diff options
Diffstat (limited to 'src/exchange/taler-exchange-httpd_batch-withdraw.c')
| -rw-r--r-- | src/exchange/taler-exchange-httpd_batch-withdraw.c | 734 |
1 files changed, 734 insertions, 0 deletions
diff --git a/src/exchange/taler-exchange-httpd_batch-withdraw.c b/src/exchange/taler-exchange-httpd_batch-withdraw.c new file mode 100644 index 00000000..a6302aad --- /dev/null +++ b/src/exchange/taler-exchange-httpd_batch-withdraw.c @@ -0,0 +1,734 @@ +/* + This file is part of TALER + Copyright (C) 2014-2022 Taler Systems SA + + 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_batch-withdraw.c + * @brief Handle /reserves/$RESERVE_PUB/batch-withdraw requests + * @author Florian Dold + * @author Benedikt Mueller + * @author Christian Grothoff + */ +#include "platform.h" +#include <gnunet/gnunet_util_lib.h> +#include <jansson.h> +#include "taler_json_lib.h" +#include "taler_mhd_lib.h" +#include "taler-exchange-httpd_batch-withdraw.h" +#include "taler-exchange-httpd_responses.h" +#include "taler-exchange-httpd_keys.h" + + +/** + * Information per planchet in the batch. + */ +struct PlanchetContext +{ + + /** + * Hash of the (blinded) message to be signed by the Exchange. + */ + struct TALER_BlindedCoinHashP h_coin_envelope; + + /** + * Value of the coin being exchanged (matching the denomination key) + * plus the transaction fee. We include this in what is being + * signed so that we can verify a reserve's remaining total balance + * without needing to access the respective denomination key + * information each time. + */ + struct TALER_Amount amount_with_fee; + + /** + * Blinded planchet. + */ + struct TALER_BlindedPlanchet blinded_planchet; + + /** + * Set to the resulting signed coin data to be returned to the client. + */ + struct TALER_EXCHANGEDB_CollectableBlindcoin collectable; + +}; + +/** + * Context for #batch_withdraw_transaction. + */ +struct BatchWithdrawContext +{ + + /** + * Public key of the reserv. + */ + const struct TALER_ReservePublicKeyP *reserve_pub; + + /** + * KYC status of the reserve used for the operation. + */ + struct TALER_EXCHANGEDB_KycStatus kyc; + + /** + * Array of @e planchets_length planchets we are processing. + */ + struct PlanchetContext *planchets; + + /** + * Total amount from all coins with fees. + */ + struct TALER_Amount batch_total; + + /** + * Length of the @e planchets array. + */ + unsigned int planchets_length; + +}; + + +/** + * Send reserve history information to client with the + * message that we have insufficient funds for the + * requested withdraw operation. + * + * @param connection connection to the client + * @param ebalance expected balance based on our database + * @param withdraw_amount amount that the client requested to withdraw + * @param rh reserve history to return + * @return MHD result code + */ +static MHD_RESULT +reply_withdraw_insufficient_funds ( + struct MHD_Connection *connection, + const struct TALER_Amount *ebalance, + const struct TALER_Amount *withdraw_amount, + const struct TALER_EXCHANGEDB_ReserveHistory *rh) +{ + json_t *json_history; + + json_history = TEH_RESPONSE_compile_reserve_history (rh); + if (NULL == json_history) + return TALER_MHD_reply_with_error (connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_EXCHANGE_WITHDRAW_HISTORY_ERROR_INSUFFICIENT_FUNDS, + NULL); + return TALER_MHD_REPLY_JSON_PACK ( + connection, + MHD_HTTP_CONFLICT, + TALER_JSON_pack_ec (TALER_EC_EXCHANGE_WITHDRAW_INSUFFICIENT_FUNDS), + TALER_JSON_pack_amount ("balance", + ebalance), + TALER_JSON_pack_amount ("requested_amount", + withdraw_amount), + GNUNET_JSON_pack_array_steal ("history", + json_history)); +} + + +/** + * Function implementing withdraw transaction. Runs the + * transaction logic; IF it returns a non-error code, the transaction + * logic MUST NOT queue a MHD response. IF it returns an hard error, + * the transaction logic MUST queue a MHD response and set @a mhd_ret. + * IF it returns the soft error code, the function MAY be called again + * to retry and MUST not queue a MHD response. + * + * Note that "wc->collectable.sig" is set before entering this function as we + * signed before entering the transaction. + * + * @param cls a `struct BatchWithdrawContext *` + * @param connection MHD request which triggered the transaction + * @param[out] mhd_ret set to MHD response status for @a connection, + * if transaction failed (!) + * @return transaction status + */ +static enum GNUNET_DB_QueryStatus +batch_withdraw_transaction (void *cls, + struct MHD_Connection *connection, + MHD_RESULT *mhd_ret) +{ + struct BatchWithdrawContext *wc = cls; + struct GNUNET_TIME_Timestamp now; + uint64_t ruuid; + enum GNUNET_DB_QueryStatus qs; + bool balance_ok = false; + bool found = false; + + now = GNUNET_TIME_timestamp_get (); + qs = TEH_plugin->do_batch_withdraw (TEH_plugin->cls, + now, + wc->reserve_pub, + &wc->batch_total, + &balance_ok, + &found, + &wc->kyc, + &ruuid); + if (0 > qs) + { + if (GNUNET_DB_STATUS_HARD_ERROR == qs) + *mhd_ret = TALER_MHD_reply_with_error (connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_GENERIC_DB_FETCH_FAILED, + "update_reserve_batch_withdraw"); + return qs; + } + if (! found) + { + *mhd_ret = TALER_MHD_reply_with_error (connection, + MHD_HTTP_NOT_FOUND, + TALER_EC_EXCHANGE_WITHDRAW_RESERVE_UNKNOWN, + NULL); + return GNUNET_DB_STATUS_HARD_ERROR; + } + if (! balance_ok) + { + /* FIXME: logic shared with normal withdraw + => refactor and move to new TEH_responses function! */ + struct TALER_EXCHANGEDB_ReserveHistory *rh; + struct TALER_Amount balance; + + TEH_plugin->rollback (TEH_plugin->cls); + // FIXME: maybe start read-committed here? + if (GNUNET_OK != + TEH_plugin->start (TEH_plugin->cls, + "get_reserve_history on insufficient balance")) + { + GNUNET_break (0); + if (NULL != mhd_ret) + *mhd_ret = TALER_MHD_reply_with_error (connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_GENERIC_DB_START_FAILED, + NULL); + return GNUNET_DB_STATUS_HARD_ERROR; + } + /* The reserve does not have the required amount (actual + * amount + withdraw fee) */ + qs = TEH_plugin->get_reserve_history (TEH_plugin->cls, + &wc->collectable.reserve_pub, + &balance, + &rh); + if (NULL == rh) + { + if (GNUNET_DB_STATUS_HARD_ERROR == qs) + *mhd_ret = TALER_MHD_reply_with_error (connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_GENERIC_DB_FETCH_FAILED, + "reserve history"); + return GNUNET_DB_STATUS_HARD_ERROR; + } + *mhd_ret = reply_withdraw_insufficient_funds ( + connection, + &balance, + &wc->batch_total, + rh); + TEH_plugin->free_reserve_history (TEH_plugin->cls, + rh); + return GNUNET_DB_STATUS_HARD_ERROR; + } + + if ( (TEH_KYC_NONE != TEH_kyc_config.mode) && + (! wc->kyc.ok) && + (TALER_EXCHANGEDB_KYC_W2W == wc->kyc.type) ) + { + /* Wallet-to-wallet payments _always_ require KYC */ + *mhd_ret = TALER_MHD_REPLY_JSON_PACK ( + connection, + MHD_HTTP_ACCEPTED, + GNUNET_JSON_pack_uint64 ("payment_target_uuid", + wc->kyc.payment_target_uuid)); + return GNUNET_DB_STATUS_HARD_ERROR; + } + if ( (TEH_KYC_NONE != TEH_kyc_config.mode) && + (! wc->kyc.ok) && + (TALER_EXCHANGEDB_KYC_WITHDRAW == wc->kyc.type) && + (! GNUNET_TIME_relative_is_zero (TEH_kyc_config.withdraw_period)) ) + { + /* Withdraws require KYC if above threshold */ + enum GNUNET_DB_QueryStatus qs2; + bool below_limit; + + qs2 = TEH_plugin->do_withdraw_limit_check ( + TEH_plugin->cls, + ruuid, + GNUNET_TIME_absolute_subtract (now.abs_time, + TEH_kyc_config.withdraw_period), + &TEH_kyc_config.withdraw_limit, + &below_limit); + if (0 > qs2) + { + GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs2); + if (GNUNET_DB_STATUS_HARD_ERROR == qs2) + *mhd_ret = TALER_MHD_reply_with_error (connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_GENERIC_DB_FETCH_FAILED, + "do_withdraw_limit_check"); + return qs2; + } + if (! below_limit) + { + *mhd_ret = TALER_MHD_REPLY_JSON_PACK ( + connection, + MHD_HTTP_ACCEPTED, + GNUNET_JSON_pack_uint64 ("payment_target_uuid", + wc->kyc.payment_target_uuid)); + return GNUNET_DB_STATUS_HARD_ERROR; + } + } + + /* Add information about each planchet in the batch */ + for (unsigned int i = 0; i<wc->planchets_length; i++) + { + struct PlanchetContext *pc = &wc->planchets[i]; + const struct TALER_BlindedPlanchet *bp = &pc->blinded_planchet; + const struct TALER_CsNonce *nonce; + bool denom_unknown = true; + bool conflict = true; + bool nonce_reuse = true; + + nonce = (TALER_DENOMINATION_CS == bp->cipher) + ? &bp->details.cs_blinded_planchet.nonce + : NULL; + qs = TEH_plugin->do_batch_withdraw_insert (TEH_plugin->cls, + nonce, + &wc->collectable, + now, + ruuid, + &denom_unknown, + &conflict, + &nonce_reuse); + if (0 > qs) + { + if (GNUNET_DB_STATUS_HARD_ERROR == qs) + *mhd_ret = TALER_MHD_reply_with_error (connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_GENERIC_DB_FETCH_FAILED, + "do_withdraw"); + return qs; + } + if (denom_unknown) + { + GNUNET_break (0); + *mhd_ret = TALER_MHD_reply_with_error (connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_GENERIC_DB_INVARIANT_FAILURE, + NULL); + return GNUNET_DB_STATUS_HARD_ERROR; + } + if ( (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs) || + (conflict) ) + { + GNUNET_log (GNUNET_ERROR_TYPE_WARNING, + "Idempotent coin in batch, not allowed. Aborting.\n"); + *mhd_ret = TALER_MHD_reply_with_error (connection, + MHD_HTTP_CONFLICT, + TALER_EC_EXCHANGE_BATCH_IDEMPOTENT_PLANCHET, + NULL); + return GNUNET_DB_STATUS_HARD_ERROR; + } + if (nonce_reuse) + { + GNUNET_break_op (0); + *mhd_ret = TALER_MHD_reply_with_error (connection, + MHD_HTTP_BAD_REQUEST, + TALER_EC_EXCHANGE_WITHDRAW_NONCE_REUSE, + NULL); + return GNUNET_DB_STATUS_HARD_ERROR; + } + } + + return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT; +} + + +/** + * Check if the @a rc is replayed and we already have an + * answer. If so, replay the existing answer and return the + * HTTP response. + * + * @param rc request context + * @param[in,out] wc parsed request data + * @param[out] mret HTTP status, set if we return true + * @return true if the request is idempotent with an existing request + * false if we did not find the request in the DB and did not set @a mret + */ +static bool +check_request_idempotent (struct TEH_RequestContext *rc, + struct BatchWithdrawContext *wc, + MHD_RESULT *mret) +{ + /* FIXME: Not yet supported. Do we want to, or simply + generate an error in this case? */ +#if FIXME + enum GNUNET_DB_QueryStatus qs; + + qs = TEH_plugin->get_withdraw_info (TEH_plugin->cls, + &wc->h_coin_envelope, + &wc->collectable); + if (0 > qs) + { + GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs); + if (GNUNET_DB_STATUS_HARD_ERROR == qs) + *mret = TALER_MHD_reply_with_error (rc->connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_GENERIC_DB_FETCH_FAILED, + "get_withdraw_info"); + return true; /* well, kind-of */ + } + if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs) + return false; + /* generate idempotent reply */ + *mret = TALER_MHD_REPLY_JSON_PACK ( + rc->connection, + MHD_HTTP_OK, + TALER_JSON_pack_blinded_denom_sig ("ev_sig", + &wc->collectable.sig)); + TALER_blinded_denom_sig_free (&wc->collectable.sig); + return true; +#else + return false; +#endif +} + + +/** + * The request was parsed successfully. Prepare + * our side for the main DB transaction. + * + * @param rc request details + * @param wc storage for request processing + * @return MHD result for the @a rc + */ +static MHD_RESULT +prepare_transaction (struct TEH_RequestContext *rc, + struct BatchWithdrawContext *wc) +{ + /* Note: We could check the reserve balance here, + just to be reasonably sure that the reserve has + a sufficient balance before doing the "expensive" + signatures... */ + /* Sign before transaction! */ + for (unsigned int i = 0; i<wc->planchets_length; i++) + { + struct PlanchetContext *pc = &wc->planchets[i]; + enum TALER_ErrorCode ec; + + ec = TEH_keys_denomination_sign_withdraw ( + &pc->collectable.denom_pub_hash, + &pc->blinded_planchet, + &pc->collectable.sig); + if (TALER_EC_NONE != ec) + { + GNUNET_break (0); + return TALER_MHD_reply_with_ec (rc->connection, + ec, + NULL); + } + } + + /* run transaction */ + { + MHD_RESULT mhd_ret; + + if (GNUNET_OK != + TEH_DB_run_transaction (rc->connection, + "run batch withdraw", + TEH_MT_REQUEST_WITHDRAW, + &mhd_ret, + &batch_withdraw_transaction, + wc)) + { + return mhd_ret; + } + } + /* return final positive response */ + { + json_t *sigs; + + sigs = json_array (); + GNUNET_assert (NULL != sigs); + for (unsigned int i = 0; i<wc->planchets_length; i++) + { + struct PlanchetContext *pc = &wc->planchets[i]; + + GNUNET_assert ( + 0 == + json_array_append_new ( + sigs, + GNUNET_JSON_PACK ( + TALER_JSON_pack_blinded_denom_sig ( + "ev_sig", + &pc->collectable.sig)))); + } + return TALER_MHD_REPLY_JSON_PACK ( + rc->connection, + MHD_HTTP_OK, + GNUNET_JSON_pack_array_steal ("ev_sigs", + sigs)); + } +} + + +/** + * Continue processing the request @a rc by parsing the + * @a planchets and then running the transaction. + * + * @param rc request details + * @param wc storage for request processing + * @param planchets array of planchets to parse + * @return MHD result for the @a rc + */ +static MHD_RESULT +parse_planchets (struct TEH_RequestContext *rc, + struct BatchWithdrawContext *wc, + const json_t *planchets) +{ + struct TEH_KeyStateHandle *ksh; + MHD_RESULT mret; + + ksh = TEH_keys_get_state (); + if (NULL == ksh) + { + if (! check_request_idempotent (rc, + wc, + &mret)) + { + return TALER_MHD_reply_with_error (rc->connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_EXCHANGE_GENERIC_KEYS_MISSING, + NULL); + } + return mret; + } + for (unsigned int i = 0; i<wc->planchets_length; i++) + { + struct PlanchetContext *pc = &wc->planchets[i]; + struct GNUNET_JSON_Specification ispec[] = { + GNUNET_JSON_spec_fixed_auto ("reserve_sig", + &pc->collectable.reserve_sig), + GNUNET_JSON_spec_fixed_auto ("denom_pub_hash", + &pc->collectable.denom_pub_hash), + TALER_JSON_spec_blinded_planchet ("coin_ev", + &pc->blinded_planchet), + GNUNET_JSON_spec_end () + }; + struct TEH_DenominationKey *dk; + + { + enum GNUNET_GenericReturnValue res; + + res = TALER_MHD_parse_json_data (rc->connection, + json_array_get (planchets, + i), + ispec); + if (GNUNET_OK != res) + return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES; + } + pc->collectable.reserve_pub = *wc->reserve_pub; + dk = TEH_keys_denomination_by_hash2 (ksh, + &pc->collectable.denom_pub_hash, + NULL, + NULL); + if (NULL == dk) + { + if (! check_request_idempotent (rc, + wc, + &mret)) + { + return TEH_RESPONSE_reply_unknown_denom_pub_hash ( + rc->connection, + &pc->collectable.denom_pub_hash); + } + return mret; + } + if (GNUNET_TIME_absolute_is_past (dk->meta.expire_withdraw.abs_time)) + { + /* This denomination is past the expiration time for withdraws */ + if (! check_request_idempotent (rc, + wc, + &mret)) + { + GNUNET_JSON_parse_free (spec); + return TEH_RESPONSE_reply_expired_denom_pub_hash ( + rc->connection, + &wc->collectable.denom_pub_hash, + TALER_EC_EXCHANGE_GENERIC_DENOMINATION_EXPIRED, + "WITHDRAW"); + } + return mret; + } + if (GNUNET_TIME_absolute_is_future (dk->meta.start.abs_time)) + { + /* This denomination is not yet valid, no need to check + for idempotency! */ + return TEH_RESPONSE_reply_expired_denom_pub_hash ( + rc->connection, + &wc->collectable.denom_pub_hash, + TALER_EC_EXCHANGE_GENERIC_DENOMINATION_VALIDITY_IN_FUTURE, + "WITHDRAW"); + } + if (dk->recoup_possible) + { + /* This denomination has been revoked */ + if (! check_request_idempotent (rc, + wc, + &mret)) + { + return TEH_RESPONSE_reply_expired_denom_pub_hash ( + rc->connection, + &wc->collectable.denom_pub_hash, + TALER_EC_EXCHANGE_GENERIC_DENOMINATION_REVOKED, + "WITHDRAW"); + } + return mret; + } + if (dk->denom_pub.cipher != wc->blinded_planchet.cipher) + { + /* denomination cipher and blinded planchet cipher not the same */ + return TALER_MHD_reply_with_error (rc->connection, + MHD_HTTP_BAD_REQUEST, + TALER_EC_EXCHANGE_GENERIC_CIPHER_MISMATCH, + NULL); + } + if (0 > + TALER_amount_add (&pc->collectable.amount_with_fee, + &dk->meta.value, + &dk->meta.fees.withdraw)) + { + return TALER_MHD_reply_with_error (rc->connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_EXCHANGE_WITHDRAW_AMOUNT_FEE_OVERFLOW, + NULL); + } + if (0 > + TALER_amount_add (&wc->batch_total, + &wc->batch_total, + pc->collectable.amount_with_fee)) + { + return TALER_MHD_reply_with_error (rc->connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_EXCHANGE_WITHDRAW_AMOUNT_FEE_OVERFLOW, + NULL); + } + + if (GNUNET_OK != + TALER_coin_ev_hash (&pc->blinded_planchet, + &pc->collectable.denom_pub_hash, + &pc->collectable.h_coin_envelope)) + { + GNUNET_break (0); + GNUNET_JSON_parse_free (spec); + return TALER_MHD_reply_with_error (rc->connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE, + NULL); + } + TEH_METRICS_num_verifications[TEH_MT_SIGNATURE_EDDSA]++; + if (GNUNET_OK != + TALER_wallet_withdraw_verify (&pc->collectable.denom_pub_hash, + &pc->collectable.amount_with_fee, + &pc->collectable.h_coin_envelope, + &pc->collectable.reserve_pub, + &pc->collectable.reserve_sig)) + { + GNUNET_break_op (0); + GNUNET_JSON_parse_free (spec); + return TALER_MHD_reply_with_error (rc->connection, + MHD_HTTP_FORBIDDEN, + TALER_EC_EXCHANGE_WITHDRAW_RESERVE_SIGNATURE_INVALID, + NULL); + } + } + /* everything parsed */ + return prepare_transaction (rc, + wc); +} + + +MHD_RESULT +TEH_handler_batch_withdraw (struct TEH_RequestContext *rc, + const struct TALER_ReservePublicKeyP *reserve_pub, + const json_t *root) +{ + struct BatchWithdrawContext wc; + json_t *planchets; + struct GNUNET_JSON_Specification spec[] = { + GNUNET_JSON_spec_json ("planchets", + &planchets), + GNUNET_JSON_spec_end () + }; + + memset (&wc, + 0, + sizeof (wc)); + TALER_amount_set_zero (TEH_currency, + &wc.batch_total); + wc.reserve_pub = reserve_pub; + + { + enum GNUNET_GenericReturnValue res; + + res = TALER_MHD_parse_json_data (rc->connection, + root, + spec); + if (GNUNET_OK != res) + return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES; + } + if ( (! json_is_array (planchets)) || + (0 == json_array_size (planchets)) ) + { + GNUNET_JSON_parse_free (spec); + GNUNET_break_op (0); + return TALER_MHD_reply_with_error (rc->connection, + MHD_HTTP_BAD_REQUEST, + TALER_EC_GENERIC_PARAMETER_MALFORMED, + "planchets"); + } + wc.planchets_length = json_array_size (planchets); + if (wc.planchets_length > TALER_MAX_FRESH_COINS) + { + GNUNET_JSON_parse_free (spec); + GNUNET_break_op (0); + return TALER_MHD_reply_with_error (rc->connection, + MHD_HTTP_BAD_REQUEST, + TALER_EC_GENERIC_PARAMETER_MALFORMED, + "too many planchets"); + } + { + struct PlanchetContext splanchets[wc.planchets_length]; + MHD_RESULT ret; + + memset (splanchets, + 0, + sizeof (splanchets)); + wc.planchets = splanchets; + ret = parse_planchets (rc, + &wc, + planchets); + /* Clean up */ + for (unsigned int i = 0; i<wc.planchets_length; i++) + { + struct PlanchetContext *pc = &wc->planchets[i]; + + // FIXME: Free more of memory in pc! + TALER_blinded_denom_sig_free (&pc->collectable.sig); + } + GNUNET_JSON_parse_free (spec); + return ret; + } +} + + +/* end of taler-exchange-httpd_batch-withdraw.c */ |