/* This file is part of TALER Copyright (C) 2014, 2015 GNUnet e.V. 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 */ /** * @file exchange-lib/exchange_api_handle.c * @brief Implementation of the "handle" component of the exchange's HTTP API * @author Sree Harsha Totakura * @author Christian Grothoff */ #include "platform.h" #include #include #include #include "taler_json_lib.h" #include "taler_exchange_service.h" #include "taler_signatures.h" #include "exchange_api_handle.h" /** * Log error related to CURL operations. * * @param type log level * @param function which function failed to run * @param code what was the curl error code */ #define CURL_STRERROR(type, function, code) \ GNUNET_log (type, "Curl function `%s' has failed at `%s:%d' with error: %s", \ function, __FILE__, __LINE__, curl_easy_strerror (code)); /** * Stages of initialization for the `struct TALER_EXCHANGE_Handle` */ enum ExchangeHandleState { /** * Just allocated. */ MHS_INIT = 0, /** * Obtained the exchange's certification data and keys. */ MHS_CERT = 1, /** * Failed to initialize (fatal). */ MHS_FAILED = 2 }; /** * Data for the request to get the /keys of a exchange. */ struct KeysRequest; /** * Handle to the exchange */ struct TALER_EXCHANGE_Handle { /** * The context of this handle */ struct GNUNET_CURL_Context *ctx; /** * The URL of the exchange (i.e. "http://exchange.taler.net/") */ char *url; /** * Function to call with the exchange's certification data, * NULL if this has already been done. */ TALER_EXCHANGE_CertificationCallback cert_cb; /** * Closure to pass to @e cert_cb. */ void *cert_cb_cls; /** * Data for the request to get the /keys of a exchange, * NULL once we are past stage #MHS_INIT. */ struct KeysRequest *kr; /** * Key data of the exchange, only valid if * @e handshake_complete is past stage #MHS_CERT. */ struct TALER_EXCHANGE_Keys key_data; /** * When does @e key_data expire? */ struct GNUNET_TIME_Absolute key_data_expiration; /** * Raw key data of the exchange, only valid if * @e handshake_complete is past stage #MHS_CERT. */ json_t *key_data_raw; /** * Stage of the exchange's initialization routines. */ enum ExchangeHandleState state; }; /* ***************** Internal /keys fetching ************* */ /** * Data for the request to get the /keys of a exchange. */ struct KeysRequest { /** * The connection to exchange this request handle will use */ struct TALER_EXCHANGE_Handle *exchange; /** * The url for this handle */ char *url; /** * Entry for this request with the `struct GNUNET_CURL_Context`. */ struct GNUNET_CURL_Job *job; /** * Expiration time according to "Expire:" header. * 0 if not provided by the server. */ struct GNUNET_TIME_Absolute expire; }; /** * Release memory occupied by a keys request. * Note that this does not cancel the request * itself. * * @param kr request to free */ static void free_keys_request (struct KeysRequest *kr) { GNUNET_free (kr->url); GNUNET_free (kr); } #define EXITIF(cond) \ do { \ if (cond) { GNUNET_break (0); goto EXITIF_exit; } \ } while (0) /** * Parse a exchange's signing key encoded in JSON. * * @param[out] sign_key where to return the result * @param[in] sign_key_obj json to parse * @param master_key master key to use to verify signature * @return #GNUNET_OK if all is fine, #GNUNET_SYSERR if the signature is * invalid or the json malformed. */ static int parse_json_signkey (struct TALER_EXCHANGE_SigningPublicKey *sign_key, json_t *sign_key_obj, const struct TALER_MasterPublicKeyP *master_key) { struct TALER_ExchangeSigningKeyValidityPS sign_key_issue; struct GNUNET_CRYPTO_EddsaSignature sig; struct GNUNET_TIME_Absolute valid_from; struct GNUNET_TIME_Absolute valid_until; struct GNUNET_TIME_Absolute valid_legal; struct GNUNET_JSON_Specification spec[] = { GNUNET_JSON_spec_fixed_auto ("master_sig", &sig), GNUNET_JSON_spec_fixed_auto ("key", &sign_key_issue.signkey_pub), GNUNET_JSON_spec_absolute_time ("stamp_start", &valid_from), GNUNET_JSON_spec_absolute_time ("stamp_expire", &valid_until), GNUNET_JSON_spec_absolute_time ("stamp_end", &valid_legal), GNUNET_JSON_spec_end() }; if (GNUNET_OK != GNUNET_JSON_parse (sign_key_obj, spec, NULL, NULL)) { GNUNET_break_op (0); return GNUNET_SYSERR; } sign_key_issue.purpose.purpose = htonl (TALER_SIGNATURE_MASTER_SIGNING_KEY_VALIDITY); sign_key_issue.purpose.size = htonl (sizeof (struct TALER_ExchangeSigningKeyValidityPS) - offsetof (struct TALER_ExchangeSigningKeyValidityPS, purpose)); sign_key_issue.master_public_key = *master_key; sign_key_issue.start = GNUNET_TIME_absolute_hton (valid_from); sign_key_issue.expire = GNUNET_TIME_absolute_hton (valid_until); sign_key_issue.end = GNUNET_TIME_absolute_hton (valid_legal); if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MASTER_SIGNING_KEY_VALIDITY, &sign_key_issue.purpose, &sig, &master_key->eddsa_pub)) { GNUNET_break_op (0); return GNUNET_SYSERR; } sign_key->valid_from = valid_from; sign_key->valid_until = valid_until; sign_key->key = sign_key_issue.signkey_pub; return GNUNET_OK; } /** * Parse a exchange's denomination key encoded in JSON. * * @param[out] denom_key where to return the result * @param[in] denom_key_obj json to parse * @param master_key master key to use to verify signature * @param hash_context where to accumulate data for signature verification * @return #GNUNET_OK if all is fine, #GNUNET_SYSERR if the signature is * invalid or the json malformed. */ static int parse_json_denomkey (struct TALER_EXCHANGE_DenomPublicKey *denom_key, json_t *denom_key_obj, struct TALER_MasterPublicKeyP *master_key, struct GNUNET_HashContext *hash_context) { struct GNUNET_TIME_Absolute valid_from; struct GNUNET_TIME_Absolute withdraw_valid_until; struct GNUNET_TIME_Absolute expire_deposit; struct GNUNET_TIME_Absolute expire_legal; struct TALER_Amount value; struct TALER_Amount fee_withdraw; struct TALER_Amount fee_deposit; struct TALER_Amount fee_refresh; struct TALER_Amount fee_refund; struct TALER_DenominationKeyValidityPS denom_key_issue; struct GNUNET_CRYPTO_RsaPublicKey *pk; struct GNUNET_CRYPTO_EddsaSignature sig; struct GNUNET_JSON_Specification spec[] = { GNUNET_JSON_spec_fixed_auto ("master_sig", &sig), GNUNET_JSON_spec_absolute_time ("stamp_expire_deposit", &expire_deposit), GNUNET_JSON_spec_absolute_time ("stamp_expire_withdraw", &withdraw_valid_until), GNUNET_JSON_spec_absolute_time ("stamp_start", &valid_from), GNUNET_JSON_spec_absolute_time ("stamp_expire_legal", &expire_legal), TALER_JSON_spec_amount ("value", &value), TALER_JSON_spec_amount ("fee_withdraw", &fee_withdraw), TALER_JSON_spec_amount ("fee_deposit", &fee_deposit), TALER_JSON_spec_amount ("fee_refresh", &fee_refresh), TALER_JSON_spec_amount ("fee_refund", &fee_refund), GNUNET_JSON_spec_rsa_public_key ("denom_pub", &pk), GNUNET_JSON_spec_end() }; if (GNUNET_OK != GNUNET_JSON_parse (denom_key_obj, spec, NULL, NULL)) { GNUNET_break_op (0); return GNUNET_SYSERR; } memset (&denom_key_issue, 0, sizeof (denom_key_issue)); GNUNET_CRYPTO_rsa_public_key_hash (pk, &denom_key_issue.denom_hash); denom_key_issue.purpose.purpose = htonl (TALER_SIGNATURE_MASTER_DENOMINATION_KEY_VALIDITY); denom_key_issue.purpose.size = htonl (sizeof (struct TALER_DenominationKeyValidityPS)); denom_key_issue.master = *master_key; denom_key_issue.start = GNUNET_TIME_absolute_hton (valid_from); denom_key_issue.expire_withdraw = GNUNET_TIME_absolute_hton (withdraw_valid_until); denom_key_issue.expire_deposit = GNUNET_TIME_absolute_hton (expire_deposit); denom_key_issue.expire_legal = GNUNET_TIME_absolute_hton (expire_legal); TALER_amount_hton (&denom_key_issue.value, &value); TALER_amount_hton (&denom_key_issue.fee_withdraw, &fee_withdraw); TALER_amount_hton (&denom_key_issue.fee_deposit, &fee_deposit); TALER_amount_hton (&denom_key_issue.fee_refresh, &fee_refresh); TALER_amount_hton (&denom_key_issue.fee_refund, &fee_refund); EXITIF (GNUNET_SYSERR == GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_MASTER_DENOMINATION_KEY_VALIDITY, &denom_key_issue.purpose, &sig, &master_key->eddsa_pub)); GNUNET_CRYPTO_hash_context_read (hash_context, &denom_key_issue.denom_hash, sizeof (struct GNUNET_HashCode)); denom_key->key.rsa_public_key = pk; denom_key->h_key = denom_key_issue.denom_hash; denom_key->valid_from = valid_from; denom_key->withdraw_valid_until = withdraw_valid_until; denom_key->expire_deposit = expire_deposit; denom_key->expire_legal = expire_legal; denom_key->value = value; denom_key->fee_withdraw = fee_withdraw; denom_key->fee_deposit = fee_deposit; denom_key->fee_refresh = fee_refresh; denom_key->fee_refund = fee_refund; return GNUNET_OK; EXITIF_exit: GNUNET_JSON_parse_free (spec); return GNUNET_SYSERR; } /** * Parse a exchange's auditor information encoded in JSON. * * @param[out] auditor where to return the result * @param[in] auditor_obj json to parse * @param key_data information about denomination keys * @return #GNUNET_OK if all is fine, #GNUNET_SYSERR if the signature is * invalid or the json malformed. */ static int parse_json_auditor (struct TALER_EXCHANGE_AuditorInformation *auditor, json_t *auditor_obj, const struct TALER_EXCHANGE_Keys *key_data) { json_t *keys; json_t *key; unsigned int len; unsigned int off; unsigned int i; const char *auditor_url; struct TALER_ExchangeKeyValidityPS kv; struct GNUNET_JSON_Specification spec[] = { GNUNET_JSON_spec_fixed_auto ("auditor_pub", &auditor->auditor_pub), GNUNET_JSON_spec_string ("auditor_url", &auditor_url), GNUNET_JSON_spec_json ("denomination_keys", &keys), GNUNET_JSON_spec_end() }; if (GNUNET_OK != GNUNET_JSON_parse (auditor_obj, spec, NULL, NULL)) { GNUNET_break_op (0); return GNUNET_SYSERR; } auditor->auditor_url = GNUNET_strdup (auditor_url); kv.purpose.purpose = htonl (TALER_SIGNATURE_AUDITOR_EXCHANGE_KEYS); kv.purpose.size = htonl (sizeof (struct TALER_ExchangeKeyValidityPS)); GNUNET_CRYPTO_hash (auditor_url, strlen (auditor_url) + 1, &kv.auditor_url_hash); kv.master = key_data->master_pub; len = json_array_size (keys); auditor->denom_keys = GNUNET_new_array (len, const struct TALER_EXCHANGE_DenomPublicKey *); i = 0; off = 0; json_array_foreach (keys, i, key) { struct TALER_AuditorSignatureP auditor_sig; struct GNUNET_HashCode denom_h; const struct TALER_EXCHANGE_DenomPublicKey *dk; unsigned int j; struct GNUNET_JSON_Specification spec[] = { GNUNET_JSON_spec_fixed_auto ("denom_pub_h", &denom_h), GNUNET_JSON_spec_fixed_auto ("auditor_sig", &auditor_sig), GNUNET_JSON_spec_end() }; if (GNUNET_OK != GNUNET_JSON_parse (key, spec, NULL, NULL)) { GNUNET_break_op (0); continue; } dk = NULL; for (j=0;jnum_denom_keys;j++) { if (0 == memcmp (&denom_h, &key_data->denom_keys[j].h_key, sizeof (struct GNUNET_HashCode))) { dk = &key_data->denom_keys[j]; break; } } if (NULL == dk) { GNUNET_break_op (0); continue; } kv.start = GNUNET_TIME_absolute_hton (dk->valid_from); kv.expire_withdraw = GNUNET_TIME_absolute_hton (dk->withdraw_valid_until); kv.expire_deposit = GNUNET_TIME_absolute_hton (dk->expire_deposit); kv.expire_legal = GNUNET_TIME_absolute_hton (dk->expire_legal); TALER_amount_hton (&kv.value, &dk->value); TALER_amount_hton (&kv.fee_withdraw, &dk->fee_withdraw); TALER_amount_hton (&kv.fee_deposit, &dk->fee_deposit); TALER_amount_hton (&kv.fee_refresh, &dk->fee_refresh); TALER_amount_hton (&kv.fee_refund, &dk->fee_refund); kv.denom_hash = dk->h_key; if (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_AUDITOR_EXCHANGE_KEYS, &kv.purpose, &auditor_sig.eddsa_sig, &auditor->auditor_pub.eddsa_pub)) { GNUNET_break_op (0); continue; } auditor->denom_keys[off] = dk; off++; } auditor->num_denom_keys = off; return GNUNET_OK; } /** * Decode the JSON in @a resp_obj from the /keys response and store the data * in the @a key_data. * * @param[in] resp_obj JSON object to parse * @param[out] key_data where to store the results we decoded * @return #GNUNET_OK on success, #GNUNET_SYSERR on error (malformed JSON) */ static int decode_keys_json (const json_t *resp_obj, struct TALER_EXCHANGE_Keys *key_data) { struct GNUNET_TIME_Absolute list_issue_date; struct TALER_ExchangeSignatureP sig; struct TALER_ExchangeKeySetPS ks; struct GNUNET_HashContext *hash_context; struct TALER_ExchangePublicKeyP pub; memset (key_data, 0, sizeof (struct TALER_EXCHANGE_Keys)); if (JSON_OBJECT != json_typeof (resp_obj)) return GNUNET_SYSERR; hash_context = GNUNET_CRYPTO_hash_context_start (); /* parse the master public key and issue date of the response */ { struct GNUNET_JSON_Specification spec[] = { GNUNET_JSON_spec_fixed_auto ("master_public_key", &key_data->master_pub), GNUNET_JSON_spec_fixed_auto ("eddsa_sig", &sig), GNUNET_JSON_spec_fixed_auto ("eddsa_pub", &pub), GNUNET_JSON_spec_absolute_time ("list_issue_date", &list_issue_date), GNUNET_JSON_spec_end() }; EXITIF (GNUNET_OK != GNUNET_JSON_parse (resp_obj, spec, NULL, NULL)); } /* parse the signing keys */ { json_t *sign_keys_array; json_t *sign_key_obj; unsigned int index; EXITIF (NULL == (sign_keys_array = json_object_get (resp_obj, "signkeys"))); EXITIF (JSON_ARRAY != json_typeof (sign_keys_array)); EXITIF (0 == (key_data->num_sign_keys = json_array_size (sign_keys_array))); key_data->sign_keys = GNUNET_new_array (key_data->num_sign_keys, struct TALER_EXCHANGE_SigningPublicKey); index = 0; json_array_foreach (sign_keys_array, index, sign_key_obj) { EXITIF (GNUNET_SYSERR == parse_json_signkey (&key_data->sign_keys[index], sign_key_obj, &key_data->master_pub)); } } /* parse the denomination keys */ { json_t *denom_keys_array; json_t *denom_key_obj; unsigned int index; EXITIF (NULL == (denom_keys_array = json_object_get (resp_obj, "denoms"))); EXITIF (JSON_ARRAY != json_typeof (denom_keys_array)); EXITIF (0 == (key_data->num_denom_keys = json_array_size (denom_keys_array))); key_data->denom_keys = GNUNET_new_array (key_data->num_denom_keys, struct TALER_EXCHANGE_DenomPublicKey); index = 0; json_array_foreach (denom_keys_array, index, denom_key_obj) { EXITIF (GNUNET_SYSERR == parse_json_denomkey (&key_data->denom_keys[index], denom_key_obj, &key_data->master_pub, hash_context)); } } /* parse the auditor information */ { json_t *auditors_array; json_t *auditor_info; unsigned int len; unsigned int index; EXITIF (NULL == (auditors_array = json_object_get (resp_obj, "auditors"))); EXITIF (JSON_ARRAY != json_typeof (auditors_array)); len = json_array_size (auditors_array); if (0 != len) { key_data->auditors = GNUNET_new_array (len, struct TALER_EXCHANGE_AuditorInformation); index = 0; json_array_foreach (auditors_array, index, auditor_info) { EXITIF (GNUNET_SYSERR == parse_json_auditor (&key_data->auditors[index], auditor_info, key_data)); } } } /* Validate signature... */ ks.purpose.size = htonl (sizeof (ks)); ks.purpose.purpose = htonl (TALER_SIGNATURE_EXCHANGE_KEY_SET); ks.list_issue_date = GNUNET_TIME_absolute_hton (list_issue_date); GNUNET_CRYPTO_hash_context_finish (hash_context, &ks.hc); hash_context = NULL; EXITIF (GNUNET_OK != TALER_EXCHANGE_test_signing_key (key_data, &pub)); EXITIF (GNUNET_OK != GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_EXCHANGE_KEY_SET, &ks.purpose, &sig.eddsa_signature, &pub.eddsa_pub)); return GNUNET_OK; EXITIF_exit: if (NULL != hash_context) GNUNET_CRYPTO_hash_context_abort (hash_context); return GNUNET_SYSERR; } /** * Free key data object. * * @param key_data data to free (pointer itself excluded) */ static void free_key_data (struct TALER_EXCHANGE_Keys *key_data) { unsigned int i; GNUNET_array_grow (key_data->sign_keys, key_data->num_sign_keys, 0); for (i=0;inum_denom_keys;i++) GNUNET_CRYPTO_rsa_public_key_free (key_data->denom_keys[i].key.rsa_public_key); GNUNET_array_grow (key_data->denom_keys, key_data->num_denom_keys, 0); GNUNET_array_grow (key_data->auditors, key_data->num_auditors, 0); } /** * Initiate download of /keys from the exchange. * * @param exchange where to download /keys from */ static void request_keys (struct TALER_EXCHANGE_Handle *exchange); /** * Check if our current response for /keys is valid, and if * not trigger download. * * @param exchange exchange to check keys for * @return until when the response is current, 0 if we are re-downloading */ struct GNUNET_TIME_Absolute TALER_EXCHANGE_check_keys_current (struct TALER_EXCHANGE_Handle *exchange) { if (NULL != exchange->kr) return GNUNET_TIME_UNIT_ZERO_ABS; if (0 < GNUNET_TIME_absolute_get_remaining (exchange->key_data_expiration).rel_value_us) return exchange->key_data_expiration; request_keys (exchange); return GNUNET_TIME_UNIT_ZERO_ABS; } /** * Callback used when downloading the reply to a /keys request * is complete. * * @param cls the `struct KeysRequest` * @param response_code HTTP response code, 0 on error * @param resp_obj parsed JSON result, NULL on error */ static void keys_completed_cb (void *cls, long response_code, const json_t *resp_obj) { struct KeysRequest *kr = cls; struct TALER_EXCHANGE_Handle *exchange = kr->exchange; struct TALER_EXCHANGE_Keys kd; struct TALER_EXCHANGE_Keys kd_old; GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received keys from URL `%s' with status %ld.\n", kr->url, response_code); kd_old = exchange->key_data; switch (response_code) { case 0: break; case MHD_HTTP_OK: if (NULL == resp_obj) { response_code = 0; break; } if (GNUNET_OK != decode_keys_json (resp_obj, &kd)) { response_code = 0; break; } exchange->key_data = kd; json_decref (exchange->key_data_raw); exchange->key_data_raw = json_deep_copy (resp_obj); break; default: GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Unexpected response code %u\n", (unsigned int) response_code); break; } if (MHD_HTTP_OK != response_code) { exchange->kr = NULL; free_keys_request (kr); exchange->state = MHS_FAILED; /* notify application that we failed */ exchange->cert_cb (exchange->cert_cb_cls, NULL); if (NULL != exchange->key_data_raw) { json_decref (exchange->key_data_raw); exchange->key_data_raw = NULL; } free_key_data (&kd_old); return; } exchange->kr = NULL; exchange->key_data_expiration = kr->expire; free_keys_request (kr); exchange->state = MHS_CERT; /* notify application about the key information */ exchange->cert_cb (exchange->cert_cb_cls, &exchange->key_data); free_key_data (&kd_old); } /* ********************* library internal API ********* */ /** * Get the context of a exchange. * * @param h the exchange handle to query * @return ctx context to execute jobs in */ struct GNUNET_CURL_Context * MAH_handle_to_context (struct TALER_EXCHANGE_Handle *h) { return h->ctx; } /** * Check if the handle is ready to process requests. * * @param h the exchange handle to query * @return #GNUNET_YES if we are ready, #GNUNET_NO if not */ int MAH_handle_is_ready (struct TALER_EXCHANGE_Handle *h) { return (MHS_CERT == h->state) ? GNUNET_YES : GNUNET_NO; } /** * Obtain the URL to use for an API request. * * @param base_url base URL of the exchange (i.e. "http://exchange/") * @param path Taler API path (i.e. "/reserve/withdraw") * @return the full URI to use with cURL */ char * MAH_path_to_url (struct TALER_EXCHANGE_Handle *exchange, const char *path) { return MAH_path_to_url2 (exchange->url, path); } /** * Obtain the URL to use for an API request. * * @param base_url base URL of the exchange (i.e. "http://exchange/") * @param path Taler API path (i.e. "/reserve/withdraw") * @return the full URI to use with cURL */ char * MAH_path_to_url2 (const char *base_url, const char *path) { char *url; if ( ('/' == path[0]) && (0 < strlen (base_url)) && ('/' == base_url[strlen (base_url) - 1]) ) path++; /* avoid generating URL with "//" from concat */ GNUNET_asprintf (&url, "%s%s", base_url, path); return url; } /** * Parse HTTP timestamp. * * @param date header to parse header * @param at where to write the result * @return #GNUNET_OK on success */ static int parse_date_string (const char *date, struct GNUNET_TIME_Absolute *at) { static const char *const days[] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }; static const char *const mons[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" }; struct tm now; time_t t; char day[3]; char mon[3]; unsigned int i; unsigned int mday; unsigned int year; unsigned int h; unsigned int m; unsigned int s; if (7 != sscanf (date, "%3s, %02u %3s %04u %02u:%02u:%02u GMT", day, &mday, mon, &year, &h, &m, &s)) return GNUNET_SYSERR; memset (&now, 0, sizeof (now)); now.tm_year = year - 1900; now.tm_mday = mday; now.tm_hour = h; now.tm_min = m; now.tm_sec = s; now.tm_wday = 7; for (i=0;i<7;i++) if (0 == strcasecmp (days[i], day)) now.tm_wday = i; now.tm_mon = 12; for (i=0;i<12;i++) if (0 == strcasecmp (mons[i], mon)) now.tm_mon = i; if ( (7 == now.tm_mday) || (12 == now.tm_mon) ) return GNUNET_SYSERR; t = mktime (&now); at->abs_value_us = 1000LL * 1000LL * t; return GNUNET_OK; } /** * Function called for each header in the HTTP /keys response. * Finds the "Expire:" header and parses it, storing the result * in the "expire" field fo the keys request. * * @param buffer header data received * @param size size of an item in @a buffer * @param nitems number of items in @a buffer * @param userdata the `struct KeysRequest` * @return `size * nitems` on success (everything else aborts) */ static size_t header_cb (char *buffer, size_t size, size_t nitems, void *userdata) { struct KeysRequest *kr = userdata; size_t total = size * nitems; char *val; if (total < strlen (MHD_HTTP_HEADER_EXPIRES ": ")) return total; if (0 != strncasecmp (MHD_HTTP_HEADER_EXPIRES ": ", buffer, strlen (MHD_HTTP_HEADER_EXPIRES ": "))) return total; val = GNUNET_strndup (&buffer[strlen (MHD_HTTP_HEADER_EXPIRES ": ")], total - strlen (MHD_HTTP_HEADER_EXPIRES ": ")); if (GNUNET_OK != parse_date_string (val, &kr->expire)) { GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "Failed to parse %s-header `%s'\n", MHD_HTTP_HEADER_EXPIRES, val); } GNUNET_free (val); return total; } /* ********************* public API ******************* */ /** * Initialise a connection to the exchange. Will connect to the * exchange and obtain information about the exchange's master public * key and the exchange's auditor. The respective information will * be passed to the @a cert_cb once available, and all future * interactions with the exchange will be checked to be signed * (where appropriate) by the respective master key. * * @param ctx the context * @param url HTTP base URL for the exchange * @param cert_cb function to call with the exchange's certification information * @param cert_cb_cls closure for @a cert_cb * @param ... list of additional arguments, terminated by #TALER_EXCHANGE_OPTION_END. * @return the exchange handle; NULL upon error */ struct TALER_EXCHANGE_Handle * TALER_EXCHANGE_connect (struct GNUNET_CURL_Context *ctx, const char *url, TALER_EXCHANGE_CertificationCallback cert_cb, void *cert_cb_cls, ...) { struct TALER_EXCHANGE_Handle *exchange; exchange = GNUNET_new (struct TALER_EXCHANGE_Handle); exchange->ctx = ctx; exchange->url = GNUNET_strdup (url); exchange->cert_cb = cert_cb; exchange->cert_cb_cls = cert_cb_cls; request_keys (exchange); return exchange; } /** * Initiate download of /keys from the exchange. * * @param exchange where to download /keys from */ static void request_keys (struct TALER_EXCHANGE_Handle *exchange) { struct KeysRequest *kr; CURL *eh; GNUNET_assert (NULL == exchange->kr); kr = GNUNET_new (struct KeysRequest); kr->exchange = exchange; kr->url = MAH_path_to_url (exchange, "/keys"); GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Requesting keys with URL `%s'.\n", kr->url); eh = curl_easy_init (); GNUNET_assert (CURLE_OK == curl_easy_setopt (eh, CURLOPT_VERBOSE, 0)); GNUNET_assert (CURLE_OK == curl_easy_setopt (eh, CURLOPT_TIMEOUT, (long) 300)); GNUNET_assert (CURLE_OK == curl_easy_setopt (eh, CURLOPT_HEADERFUNCTION, &header_cb)); GNUNET_assert (CURLE_OK == curl_easy_setopt (eh, CURLOPT_HEADERDATA, kr)); GNUNET_assert (CURLE_OK == curl_easy_setopt (eh, CURLOPT_URL, kr->url)); kr->job = GNUNET_CURL_job_add (exchange->ctx, eh, GNUNET_NO, &keys_completed_cb, kr); exchange->kr = kr; } /** * Disconnect from the exchange * * @param exchange the exchange handle */ void TALER_EXCHANGE_disconnect (struct TALER_EXCHANGE_Handle *exchange) { if (NULL != exchange->kr) { GNUNET_CURL_job_cancel (exchange->kr->job); free_keys_request (exchange->kr); exchange->kr = NULL; } free_key_data (&exchange->key_data); if (NULL != exchange->key_data_raw) { json_decref (exchange->key_data_raw); exchange->key_data_raw = NULL; } GNUNET_free (exchange->url); GNUNET_free (exchange); } /** * Test if the given @a pub is a the current signing key from the exchange * according to @a keys. * * @param keys the exchange's key set * @param pub claimed current online signing key for the exchange * @return #GNUNET_OK if @a pub is (according to /keys) a current signing key */ int TALER_EXCHANGE_test_signing_key (const struct TALER_EXCHANGE_Keys *keys, const struct TALER_ExchangePublicKeyP *pub) { struct GNUNET_TIME_Absolute now; unsigned int i; /* we will check using a tolerance of 1h for the time */ now = GNUNET_TIME_absolute_get (); for (i=0;inum_sign_keys;i++) if ( (keys->sign_keys[i].valid_from.abs_value_us <= now.abs_value_us + 60 * 60 * 1000LL * 1000LL) && (keys->sign_keys[i].valid_until.abs_value_us > now.abs_value_us - 60 * 60 * 1000LL * 1000LL) && (0 == memcmp (pub, &keys->sign_keys[i].key, sizeof (struct TALER_ExchangePublicKeyP))) ) return GNUNET_OK; return GNUNET_SYSERR; } /** * Obtain the denomination key details from the exchange. * * @param keys the exchange's key set * @param pk public key of the denomination to lookup * @return details about the given denomination key, NULL if the key is * not found */ const struct TALER_EXCHANGE_DenomPublicKey * TALER_EXCHANGE_get_denomination_key (const struct TALER_EXCHANGE_Keys *keys, const struct TALER_DenominationPublicKey *pk) { unsigned int i; for (i=0;inum_denom_keys;i++) if (0 == GNUNET_CRYPTO_rsa_public_key_cmp (pk->rsa_public_key, keys->denom_keys[i].key.rsa_public_key)) return &keys->denom_keys[i]; return NULL; } /** * Obtain the denomination key details from the exchange. * * @param keys the exchange's key set * @param hc hash of the public key of the denomination to lookup * @return details about the given denomination key */ const struct TALER_EXCHANGE_DenomPublicKey * TALER_EXCHANGE_get_denomination_key_by_hash (const struct TALER_EXCHANGE_Keys *keys, const struct GNUNET_HashCode *hc) { unsigned int i; for (i=0;inum_denom_keys;i++) if (0 == memcmp (hc, &keys->denom_keys[i].h_key, sizeof (struct GNUNET_HashCode))) return &keys->denom_keys[i]; return NULL; } /** * Obtain the keys from the exchange. * * @param exchange the exchange handle * @return the exchange's key set */ const struct TALER_EXCHANGE_Keys * TALER_EXCHANGE_get_keys (struct TALER_EXCHANGE_Handle *exchange) { (void) TALER_EXCHANGE_check_keys_current (exchange); return &exchange->key_data; } /** * Obtain the keys from the exchange in the * raw JSON format * * @param exchange the exchange handle * @return the exchange's keys in raw JSON */ json_t * TALER_EXCHANGE_get_keys_raw (struct TALER_EXCHANGE_Handle *exchange) { (void) TALER_EXCHANGE_check_keys_current (exchange); return json_deep_copy (exchange->key_data_raw); } /* end of exchange_api_handle.c */