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adapt withdraw2 API to support new tip-pickup design (#6173)

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This commit is contained in:
Christian Grothoff 2020-04-12 19:22:45 +02:00
parent 00350bc228
commit 9e3371ae9b
No known key found for this signature in database
GPG Key ID: 939E6BE1E29FC3CC
5 changed files with 629 additions and 511 deletions
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10
src/include/taler_error_codes.h
View File

@ -416,6 +416,12 @@ enum TALER_ErrorCode
*/
TALER_EC_WITHDRAW_REPLY_MALFORMED = 1118,
/**
* The client failed to unblind the blind signature. This error is not
* used in the protocol but created client-side.
*/
TALER_EC_WITHDRAW_UNBLIND_FAILURE = 1119,
/**
* The exchange failed to obtain the transaction history of the given
* reserve from the database. This response is provided with HTTP
@ -1203,14 +1209,14 @@ enum TALER_ErrorCode
* insufficient to satisfy the required amount for the contract. The
* client should revisit the logic used to calculate fees it must
* cover. This response is provided with HTTP status code
* #MHD_HTTP_BAD_REQUEST.
* #MHD_HTTP_ACCEPTED.
*/
TALER_EC_PAY_PAYMENT_INSUFFICIENT_DUE_TO_FEES = 2108,
/**
* Even if we do not consider deposit and wire fees, the payment is
* insufficient to satisfy the required amount for the contract. This
* response is provided with HTTP status code #MHD_HTTP_BAD_REQUEST.
* response is provided with HTTP status code #MHD_HTTP_ACCEPTED.
*/
TALER_EC_PAY_PAYMENT_INSUFFICIENT = 2109,

61
src/include/taler_exchange_service.h
View File

@ -1249,10 +1249,45 @@ TALER_EXCHANGE_withdraw (
void *res_cb_cls);
/**
* Cancel a withdraw status request. This function cannot be used
* on a request handle if a response is already served for it.
*
* @param wh the withdraw handle
*/
void
TALER_EXCHANGE_withdraw_cancel (struct TALER_EXCHANGE_WithdrawHandle *wh);
/**
* Callbacks of this type are used to serve the result of submitting a
* withdraw request to a exchange without the (un)blinding factor.
*
* @param cls closure
* @param hr HTTP response data
* @param blind_sig blind signature over the coin, NULL on error
*/
typedef void
(*TALER_EXCHANGE_Withdraw2Callback) (
void *cls,
const struct TALER_EXCHANGE_HttpResponse *hr,
const struct GNUNET_CRYPTO_RsaSignature *blind_sig);
/**
* @brief A /reserves/$RESERVE_PUB/withdraw Handle, 2nd variant.
* This variant does not do the blinding/unblinding and only
* fetches the blind signature on the already blinded planchet.
* Used internally by the `struct TALER_EXCHANGE_WithdrawHandle`
* implementation as well as for the tipping logic of merchants.
*/
struct TALER_EXCHANGE_Withdraw2Handle;
/**
* Withdraw a coin from the exchange using a /reserves/$RESERVE_PUB/withdraw
* request. This API is typically used by a wallet to withdraw a tip
* where the reserve's signature was created by the merchant already.
* request. This API is typically used by a merchant to withdraw a tip
* where the blinding factor is unknown to the merchant.
*
* Note that to ensure that no money is lost in case of hardware
* failures, the caller must have committed (most of) the arguments to
@ -1260,25 +1295,19 @@ TALER_EXCHANGE_withdraw (
* same arguments in case of failures.
*
* @param exchange the exchange handle; the exchange must be ready to operate
* @param pk kind of coin to create
* @param reserve_sig signature from the reserve authorizing the withdrawal
* @param reserve_pub public key of the reserve to withdraw from
* @param ps secrets of the planchet
* caller must have committed this value to disk before the call (with @a pk)
* @param pd planchet details of the planchet to withdraw
* @param reserve_priv private key of the reserve to withdraw from
* @param res_cb the callback to call when the final result for this request is available
* @param res_cb_cls closure for @a res_cb
* @return NULL
* if the inputs are invalid (i.e. denomination key not with this exchange).
* In this case, the callback is not called.
*/
struct TALER_EXCHANGE_WithdrawHandle *
TALER_EXCHANGE_withdraw2 (
struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_EXCHANGE_DenomPublicKey *pk,
const struct TALER_ReserveSignatureP *reserve_sig,
const struct TALER_ReservePublicKeyP *reserve_pub,
const struct TALER_PlanchetSecretsP *ps,
TALER_EXCHANGE_WithdrawCallback res_cb,
struct TALER_EXCHANGE_Withdraw2Handle *
TALER_EXCHANGE_withdraw2 (struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_PlanchetDetail *pd,
const struct TALER_ReservePrivateKeyP *reserve_priv,
TALER_EXCHANGE_Withdraw2Callback res_cb,
void *res_cb_cls);
@ -1289,7 +1318,7 @@ TALER_EXCHANGE_withdraw2 (
* @param wh the withdraw handle
*/
void
TALER_EXCHANGE_withdraw_cancel (struct TALER_EXCHANGE_WithdrawHandle *wh);
TALER_EXCHANGE_withdraw2_cancel (struct TALER_EXCHANGE_Withdraw2Handle *wh);
/* ********************* /refresh/melt+reveal ***************************** */

1
src/lib/Makefile.am
View File

@ -35,6 +35,7 @@ libtalerexchange_la_SOURCES = \
exchange_api_reserves_get.c \
exchange_api_transfers_get.c \
exchange_api_withdraw.c \
exchange_api_withdraw2.c \
exchange_api_wire.c
libtalerexchange_la_LIBADD = \
libtalerauditor.la \

551
src/lib/exchange_api_withdraw.c
View File

@ -16,7 +16,7 @@
*/
/**
* @file lib/exchange_api_withdraw.c
* @brief Implementation of the /reserves/$RESERVE_PUB/withdraw requests
* @brief Implementation of /reserves/$RESERVE_PUB/withdraw requests with blinding/unblinding
* @author Christian Grothoff
*/
#include "platform.h"
@ -44,26 +44,20 @@ struct TALER_EXCHANGE_WithdrawHandle
struct TALER_EXCHANGE_Handle *exchange;
/**
* The url for this request.
* Handle for the actual (internal) withdraw operation.
*/
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;
struct TALER_EXCHANGE_Withdraw2Handle *wh2;
/**
* Function to call with the result.
*/
TALER_EXCHANGE_WithdrawCallback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Secrets of the planchet.
*/
@ -74,412 +68,71 @@ struct TALER_EXCHANGE_WithdrawHandle
*/
struct TALER_EXCHANGE_DenomPublicKey pk;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Hash of the public key of the coin we are signing.
*/
struct GNUNET_HashCode c_hash;
/**
* Public key of the reserve we are withdrawing from.
*/
struct TALER_ReservePublicKeyP reserve_pub;
};
/**
* We got a 200 OK response for the /reserves/$RESERVE_PUB/withdraw operation.
* Extract the coin's signature and return it to the caller. The signature we
* get from the exchange is for the blinded value. Thus, we first must
* unblind it and then should verify its validity against our coin's hash.
*
* If everything checks out, we return the unblinded signature
* to the application via the callback.
*
* @param wh operation handle
* @param json reply from the exchange
* @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
*/
static int
reserve_withdraw_ok (struct TALER_EXCHANGE_WithdrawHandle *wh,
const json_t *json)
{
struct GNUNET_CRYPTO_RsaSignature *blind_sig;
struct TALER_FreshCoin fc;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_rsa_signature ("ev_sig",
&blind_sig),
GNUNET_JSON_spec_end ()
};
struct TALER_EXCHANGE_HttpResponse hr = {
.reply = json,
.http_status = MHD_HTTP_OK
};
if (GNUNET_OK !=
GNUNET_JSON_parse (json,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
TALER_planchet_to_coin (&wh->pk.key,
blind_sig,
&wh->ps,
&wh->c_hash,
&fc))
{
GNUNET_break_op (0);
GNUNET_JSON_parse_free (spec);
return GNUNET_SYSERR;
}
GNUNET_JSON_parse_free (spec);
/* signature is valid, return it to the application */
wh->cb (wh->cb_cls,
&hr,
&fc.sig);
/* make sure callback isn't called again after return */
wh->cb = NULL;
GNUNET_CRYPTO_rsa_signature_free (fc.sig.rsa_signature);
return GNUNET_OK;
}
/**
* We got a 409 CONFLICT response for the /reserves/$RESERVE_PUB/withdraw operation.
* Check the signatures on the withdraw transactions in the provided
* history and that the balances add up. We don't do anything directly
* with the information, as the JSON will be returned to the application.
* However, our job is ensuring that the exchange followed the protocol, and
* this in particular means checking all of the signatures in the history.
*
* @param wh operation handle
* @param json reply from the exchange
* @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
*/
static int
reserve_withdraw_payment_required (
struct TALER_EXCHANGE_WithdrawHandle *wh,
const json_t *json)
{
struct TALER_Amount balance;
struct TALER_Amount balance_from_history;
struct TALER_Amount requested_amount;
json_t *history;
size_t len;
struct GNUNET_JSON_Specification spec[] = {
TALER_JSON_spec_amount ("balance", &balance),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (json,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
history = json_object_get (json,
"history");
if (NULL == history)
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
/* go over transaction history and compute
total incoming and outgoing amounts */
len = json_array_size (history);
{
struct TALER_EXCHANGE_ReserveHistory *rhistory;
/* Use heap allocation as "len" may be very big and thus this may
not fit on the stack. Use "GNUNET_malloc_large" as a malicious
exchange may theoretically try to crash us by giving a history
that does not fit into our memory. */
rhistory = GNUNET_malloc_large (sizeof (struct
TALER_EXCHANGE_ReserveHistory)
* len);
if (NULL == rhistory)
{
GNUNET_break (0);
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
TALER_EXCHANGE_parse_reserve_history (wh->exchange,
history,
&wh->reserve_pub,
balance.currency,
&balance_from_history,
len,
rhistory))
{
GNUNET_break_op (0);
TALER_EXCHANGE_free_reserve_history (rhistory,
len);
return GNUNET_SYSERR;
}
TALER_EXCHANGE_free_reserve_history (rhistory,
len);
}
if (0 !=
TALER_amount_cmp (&balance_from_history,
&balance))
{
/* exchange cannot add up balances!? */
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
/* Compute how much we expected to charge to the reserve */
if (0 >
TALER_amount_add (&requested_amount,
&wh->pk.value,
&wh->pk.fee_withdraw))
{
/* Overflow here? Very strange, our CPU must be fried... */
GNUNET_break (0);
return GNUNET_SYSERR;
}
/* Check that funds were really insufficient */
if (0 >= TALER_amount_cmp (&requested_amount,
&balance))
{
/* Requested amount is smaller or equal to reported balance,
so this should not have failed. */
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
return GNUNET_OK;
}
/**
* Function called when we're done processing the
* HTTP /reserves/$RESERVE_PUB/withdraw request.
*
* @param cls the `struct TALER_EXCHANGE_WithdrawHandle`
* @param response_code HTTP response code, 0 on error
* @param response parsed JSON result, NULL on error
* @param hr HTTP response data
* @param blind_sig blind signature over the coin, NULL on error
*/
static void
handle_reserve_withdraw_finished (void *cls,
long response_code,
const void *response)
handle_reserve_withdraw_finished (
void *cls,
const struct TALER_EXCHANGE_HttpResponse *hr,
const struct GNUNET_CRYPTO_RsaSignature *blind_sig)
{
struct TALER_EXCHANGE_WithdrawHandle *wh = cls;
const json_t *j = response;
struct TALER_EXCHANGE_HttpResponse hr = {
.reply = j,
.http_status = (unsigned int) response_code
};
wh->job = NULL;
switch (response_code)
wh->wh2 = NULL;
if (MHD_HTTP_OK != hr->http_status)
{
case 0:
hr.ec = TALER_EC_INVALID_RESPONSE;
break;
case MHD_HTTP_OK:
if (GNUNET_OK !=
reserve_withdraw_ok (wh,
j))
{
GNUNET_break_op (0);
hr.http_status = 0;
hr.ec = TALER_EC_WITHDRAW_REPLY_MALFORMED;
break;
}
GNUNET_assert (NULL == wh->cb);
TALER_EXCHANGE_withdraw_cancel (wh);
return;
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 */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_CONFLICT:
/* The exchange says that the reserve has insufficient funds;
check the signatures in the history... */
if (GNUNET_OK !=
reserve_withdraw_payment_required (wh,
j))
{
GNUNET_break_op (0);
hr.http_status = 0;
hr.ec = TALER_EC_WITHDRAW_REPLY_MALFORMED;
wh->cb (wh->cb_cls,
hr,
NULL);
}
else
{
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
struct TALER_FreshCoin fc;
if (GNUNET_OK !=
TALER_planchet_to_coin (&wh->pk.key,
blind_sig,
&wh->ps,
&wh->c_hash,
&fc))
{
struct TALER_EXCHANGE_HttpResponse hrx = {
.reply = hr->reply,
.http_status = 0,
.ec = TALER_EC_WITHDRAW_UNBLIND_FAILURE
};
wh->cb (wh->cb_cls,
&hrx,
NULL);
}
break;
case MHD_HTTP_FORBIDDEN:
GNUNET_break_op (0);
/* 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 */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_NOT_FOUND:
/* Nothing really to verify, the exchange basically just says
that it doesn't know this reserve. Can happen if we
query before the wire transfer went through.
We should simply pass the JSON reply to the application. */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_INTERNAL_SERVER_ERROR:
/* Server had an internal issue; we should retry, but this API
leaves this to the application */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
default:
/* unexpected response code */
GNUNET_break_op (0);
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Unexpected response code %u/%d\n",
(unsigned int) response_code,
(int) hr.ec);
break;
}
if (NULL != wh->cb)
else
{
wh->cb (wh->cb_cls,
&hr,
NULL);
wh->cb = NULL;
hr,
&fc.sig);
GNUNET_CRYPTO_rsa_signature_free (fc.sig.rsa_signature);
}
}
TALER_EXCHANGE_withdraw_cancel (wh);
}
/**
* Helper function for #TALER_EXCHANGE_withdraw2() and
* #TALER_EXCHANGE_withdraw().
*
* @param exchange the exchange handle; the exchange must be ready to operate
* @param pk kind of coin to create
* @param reserve_sig signature from the reserve authorizing the withdrawal
* @param reserve_pub public key of the reserve to withdraw from
* @param ps secrets of the planchet
* caller must have committed this value to disk before the call (with @a pk)
* @param pd planchet details matching @a ps
* @param c_hash hash over the coin's public key
* @param res_cb the callback to call when the final result for this request is available
* @param res_cb_cls closure for @a res_cb
* @return NULL
* if the inputs are invalid (i.e. denomination key not with this exchange).
* In this case, the callback is not called.
*/
struct TALER_EXCHANGE_WithdrawHandle *
reserve_withdraw_internal (struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_EXCHANGE_DenomPublicKey *pk,
const struct TALER_ReserveSignatureP *reserve_sig,
const struct TALER_ReservePublicKeyP *reserve_pub,
const struct TALER_PlanchetSecretsP *ps,
const struct TALER_PlanchetDetail *pd,
const struct GNUNET_HashCode *c_hash,
TALER_EXCHANGE_WithdrawCallback res_cb,
void *res_cb_cls)
{
struct TALER_EXCHANGE_WithdrawHandle *wh;
struct GNUNET_CURL_Context *ctx;
json_t *withdraw_obj;
CURL *eh;
struct GNUNET_HashCode h_denom_pub;
char arg_str[sizeof (struct TALER_ReservePublicKeyP) * 2 + 32];
{
char pub_str[sizeof (struct TALER_ReservePublicKeyP) * 2];
char *end;
end = GNUNET_STRINGS_data_to_string (reserve_pub,
sizeof (struct
TALER_ReservePublicKeyP),
pub_str,
sizeof (pub_str));
*end = '\0';
GNUNET_snprintf (arg_str,
sizeof (arg_str),
"/reserves/%s/withdraw",
pub_str);
}
wh = GNUNET_new (struct TALER_EXCHANGE_WithdrawHandle);
wh->exchange = exchange;
wh->cb = res_cb;
wh->cb_cls = res_cb_cls;
wh->pk = *pk;
wh->pk.key.rsa_public_key
= GNUNET_CRYPTO_rsa_public_key_dup (pk->key.rsa_public_key);
wh->reserve_pub = *reserve_pub;
wh->c_hash = *c_hash;
GNUNET_CRYPTO_rsa_public_key_hash (pk->key.rsa_public_key,
&h_denom_pub);
withdraw_obj = json_pack ("{s:o, s:o," /* denom_pub_hash and coin_ev */
" s:o}",/* reserve_pub and reserve_sig */
"denom_pub_hash", GNUNET_JSON_from_data_auto (
&h_denom_pub),
"coin_ev", GNUNET_JSON_from_data (pd->coin_ev,
pd->coin_ev_size),
"reserve_sig", GNUNET_JSON_from_data_auto (
reserve_sig));
if (NULL == withdraw_obj)
{
GNUNET_break (0);
GNUNET_CRYPTO_rsa_public_key_free (wh->pk.key.rsa_public_key);
GNUNET_free (wh);
return NULL;
}
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Attempting to withdraw from reserve %s\n",
TALER_B2S (reserve_pub));
wh->ps = *ps;
wh->url = TEAH_path_to_url (exchange,
arg_str);
eh = TALER_EXCHANGE_curl_easy_get_ (wh->url);
if ( (NULL == eh) ||
(GNUNET_OK !=
TALER_curl_easy_post (&wh->ctx,
eh,
withdraw_obj)) )
{
GNUNET_break (0);
if (NULL != eh)
curl_easy_cleanup (eh);
json_decref (withdraw_obj);
GNUNET_free (wh->url);
GNUNET_CRYPTO_rsa_public_key_free (wh->pk.key.rsa_public_key);
GNUNET_free (wh);
return NULL;
}
json_decref (withdraw_obj);
ctx = TEAH_handle_to_context (exchange);
wh->job = GNUNET_CURL_job_add2 (ctx,
eh,
wh->ctx.headers,
&handle_reserve_withdraw_finished,
wh);
return wh;
}
/**
* Withdraw a coin from the exchange using a /reserve/withdraw request. Note
* that to ensure that no money is lost in case of hardware failures,
@ -507,114 +160,32 @@ TALER_EXCHANGE_withdraw (
TALER_EXCHANGE_WithdrawCallback res_cb,
void *res_cb_cls)
{
struct TALER_Amount amount_with_fee;
struct TALER_ReserveSignatureP reserve_sig;
struct TALER_WithdrawRequestPS req;
struct TALER_PlanchetDetail pd;
struct TALER_EXCHANGE_WithdrawHandle *wh;
struct GNUNET_HashCode c_hash;
GNUNET_CRYPTO_eddsa_key_get_public (&reserve_priv->eddsa_priv,
&req.reserve_pub.eddsa_pub);
req.purpose.size = htonl (sizeof (struct TALER_WithdrawRequestPS));
req.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_RESERVE_WITHDRAW);
if (0 >
TALER_amount_add (&amount_with_fee,
&pk->fee_withdraw,
&pk->value))
{
/* exchange gave us denomination keys that overflow like this!? */
GNUNET_break_op (0);
return NULL;
}
TALER_amount_hton (&req.amount_with_fee,
&amount_with_fee);
TALER_amount_hton (&req.withdraw_fee,
&pk->fee_withdraw);
wh = GNUNET_new (struct TALER_EXCHANGE_WithdrawHandle);
wh->exchange = exchange;
wh->cb = res_cb;
wh->cb_cls = res_cb_cls;
wh->pk = *pk;
wh->ps = *ps;
if (GNUNET_OK !=
TALER_planchet_prepare (&pk->key,
ps,
&c_hash,
&wh->c_hash,
&pd))
{
GNUNET_break_op (0);
GNUNET_free (wh);
return NULL;
}
req.h_denomination_pub = pd.denom_pub_hash;
GNUNET_CRYPTO_hash (pd.coin_ev,
pd.coin_ev_size,
&req.h_coin_envelope);
GNUNET_CRYPTO_eddsa_sign (&reserve_priv->eddsa_priv,
&req,
&reserve_sig.eddsa_signature);
wh = reserve_withdraw_internal (exchange,
pk,
&reserve_sig,
&req.reserve_pub,
ps,
wh->pk.key.rsa_public_key
= GNUNET_CRYPTO_rsa_public_key_dup (pk->key.rsa_public_key);
wh->wh2 = TALER_EXCHANGE_withdraw2 (exchange,
&pd,
&c_hash,
res_cb,
res_cb_cls);
GNUNET_free (pd.coin_ev);
return wh;
}
/**
* Withdraw a coin from the exchange using a /reserve/withdraw
* request. This API is typically used by a wallet to withdraw a tip
* where the reserve's signature was created by the merchant already.
*
* Note that to ensure that no money is lost in case of hardware
* failures, the caller must have committed (most of) the arguments to
* disk before calling, and be ready to repeat the request with the
* same arguments in case of failures.
*
* @param exchange the exchange handle; the exchange must be ready to operate
* @param pk kind of coin to create
* @param reserve_sig signature from the reserve authorizing the withdrawal
* @param reserve_pub public key of the reserve to withdraw from
* @param ps secrets of the planchet
* caller must have committed this value to disk before the call (with @a pk)
* @param res_cb the callback to call when the final result for this request is available
* @param res_cb_cls closure for @a res_cb
* @return NULL
* if the inputs are invalid (i.e. denomination key not with this exchange).
* In this case, the callback is not called.
*/
struct TALER_EXCHANGE_WithdrawHandle *
TALER_EXCHANGE_withdraw2 (
struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_EXCHANGE_DenomPublicKey *pk,
const struct TALER_ReserveSignatureP *reserve_sig,
const struct TALER_ReservePublicKeyP *reserve_pub,
const struct TALER_PlanchetSecretsP *ps,
TALER_EXCHANGE_WithdrawCallback res_cb,
void *res_cb_cls)
{
struct TALER_EXCHANGE_WithdrawHandle *wh;
struct GNUNET_HashCode c_hash;
struct TALER_PlanchetDetail pd;
if (GNUNET_OK !=
TALER_planchet_prepare (&pk->key,
ps,
&c_hash,
&pd))
{
GNUNET_break_op (0);
return NULL;
}
wh = reserve_withdraw_internal (exchange,
pk,
reserve_sig,
reserve_pub,
ps,
&pd,
&c_hash,
res_cb,
res_cb_cls);
reserve_priv,
&handle_reserve_withdraw_finished,
wh);
GNUNET_free (pd.coin_ev);
return wh;
}
@ -629,13 +200,11 @@ TALER_EXCHANGE_withdraw2 (
void
TALER_EXCHANGE_withdraw_cancel (struct TALER_EXCHANGE_WithdrawHandle *wh)
{
if (NULL != wh->job)
if (NULL != wh->wh2)
{
GNUNET_CURL_job_cancel (wh->job);
wh->job = NULL;
TALER_EXCHANGE_withdraw2_cancel (wh->wh2);
wh->wh2 = NULL;
}
GNUNET_free (wh->url);
TALER_curl_easy_post_finished (&wh->ctx);
GNUNET_CRYPTO_rsa_public_key_free (wh->pk.key.rsa_public_key);
GNUNET_free (wh);
}

513
src/lib/exchange_api_withdraw2.c Normal file
View File

@ -0,0 +1,513 @@
/*
This file is part of TALER
Copyright (C) 2014-2020 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_withdraw2.c
* @brief Implementation of /reserves/$RESERVE_PUB/withdraw requests without blinding/unblinding
* @author Christian Grothoff
*/
#include "platform.h"
#include <jansson.h>
#include <microhttpd.h> /* just for HTTP status codes */
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <gnunet/gnunet_curl_lib.h>
#include "taler_exchange_service.h"
#include "taler_json_lib.h"
#include "exchange_api_handle.h"
#include "taler_signatures.h"
#include "exchange_api_curl_defaults.h"
/**
* @brief A Withdraw Handle
*/
struct TALER_EXCHANGE_Withdraw2Handle
{
/**
* The connection to exchange this request handle will use
*/
struct TALER_EXCHANGE_Handle *exchange;
/**
* The url for this request.
*/
char *url;
/**
* Handle for the request.
*/
struct GNUNET_CURL_Job *job;
/**
* Function to call with the result.
*/
TALER_EXCHANGE_Withdraw2Callback cb;
/**
* Closure for @a cb.
*/
void *cb_cls;
/**
* Context for #TEH_curl_easy_post(). Keeps the data that must
* persist for Curl to make the upload.
*/
struct TALER_CURL_PostContext post_ctx;
/**
* Total amount requested (value plus withdraw fee).
*/
struct TALER_Amount requested_amount;
/**
* Public key of the reserve we are withdrawing from.
*/
struct TALER_ReservePublicKeyP reserve_pub;
};
/**
* We got a 200 OK response for the /reserves/$RESERVE_PUB/withdraw operation.
* Extract the coin's signature and return it to the caller. The signature we
* get from the exchange is for the blinded value. Thus, we first must
* unblind it and then should verify its validity against our coin's hash.
*
* If everything checks out, we return the unblinded signature
* to the application via the callback.
*
* @param wh operation handle
* @param json reply from the exchange
* @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
*/
static int
reserve_withdraw_ok (struct TALER_EXCHANGE_Withdraw2Handle *wh,
const json_t *json)
{
struct GNUNET_CRYPTO_RsaSignature *blind_sig;
struct GNUNET_JSON_Specification spec[] = {
GNUNET_JSON_spec_rsa_signature ("ev_sig",
&blind_sig),
GNUNET_JSON_spec_end ()
};
struct TALER_EXCHANGE_HttpResponse hr = {
.reply = json,
.http_status = MHD_HTTP_OK
};
if (GNUNET_OK !=
GNUNET_JSON_parse (json,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
/* signature is valid, return it to the application */
wh->cb (wh->cb_cls,
&hr,
blind_sig);
/* make sure callback isn't called again after return */
wh->cb = NULL;
GNUNET_JSON_parse_free (spec);
return GNUNET_OK;
}
/**
* We got a 409 CONFLICT response for the /reserves/$RESERVE_PUB/withdraw operation.
* Check the signatures on the withdraw transactions in the provided
* history and that the balances add up. We don't do anything directly
* with the information, as the JSON will be returned to the application.
* However, our job is ensuring that the exchange followed the protocol, and
* this in particular means checking all of the signatures in the history.
*
* @param wh operation handle
* @param json reply from the exchange
* @return #GNUNET_OK on success, #GNUNET_SYSERR on errors
*/
static int
reserve_withdraw_payment_required (
struct TALER_EXCHANGE_Withdraw2Handle *wh,
const json_t *json)
{
struct TALER_Amount balance;
struct TALER_Amount balance_from_history;
json_t *history;
size_t len;
struct GNUNET_JSON_Specification spec[] = {
TALER_JSON_spec_amount ("balance", &balance),
GNUNET_JSON_spec_end ()
};
if (GNUNET_OK !=
GNUNET_JSON_parse (json,
spec,
NULL, NULL))
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
history = json_object_get (json,
"history");
if (NULL == history)
{
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
/* go over transaction history and compute
total incoming and outgoing amounts */
len = json_array_size (history);
{
struct TALER_EXCHANGE_ReserveHistory *rhistory;
/* Use heap allocation as "len" may be very big and thus this may
not fit on the stack. Use "GNUNET_malloc_large" as a malicious
exchange may theoretically try to crash us by giving a history
that does not fit into our memory. */
rhistory = GNUNET_malloc_large (sizeof (struct
TALER_EXCHANGE_ReserveHistory)
* len);
if (NULL == rhistory)
{
GNUNET_break (0);
return GNUNET_SYSERR;
}
if (GNUNET_OK !=
TALER_EXCHANGE_parse_reserve_history (wh->exchange,
history,
&wh->reserve_pub,
balance.currency,
&balance_from_history,
len,
rhistory))
{
GNUNET_break_op (0);
TALER_EXCHANGE_free_reserve_history (rhistory,
len);
return GNUNET_SYSERR;
}
TALER_EXCHANGE_free_reserve_history (rhistory,
len);
}
if (0 !=
TALER_amount_cmp (&balance_from_history,
&balance))
{
/* exchange cannot add up balances!? */
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
/* Check that funds were really insufficient */
if (0 >= TALER_amount_cmp (&wh->requested_amount,
&balance))
{
/* Requested amount is smaller or equal to reported balance,
so this should not have failed. */
GNUNET_break_op (0);
return GNUNET_SYSERR;
}
return GNUNET_OK;
}
/**
* Function called when we're done processing the
* HTTP /reserves/$RESERVE_PUB/withdraw request.
*
* @param cls the `struct TALER_EXCHANGE_WithdrawHandle`
* @param response_code HTTP response code, 0 on error
* @param response parsed JSON result, NULL on error
*/
static void
handle_reserve_withdraw_finished (void *cls,
long response_code,
const void *response)
{
struct TALER_EXCHANGE_Withdraw2Handle *wh = cls;
const json_t *j = response;
struct TALER_EXCHANGE_HttpResponse hr = {
.reply = j,
.http_status = (unsigned int) response_code
};
wh->job = NULL;
switch (response_code)
{
case 0:
hr.ec = TALER_EC_INVALID_RESPONSE;
break;
case MHD_HTTP_OK:
if (GNUNET_OK !=
reserve_withdraw_ok (wh,
j))
{
GNUNET_break_op (0);
hr.http_status = 0;
hr.ec = TALER_EC_WITHDRAW_REPLY_MALFORMED;
break;
}
GNUNET_assert (NULL == wh->cb);
TALER_EXCHANGE_withdraw2_cancel (wh);
return;
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 */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_CONFLICT:
/* The exchange says that the reserve has insufficient funds;
check the signatures in the history... */
if (GNUNET_OK !=
reserve_withdraw_payment_required (wh,
j))
{
GNUNET_break_op (0);
hr.http_status = 0;
hr.ec = TALER_EC_WITHDRAW_REPLY_MALFORMED;
}
else
{
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
}
break;
case MHD_HTTP_FORBIDDEN:
GNUNET_break_op (0);
/* 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 */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_NOT_FOUND:
/* Nothing really to verify, the exchange basically just says
that it doesn't know this reserve. Can happen if we
query before the wire transfer went through.
We should simply pass the JSON reply to the application. */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
case MHD_HTTP_INTERNAL_SERVER_ERROR:
/* Server had an internal issue; we should retry, but this API
leaves this to the application */
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
break;
default:
/* unexpected response code */
GNUNET_break_op (0);
hr.ec = TALER_JSON_get_error_code (j);
hr.hint = TALER_JSON_get_error_hint (j);
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"Unexpected response code %u/%d\n",
(unsigned int) response_code,
(int) hr.ec);
break;
}
if (NULL != wh->cb)
{
wh->cb (wh->cb_cls,
&hr,
NULL);
wh->cb = NULL;
}
TALER_EXCHANGE_withdraw2_cancel (wh);
}
/**
* Withdraw a coin from the exchange using a /reserve/withdraw
* request. This API is typically used by a wallet to withdraw a tip
* where the reserve's signature was created by the merchant already.
*
* Note that to ensure that no money is lost in case of hardware
* failures, the caller must have committed (most of) the arguments to
* disk before calling, and be ready to repeat the request with the
* same arguments in case of failures.
*
* @param exchange the exchange handle; the exchange must be ready to operate
* @param pk kind of coin to create
* @param reserve_sig signature from the reserve authorizing the withdrawal
* @param reserve_pub public key of the reserve to withdraw from
* @param ps secrets of the planchet
* caller must have committed this value to disk before the call (with @a pk)
* @param res_cb the callback to call when the final result for this request is available
* @param res_cb_cls closure for @a res_cb
* @return NULL
* if the inputs are invalid (i.e. denomination key not with this exchange).
* In this case, the callback is not called.
*/
struct TALER_EXCHANGE_Withdraw2Handle *
TALER_EXCHANGE_withdraw2 (
struct TALER_EXCHANGE_Handle *exchange,
const struct TALER_PlanchetDetail *pd,
const struct TALER_ReservePrivateKeyP *reserve_priv,
TALER_EXCHANGE_Withdraw2Callback res_cb,
void *res_cb_cls)
{
struct TALER_EXCHANGE_Withdraw2Handle *wh;
const struct TALER_EXCHANGE_Keys *keys;
const struct TALER_EXCHANGE_DenomPublicKey *dk;
struct TALER_ReserveSignatureP reserve_sig;
char arg_str[sizeof (struct TALER_ReservePublicKeyP) * 2 + 32];
keys = TALER_EXCHANGE_get_keys (exchange);
if (NULL == keys)
{
GNUNET_break (0);
return NULL;
}
dk = TALER_EXCHANGE_get_denomination_key_by_hash (keys,
&pd->denom_pub_hash);
if (NULL == dk)
{
GNUNET_break (0);
return NULL;
}
wh = GNUNET_new (struct TALER_EXCHANGE_Withdraw2Handle);
wh->exchange = exchange;
wh->cb = res_cb;
wh->cb_cls = res_cb_cls;
/* Compute how much we expected to charge to the reserve */
if (0 >
TALER_amount_add (&wh->requested_amount,
&dk->value,
&dk->fee_withdraw))
{
/* Overflow here? Very strange, our CPU must be fried... */
GNUNET_break (0);
GNUNET_free (wh);
return NULL;
}
GNUNET_CRYPTO_eddsa_key_get_public (&reserve_priv->eddsa_priv,
&wh->reserve_pub.eddsa_pub);
{
char pub_str[sizeof (struct TALER_ReservePublicKeyP) * 2];
char *end;
end = GNUNET_STRINGS_data_to_string (
&wh->reserve_pub,
sizeof (struct TALER_ReservePublicKeyP),
pub_str,
sizeof (pub_str));
*end = '\0';
GNUNET_snprintf (arg_str,
sizeof (arg_str),
"/reserves/%s/withdraw",
pub_str);
}
{
struct TALER_WithdrawRequestPS req = {
.purpose.size = htonl (sizeof (struct TALER_WithdrawRequestPS)),
.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_RESERVE_WITHDRAW),
.reserve_pub = wh->reserve_pub,
.h_denomination_pub = pd->denom_pub_hash
};
TALER_amount_hton (&req.amount_with_fee,
&wh->requested_amount);
TALER_amount_hton (&req.withdraw_fee,
&dk->fee_withdraw);
GNUNET_CRYPTO_hash (pd->coin_ev,
pd->coin_ev_size,
&req.h_coin_envelope);
GNUNET_CRYPTO_eddsa_sign (&reserve_priv->eddsa_priv,
&req,
&reserve_sig.eddsa_signature);
}
{
json_t *withdraw_obj;
withdraw_obj = json_pack ("{s:o, s:o, s:o}",
"denom_pub_hash",
GNUNET_JSON_from_data_auto (&pd->denom_pub_hash),
"coin_ev",
GNUNET_JSON_from_data (pd->coin_ev,
pd->coin_ev_size),
"reserve_sig",
GNUNET_JSON_from_data_auto (&reserve_sig));
if (NULL == withdraw_obj)
{
GNUNET_break (0);
GNUNET_free (wh);
return NULL;
}
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Attempting to withdraw from reserve %s\n",
TALER_B2S (&wh->reserve_pub));
wh->url = TEAH_path_to_url (exchange,
arg_str);
{
CURL *eh;
struct GNUNET_CURL_Context *ctx;
ctx = TEAH_handle_to_context (exchange);
eh = TALER_EXCHANGE_curl_easy_get_ (wh->url);
if ( (NULL == eh) ||
(GNUNET_OK !=
TALER_curl_easy_post (&wh->post_ctx,
eh,
withdraw_obj)) )
{
GNUNET_break (0);
if (NULL != eh)
curl_easy_cleanup (eh);
json_decref (withdraw_obj);
GNUNET_free (wh->url);
GNUNET_free (wh);
return NULL;
}
json_decref (withdraw_obj);
wh->job = GNUNET_CURL_job_add2 (ctx,
eh,
wh->post_ctx.headers,
&handle_reserve_withdraw_finished,
wh);
}
}
return wh;
}
/**
* Cancel a withdraw status request. This function cannot be used
* on a request handle if a response is already served for it.
*
* @param wh the withdraw sign request handle
*/
void
TALER_EXCHANGE_withdraw2_cancel (struct TALER_EXCHANGE_Withdraw2Handle *wh)
{
if (NULL != wh->job)
{
GNUNET_CURL_job_cancel (wh->job);
wh->job = NULL;
}
GNUNET_free (wh->url);
TALER_curl_easy_post_finished (&wh->post_ctx);
GNUNET_free (wh);
}