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authorChristian Grothoff <christian@grothoff.org>2020-02-29 16:42:10 +0100
committerChristian Grothoff <christian@grothoff.org>2020-02-29 16:42:10 +0100
commit0a2b049864c8dae0c53c203d46fca89e0e66849d (patch)
tree3e836be37902320a4a3a099ee62d960198057952 /src/lib/exchange_api_link.c
parentde9ab28ab9e55597baf2ca32194ec65b441f0f36 (diff)
downloadexchange-0a2b049864c8dae0c53c203d46fca89e0e66849d.tar.gz
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big rename fest related to #6067 API renaming
Diffstat (limited to 'src/lib/exchange_api_link.c')
-rw-r--r--src/lib/exchange_api_link.c488
1 files changed, 488 insertions, 0 deletions
diff --git a/src/lib/exchange_api_link.c b/src/lib/exchange_api_link.c
new file mode 100644
index 00000000..3204ca84
--- /dev/null
+++ b/src/lib/exchange_api_link.c
@@ -0,0 +1,488 @@
+/*
+ This file is part of TALER
+ Copyright (C) 2015-2020 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_link.c
+ * @brief Implementation of the /coins/$COIN_PUB/link request
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <microhttpd.h> /* just for HTTP status codes */
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_curl_lib.h>
+#include "taler_exchange_service.h"
+#include "taler_json_lib.h"
+#include "exchange_api_handle.h"
+#include "taler_signatures.h"
+#include "exchange_api_curl_defaults.h"
+
+
+/**
+ * @brief A /coins/$COIN_PUB/link Handle
+ */
+struct TALER_EXCHANGE_LinkHandle
+{
+
+ /**
+ * 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_LinkCallback link_cb;
+
+ /**
+ * Closure for @e cb.
+ */
+ void *link_cb_cls;
+
+ /**
+ * Private key of the coin, required to decode link information.
+ */
+ struct TALER_CoinSpendPrivateKeyP coin_priv;
+
+};
+
+
+/**
+ * Parse the provided linkage data from the "200 OK" response
+ * for one of the coins.
+ *
+ * @param lh link handle
+ * @param json json reply with the data for one coin
+ * @param coin_num number of the coin to decode
+ * @param trans_pub our transfer public key
+ * @param[out] coin_priv where to return private coin key
+ * @param[out] sig where to return private coin signature
+ * @param[out] pub where to return the public key for the coin
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
+ */
+static int
+parse_link_coin (const struct TALER_EXCHANGE_LinkHandle *lh,
+ const json_t *json,
+ unsigned int coin_num,
+ const struct TALER_TransferPublicKeyP *trans_pub,
+ struct TALER_CoinSpendPrivateKeyP *coin_priv,
+ struct TALER_DenominationSignature *sig,
+ struct TALER_DenominationPublicKey *pub)
+{
+ struct GNUNET_CRYPTO_RsaSignature *bsig;
+ struct GNUNET_CRYPTO_RsaPublicKey *rpub;
+ struct TALER_CoinSpendSignatureP link_sig;
+ struct GNUNET_JSON_Specification spec[] = {
+ GNUNET_JSON_spec_rsa_public_key ("denom_pub", &rpub),
+ GNUNET_JSON_spec_rsa_signature ("ev_sig", &bsig),
+ GNUNET_JSON_spec_fixed_auto ("link_sig", &link_sig),
+ GNUNET_JSON_spec_end ()
+ };
+ struct TALER_TransferSecretP secret;
+ struct TALER_PlanchetSecretsP fc;
+
+ /* parse reply */
+ if (GNUNET_OK !=
+ GNUNET_JSON_parse (json,
+ spec,
+ NULL, NULL))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+
+ TALER_link_recover_transfer_secret (trans_pub,
+ &lh->coin_priv,
+ &secret);
+ TALER_planchet_setup_refresh (&secret,
+ coin_num,
+ &fc);
+
+ /* extract coin and signature */
+ *coin_priv = fc.coin_priv;
+ sig->rsa_signature
+ = GNUNET_CRYPTO_rsa_unblind (bsig,
+ &fc.blinding_key.bks,
+ rpub);
+ /* verify link_sig */
+ {
+ struct TALER_LinkDataPS ldp;
+ struct TALER_PlanchetDetail pd;
+
+ ldp.purpose.size = htonl (sizeof (ldp));
+ ldp.purpose.purpose = htonl (TALER_SIGNATURE_WALLET_COIN_LINK);
+ GNUNET_CRYPTO_eddsa_key_get_public (&lh->coin_priv.eddsa_priv,
+ &ldp.old_coin_pub.eddsa_pub);
+ ldp.transfer_pub = *trans_pub;
+ pub->rsa_public_key = rpub;
+ if (GNUNET_OK !=
+ TALER_planchet_prepare (pub,
+ &fc,
+ &pd))
+ {
+ GNUNET_break (0);
+ GNUNET_JSON_parse_free (spec);
+ return GNUNET_SYSERR;
+ }
+ ldp.h_denom_pub = pd.denom_pub_hash;
+ GNUNET_CRYPTO_hash (pd.coin_ev,
+ pd.coin_ev_size,
+ &ldp.coin_envelope_hash);
+ GNUNET_free (pd.coin_ev);
+
+ if (GNUNET_OK !=
+ GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_WALLET_COIN_LINK,
+ &ldp.purpose,
+ &link_sig.eddsa_signature,
+ &ldp.old_coin_pub.eddsa_pub))
+ {
+ GNUNET_break_op (0);
+ GNUNET_JSON_parse_free (spec);
+ return GNUNET_SYSERR;
+ }
+ }
+
+ /* clean up */
+ pub->rsa_public_key = GNUNET_CRYPTO_rsa_public_key_dup (rpub);
+ GNUNET_JSON_parse_free (spec);
+ return GNUNET_OK;
+}
+
+
+/**
+ * Parse the provided linkage data from the "200 OK" response
+ * for one of the coins.
+ *
+ * @param[in,out] lh link handle (callback may be zero'ed out)
+ * @param json json reply with the data for one coin
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
+ */
+static int
+parse_link_ok (struct TALER_EXCHANGE_LinkHandle *lh,
+ const json_t *json)
+{
+ unsigned int session;
+ unsigned int num_coins;
+ int ret;
+
+ if (! json_is_array (json))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ num_coins = 0;
+ /* Theoretically, a coin may have been melted repeatedly
+ into different sessions; so the response is an array
+ which contains information by melting session. That
+ array contains another array. However, our API returns
+ a single 1d array, so we flatten the 2d array that is
+ returned into a single array. Note that usually a coin
+ is melted at most once, and so we'll only run this
+ loop once for 'session=0' in most cases.
+
+ num_coins tracks the size of the 1d array we return,
+ whilst 'i' and 'session' track the 2d array. *///
+ for (session = 0; session<json_array_size (json); session++)
+ {
+ json_t *jsona;
+ struct GNUNET_JSON_Specification spec[] = {
+ GNUNET_JSON_spec_json ("new_coins", &jsona),
+ GNUNET_JSON_spec_end ()
+ };
+
+ if (GNUNET_OK !=
+ GNUNET_JSON_parse (json_array_get (json,
+ session),
+ spec,
+ NULL, NULL))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ if (! json_is_array (jsona))
+ {
+ GNUNET_break_op (0);
+ GNUNET_JSON_parse_free (spec);
+ return GNUNET_SYSERR;
+ }
+
+ /* count all coins over all sessions */
+ num_coins += json_array_size (jsona);
+ GNUNET_JSON_parse_free (spec);
+ }
+ /* Now that we know how big the 1d array is, allocate
+ and fill it. */
+ {
+ unsigned int off_coin; /* index into 1d array */
+ unsigned int i;
+ struct TALER_CoinSpendPrivateKeyP coin_privs[GNUNET_NZL (num_coins)];
+ struct TALER_DenominationSignature sigs[GNUNET_NZL (num_coins)];
+ struct TALER_DenominationPublicKey pubs[GNUNET_NZL (num_coins)];
+
+ memset (sigs, 0, sizeof (sigs));
+ memset (pubs, 0, sizeof (pubs));
+ off_coin = 0;
+ for (session = 0; session<json_array_size (json); session++)
+ {
+ json_t *jsona;
+ struct TALER_TransferPublicKeyP trans_pub;
+ struct GNUNET_JSON_Specification spec[] = {
+ GNUNET_JSON_spec_json ("new_coins",
+ &jsona),
+ GNUNET_JSON_spec_fixed_auto ("transfer_pub",
+ &trans_pub),
+ GNUNET_JSON_spec_end ()
+ };
+
+ if (GNUNET_OK !=
+ GNUNET_JSON_parse (json_array_get (json,
+ session),
+ spec,
+ NULL, NULL))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ if (! json_is_array (jsona))
+ {
+ GNUNET_break_op (0);
+ GNUNET_JSON_parse_free (spec);
+ return GNUNET_SYSERR;
+ }
+
+ /* decode all coins */
+ for (i = 0; i<json_array_size (jsona); i++)
+ {
+ GNUNET_assert (i + off_coin < num_coins);
+ if (GNUNET_OK !=
+ parse_link_coin (lh,
+ json_array_get (jsona,
+ i),
+ i,
+ &trans_pub,
+ &coin_privs[i + off_coin],
+ &sigs[i + off_coin],
+ &pubs[i + off_coin]))
+ {
+ GNUNET_break_op (0);
+ break;
+ }
+ }
+ /* check if we really got all, then invoke callback */
+ off_coin += i;
+ if (i != json_array_size (jsona))
+ {
+ GNUNET_break_op (0);
+ ret = GNUNET_SYSERR;
+ GNUNET_JSON_parse_free (spec);
+ break;
+ }
+ GNUNET_JSON_parse_free (spec);
+ } /* end of for (session) */
+
+ if (off_coin == num_coins)
+ {
+ lh->link_cb (lh->link_cb_cls,
+ MHD_HTTP_OK,
+ TALER_EC_NONE,
+ num_coins,
+ coin_privs,
+ sigs,
+ pubs,
+ json);
+ lh->link_cb = NULL;
+ ret = GNUNET_OK;
+ }
+ else
+ {
+ GNUNET_break_op (0);
+ ret = GNUNET_SYSERR;
+ }
+
+ /* clean up */
+ GNUNET_assert (off_coin <= num_coins);
+ for (i = 0; i<off_coin; i++)
+ {
+ if (NULL != sigs[i].rsa_signature)
+ GNUNET_CRYPTO_rsa_signature_free (sigs[i].rsa_signature);
+ if (NULL != pubs[i].rsa_public_key)
+ GNUNET_CRYPTO_rsa_public_key_free (pubs[i].rsa_public_key);
+ }
+ }
+ return ret;
+}
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP /coins/$COIN_PUB/link request.
+ *
+ * @param cls the `struct TALER_EXCHANGE_LinkHandle`
+ * @param response_code HTTP response code, 0 on error
+ * @param response parsed JSON result, NULL on error
+ */
+static void
+handle_link_finished (void *cls,
+ long response_code,
+ const void *response)
+{
+ struct TALER_EXCHANGE_LinkHandle *lh = cls;
+ const json_t *j = response;
+
+ lh->job = NULL;
+ switch (response_code)
+ {
+ case 0:
+ break;
+ case MHD_HTTP_OK:
+ if (GNUNET_OK !=
+ parse_link_ok (lh,
+ j))
+ {
+ GNUNET_break_op (0);
+ response_code = 0;
+ }
+ break;
+ 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 */
+ break;
+ case MHD_HTTP_NOT_FOUND:
+ /* Nothing really to verify, exchange says this coin was not melted; we
+ should pass the JSON reply to the application */
+ break;
+ case MHD_HTTP_INTERNAL_SERVER_ERROR:
+ /* Server had an internal issue; we should retry, but this API
+ leaves this to the application */
+ break;
+ default:
+ /* unexpected response code */
+ GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+ "Unexpected response code %u\n",
+ (unsigned int) response_code);
+ GNUNET_break (0);
+ response_code = 0;
+ break;
+ }
+ if (NULL != lh->link_cb)
+ lh->link_cb (lh->link_cb_cls,
+ response_code,
+ TALER_JSON_get_error_code (j),
+ 0,
+ NULL,
+ NULL,
+ NULL,
+ j);
+ TALER_EXCHANGE_link_cancel (lh);
+}
+
+
+/**
+ * Submit a link request to the exchange and get the exchange's response.
+ *
+ * This API is typically not used by anyone, it is more a threat against those
+ * trying to receive a funds transfer by abusing the refresh protocol.
+ *
+ * @param exchange the exchange handle; the exchange must be ready to operate
+ * @param coin_priv private key to request link data for
+ * @param link_cb the callback to call with the useful result of the
+ * refresh operation the @a coin_priv was involved in (if any)
+ * @param link_cb_cls closure for @a link_cb
+ * @return a handle for this request
+ */
+struct TALER_EXCHANGE_LinkHandle *
+TALER_EXCHANGE_link (struct TALER_EXCHANGE_Handle *exchange,
+ const struct TALER_CoinSpendPrivateKeyP *coin_priv,
+ TALER_EXCHANGE_LinkCallback link_cb,
+ void *link_cb_cls)
+{
+ struct TALER_EXCHANGE_LinkHandle *lh;
+ CURL *eh;
+ struct GNUNET_CURL_Context *ctx;
+ struct TALER_CoinSpendPublicKeyP coin_pub;
+ char arg_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2 + 32];
+
+ if (GNUNET_YES !=
+ TEAH_handle_is_ready (exchange))
+ {
+ GNUNET_break (0);
+ return NULL;
+ }
+
+ GNUNET_CRYPTO_eddsa_key_get_public (&coin_priv->eddsa_priv,
+ &coin_pub.eddsa_pub);
+ {
+ char pub_str[sizeof (struct TALER_CoinSpendPublicKeyP) * 2];
+ char *end;
+
+ end = GNUNET_STRINGS_data_to_string (&coin_pub,
+ sizeof (struct
+ TALER_CoinSpendPublicKeyP),
+ pub_str,
+ sizeof (pub_str));
+ *end = '\0';
+ GNUNET_snprintf (arg_str,
+ sizeof (arg_str),
+ "/coins/%s/link",
+ pub_str);
+ }
+ lh = GNUNET_new (struct TALER_EXCHANGE_LinkHandle);
+ lh->exchange = exchange;
+ lh->link_cb = link_cb;
+ lh->link_cb_cls = link_cb_cls;
+ lh->coin_priv = *coin_priv;
+ lh->url = TEAH_path_to_url (exchange,
+ arg_str);
+ eh = TEL_curl_easy_get (lh->url);
+ ctx = TEAH_handle_to_context (exchange);
+ lh->job = GNUNET_CURL_job_add (ctx,
+ eh,
+ GNUNET_YES,
+ &handle_link_finished,
+ lh);
+ return lh;
+}
+
+
+/**
+ * Cancel a link request. This function cannot be used
+ * on a request handle if the callback was already invoked.
+ *
+ * @param lh the link handle
+ */
+void
+TALER_EXCHANGE_link_cancel (struct TALER_EXCHANGE_LinkHandle *lh)
+{
+ if (NULL != lh->job)
+ {
+ GNUNET_CURL_job_cancel (lh->job);
+ lh->job = NULL;
+ }
+ GNUNET_free (lh->url);
+ GNUNET_free (lh);
+}
+
+
+/* end of exchange_api_link.c */