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towards age-withdraw and -reveal API

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This commit is contained in:
Özgür Kesim 2023-07-13 08:45:05 +02:00
parent e0f78bc3c9
commit fde760aef0
Signed by: oec
GPG Key ID: 3D76A56D79EDD9D7
4 changed files with 556 additions and 19 deletions
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108
src/include/taler_exchange_service.h
View File

@ -2745,7 +2745,7 @@ TALER_EXCHANGE_batch_withdraw2_cancel (
/* ********************* /reserve/$RESERVE_PUB/age-withdraw *************** */
/**
* @brief Information needed to withdraw age restricted coins.
* @brief Information needed to withdraw (and reveal) age restricted coins.
*/
struct TALER_EXCHANGE_AgeWithdrawCoinInput
{
@ -2753,7 +2753,7 @@ struct TALER_EXCHANGE_AgeWithdrawCoinInput
* The master secret from which we derive all other relevant values for
* the coin: private key, nonces (if applicable) and age restriction
*/
const struct TALER_PlanchetMasterSecretP secret[TALER_CNC_KAPPA];
const struct TALER_PlanchetMasterSecretP secrets[TALER_CNC_KAPPA];
/**
* The denomination of the coin. Must support age restriction, i.e
@ -2794,6 +2794,11 @@ struct TALER_EXCHANGE_AgeWithdrawResponse
*/
uint8_t noreveal_index;
/**
* The commitment of the call to /age-withdraw
*/
struct TALER_AgeWithdrawCommitmentHashP h_commitment;
/**
* Signature of the exchange over the origina TALER_AgeWithdrawRequestPS
*/
@ -2842,7 +2847,7 @@ TALER_EXCHANGE_age_withdraw (
struct TALER_EXCHANGE_Keys *keys,
const struct TALER_ReservePrivateKeyP *reserve_priv,
size_t num_coins,
const struct TALER_EXCHANGE_AgeWithdrawCoinInput coin_inputs[const static
const struct TALER_EXCHANGE_AgeWithdrawCoinInput coin_inputs[static
num_coins],
uint8_t max_age,
TALER_EXCHANGE_AgeWithdrawCallback res_cb,
@ -2859,6 +2864,103 @@ TALER_EXCHANGE_age_withdraw_cancel (
struct TALER_EXCHANGE_AgeWithdrawHandle *awh);
/* ********************* /age-withdraw/$ACH/reveal ************************ */
/**
* @brief A handle to a /age-withdraw/$ACH/reveal request
*/
struct TALER_EXCHANGE_AgeWithdrawRevealHandle;
/**
*
*/
struct TALER_EXCHANGE_AgeWithdrawRevealResponse
{
/**
* HTTP response data.
*/
struct TALER_EXCHANGE_HttpResponse hr;
/**
* Details about the response
*/
union
{
/**
* Details if the status is #MHD_HTTP_OK.
*/
struct
{
/**
* Number of coins returned.
*/
unsigned int num_coins;
/**
* Array of @e num_coins values about the coins obtained via the reveal
* operation. The array give thes coins in the same order (and should
* have the same length) in which the original age-withdraw request
* specified the respective denomination keys.
*/
const struct TALER_EXCHANGE_RevealedCoinInfo *coins;
} ok;
/* FIXME[oec]: error cases */
} details;
};
typedef void
(*TALER_EXCHANGE_AgeWithdrawRevealCallback)(
void *cls,
const struct TALER_EXCHANGE_AgeWithdrawRevealResponse *awr);
/**
* Submit an age-withdraw-reveal request to the exchange and get the exchange's
* response.
*
* This API is typically used by a wallet. Note that to ensure that
* no money is lost in case of hardware failures, the provided
* argument @a rd should be committed to persistent storage
* prior to calling this function.
*
* @param curl_ctx The curl context
* @param exchange_url The base url of the exchange
* @param reserve_priv The pivate key to the reserve
* @param num_coins The number of elements in @e coin_inputs
* @param coins_input The input for the coins to withdraw
* @param noreveal_index The index into each of the kappa coin candidates, that should not be revealed to the exchange
* @param h_commitment The commmitment from the previous call to /age-withdraw
* @param res_cb A callback for the result, maybe NULL
* @param res_cb_cls A closure for @e res_cb, maybe NULL
* @return a handle for this request; NULL if the argument was invalid.
* In this case, the callback will not be called.
*/
struct TALER_EXCHANGE_AgeWithdrawRevealHandle *
TALER_EXCHANGE_age_withdraw_reveal (
struct GNUNET_CURL_Context *curl_ctx,
const char *exchange_url,
size_t num_coins,
const struct TALER_EXCHANGE_AgeWithdrawCoinInput coins_input[static
num_coins],
uint8_t noreveal_index,
const struct TALER_AgeWithdrawCommitmentHashP *h_commitment,
TALER_EXCHANGE_AgeWithdrawRevealCallback res_cb,
void *res_cb_cls);
/**
* @brief Cancel an age-withdraw-reveal request
*
* @param awrh Handle to an age-withdraw-reqveal request
*/
void
TALER_EXCHANGE_age_withdraw_reveal_cancel (
struct TALER_EXCHANGE_AgeWithdrawRevealHandle *awrh);
/* ********************* /refresh/melt+reveal ***************************** */

1
src/lib/Makefile.am
View File

@ -23,6 +23,7 @@ libtalerexchange_la_LDFLAGS = \
libtalerexchange_la_SOURCES = \
exchange_api_add_aml_decision.c \
exchange_api_age_withdraw.c \
exchange_api_age_withdraw_reveal.c \
exchange_api_auditor_add_denomination.c \
exchange_api_batch_deposit.c \
exchange_api_batch_withdraw.c \

31
src/lib/exchange_api_age_withdraw.c
View File

@ -235,7 +235,8 @@ reserve_age_withdraw_ok (
{
struct TALER_EXCHANGE_AgeWithdrawResponse response = {
.hr.reply = j_response,
.hr.http_status = MHD_HTTP_OK
.hr.http_status = MHD_HTTP_OK,
.details.ok.h_commitment = awh->h_commitment
};
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_uint8 ("noreaveal_index",
@ -568,12 +569,13 @@ perform_protocol (
/* Build the candidate array */
{
const struct CoinCandidate *can = awh->coin_data[i].coin_candidates;
json_t *j_can = json_array ();
FAIL_IF (NULL == j_can);
for (size_t k = 0; k < TALER_CNC_KAPPA; k++)
{
const struct CoinCandidate *can =
&awh->coin_data[i].coin_candidates[k];
json_t *jc = GNUNET_JSON_PACK (
TALER_JSON_pack_blinded_planchet (
NULL,
@ -591,20 +593,17 @@ perform_protocol (
}
}
/* Build the hash of the commitment */
GNUNET_CRYPTO_hash_context_finish (coins_hctx,
&awh->h_commitment.hash);
/* Sign the request */
{
struct TALER_AgeWithdrawCommitmentHashP coins_commitment_h;
GNUNET_CRYPTO_hash_context_finish (coins_hctx,
&coins_commitment_h.hash);
TALER_wallet_age_withdraw_sign (&coins_commitment_h,
&awh->amount_with_fee,
&awh->age_mask,
awh->max_age,
awh->reserve_priv,
&awh->reserve_sig);
}
TALER_wallet_age_withdraw_sign (&awh->h_commitment,
&awh->amount_with_fee,
&awh->age_mask,
awh->max_age,
awh->reserve_priv,
&awh->reserve_sig);
/* Initiate the POST-request */
j_request_body = GNUNET_JSON_PACK (
@ -833,7 +832,7 @@ prepare_coins (
{
struct CoinCandidate *can = &cd->coin_candidates[k];
can->secret = input->secret[k];
can->secret = input->secrets[k];
/* Derive the age restriction from the given secret and
* the maximum age */

435
src/lib/exchange_api_age_withdraw_reveal.c Normal file
View File

@ -0,0 +1,435 @@
/*
This file is part of TALER
Copyright (C) 2023 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_age_withdraw_reveal.c
* @brief Implementation of /age-withdraw/$ACH/reveal requests
* @author Özgür Kesim
*/
#include "platform.h"
#include <gnunet/gnunet_common.h>
#include <jansson.h>
#include <microhttpd.h> /* just for HTTP status codes */
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_curl_lib.h"
#include "taler_json_lib.h"
#include "taler_exchange_service.h"
#include "exchange_api_common.h"
#include "exchange_api_handle.h"
#include "taler_signatures.h"
#include "exchange_api_curl_defaults.h"
/**
* Handler for a running age-withdraw-reveal request
*/
struct TALER_EXCHANGE_AgeWithdrawRevealHandle
{
/* The index not to be disclosed */
uint8_t noreveal_index;
/* The age-withdraw commitment */
struct TALER_AgeWithdrawCommitmentHashP h_commitment;
/* Number of coins */
size_t num_coins;
/* The n*kappa coin secrets from the age-withdraw commitment */
const struct TALER_EXCHANGE_AgeWithdrawCoinInput *coins_input;
/* The curl context for the request */
struct GNUNET_CURL_Context *curl_ctx;
/* The url for the reveal request */
const char *request_url;
/**
* CURL handle for the request job.
*/
struct GNUNET_CURL_Job *job;
/**
* Post Context
*/
struct TALER_CURL_PostContext post_ctx;
/* Callback */
TALER_EXCHANGE_AgeWithdrawRevealCallback callback;
/* Reveal */
void *callback_cls;
};
/**
* We got a 200 OK response for the /age-withdraw/$ACH/reveal operation.
* Extract the signed blindedcoins and return it to the caller.
*
* @param awrh operation handle
* @param j_response reply from the exchange
* @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
*/
static enum GNUNET_GenericReturnValue
age_withdraw_reveal_ok (
struct TALER_EXCHANGE_AgeWithdrawRevealHandle *awrh,
const json_t *j_response)
{
struct TALER_EXCHANGE_AgeWithdrawRevealResponse response = {
.hr.reply = j_response,
.hr.http_status = MHD_HTTP_OK,
.details.ok.num_coins = awrh->num_coins
};
const json_t *j_sigs;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_array_const ("ev_sigs",
&j_sigs),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK!=
GNUNET_JSON_parse (j_response,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
if (awrh->num_coins != json_array_size (j_sigs))
{
/* Number of coins generated does not match our expectation */
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
for (size_t n = 0; n < awrh->num_coins; n++)
{
// TODO[oec] extract the individual coins.
}
awrh->callback (awrh->callback_cls,
&response);
/* make sure the callback isn't called again */
awrh->callback = NULL;
return GNUNET_OK;
}
/**
* Function called when we're done processing the
* HTTP /age-withdraw/$ACH/reveal request.
*
* @param cls the `struct TALER_EXCHANGE_AgeWithdrawRevealHandle`
* @param response_code The HTTP response code
* @param response response data
*/
static void
handle_age_withdraw_reveal_finished (
void *cls,
long response_code,
const void *response)
{
struct TALER_EXCHANGE_AgeWithdrawRevealHandle *awrh = cls;
const json_t *j_response = response;
struct TALER_EXCHANGE_AgeWithdrawRevealResponse awr = {
.hr.reply = j_response,
.hr.http_status = (unsigned int) response_code
};
awrh->job = NULL;
switch (response_code)
{
case 0:
awr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
break;
case MHD_HTTP_OK:
if (GNUNET_OK !=
age_withdraw_reveal_ok (awrh,
j_response))
{
GNUNET_break_op (0);
awr.hr.http_status = 0;
awr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
break;
}
GNUNET_assert (NULL == awrh->callback);
TALER_EXCHANGE_age_withdraw_reveal_cancel (awrh);
return;
case MHD_HTTP_UNAVAILABLE_FOR_LEGAL_REASONS:
/* only validate reply is well-formed */
{
uint64_t ptu;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_uint64 ("legitimization_uuid",
&ptu),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (j_response,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
awr.hr.http_status = 0;
awr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
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 */
awr.hr.ec = TALER_JSON_get_error_code (j_response);
awr.hr.hint = TALER_JSON_get_error_hint (j_response);
break;
case MHD_HTTP_FORBIDDEN:
GNUNET_break_op (0);
/**
* This should never happen, as we don't sent any signatures
* to the exchange to verify. We should simply pass the JSON reply
* to the application
**/
awr.hr.ec = TALER_JSON_get_error_code (j_response);
awr.hr.hint = TALER_JSON_get_error_hint (j_response);
break;
case MHD_HTTP_NOT_FOUND:
/* Nothing really to verify, the exchange basically just says
that it doesn't know this age-withraw commitment. */
awr.hr.ec = TALER_JSON_get_error_code (j_response);
awr.hr.hint = TALER_JSON_get_error_hint (j_response);
break;
case MHD_HTTP_CONFLICT:
/* An age commitment for one of the coins did not fulfill
* the required maximum age requirement of the corresponding
* reserve.
* Error code: TALER_EC_EXCHANGE_GENERIC_COIN_AGE_REQUIREMENT_FAILURE.
*/
awr.hr.ec = TALER_JSON_get_error_code (j_response);
awr.hr.hint = TALER_JSON_get_error_hint (j_response);
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 */
awr.hr.ec = TALER_JSON_get_error_code (j_response);
awr.hr.hint = TALER_JSON_get_error_hint (j_response);
break;
case MHD_HTTP_INTERNAL_SERVER_ERROR:
/* Server had an internal issue; we should retry, but this API
leaves this to the application */
awr.hr.ec = TALER_JSON_get_error_code (j_response);
awr.hr.hint = TALER_JSON_get_error_hint (j_response);
break;
default:
/* unexpected response code */
GNUNET_break_op (0);
awr.hr.ec = TALER_JSON_get_error_code (j_response);
awr.hr.hint = TALER_JSON_get_error_hint (j_response);
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Unexpected response code %u/%d for exchange age-withdraw\n",
(unsigned int) response_code,
(int) awr.hr.ec);
break;
}
awrh->callback (awrh->callback_cls,
&awr);
TALER_EXCHANGE_age_withdraw_reveal_cancel (awrh);
}
/**
* Prepares the request URL for the age-withdraw-reveal request
*
* @param exchange_url The base-URL to the exchange
* @param[in,out] awrh The handler
* @return GNUNET_OK on success, GNUNET_SYSERR otherwise
*/
static
enum GNUNET_GenericReturnValue
prepare_url (
const char *exchange_url,
struct TALER_EXCHANGE_AgeWithdrawRevealHandle *awrh)
{
char arg_str[sizeof (struct TALER_AgeWithdrawCommitmentHashP) * 2 + 32];
char pub_str[sizeof (struct TALER_AgeWithdrawCommitmentHashP) * 2];
char *end;
end = GNUNET_STRINGS_data_to_string (&awrh->h_commitment,
sizeof (awrh->h_commitment),
pub_str,
sizeof (pub_str));
*end = '\0';
GNUNET_snprintf (arg_str,
sizeof (arg_str),
"age-withraw/%s/reveal",
pub_str);
awrh->request_url = TALER_url_join (exchange_url,
arg_str,
NULL);
if (NULL == awrh->request_url)
{
GNUNET_break (0);
TALER_EXCHANGE_age_withdraw_reveal_cancel (awrh);
return GNUNET_SYSERR;
}
return GNUNET_OK;
}
/**
* Call /age-withdraw/$ACH/reveal
*
* @param awrh The handler
* @param num_coins Number of coin candidates in reveal_inputs
* @param reveal_inputs The secrets of the coin candidates
*/
static
void
perform_protocol (
struct TALER_EXCHANGE_AgeWithdrawRevealHandle *awrh)
{
CURL *curlh = NULL;
json_t *j_request_body = NULL;
json_t *j_array_of_secrets = NULL;
json_t *j_secrets = NULL;
json_t *j_sec = NULL;
#define FAIL_IF(cond) \
do { \
if ((cond)) \
{ \
GNUNET_break (! (cond)); \
goto ERROR; \
} \
} while(0)
for (size_t n = 0; n < awrh->num_coins; n++)
{
const struct TALER_PlanchetMasterSecretP *secrets =
awrh->coins_input[n].secrets;
j_secrets = json_array ();
FAIL_IF (NULL == j_secrets);
for (uint8_t k = 0; k < TALER_CNC_KAPPA; k++)
{
const struct TALER_PlanchetMasterSecretP *secret = &secrets[k];
if (awrh->noreveal_index == k)
continue;
j_sec = GNUNET_JSON_PACK (
GNUNET_JSON_pack_data_auto (NULL, secret));
FAIL_IF (NULL == j_sec);
FAIL_IF (0 < json_array_append_new (j_secrets,
j_sec));
}
FAIL_IF (0 < json_array_append_new (j_array_of_secrets,
j_secrets));
}
j_request_body = GNUNET_JSON_PACK (
GNUNET_JSON_pack_array_steal ("disclosed_coin_secrets",
j_array_of_secrets));
FAIL_IF (NULL == j_request_body);
curlh = TALER_EXCHANGE_curl_easy_get_ (awrh->request_url);
FAIL_IF (NULL == curlh);
FAIL_IF (GNUNET_OK !=
TALER_curl_easy_post (&awrh->post_ctx,
curlh,
j_request_body));
json_decref (j_request_body);
j_request_body = NULL;
awrh->job = GNUNET_CURL_job_add2 (awrh->curl_ctx,
curlh,
awrh->post_ctx.headers,
&handle_age_withdraw_reveal_finished,
awrh);
FAIL_IF (NULL == awrh->job);
/* No error, return */
return;
ERROR:
if (NULL != j_sec)
json_decref (j_sec);
if (NULL != j_secrets)
json_decref (j_secrets);
if (NULL != j_array_of_secrets)
json_decref (j_array_of_secrets);
if (NULL != j_request_body)
json_decref (j_request_body);
if (NULL != curlh)
curl_easy_cleanup (curlh);
TALER_EXCHANGE_age_withdraw_reveal_cancel (awrh);
return;
#undef FAIL_IF
}
struct TALER_EXCHANGE_AgeWithdrawRevealHandle *
TALER_EXCHANGE_age_withdraw_reveal (
struct GNUNET_CURL_Context *curl_ctx,
const char *exchange_url,
size_t num_coins,
const struct TALER_EXCHANGE_AgeWithdrawCoinInput coins_input[static
num_coins],
uint8_t noreveal_index,
const struct TALER_AgeWithdrawCommitmentHashP *h_commitment,
TALER_EXCHANGE_AgeWithdrawRevealCallback reveal_cb,
void *reveal_cb_cls)
{
struct TALER_EXCHANGE_AgeWithdrawRevealHandle *awrh =
GNUNET_new (struct TALER_EXCHANGE_AgeWithdrawRevealHandle);
awrh->curl_ctx = curl_ctx;
awrh->noreveal_index = noreveal_index;
awrh->callback = reveal_cb;
awrh->callback_cls = reveal_cb_cls;
awrh->h_commitment = *h_commitment;
awrh->num_coins = num_coins;
awrh->coins_input = coins_input;
if (GNUNET_OK !=
prepare_url (exchange_url,
awrh))
return NULL;
perform_protocol (awrh);
return awrh;
}
void
TALER_EXCHANGE_age_withdraw_reveal_cancel (
struct TALER_EXCHANGE_AgeWithdrawRevealHandle *awrh)
{
/* FIXME[oec] */
(void) awrh;
}
/* exchange_api_age_withdraw_reveal.c */