diff options
Diffstat (limited to 'src/exchange/taler-exchange-httpd_melt.c')
| -rw-r--r-- | src/exchange/taler-exchange-httpd_melt.c | 203 |
1 files changed, 114 insertions, 89 deletions
diff --git a/src/exchange/taler-exchange-httpd_melt.c b/src/exchange/taler-exchange-httpd_melt.c index 86d0b32b4..77fb19362 100644 --- a/src/exchange/taler-exchange-httpd_melt.c +++ b/src/exchange/taler-exchange-httpd_melt.c @@ -1,6 +1,6 @@ /* This file is part of TALER - Copyright (C) 2014-2019 Taler Systems SA + 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 Affero General Public License as published by the Free Software @@ -15,7 +15,7 @@ */ /** * @file taler-exchange-httpd_melt.c - * @brief Handle /refresh/melt requests + * @brief Handle melt requests * @author Florian Dold * @author Benedikt Mueller * @author Christian Grothoff @@ -33,7 +33,7 @@ /** - * Send a response for a failed "/refresh/melt" request. The + * Send a response for a failed "melt" request. The * transaction history of the given coin demonstrates that the * @a residual value of the coin is below the @a requested * contribution of the coin for the melt. Thus, the exchange @@ -48,14 +48,13 @@ * @return a MHD result code */ static int -reply_melt_insufficient_funds (struct MHD_Connection *connection, - const struct - TALER_CoinSpendPublicKeyP *coin_pub, - const struct TALER_Amount *coin_value, - struct TALER_EXCHANGEDB_TransactionList * - tl, - const struct TALER_Amount *requested, - const struct TALER_Amount *residual) +reply_melt_insufficient_funds ( + struct MHD_Connection *connection, + const struct TALER_CoinSpendPublicKeyP *coin_pub, + const struct TALER_Amount *coin_value, + struct TALER_EXCHANGEDB_TransactionList *tl, + const struct TALER_Amount *requested, + const struct TALER_Amount *residual) { json_t *history; @@ -88,7 +87,7 @@ reply_melt_insufficient_funds (struct MHD_Connection *connection, /** - * Send a response to a "/refresh/melt" request. + * Send a response to a "melt" request. * * @param connection the connection to send the response to * @param rc value the client commited to @@ -100,15 +99,15 @@ reply_melt_success (struct MHD_Connection *connection, const struct TALER_RefreshCommitmentP *rc, uint32_t noreveal_index) { - struct TALER_RefreshMeltConfirmationPS body; struct TALER_ExchangePublicKeyP pub; struct TALER_ExchangeSignatureP sig; - json_t *sig_json; + struct TALER_RefreshMeltConfirmationPS body = { + .purpose.size = htonl (sizeof (body)), + .purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_MELT), + .rc = *rc, + .noreveal_index = htonl (noreveal_index) + }; - body.purpose.size = htonl (sizeof (struct TALER_RefreshMeltConfirmationPS)); - body.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_CONFIRM_MELT); - body.rc = *rc; - body.noreveal_index = htonl (noreveal_index); if (GNUNET_OK != TEH_KS_sign (&body.purpose, &pub, @@ -119,22 +118,20 @@ reply_melt_success (struct MHD_Connection *connection, TALER_EC_EXCHANGE_BAD_CONFIGURATION, "no keys"); } - sig_json = GNUNET_JSON_from_data_auto (&sig); - GNUNET_assert (NULL != sig_json); - return TALER_MHD_reply_json_pack (connection, - MHD_HTTP_OK, - "{s:i, s:o, s:o}", - "noreveal_index", (int) noreveal_index, - "exchange_sig", sig_json, - "exchange_pub", - GNUNET_JSON_from_data_auto (&pub)); + return TALER_MHD_reply_json_pack ( + connection, + MHD_HTTP_OK, + "{s:i, s:o, s:o}", + "noreveal_index", (int) noreveal_index, + "exchange_sig", GNUNET_JSON_from_data_auto (&sig), + "exchange_pub", GNUNET_JSON_from_data_auto (&pub)); } /** - * Context for the /refresh/melt operation. + * Context for the melt operation. */ -struct RefreshMeltContext +struct MeltContext { /** @@ -176,7 +173,7 @@ struct RefreshMeltContext static enum GNUNET_DB_QueryStatus refresh_check_melt (struct MHD_Connection *connection, struct TALER_EXCHANGEDB_Session *session, - struct RefreshMeltContext *rmc, + struct MeltContext *rmc, int *mhd_ret) { struct TALER_EXCHANGEDB_TransactionList *tl; @@ -186,7 +183,7 @@ refresh_check_melt (struct MHD_Connection *connection, /* Start with cost of this melt transaction */ spent = rmc->refresh_session.amount_with_fee; - /* add historic transaction costs of this coin, including recoups as + /* get historic transaction costs of this coin, including recoups as we might be a zombie coin */ qs = TEH_plugin->get_coin_transactions (TEH_plugin->cls, session, @@ -204,20 +201,23 @@ refresh_check_melt (struct MHD_Connection *connection, } if (rmc->zombie_required) { + /* The denomination key is only usable for a melt if this is a true + zombie coin, i.e. it was refreshed and the resulting fresh coin was + then recouped. Check that this is truly the case. */ for (struct TALER_EXCHANGEDB_TransactionList *tp = tl; NULL != tp; tp = tp->next) { if (TALER_EXCHANGEDB_TT_OLD_COIN_RECOUP == tp->type) { - rmc->zombie_required = GNUNET_NO; /* was satisfied! */ + rmc->zombie_required = GNUNET_NO; /* clear flag: was satisfied! */ break; } } - if (rmc->zombie_required) + if (GNUNET_YES == rmc->zombie_required) { /* zombie status not satisfied */ - GNUNET_break (0); + GNUNET_break_op (0); TEH_plugin->free_coin_transaction_list (TEH_plugin->cls, tl); *mhd_ret = TALER_MHD_reply_with_error (connection, @@ -244,8 +244,8 @@ refresh_check_melt (struct MHD_Connection *connection, /* Refuse to refresh when the coin's value is insufficient for the cost of all transactions. */ - if (TALER_amount_cmp (&rmc->coin_value, - &spent) < 0) + if (0 > TALER_amount_cmp (&rmc->coin_value, + &spent)) { struct TALER_Amount coin_residual; @@ -253,14 +253,13 @@ refresh_check_melt (struct MHD_Connection *connection, TALER_amount_subtract (&coin_residual, &spent, &rmc->refresh_session.amount_with_fee)); - *mhd_ret = reply_melt_insufficient_funds (connection, - &rmc->refresh_session.coin - .coin_pub, - &rmc->coin_value, - tl, - &rmc->refresh_session. - amount_with_fee, - &coin_residual); + *mhd_ret = reply_melt_insufficient_funds ( + connection, + &rmc->refresh_session.coin.coin_pub, + &rmc->coin_value, + tl, + &rmc->refresh_session.amount_with_fee, + &coin_residual); TEH_plugin->free_coin_transaction_list (TEH_plugin->cls, tl); return GNUNET_DB_STATUS_HARD_ERROR; @@ -274,7 +273,7 @@ refresh_check_melt (struct MHD_Connection *connection, /** - * Execute a "/refresh/melt". We have been given a list of valid + * Execute a "melt". We have been given a list of valid * coins and a request to melt them into the given @a * refresh_session_pub. Check that the coins all have the required * value left and if so, store that they have been melted and confirm @@ -286,7 +285,7 @@ refresh_check_melt (struct MHD_Connection *connection, * the soft error code, the function MAY be called again to retry and * MUST not queue a MHD response. * - * @param cls our `struct RefreshMeltContext` + * @param cls our `struct MeltContext` * @param connection MHD request which triggered the transaction * @param session database session to use * @param[out] mhd_ret set to MHD response status for @a connection, @@ -299,18 +298,18 @@ melt_transaction (void *cls, struct TALER_EXCHANGEDB_Session *session, int *mhd_ret) { - struct RefreshMeltContext *rmc = cls; + struct MeltContext *rmc = cls; enum GNUNET_DB_QueryStatus qs; uint32_t noreveal_index; - /* Check if we already created such a session */ + /* Check if we already created a matching refresh_session */ qs = TEH_plugin->get_melt_index (TEH_plugin->cls, session, &rmc->refresh_session.rc, &noreveal_index); if (GNUNET_DB_STATUS_SUCCESS_ONE_RESULT == qs) { - TALER_LOG_DEBUG ("Found already-melted coin\n"); + TALER_LOG_DEBUG ("Coin was previously melted, returning old reply\n"); *mhd_ret = reply_melt_success (connection, &rmc->refresh_session.rc, noreveal_index); @@ -335,13 +334,12 @@ melt_transaction (void *cls, rmc, mhd_ret); if (0 > qs) - return qs; + return qs; /* if we failed, tell caller */ /* pick challenge and persist it */ rmc->refresh_session.noreveal_index = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_STRONG, TALER_CNC_KAPPA); - if (0 >= (qs = TEH_plugin->insert_melt (TEH_plugin->cls, session, @@ -362,7 +360,7 @@ melt_transaction (void *cls, /** - * Handle a "/refresh/melt" request after the first parsing has + * Handle a "melt" request after the first parsing has * happened. We now need to validate the coins being melted and the * session signature and then hand things of to execute the melt * operation. This function parses the JSON arrays and then passes @@ -374,9 +372,8 @@ melt_transaction (void *cls, */ static int handle_melt (struct MHD_Connection *connection, - struct RefreshMeltContext *rmc) + struct MeltContext *rmc) { - /* verify signature of coin for melt operation */ { struct TALER_RefreshMeltCoinAffirmationPS body; @@ -392,12 +389,11 @@ handle_melt (struct MHD_Connection *connection, body.coin_pub = rmc->refresh_session.coin.coin_pub; if (GNUNET_OK != - GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_MELT, - &body.purpose, - &rmc->refresh_session.coin_sig. - eddsa_signature, - &rmc->refresh_session.coin.coin_pub. - eddsa_pub)) + GNUNET_CRYPTO_eddsa_verify ( + TALER_SIGNATURE_WALLET_COIN_MELT, + &body.purpose, + &rmc->refresh_session.coin_sig.eddsa_signature, + &rmc->refresh_session.coin.coin_pub.eddsa_pub)) { GNUNET_break_op (0); return TALER_MHD_reply_with_error (connection, @@ -407,7 +403,7 @@ handle_melt (struct MHD_Connection *connection, } } - /* run transaction */ + /* run database transaction */ { int mhd_ret; @@ -420,7 +416,7 @@ handle_melt (struct MHD_Connection *connection, return mhd_ret; } - /* generate ordinary response */ + /* Success. Generate ordinary response. */ return reply_melt_success (connection, &rmc->refresh_session.rc, rmc->refresh_session.noreveal_index); @@ -437,9 +433,10 @@ handle_melt (struct MHD_Connection *connection, */ static int check_for_denomination_key (struct MHD_Connection *connection, - struct RefreshMeltContext *rmc) + struct MeltContext *rmc) { struct TEH_KS_StateHandle *key_state; + int coin_is_dirty = GNUNET_NO; key_state = TEH_KS_acquire (GNUNET_TIME_absolute_get ()); if (NULL == key_state) @@ -458,40 +455,46 @@ check_for_denomination_key (struct MHD_Connection *connection, unsigned int hc; enum TALER_ErrorCode ec; - dki = TEH_KS_denomination_key_lookup_by_hash (key_state, - &rmc->refresh_session.coin. - denom_pub_hash, - TEH_KS_DKU_DEPOSIT, - &ec, - &hc); + dki = TEH_KS_denomination_key_lookup_by_hash ( + key_state, + &rmc->refresh_session.coin.denom_pub_hash, + TEH_KS_DKU_DEPOSIT, + &ec, + &hc); /* Consider case that denomination was revoked but this coin was already seen and thus refresh is OK. */ if (NULL == dki) { - dki = TEH_KS_denomination_key_lookup_by_hash (key_state, - &rmc->refresh_session.coin. - denom_pub_hash, - TEH_KS_DKU_RECOUP, - &ec, - &hc); + dki = TEH_KS_denomination_key_lookup_by_hash ( + key_state, + &rmc->refresh_session.coin.denom_pub_hash, + TEH_KS_DKU_RECOUP, + &ec, + &hc); if (NULL != dki) { struct GNUNET_HashCode denom_hash; enum GNUNET_DB_QueryStatus qs; - qs = TEH_plugin->get_coin_denomination (TEH_plugin->cls, - NULL, - &rmc->refresh_session.coin. - coin_pub, - &denom_hash); + /* Check that the coin is dirty (we have seen it before), as we will + not just allow melting of a *fresh* coin where the denomination was + revoked (those must be recouped) */ + qs = TEH_plugin->get_coin_denomination ( + TEH_plugin->cls, + NULL, + &rmc->refresh_session.coin.coin_pub, + &denom_hash); if (0 > qs) { TEH_KS_release (key_state); + /* There is no good reason for a serialization failure here: */ + GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR != qs); return TALER_MHD_reply_with_error (connection, MHD_HTTP_INTERNAL_SERVER_ERROR, TALER_EC_REFRESH_MELT_DB_FETCH_ERROR, "failed to find information about old coin"); } + /* sanity check */ GNUNET_break (0 == GNUNET_memcmp (&denom_hash, &rmc->refresh_session.coin.denom_pub_hash)); @@ -500,11 +503,17 @@ check_for_denomination_key (struct MHD_Connection *connection, /* We never saw this coin before, so _this_ justification is not OK */ dki = NULL; } + else + { + /* Minor optimization: no need to run the + #TEH_DB_know_coin_transaction below */ + coin_is_dirty = GNUNET_YES; + } } } - /* Consider the case that the denomination expired for deposits, - but /refresh/recoup refilled the balance of the 'zombie' coin + /* Consider the case that the denomination expired for deposits, but + recoup of a refreshed coin refilled the balance of the 'zombie' coin and we should thus allow the refresh during the legal period. */ if (NULL == dki) { @@ -515,21 +524,35 @@ check_for_denomination_key (struct MHD_Connection *connection, &ec, &hc); if (NULL != dki) - rmc->zombie_required = GNUNET_YES; + rmc->zombie_required = GNUNET_YES; /* check later that zombie is satisfied */ } if (NULL == dki) { TEH_KS_release (key_state); - TALER_LOG_WARNING ("Unknown denomination key in /refresh/melt request\n"); return TALER_MHD_reply_with_error (connection, hc, ec, "unknown denomination"); } + TALER_amount_ntoh (&rmc->coin_refresh_fee, &dki->issue.properties.fee_refresh); TALER_amount_ntoh (&rmc->coin_value, &dki->issue.properties.value); + /* check client used sane currency */ + if (GNUNET_YES != + TALER_amount_cmp_currency (&rmc->refresh_session.amount_with_fee, + &rmc->coin_value) ) + { + GNUNET_break_op (0); + TEH_KS_release (key_state); + return TALER_MHD_reply_with_error (connection, + MHD_HTTP_BAD_REQUEST, + TALER_EC_MELT_CURRENCY_MISSMATCH, + "value_with_fee"); + + } + /* check coin is actually properly signed */ if (GNUNET_OK != TALER_test_coin_valid (&rmc->refresh_session.coin, &dki->denom_pub)) @@ -545,7 +568,8 @@ check_for_denomination_key (struct MHD_Connection *connection, TEH_KS_release (key_state); /* run actual logic, now that the request was parsed */ - /* make sure coin is 'known' in database */ + /* First, make sure coin is 'known' in database */ + if (GNUNET_NO == coin_is_dirty) { struct TEH_DB_KnowCoinContext kcc; int mhd_ret; @@ -554,7 +578,7 @@ check_for_denomination_key (struct MHD_Connection *connection, kcc.connection = connection; if (GNUNET_OK != TEH_DB_run_transaction (connection, - "know coin for refresh-melt", + "know coin for melt", &mhd_ret, &TEH_DB_know_coin_transaction, &kcc)) @@ -562,8 +586,9 @@ check_for_denomination_key (struct MHD_Connection *connection, } /* sanity-check that "total melt amount > melt fee" */ - if (TALER_amount_cmp (&rmc->coin_refresh_fee, - &rmc->refresh_session.amount_with_fee) > 0) + if (0 < + TALER_amount_cmp (&rmc->coin_refresh_fee, + &rmc->refresh_session.amount_with_fee)) { GNUNET_break_op (0); return TALER_MHD_reply_with_error (connection, @@ -592,7 +617,7 @@ TEH_handler_melt (struct MHD_Connection *connection, const struct TALER_CoinSpendPublicKeyP *coin_pub, const json_t *root) { - struct RefreshMeltContext rmc; + struct MeltContext rmc; int res; struct GNUNET_JSON_Specification spec[] = { TALER_JSON_spec_denomination_signature ("denom_sig", |