin_priv,
&coin->coin_sig);
jdeposit = GNUNET_JSON_PACK (
GNUNET_JSON_pack_allow_null (
GNUNET_JSON_pack_data_auto ("h_age_commitment",
achp)),
GNUNET_JSON_pack_allow_null (
GNUNET_JSON_pack_data_auto ("age_attestation",
attestp)),
TALER_JSON_pack_amount ("amount",
&deposit->amount),
GNUNET_JSON_pack_data_auto ("denom_pub_hash",
&deposit->h_denom_pub),
TALER_JSON_pack_denom_sig ("ub_sig",
&deposit->denom_sig),
GNUNET_JSON_pack_data_auto ("coin_pub",
&coin->coin_pub),
GNUNET_JSON_pack_data_auto ("coin_sig",
&coin->coin_sig));
GNUNET_assert (0 ==
json_array_append_new (deposit_arr,
jdeposit));
}
create_obj = GNUNET_JSON_PACK (
GNUNET_JSON_pack_array_steal ("deposits",
deposit_arr));
GNUNET_assert (NULL != create_obj);
eh = TALER_EXCHANGE_curl_easy_get_ (pch->url);
if ( (NULL == eh) ||
(GNUNET_OK !=
TALER_curl_easy_post (&pch->ctx,
eh,
create_obj)) )
{
GNUNET_break (0);
if (NULL != eh)
curl_easy_cleanup (eh);
json_decref (create_obj);
GNUNET_free (pch->base_url);
GNUNET_free (pch->url);
GNUNET_free (pch->coins);
GNUNET_free (pch);
return NULL;
}
json_decref (create_obj);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"URL for purse deposit: `%s'\n",
pch->url);
ctx = TEAH_handle_to_context (exchange);
pch->job = GNUNET_CURL_job_add2 (ctx,
eh,
pch->ctx.headers,
&handle_purse_deposit_finished,
pch);
return pch;
}
void
TALER_EXCHANGE_purse_deposit_cancel (
struct TALER_EXCHANGE_PurseDepositHandle *pch)
{
if (NULL != pch->job)
{
GNUNET_CURL_job_cancel (pch->job);
pch->job = NULL;
}
GNUNET_free (pch->base_url);
GNUNET_free (pch->url);
GNUNET_free (pch->coins);
TALER_curl_easy_post_finished (&pch->ctx);
GNUNET_free (pch);
}
/* end of exchange_api_purse_deposit.c */
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