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implement /payback parsing and signature verification

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This commit is contained in:
Christian Grothoff 2017-03-29 14:43:54 +02:00
parent 8d9dc14227
commit b38134ea4a
No known key found for this signature in database
GPG Key ID: 939E6BE1E29FC3CC
9 changed files with 315 additions and 12 deletions
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1
src/exchange/Makefile.am
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@ -37,6 +37,7 @@ taler_exchange_httpd_SOURCES = \
taler-exchange-httpd_keystate.c taler-exchange-httpd_keystate.h \
taler-exchange-httpd_mhd.c taler-exchange-httpd_mhd.h \
taler-exchange-httpd_parsing.c taler-exchange-httpd_parsing.h \
taler-exchange-httpd_payback.c taler-exchange-httpd_payback.h \
taler-exchange-httpd_refresh.c taler-exchange-httpd_refresh.h \
taler-exchange-httpd_refund.c taler-exchange-httpd_refund.h \
taler-exchange-httpd_reserve.c taler-exchange-httpd_reserve.h \

23
src/exchange/taler-exchange-httpd_db.c
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@ -2256,4 +2256,27 @@ TEH_DB_execute_track_transaction (struct MHD_Connection *connection,
}
/**
* Execute a "/payback". The validity of the coin and signature have
* already been checked. The database must now check that the coin is
* not (double) spent, and execute the transaction (record details,
* generate success or failure response).
*
* @param connection the MHD connection to handle
* @param coin information about the coin
* @param coin_bks blinding data of the coin (to be checked)
* @param coin_sig signature of the coin
* @return MHD result code
*/
int
TEH_DB_execute_payback (struct MHD_Connection *connection,
const struct TALER_CoinPublicInfo *coin,
const struct TALER_DenominationBlindingKeyP *coin_bks,
const struct TALER_CoinSpendSignatureP *coin_sig)
{
GNUNET_break (0); /* not implemented (#3887) */
return MHD_NO;
}
/* end of taler-exchange-httpd_db.c */

19
src/exchange/taler-exchange-httpd_db.h
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@ -236,5 +236,24 @@ TEH_DB_execute_track_transaction (struct MHD_Connection *connection,
const struct TALER_MerchantPublicKeyP *merchant_pub);
/**
* Execute a "/payback". The validity of the coin and signature have
* already been checked. The database must now check that the coin is
* not (double) spent, and execute the transaction (record details,
* generate success or failure response).
*
* @param connection the MHD connection to handle
* @param coin information about the coin
* @param coin_bks blinding data of the coin (to be checked)
* @param coin_sig signature of the coin
* @return MHD result code
*/
int
TEH_DB_execute_payback (struct MHD_Connection *connection,
const struct TALER_CoinPublicInfo *coin,
const struct TALER_DenominationBlindingKeyP *coin_bks,
const struct TALER_CoinSpendSignatureP *coin_sig);
#endif
/* TALER_EXCHANGE_HTTPD_DB_H */

3
src/exchange/taler-exchange-httpd_keystate.c
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@ -806,6 +806,9 @@ TEH_KS_denomination_key_lookup (const struct TEH_KS_StateHandle *key_state,
return NULL;
}
break;
case TEH_KS_DKU_PAYBACK:
GNUNET_break (0); /* not implemented (#3887) */
return NULL;
}
return dki;
}

9
src/exchange/taler-exchange-httpd_keystate.h
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@ -92,9 +92,14 @@ enum TEH_KS_DenominationKeyUse {
TEH_KS_DKU_WITHDRAW,
/**
* The key is to be usd for a /deposit or /refresh (melt) operation.
* The key is to be used for a /deposit or /refresh (melt) operation.
*/
TEH_KS_DKU_DEPOSIT
TEH_KS_DKU_DEPOSIT,
/**
* The key is to be used for a /payback operation.
*/
TEH_KS_DKU_PAYBACK
};

180
src/exchange/taler-exchange-httpd_payback.c Normal file
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@ -0,0 +1,180 @@
/*
This file is part of TALER
Copyright (C) 2017 Inria and GNUnet e.V.
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU Affero 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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License along with
TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* @file taler-exchange-httpd_payback.c
* @brief Handle /payback requests; parses the POST and JSON and
* verifies the coin signature before handing things off
* to the database.
* @author Christian Grothoff
*/
#include "platform.h"
#include <gnunet/gnunet_util_lib.h>
#include <gnunet/gnunet_json_lib.h>
#include <jansson.h>
#include <microhttpd.h>
#include <pthread.h>
#include "taler_json_lib.h"
#include "taler-exchange-httpd_parsing.h"
#include "taler-exchange-httpd_payback.h"
#include "taler-exchange-httpd_responses.h"
#include "taler-exchange-httpd_keystate.h"
#include "taler-exchange-httpd_validation.h"
/**
* We have parsed the JSON information about the payback request. Do
* some basic sanity checks (especially that the signature on the
* request and coin is valid) and then execute the payback operation.
* Note that we need the DB to check the fee structure, so this is not
* done here.
*
* @param connection the MHD connection to handle
* @param coin information about the coin
* @param coin_bks blinding data of the coin (to be checked)
* @param coin_sig signature of the coin
* @return MHD result code
*/
static int
verify_and_execute_payback (struct MHD_Connection *connection,
const struct TALER_CoinPublicInfo *coin,
const struct TALER_DenominationBlindingKeyP *coin_bks,
const struct TALER_CoinSpendSignatureP *coin_sig)
{
struct TEH_KS_StateHandle *key_state;
const struct TALER_EXCHANGEDB_DenominationKeyIssueInformation *dki;
struct TALER_PaybackRequestPS pr;
/* check denomination exists and is in payback mode */
key_state = TEH_KS_acquire ();
dki = TEH_KS_denomination_key_lookup (key_state,
&coin->denom_pub,
TEH_KS_DKU_PAYBACK);
if (NULL == dki)
{
TEH_KS_release (key_state);
TALER_LOG_WARNING ("Denomination key in /payback request not in payback mode\n");
return TEH_RESPONSE_reply_arg_unknown (connection,
TALER_EC_PAYBACK_DENOMINATION_KEY_UNKNOWN,
"denom_pub");
}
/* check denomination signature */
if (GNUNET_YES !=
TALER_test_coin_valid (coin))
{
TALER_LOG_WARNING ("Invalid coin passed for /payback\n");
TEH_KS_release (key_state);
return TEH_RESPONSE_reply_signature_invalid (connection,
TALER_EC_PAYBACK_DENOMINATION_SIGNATURE_INVALID,
"denom_sig");
}
/* check payback request signature */
pr.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_PAYBACK);
pr.purpose.size = htonl (sizeof (struct TALER_PaybackRequestPS));
pr.coin_pub = coin->coin_pub;
pr.h_denom_pub = dki->issue.properties.denom_hash;
pr.coin_blind = *coin_bks;
TEH_KS_release (key_state);
if (GNUNET_OK !=
GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_PAYBACK,
&pr.purpose,
&coin_sig->eddsa_signature,
&coin->coin_pub.eddsa_pub))
{
TALER_LOG_WARNING ("Invalid signature on /payback request\n");
return TEH_RESPONSE_reply_signature_invalid (connection,
TALER_EC_PAYBACK_SIGNATURE_INVALID,
"coin_sig");
}
return TEH_DB_execute_payback (connection,
coin,
coin_bks,
coin_sig);
}
/**
* Handle a "/payback" request. Parses the JSON, and, if successful,
* passes the JSON data to #parse_and_handle_payback_request() to
* further check the details of the operation specified. If
* everything checks out, this will ultimately lead to the "/refund"
* being executed, or rejected.
*
* @param rh context of the handler
* @param connection the MHD connection to handle
* @param[in,out] connection_cls the connection's closure (can be updated)
* @param upload_data upload data
* @param[in,out] upload_data_size number of bytes (left) in @a upload_data
* @return MHD result code
*/
int
TEH_PAYBACK_handler_payback (struct TEH_RequestHandler *rh,
struct MHD_Connection *connection,
void **connection_cls,
const char *upload_data,
size_t *upload_data_size)
{
json_t *json;
int res;
struct TALER_CoinPublicInfo coin;
struct TALER_DenominationBlindingKeyP coin_bks;
struct TALER_CoinSpendSignatureP coin_sig;
struct GNUNET_JSON_Specification spec[] = {
TALER_JSON_spec_denomination_public_key ("denom_pub",
&coin.denom_pub),
TALER_JSON_spec_denomination_signature ("ub_sig",
&coin.denom_sig),
GNUNET_JSON_spec_fixed_auto ("coin_pub",
&coin.coin_pub),
GNUNET_JSON_spec_fixed_auto ("coin_blind_key_secret",
&coin_bks),
GNUNET_JSON_spec_fixed_auto ("coin_sig",
&coin_sig),
GNUNET_JSON_spec_end ()
};
res = TEH_PARSE_post_json (connection,
connection_cls,
upload_data,
upload_data_size,
&json);
if (GNUNET_SYSERR == res)
return MHD_NO;
if ( (GNUNET_NO == res) || (NULL == json) )
return MHD_YES;
res = TEH_PARSE_json_data (connection,
json,
spec);
json_decref (json);
if (GNUNET_SYSERR == res)
return MHD_NO; /* hard failure */
if (GNUNET_NO == res)
return MHD_YES; /* failure */
res = verify_and_execute_payback (connection,
&coin,
&coin_bks,
&coin_sig);
GNUNET_JSON_parse_free (spec);
return res;
}
/* end of taler-exchange-httpd_payback.c */

51
src/exchange/taler-exchange-httpd_payback.h Normal file
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@ -0,0 +1,51 @@
/*
This file is part of TALER
Copyright (C) 2017 GNUnet e.V.
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU Affero 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 Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License along with
TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* @file taler-exchange-httpd_payback.h
* @brief Handle /payback requests
* @author Christian Grothoff
*/
#ifndef TALER_EXCHANGE_HTTPD_PAYBACK_H
#define TALER_EXCHANGE_HTTPD_PAYBACK_H
#include <gnunet/gnunet_util_lib.h>
#include <microhttpd.h>
#include "taler-exchange-httpd.h"
/**
* Handle a "/payback" request. Parses the JSON, and, if successful,
* passes the JSON data to #parse_and_handle_payback_request() to
* further check the details of the operation specified. If
* everything checks out, this will ultimately lead to the "/refund"
* being executed, or rejected.
*
* @param rh context of the handler
* @param connection the MHD connection to handle
* @param[in,out] connection_cls the connection's closure (can be updated)
* @param upload_data upload data
* @param[in,out] upload_data_size number of bytes (left) in @a upload_data
* @return MHD result code
*/
int
TEH_PAYBACK_handler_payback (struct TEH_RequestHandler *rh,
struct MHD_Connection *connection,
void **connection_cls,
const char *upload_data,
size_t *upload_data_size);
#endif

21
src/include/taler_error_codes.h
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@ -831,6 +831,27 @@ enum TALER_ErrorCode
*/
TALER_EC_TRACK_TRANSACTION_MERCHANT_SIGNATURE_INVALID = 1804,
/**
* The given denomination key is not in the "payback" set of the
* exchange right now. This response is provided with an
* HTTP status code of MHD_HTTP_NOT_FOUND.
*/
TALER_EC_PAYBACK_DENOMINATION_KEY_UNKNOWN = 1850,
/**
* The given coin signature is invalid for the request.
* This response is provided with an
* HTTP status code of MHD_HTTP_UNAUTHORIZED.
*/
TALER_EC_PAYBACK_SIGNATURE_INVALID = 1851,
/**
* The signature of the denomination key over the coin is not valid.
* This response is provided with HTTP status code
* MHD_HTTP_BAD_REQUEST.
*/
TALER_EC_PAYBACK_DENOMINATION_SIGNATURE_INVALID = 1852,
/* *********** Merchant backend error codes ********* */