implement exchange_api_reserves_attest.c

src/include/taler_crypto_lib.h

@@ -3201,7 +3201,13 @@ TALER_wallet_account_setup_verify (
 
 
 /**
- * FIXME.
+ * Sign request to the exchange to confirm certain
+ * @a details about the owner of a reserve.
+ *
+ * @param request_timestamp when was the request created
+ * @param details which attributes are requested
+ * @param reserve_priv private key of the reserve
+ * @param[out] reserve_sig where to store the signature
  */
 void
 TALER_wallet_reserve_attest_request_sign (
@@ -3212,7 +3218,14 @@ TALER_wallet_reserve_attest_request_sign (
 
 
 /**
- * FIXME.
+ * Verify request to the exchange to confirm certain
+ * @a details about the owner of a reserve.
+ *
+ * @param request_timestamp when was the request created
+ * @param details which attributes are requested
+ * @param reserve_priv private key of the reserve
+ * @param reserve_sig where to store the signature
+ * @return #GNUNET_OK if the signature is valid
  */
 enum GNUNET_GenericReturnValue
 TALER_wallet_reserve_attest_request_verify (
@@ -4250,6 +4263,53 @@ TALER_exchange_online_reserve_closed_verify (
   const struct TALER_ExchangeSignatureP *sig);
 
 
+/**
+ * Create signature by exchange affirming that a reserve
+ * has had certain attributes verified via KYC.
+ *
+ * @param scb function to call to create the signature
+ * @param attest_timestamp our time
+ * @param expiration_time when does the KYC data expire
+ * @param reserve_pub for which reserve are attributes attested
+ * @param attributes JSON object with attributes being attested to
+ * @param[out] pub where to write the public key
+ * @param[out] sig where to write the signature
+ * @return #TALER_EC_NONE on success
+ */
+enum TALER_ErrorCode
+TALER_exchange_online_reserve_attest_details_sign (
+  TALER_ExchangeSignCallback scb,
+  struct GNUNET_TIME_Timestamp attest_timestamp,
+  struct GNUNET_TIME_Timestamp expiration_time,
+  const struct TALER_ReservePublicKeyP *reserve_pub,
+  const json_t *attributes,
+  struct TALER_ExchangePublicKeyP *pub,
+  struct TALER_ExchangeSignatureP *sig);
+
+
+/**
+ * Verify signature by exchange affirming that a reserve
+ * has had certain attributes verified via KYC.
+ *
+ * @param scb function to call to create the signature
+ * @param attest_timestamp our time
+ * @param expiration_time when does the KYC data expire
+ * @param reserve_pub for which reserve are attributes attested
+ * @param attributes JSON object with attributes being attested to
+ * @param pub exchange public key
+ * @param sig exchange signature to verify
+ * @return #GNUNET_OK if the signature is valid
+ */
+enum GNUNET_GenericReturnValue
+TALER_exchange_online_reserve_attest_details_verify (
+  struct GNUNET_TIME_Timestamp attest_timestamp,
+  struct GNUNET_TIME_Timestamp expiration_time,
+  const struct TALER_ReservePublicKeyP *reserve_pub,
+  const json_t *attributes,
+  struct TALER_ExchangePublicKeyP *pub,
+  struct TALER_ExchangeSignatureP *sig);
+
+
 /**
  * Create signature by exchange affirming that a purse was created.
  *

src/include/taler_exchange_service.h

@@ -5451,6 +5451,30 @@ struct TALER_EXCHANGE_ReservePostAttestResult
      */
     struct
     {
+      /**
+       * Time when the exchange made the signature.
+       */
+      struct GNUNET_TIME_Timestamp exchange_time;
+
+      /**
+       * Current expiration time of the reserve.
+       */
+      struct GNUNET_TIME_Timestamp expiration_time;
+
+      /**
+       * Signature by the exchange affirming the attributes.
+       */
+      struct TALER_ExchangeSignatureP exchange_sig;
+
+      /**
+       * Online signing key used by the exchange.
+       */
+      struct TALER_ExchangePublicKeyP exchange_pub;
+
+      /**
+       * Attributes being confirmed by the exchange.
+       */
+      const json_t *attributes;
 
     } ok;
 

src/lib/Makefile.am

@@ -60,6 +60,7 @@ libtalerexchange_la_SOURCES = \
   exchange_api_refresh_common.c exchange_api_refresh_common.h \
   exchange_api_refreshes_reveal.c \
   exchange_api_refund.c \
+  exchange_api_reserves_attest.c \
   exchange_api_reserves_close.c \
   exchange_api_reserves_get.c \
   exchange_api_reserves_get_attestable.c \

src/lib/exchange_api_reserves_attest.c

@@ -0,0 +1,358 @@
+/*
+  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 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_reserves_attest.c
+ * @brief Implementation of the POST /reserves/$RESERVE_PUB/attest requests
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <jansson.h>
+#include <microhttpd.h> /* just for HTTP attest codes */
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_json_lib.h>
+#include <gnunet/gnunet_curl_lib.h>
+#include "taler_exchange_service.h"
+#include "taler_json_lib.h"
+#include "exchange_api_handle.h"
+#include "taler_signatures.h"
+#include "exchange_api_curl_defaults.h"
+
+
+/**
+ * @brief A /reserves/$RID/attest Handle
+ */
+struct TALER_EXCHANGE_ReservesAttestHandle
+{
+
+  /**
+   * 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;
+
+  /**
+   * Context for #TEH_curl_easy_post(). Keeps the data that must
+   * persist for Curl to make the upload.
+   */
+  struct TALER_CURL_PostContext post_ctx;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_EXCHANGE_ReservesPostAttestCallback cb;
+
+  /**
+   * Public key of the reserve we are querying.
+   */
+  struct TALER_ReservePublicKeyP reserve_pub;
+
+  /**
+   * Closure for @a cb.
+   */
+  void *cb_cls;
+
+};
+
+
+/**
+ * We received an #MHD_HTTP_OK attest code. Handle the JSON
+ * response.
+ *
+ * @param rsh handle of the request
+ * @param j JSON response
+ * @return #GNUNET_OK on success
+ */
+static enum GNUNET_GenericReturnValue
+handle_reserves_attest_ok (struct TALER_EXCHANGE_ReservesAttestHandle *rsh,
+                           const json_t *j)
+{
+  struct TALER_EXCHANGE_ReservePostAttestResult rs = {
+    .hr.reply = j,
+    .hr.http_status = MHD_HTTP_OK
+  };
+  json_t *attributes;
+  struct GNUNET_JSON_Specification spec[] = {
+    GNUNET_JSON_spec_timestamp ("exchange_timestamp",
+                                &rs.details.ok.exchange_time),
+    GNUNET_JSON_spec_timestamp ("exchange_timestamp",
+                                &rs.details.ok.expiration_time),
+    GNUNET_JSON_spec_fixed_auto ("exchange_sig",
+                                 &rs.details.ok.exchange_sig),
+    GNUNET_JSON_spec_fixed_auto ("exchange_pub",
+                                 &rs.details.ok.exchange_pub),
+    GNUNET_JSON_spec_json ("attributes",
+                           &attributes),
+    GNUNET_JSON_spec_end ()
+  };
+
+  if (GNUNET_OK !=
+      GNUNET_JSON_parse (j,
+                         spec,
+                         NULL,
+                         NULL))
+  {
+    GNUNET_break_op (0);
+    return GNUNET_SYSERR;
+  }
+  rs.details.ok.attributes = attributes;
+  if (GNUNET_OK !=
+      TALER_exchange_online_reserve_attest_details_verify (
+        rs.details.ok.exchange_time,
+        rs.details.ok.expiration_time,
+        &rsh->reserve_pub,
+        attributes,
+        &rs.details.ok.exchange_pub,
+        &rs.details.ok.exchange_sig))
+  {
+    GNUNET_break_op (0);
+    GNUNET_JSON_parse_free (spec);
+    return GNUNET_SYSERR;
+  }
+  // FIXME: verify exchange signature!
+  // => needs crypto API first!
+  rsh->cb (rsh->cb_cls,
+           &rs);
+  rsh->cb = NULL;
+  GNUNET_JSON_parse_free (spec);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP /reserves/$RID/attest request.
+ *
+ * @param cls the `struct TALER_EXCHANGE_ReservesAttestHandle`
+ * @param response_code HTTP response code, 0 on error
+ * @param response parsed JSON result, NULL on error
+ */
+static void
+handle_reserves_attest_finished (void *cls,
+                                 long response_code,
+                                 const void *response)
+{
+  struct TALER_EXCHANGE_ReservesAttestHandle *rsh = cls;
+  const json_t *j = response;
+  struct TALER_EXCHANGE_ReservePostAttestResult rs = {
+    .hr.reply = j,
+    .hr.http_status = (unsigned int) response_code
+  };
+
+  rsh->job = NULL;
+  switch (response_code)
+  {
+  case 0:
+    rs.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
+    break;
+  case MHD_HTTP_OK:
+    if (GNUNET_OK !=
+        handle_reserves_attest_ok (rsh,
+                                   j))
+    {
+      rs.hr.http_status = 0;
+      rs.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
+    }
+    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 */
+    GNUNET_break (0);
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_FORBIDDEN:
+    /* This should never happen, either us or the exchange is buggy
+       (or API version conflict); just pass JSON reply to the application */
+    GNUNET_break (0);
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_NOT_FOUND:
+    /* Nothing really to verify, this should never
+       happen, we should pass the JSON reply to the application */
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_CONFLICT:
+    /* Server doesn't have the requested attributes */
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_INTERNAL_SERVER_ERROR:
+    /* Server had an internal issue; we should retry, but this API
+       leaves this to the application */
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  default:
+    /* unexpected response code */
+    GNUNET_break_op (0);
+    rs.hr.ec = TALER_JSON_get_error_code (j);
+    rs.hr.hint = TALER_JSON_get_error_hint (j);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u/%d for reserves attest\n",
+                (unsigned int) response_code,
+                (int) rs.hr.ec);
+    break;
+  }
+  if (NULL != rsh->cb)
+  {
+    rsh->cb (rsh->cb_cls,
+             &rs);
+    rsh->cb = NULL;
+  }
+  TALER_EXCHANGE_reserves_attest_cancel (rsh);
+}
+
+
+struct TALER_EXCHANGE_ReservesAttestHandle *
+TALER_EXCHANGE_reserves_attest (
+  struct TALER_EXCHANGE_Handle *exchange,
+  const struct TALER_ReservePrivateKeyP *reserve_priv,
+  unsigned int attributes_length,
+  const char *const*attributes,
+  TALER_EXCHANGE_ReservesPostAttestCallback cb,
+  void *cb_cls)
+{
+  struct TALER_EXCHANGE_ReservesAttestHandle *rsh;
+  struct GNUNET_CURL_Context *ctx;
+  CURL *eh;
+  char arg_str[sizeof (struct TALER_ReservePublicKeyP) * 2 + 32];
+  struct TALER_ReserveSignatureP reserve_sig;
+  json_t *details;
+  struct GNUNET_TIME_Timestamp ts;
+
+  if (0 == attributes_length)
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  if (GNUNET_YES !=
+      TEAH_handle_is_ready (exchange))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  details = json_array ();
+  GNUNET_assert (NULL != details);
+  for (unsigned int i = 0; i<attributes_length; i++)
+  {
+    GNUNET_assert (0 ==
+                   json_array_append_new (details,
+                                          json_string (attributes[i])));
+  }
+  rsh = GNUNET_new (struct TALER_EXCHANGE_ReservesAttestHandle);
+  rsh->exchange = exchange;
+  rsh->cb = cb;
+  rsh->cb_cls = cb_cls;
+  GNUNET_CRYPTO_eddsa_key_get_public (&reserve_priv->eddsa_priv,
+                                      &rsh->reserve_pub.eddsa_pub);
+  {
+    char pub_str[sizeof (struct TALER_ReservePublicKeyP) * 2];
+    char *end;
+
+    end = GNUNET_STRINGS_data_to_string (
+      &rsh->reserve_pub,
+      sizeof (rsh->reserve_pub),
+      pub_str,
+      sizeof (pub_str));
+    *end = '\0';
+    GNUNET_snprintf (arg_str,
+                     sizeof (arg_str),
+                     "/reserves/%s/attest",
+                     pub_str);
+  }
+  rsh->url = TEAH_path_to_url (exchange,
+                               arg_str);
+  if (NULL == rsh->url)
+  {
+    json_decref (details);
+    GNUNET_free (rsh);
+    return NULL;
+  }
+  eh = TALER_EXCHANGE_curl_easy_get_ (rsh->url);
+  if (NULL == eh)
+  {
+    GNUNET_break (0);
+    json_decref (details);
+    GNUNET_free (rsh->url);
+    GNUNET_free (rsh);
+    return NULL;
+  }
+  ts = GNUNET_TIME_timestamp_get ();
+  TALER_wallet_reserve_attest_request_sign (ts,
+                                            details,
+                                            reserve_priv,
+                                            &reserve_sig);
+  {
+    json_t *attest_obj = GNUNET_JSON_PACK (
+      GNUNET_JSON_pack_data_auto ("reserve_sig",
+                                  &reserve_sig),
+      GNUNET_JSON_pack_timestamp ("request_timestamp",
+                                  ts),
+      GNUNET_JSON_pack_object_steal ("details",
+                                     details));
+
+    if (GNUNET_OK !=
+        TALER_curl_easy_post (&rsh->post_ctx,
+                              eh,
+                              attest_obj))
+    {
+      GNUNET_break (0);
+      curl_easy_cleanup (eh);
+      json_decref (attest_obj);
+      GNUNET_free (rsh->url);
+      GNUNET_free (rsh);
+      return NULL;
+    }
+    json_decref (attest_obj);
+  }
+  ctx = TEAH_handle_to_context (exchange);
+  rsh->job = GNUNET_CURL_job_add2 (ctx,
+                                   eh,
+                                   rsh->post_ctx.headers,
+                                   &handle_reserves_attest_finished,
+                                   rsh);
+  return rsh;
+}
+
+
+void
+TALER_EXCHANGE_reserves_attest_cancel (
+  struct TALER_EXCHANGE_ReservesAttestHandle *rsh)
+{
+  if (NULL != rsh->job)
+  {
+    GNUNET_CURL_job_cancel (rsh->job);
+    rsh->job = NULL;
+  }
+  TALER_curl_easy_post_finished (&rsh->post_ctx);
+  GNUNET_free (rsh->url);
+  GNUNET_free (rsh);
+}
+
+
+/* end of exchange_api_reserves_attest.c */