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exchange/src/lib/exchange_api_purse_create_with_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_create_with_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_handle.h"
#include "exchange_api_common.h"
#include "taler_signatures.h"
#include "exchange_api_curl_defaults.h"
/**
* Information we track per deposited coin.
*/
struct Deposit
{
/**
* 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_PurseCreateDepositHandle
{
/**
* 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_PurseCreateDepositCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Expected value in the purse after fees.
*/
struct TALER_Amount purse_value_after_fees;
/**
* Our encryped contract (if we had any).
*/
struct TALER_EncryptedContract econtract;
/**
* Public key of the merge capability.
*/
struct TALER_PurseMergePublicKeyP merge_pub;
/**
* Public key of the purse.
*/
struct TALER_PurseContractPublicKeyP purse_pub;
/**
* Signature with the purse key on the request.
*/
struct TALER_PurseContractSignatureP purse_sig;
/**
* Hash over the purse's contract terms.
*/
struct TALER_PrivateContractHashP h_contract_terms;
/**
* When does the purse expire.
*/
struct GNUNET_TIME_Timestamp purse_expiration;
/**
* Array of @e num_deposit deposits.
*/
struct Deposit *deposits;
/**
* How many deposits did we make?
*/
unsigned int num_deposits;
};
/**
* 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_purse_create_deposit_finished (void *cls,
long response_code,
const void *response)
{
struct TALER_EXCHANGE_PurseCreateDepositHandle *pch = cls;
const json_t *j = response;
struct TALER_EXCHANGE_PurseCreateDepositResponse 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:
{
const struct TALER_EXCHANGE_Keys *key_state;
struct GNUNET_TIME_Timestamp etime;
struct TALER_Amount total_deposited;
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_timestamp ("exchange_timestamp",
&etime),
TALER_JSON_spec_amount ("total_deposited",
pch->purse_value_after_fees.currency,
&total_deposited),
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 (pch->exchange);
if (GNUNET_OK !=
TALER_EXCHANGE_test_signing_key (key_state,
&exchange_pub))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_EXCHANGE_PURSE_CREATE_EXCHANGE_SIGNATURE_INVALID;
break;
}
if (GNUNET_OK !=
TALER_exchange_online_purse_created_verify (
etime,
pch->purse_expiration,
&pch->purse_value_after_fees,
&total_deposited,
&pch->purse_pub,
&pch->h_contract_terms,
&exchange_pub,
&exchange_sig))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_EXCHANGE_PURSE_CREATE_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);
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:
{
dr.hr.ec = TALER_JSON_get_error_code (j);
switch (dr.hr.ec)
{
case TALER_EC_EXCHANGE_PURSE_CREATE_CONFLICTING_META_DATA:
if (GNUNET_OK !=
TALER_EXCHANGE_check_purse_create_conflict_ (
&pch->purse_sig,
&pch->purse_pub,
j))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
break;
case TALER_EC_EXCHANGE_GENERIC_INSUFFICIENT_FUNDS:
{
struct TALER_Amount left;
struct TALER_CoinSpendPublicKeyP pcoin_pub;
bool found = false;
if (GNUNET_OK !=
TALER_EXCHANGE_check_coin_amount_conflict_ (
keys,
j,
&pcoin_pub,
&left))
{
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 Deposit *deposit = &pch->deposits[i];
if (0 != GNUNET_memcmp (&pcoin_pub,
&deposit->coin_pub))
continue;
if (-1 !=
TALER_amount_cmp (&left,
&deposit->contribution))
{
/* Balance was sufficient after all; operation MAY have still been possible */
GNUNET_break_op (0);
continue;
}
if (GNUNET_OK !=
TALER_EXCHANGE_check_coin_signature_conflict_ (
j,
&deposit->coin_sig))
{
GNUNET_break_op (0);
continue;
}
found = true;
break;
}
if (! found)
{
/* conflict is for a different coin! */
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
break;
}
case TALER_EC_EXCHANGE_GENERIC_COIN_CONFLICTING_DENOMINATION_KEY:
{
struct TALER_Amount left;
struct TALER_CoinSpendPublicKeyP pcoin_pub;
bool found = false;
if (GNUNET_OK !=
TALER_EXCHANGE_check_coin_amount_conflict_ (
keys,
j,
&pcoin_pub,
&left))
{
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 Deposit *deposit = &pch->deposits[i];
if (0 !=
GNUNET_memcmp (&pcoin_pub,
&deposit->coin_pub))
continue;
if (GNUNET_OK !=
TALER_EXCHANGE_check_coin_denomination_conflict_ (
j,
&deposit->h_denom_pub))
{
/* Eh, same denomination, hence no conflict */
GNUNET_break_op (0);
continue;
}
found = true;
}
if (! found)
{
/* conflict is for a different coin! */
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_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->exchange->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 Deposit *deposit = &pch->deposits[i];
if (0 !=
GNUNET_memcmp (&coin_pub,
&deposit->coin_pub))
continue;
if (0 !=
GNUNET_memcmp (&deposit->h_denom_pub,
&h_denom_pub))
{
found = true;
break;
}
if (0 !=
GNUNET_memcmp (&deposit->ahac,
&phac))
{
found = true;
break;
}
if (0 ==
GNUNET_memcmp (&coin_sig,
&deposit->coin_sig))
{
GNUNET_break_op (0);
continue;
}
found = true;
break;
}
if (! found)
{
/* conflict is for a different coin! */
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
}
case TALER_EC_EXCHANGE_PURSE_ECONTRACT_CONFLICTING_META_DATA:
if (GNUNET_OK !=
TALER_EXCHANGE_check_purse_econtract_conflict_ (
&pch->econtract.econtract_sig,
&pch->purse_pub,
j))
{
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
break;
default:
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Unexpected error code %d for conflcting deposit\n",
dr.hr.ec);
GNUNET_break_op (0);
dr.hr.http_status = 0;
dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
}
}
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;
}
pch->cb (pch->cb_cls,
&dr);
TALER_EXCHANGE_purse_create_with_deposit_cancel (pch);
}
struct TALER_EXCHANGE_PurseCreateDepositHandle *
TALER_EXCHANGE_purse_create_with_deposit (
struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_PurseContractPrivateKeyP *purse_priv,
const struct TALER_PurseMergePrivateKeyP *merge_priv,
const struct TALER_ContractDiffiePrivateP *contract_priv,
const json_t *contract_terms,
unsigned int num_deposits,
const struct TALER_EXCHANGE_PurseDeposit *deposits,
bool upload_contract,
TALER_EXCHANGE_PurseCreateDepositCallback cb,
void *cb_cls)
{
struct TALER_EXCHANGE_PurseCreateDepositHandle *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];
char *url;
uint32_t min_age = 0;
pch = GNUNET_new (struct TALER_EXCHANGE_PurseCreateDepositHandle);
pch->exchange = exchange;
pch->cb = cb;
pch->cb_cls = cb_cls;
{
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_timestamp ("pay_deadline",
&pch->purse_expiration),
TALER_JSON_spec_amount_any ("amount",
&pch->purse_value_after_fees),
GNUNET_JSON_spec_mark_optional (
GNUNET_JSON_spec_uint32 ("minimum_age",
&min_age),
NULL),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (contract_terms,
spec,
NULL, NULL))
{
GNUNET_break (0);
return NULL;
}
}
GNUNET_assert (GNUNET_YES ==
TEAH_handle_is_ready (exchange));
if (GNUNET_OK !=
TALER_JSON_contract_hash (contract_terms,
&pch->h_contract_terms))
{
GNUNET_break (0);
return NULL;
}
GNUNET_CRYPTO_eddsa_key_get_public (&purse_priv->eddsa_priv,
&pch->purse_pub.eddsa_pub);
{
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/create",
pub_str);
}
GNUNET_CRYPTO_eddsa_key_get_public (&merge_priv->eddsa_priv,
&pch->merge_pub.eddsa_pub);
pch->url = TEAH_path_to_url (exchange,
arg_str);
if (NULL == pch->url)
{
GNUNET_break (0);
GNUNET_free (pch);
return NULL;
}
pch->num_deposits = num_deposits;
pch->deposits = GNUNET_new_array (num_deposits,
struct Deposit);
deposit_arr = json_array ();
GNUNET_assert (NULL != deposit_arr);
url = TEAH_path_to_url (exchange,
"/");
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Signing with URL `%s'\n",
url);
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 Deposit *d = &pch->deposits[i];
json_t *jdeposit;
struct TALER_AgeCommitmentHash *aghp = NULL;
struct TALER_AgeAttestation attest;
struct TALER_AgeAttestation *attestp = NULL;
if (NULL != acp)
{
TALER_age_commitment_hash (&acp->commitment,
&d->ahac);
aghp = &d->ahac;
if (GNUNET_OK !=
TALER_age_commitment_attest (acp,
min_age,
&attest))
{
GNUNET_break (0);
json_decref (deposit_arr);
GNUNET_free (url);
GNUNET_free (pch);
return NULL;
}
}
d->contribution = deposit->amount;
d->h_denom_pub = deposit->h_denom_pub;
GNUNET_CRYPTO_eddsa_key_get_public (&deposit->coin_priv.eddsa_priv,
&d->coin_pub.eddsa_pub);
TALER_wallet_purse_deposit_sign (
url,
&pch->purse_pub,
&deposit->amount,
&d->h_denom_pub,
&d->ahac,
&deposit->coin_priv,
&d->coin_sig);
jdeposit = GNUNET_JSON_PACK (
GNUNET_JSON_pack_allow_null (
GNUNET_JSON_pack_data_auto ("h_age_commitment",
aghp)),
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_sig",
&d->coin_sig),
GNUNET_JSON_pack_data_auto ("coin_pub",
&d->coin_pub));
GNUNET_assert (0 ==
json_array_append_new (deposit_arr,
jdeposit));
}
GNUNET_free (url);
TALER_wallet_purse_create_sign (pch->purse_expiration,
&pch->h_contract_terms,
&pch->merge_pub,
min_age,
&pch->purse_value_after_fees,
purse_priv,
&pch->purse_sig);
if (upload_contract)
{
TALER_CRYPTO_contract_encrypt_for_merge (&pch->purse_pub,
contract_priv,
merge_priv,
contract_terms,
&pch->econtract.econtract,
&pch->econtract.econtract_size);
GNUNET_CRYPTO_ecdhe_key_get_public (&contract_priv->ecdhe_priv,
&pch->econtract.contract_pub.ecdhe_pub);
TALER_wallet_econtract_upload_sign (pch->econtract.econtract,
pch->econtract.econtract_size,
&pch->econtract.contract_pub,
purse_priv,
&pch->econtract.econtract_sig);
}
create_obj = GNUNET_JSON_PACK (
TALER_JSON_pack_amount ("amount",
&pch->purse_value_after_fees),
GNUNET_JSON_pack_uint64 ("min_age",
min_age),
GNUNET_JSON_pack_allow_null (
TALER_JSON_pack_econtract ("econtract",
upload_contract
? &pch->econtract
: NULL)),
GNUNET_JSON_pack_data_auto ("purse_sig",
&pch->purse_sig),
GNUNET_JSON_pack_data_auto ("merge_pub",
&pch->merge_pub),
GNUNET_JSON_pack_data_auto ("h_contract_terms",
&pch->h_contract_terms),
GNUNET_JSON_pack_timestamp ("purse_expiration",
pch->purse_expiration),
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->econtract.econtract);
GNUNET_free (pch->deposits);
GNUNET_free (pch->url);
GNUNET_free (pch);
return NULL;
}
json_decref (create_obj);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"URL for purse create with deposit: `%s'\n",
pch->url);
ctx = TEAH_handle_to_context (exchange);
pch->job = GNUNET_CURL_job_add2 (ctx,
eh,
pch->ctx.headers,
&handle_purse_create_deposit_finished,
pch);
return pch;
}
void
TALER_EXCHANGE_purse_create_with_deposit_cancel (
struct TALER_EXCHANGE_PurseCreateDepositHandle *pch)
{
if (NULL != pch->job)
{
GNUNET_CURL_job_cancel (pch->job);
pch->job = NULL;
}
GNUNET_free (pch->econtract.econtract);
GNUNET_free (pch->url);
GNUNET_free (pch->deposits);
TALER_curl_easy_post_finished (&pch->ctx);
GNUNET_free (pch);
}
/* end of exchange_api_purse_create_with_deposit.c */
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