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-rw-r--r--src/exchange-lib/exchange_api_refresh_link.c482
1 files changed, 482 insertions, 0 deletions
diff --git a/src/exchange-lib/exchange_api_refresh_link.c b/src/exchange-lib/exchange_api_refresh_link.c
new file mode 100644
index 000000000..9576916bc
--- /dev/null
+++ b/src/exchange-lib/exchange_api_refresh_link.c
@@ -0,0 +1,482 @@
+/*
+ This file is part of TALER
+ Copyright (C) 2015, 2016 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, If not, see
+ <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file exchange-lib/exchange_api_refresh_link.c
+ * @brief Implementation of the /refresh/link request of the exchange's HTTP API
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <curl/curl.h>
+#include <jansson.h>
+#include <microhttpd.h> /* just for HTTP status codes */
+#include <gnunet/gnunet_util_lib.h>
+#include "taler_exchange_service.h"
+#include "exchange_api_json.h"
+#include "exchange_api_context.h"
+#include "exchange_api_handle.h"
+#include "taler_signatures.h"
+
+
+/**
+ * @brief A /refresh/link Handle
+ */
+struct TALER_EXCHANGE_RefreshLinkHandle
+{
+
+ /**
+ * 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 MAC_Job *job;
+
+ /**
+ * Function to call with the result.
+ */
+ TALER_EXCHANGE_RefreshLinkCallback link_cb;
+
+ /**
+ * Closure for @e cb.
+ */
+ void *link_cb_cls;
+
+ /**
+ * Download buffer
+ */
+ struct MAC_DownloadBuffer db;
+
+ /**
+ * 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 rlh refresh link handle
+ * @param json json reply with the data for one coin
+ * @param trans_pub our transfer public key
+ * @param secret_enc encrypted key to decrypt link data
+ * @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_refresh_link_coin (const struct TALER_EXCHANGE_RefreshLinkHandle *rlh,
+ json_t *json,
+ const struct TALER_TransferPublicKeyP *trans_pub,
+ const struct TALER_EncryptedLinkSecretP *secret_enc,
+ struct TALER_CoinSpendPrivateKeyP *coin_priv,
+ struct TALER_DenominationSignature *sig,
+ struct TALER_DenominationPublicKey *pub)
+{
+ void *link_enc;
+ size_t link_enc_size;
+ struct GNUNET_CRYPTO_rsa_Signature *bsig;
+ struct GNUNET_CRYPTO_rsa_PublicKey *rpub;
+ struct MAJ_Specification spec[] = {
+ MAJ_spec_varsize ("link_enc", &link_enc, &link_enc_size),
+ MAJ_spec_rsa_public_key ("denom_pub", &rpub),
+ MAJ_spec_rsa_signature ("ev_sig", &bsig),
+ MAJ_spec_end
+ };
+ struct TALER_RefreshLinkEncrypted *rle;
+ struct TALER_RefreshLinkDecrypted *rld;
+ struct TALER_LinkSecretP secret;
+
+ /* parse reply */
+ if (GNUNET_OK !=
+ MAJ_parse_json (json,
+ spec))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+
+ /* decode and decrypt link data */
+ rle = TALER_refresh_link_encrypted_decode (link_enc,
+ link_enc_size);
+ if (NULL == rle)
+ {
+ GNUNET_break_op (0);
+ MAJ_parse_free (spec);
+ return GNUNET_SYSERR;
+ }
+ if (GNUNET_OK !=
+ TALER_link_decrypt_secret2 (secret_enc,
+ trans_pub,
+ &rlh->coin_priv,
+ &secret))
+ {
+ GNUNET_break_op (0);
+ MAJ_parse_free (spec);
+ return GNUNET_SYSERR;
+ }
+ rld = TALER_refresh_decrypt (rle,
+ &secret);
+ if (NULL == rld)
+ {
+ GNUNET_break_op (0);
+ MAJ_parse_free (spec);
+ return GNUNET_SYSERR;
+ }
+
+ /* extract coin and signature */
+ *coin_priv = rld->coin_priv;
+ sig->rsa_signature
+ = GNUNET_CRYPTO_rsa_unblind (bsig,
+ rld->blinding_key.rsa_blinding_key,
+ rpub);
+
+ /* clean up */
+ GNUNET_free (rld);
+ pub->rsa_public_key = GNUNET_CRYPTO_rsa_public_key_dup (rpub);
+ MAJ_parse_free (spec);
+ return GNUNET_OK;
+}
+
+
+/**
+ * Parse the provided linkage data from the "200 OK" response
+ * for one of the coins.
+ *
+ * @param[in,out] rlh refresh 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_refresh_link_ok (struct TALER_EXCHANGE_RefreshLinkHandle *rlh,
+ 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 MAJ_Specification spec[] = {
+ MAJ_spec_json ("new_coins", &jsona),
+ MAJ_spec_end
+ };
+
+ if (GNUNET_OK !=
+ MAJ_parse_json (json_array_get (json,
+ session),
+ spec))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ if (! json_is_array (jsona))
+ {
+ GNUNET_break_op (0);
+ MAJ_parse_free (spec);
+ return GNUNET_SYSERR;
+ }
+
+ /* count all coins over all sessions */
+ num_coins += json_array_size (jsona);
+ MAJ_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[num_coins];
+ struct TALER_DenominationSignature sigs[num_coins];
+ struct TALER_DenominationPublicKey pubs[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 TALER_EncryptedLinkSecretP secret_enc;
+ struct MAJ_Specification spec[] = {
+ MAJ_spec_json ("new_coins", &jsona),
+ MAJ_spec_fixed_auto ("transfer_pub", &trans_pub),
+ MAJ_spec_fixed_auto ("secret_enc", &secret_enc),
+ MAJ_spec_end
+ };
+
+ if (GNUNET_OK !=
+ MAJ_parse_json (json_array_get (json,
+ session),
+ spec))
+ {
+ GNUNET_break_op (0);
+ return GNUNET_SYSERR;
+ }
+ if (! json_is_array (jsona))
+ {
+ GNUNET_break_op (0);
+ MAJ_parse_free (spec);
+ return GNUNET_SYSERR;
+ }
+
+ /* decode all coins */
+ for (i=0;i<json_array_size (jsona);i++)
+ {
+ if (GNUNET_OK !=
+ parse_refresh_link_coin (rlh,
+ json_array_get (jsona,
+ i),
+ &trans_pub,
+ &secret_enc,
+ &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;
+ MAJ_parse_free (spec);
+ break;
+ }
+ MAJ_parse_free (spec);
+ } /* end of for (session) */
+
+ if (off_coin == num_coins)
+ {
+ rlh->link_cb (rlh->link_cb_cls,
+ MHD_HTTP_OK,
+ num_coins,
+ coin_privs,
+ sigs,
+ pubs,
+ json);
+ rlh->link_cb = NULL;
+ ret = GNUNET_OK;
+ }
+ else
+ {
+ GNUNET_break_op (0);
+ ret = GNUNET_SYSERR;
+ }
+
+ /* clean up */
+ 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 /refresh/link request.
+ *
+ * @param cls the `struct TALER_EXCHANGE_RefreshLinkHandle`
+ * @param eh the curl request handle
+ */
+static void
+handle_refresh_link_finished (void *cls,
+ CURL *eh)
+{
+ struct TALER_EXCHANGE_RefreshLinkHandle *rlh = cls;
+ long response_code;
+ json_t *json;
+
+ rlh->job = NULL;
+ json = MAC_download_get_result (&rlh->db,
+ eh,
+ &response_code);
+ switch (response_code)
+ {
+ case 0:
+ break;
+ case MHD_HTTP_OK:
+ if (GNUNET_OK !=
+ parse_refresh_link_ok (rlh,
+ json))
+ {
+ 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",
+ response_code);
+ GNUNET_break (0);
+ response_code = 0;
+ break;
+ }
+ if (NULL != rlh->link_cb)
+ rlh->link_cb (rlh->link_cb_cls,
+ response_code,
+ 0, NULL, NULL, NULL,
+ json);
+ json_decref (json);
+ TALER_EXCHANGE_refresh_link_cancel (rlh);
+}
+
+
+/**
+ * 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_RefreshLinkHandle *
+TALER_EXCHANGE_refresh_link (struct TALER_EXCHANGE_Handle *exchange,
+ const struct TALER_CoinSpendPrivateKeyP *coin_priv,
+ TALER_EXCHANGE_RefreshLinkCallback link_cb,
+ void *link_cb_cls)
+{
+ struct TALER_EXCHANGE_RefreshLinkHandle *rlh;
+ CURL *eh;
+ struct TALER_EXCHANGE_Context *ctx;
+ struct TALER_CoinSpendPublicKeyP coin_pub;
+ char *pub_str;
+ char *arg_str;
+
+ if (GNUNET_YES !=
+ MAH_handle_is_ready (exchange))
+ {
+ GNUNET_break (0);
+ return NULL;
+ }
+
+ GNUNET_CRYPTO_eddsa_key_get_public (&coin_priv->eddsa_priv,
+ &coin_pub.eddsa_pub);
+ pub_str = GNUNET_STRINGS_data_to_string_alloc (&coin_pub,
+ sizeof (struct TALER_CoinSpendPublicKeyP));
+ GNUNET_asprintf (&arg_str,
+ "/refresh/link?coin_pub=%s",
+ pub_str);
+ GNUNET_free (pub_str);
+
+ rlh = GNUNET_new (struct TALER_EXCHANGE_RefreshLinkHandle);
+ rlh->exchange = exchange;
+ rlh->link_cb = link_cb;
+ rlh->link_cb_cls = link_cb_cls;
+ rlh->coin_priv = *coin_priv;
+ rlh->url = MAH_path_to_url (exchange, arg_str);
+ GNUNET_free (arg_str);
+
+ eh = curl_easy_init ();
+ GNUNET_assert (CURLE_OK ==
+ curl_easy_setopt (eh,
+ CURLOPT_URL,
+ rlh->url));
+ GNUNET_assert (CURLE_OK ==
+ curl_easy_setopt (eh,
+ CURLOPT_WRITEFUNCTION,
+ &MAC_download_cb));
+ GNUNET_assert (CURLE_OK ==
+ curl_easy_setopt (eh,
+ CURLOPT_WRITEDATA,
+ &rlh->db));
+ ctx = MAH_handle_to_context (exchange);
+ rlh->job = MAC_job_add (ctx,
+ eh,
+ GNUNET_YES,
+ &handle_refresh_link_finished,
+ rlh);
+ return rlh;
+}
+
+
+/**
+ * Cancel a refresh link request. This function cannot be used
+ * on a request handle if the callback was already invoked.
+ *
+ * @param rlh the refresh link handle
+ */
+void
+TALER_EXCHANGE_refresh_link_cancel (struct TALER_EXCHANGE_RefreshLinkHandle *rlh)
+{
+ if (NULL != rlh->job)
+ {
+ MAC_job_cancel (rlh->job);
+ rlh->job = NULL;
+ }
+ GNUNET_free_non_null (rlh->db.buf);
+ GNUNET_free (rlh->url);
+ GNUNET_free (rlh);
+}
+
+
+/* end of exchange_api_refresh_link.c */