check tokens on idempotent pay request

6 files changed, 336 insertions, 18 deletions

diff --git a/src/backend/taler-merchant-httpd_post-orders-ID-pay.c b/src/backend/taler-merchant-httpd_post-orders-ID-pay.c
index 7fa93404..888ea0ba 100644
--- a/src/backend/taler-merchant-httpd_post-orders-ID-pay.c
+++ b/src/backend/taler-merchant-httpd_post-orders-ID-pay.c
@@ -259,6 +259,11 @@ struct TokenUseConfirmation
    */
   struct TALER_TokenIssuePublicKeyHashP h_issue;
 
+  /**
+   * true if we found this token in the database.
+   */
+  bool found_in_db;
+
 };
 
 
@@ -2682,6 +2687,38 @@ deposit_paid_check (
 }
 
 
+static void
+input_tokens_paid_check (
+  void *cls,
+  uint64_t spent_token_serial,
+  const struct TALER_PrivateContractHashP *h_contract_terms,
+  const struct TALER_TokenIssuePublicKeyHashP *h_issue_pub,
+  const struct TALER_TokenUsePublicKeyP *use_pub,
+  const struct TALER_TokenUseSignatureP *use_sig,
+  const struct TALER_TokenIssueSignatureP *issue_sig)
+{
+  struct PayContext *pc = cls;
+
+  for (size_t i = 0; i<pc->tokens_cnt; i++)
+  {
+    struct TokenUseConfirmation *tuc = &pc->tokens[i];
+
+    if ( (0 ==
+          GNUNET_CRYPTO_hash_cmp (&tuc->h_issue.hash,
+                                &h_issue_pub->hash)) &&
+         (0 ==
+          GNUNET_memcmp (&tuc->pub, use_pub)) &&
+         (0 ==
+          GNUNET_memcmp (&tuc->sig, use_sig)) &&
+         (0 ==
+          GNUNET_memcmp (&tuc->unblinded_sig, issue_sig)) )
+    {
+      tuc->found_in_db = true;
+      break;
+    }
+  }
+}
+
 /**
  * Handle case where contract was already paid. Either decides
  * the payment is idempotent, or refunds the excess payment.
@@ -2691,34 +2728,64 @@ deposit_paid_check (
 static void
 phase_contract_paid (struct PayContext *pc)
 {
-  enum GNUNET_DB_QueryStatus qs;
-  bool unmatched = false;
   json_t *refunds;
+  bool unmatched = false;
 
-  qs = TMH_db->lookup_deposits_by_order (TMH_db->cls,
-                                         pc->order_serial,
-                                         &deposit_paid_check,
-                                         pc);
-  /* TODO: Check tokens */
-  /* Since orders with choices can have a price of zero,
-     0 is also a valid query state */
-  if (qs < 0)
   {
-    GNUNET_break (0);
-    pay_end (pc,
-             TALER_MHD_reply_with_error (pc->connection,
-                                         MHD_HTTP_INTERNAL_SERVER_ERROR,
-                                         TALER_EC_GENERIC_DB_FETCH_FAILED,
-                                         "lookup_deposits_by_order"));
-    return;
+    enum GNUNET_DB_QueryStatus qs;
+
+    qs = TMH_db->lookup_deposits_by_order (TMH_db->cls,
+                                           pc->order_serial,
+                                           &deposit_paid_check,
+                                           pc);
+    /* Since orders with choices can have a price of zero,
+       0 is also a valid query state */
+    if (qs < 0)
+    {
+      GNUNET_break (0);
+      pay_end (pc,
+              TALER_MHD_reply_with_error (pc->connection,
+                                          MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                          TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                          "lookup_deposits_by_order"));
+      return;
+    }
   }
-  for (size_t i = 0; i<pc->coins_cnt; i++)
+  for (size_t i = 0; i<pc->coins_cnt && !unmatched; i++)
   {
     struct DepositConfirmation *dci = &pc->dc[i];
 
     if (! dci->matched_in_db)
       unmatched = true;
   }
+  /* Check if provided input tokens match token in the database */
+  {
+    enum GNUNET_DB_QueryStatus qs;
+
+    /* TODO: Use h_contract instead of order_serial here? */
+    qs = TMH_db->lookup_spent_tokens_by_order (TMH_db->cls,
+                                               pc->order_serial,
+                                               &input_tokens_paid_check,
+                                               pc);
+
+    if (qs < 0)
+    {
+      GNUNET_break (0);
+      pay_end (pc,
+              TALER_MHD_reply_with_error (pc->connection,
+                                          MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                          TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                          "lookup_spent_tokens_by_order"));
+      return;
+    }
+  }
+  for (size_t i = 0; i<pc->tokens_cnt && !unmatched; i++)
+  {
+    struct TokenUseConfirmation *tuc = &pc->tokens[i];
+
+    if (! tuc->found_in_db)
+      unmatched = true;
+  }
   if (! unmatched)
   {
     /* Everything fine, idempotent request */
@@ -2740,6 +2807,8 @@ phase_contract_paid (struct PayContext *pc)
     return;
   }
   /* Conflict, double-payment detected! */
+  /* TODO: What should we do with input tokens?
+     Currently there is no refund for tokens. */
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "Client attempted to pay extra for already paid order `%s'\n",
               pc->order_id);
diff --git a/src/backenddb/Makefile.am b/src/backenddb/Makefile.am
index 9612beec..95efe07e 100644
--- a/src/backenddb/Makefile.am
+++ b/src/backenddb/Makefile.am
@@ -180,6 +180,7 @@ libtaler_plugin_merchantdb_postgres_la_SOURCES = \
   pg_lookup_token_family_key.h pg_lookup_token_family_key.c \
   pg_insert_spent_token.h pg_insert_spent_token.c \
   pg_insert_issued_token.h pg_insert_issued_token.c \
+  pg_lookup_spent_tokens_by_order.h pg_lookup_spent_tokens_by_order.c \
   plugin_merchantdb_postgres.c \
   pg_helper.h pg_helper.c
 libtaler_plugin_merchantdb_postgres_la_LIBADD = \
diff --git a/src/backenddb/pg_lookup_spent_tokens_by_order.c b/src/backenddb/pg_lookup_spent_tokens_by_order.c
new file mode 100644
index 00000000..667cbcbc
--- /dev/null
+++ b/src/backenddb/pg_lookup_spent_tokens_by_order.c
@@ -0,0 +1,162 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2024 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 backenddb/pg_lookup_spent_tokens_by_order.c
+ * @brief Implementation of the lookup_spent_tokens_by_order function for Postgres
+ * @author Christian Blättler
+ */
+#include "platform.h"
+#include <taler/taler_error_codes.h>
+#include <taler/taler_dbevents.h>
+#include <taler/taler_pq_lib.h>
+#include "pg_lookup_spent_tokens_by_order.h"
+#include "pg_helper.h"
+#include "taler_merchantdb_plugin.h"
+
+/**
+ * Closure for lookup_spent_tokens_by_order_cb().
+ */
+struct LookupSpentTokensByOrderContext
+{
+
+  /**
+   * Plugin context.
+   */
+  struct PostgresClosure *pg;
+
+  /**
+   * Function to call with all results.
+   */
+  TALER_MERCHANTDB_UsedTokensCallback cb;
+
+  /**
+   * Closure for @e cb.
+   */
+  void *cb_cls;
+
+  /**
+   * Set to the query result.
+   */
+  enum GNUNET_DB_QueryStatus qs;
+};
+
+
+/**
+ * Function to be called with the results of a SELECT statement
+ * that has returned @a num_results results.
+ *
+ * @param cls of type `struct LookupSpentTokensByOrderContext *`
+ * @param result the postgres result
+ * @param num_results the number of results in @a result
+ */
+static void
+lookup_spent_tokens_by_order_cb (void *cls,
+                             PGresult *result,
+                             unsigned int num_results)
+{
+  struct LookupSpentTokensByOrderContext *ctx = cls;
+
+  for (unsigned int i = 0; i<num_results; i++)
+  {
+    uint64_t spent_token_serial;
+    struct TALER_PrivateContractHashP h_contract_terms;
+    struct TALER_TokenIssuePublicKeyHashP h_issue_pub;
+    struct TALER_TokenUsePublicKeyP use_pub;
+    struct TALER_TokenUseSignatureP use_sig;
+    struct TALER_TokenIssueSignatureP issue_sig;
+    struct GNUNET_PQ_ResultSpec rs[] = {
+      GNUNET_PQ_result_spec_uint64 ("spent_token_serial",
+                                    &spent_token_serial),
+      GNUNET_PQ_result_spec_auto_from_type ("h_contract_terms",
+                                            &h_contract_terms),
+      GNUNET_PQ_result_spec_auto_from_type ("h_pub",
+                                            &h_issue_pub),
+      GNUNET_PQ_result_spec_auto_from_type ("token_pub",
+                                            &use_pub),
+      GNUNET_PQ_result_spec_auto_from_type ("token_sig",
+                                            &use_sig),
+      // GNUNET_PQ_result_spec_unblinded_sig ("blind_sig",
+      //                                      &issue_sig),
+      GNUNET_PQ_result_spec_end
+    };
+
+    if (GNUNET_OK !=
+        GNUNET_PQ_extract_result (result,
+                                  rs,
+                                  i))
+    {
+      GNUNET_break (0);
+      ctx->qs = GNUNET_DB_STATUS_HARD_ERROR;
+      return;
+    }
+    ctx->cb (ctx->cb_cls,
+             spent_token_serial,
+             &h_contract_terms,
+             &h_issue_pub,
+             &use_pub,
+             &use_sig,
+             &issue_sig);
+    GNUNET_PQ_cleanup_result (rs);
+  }
+  ctx->qs = num_results;
+}
+
+
+enum GNUNET_DB_QueryStatus
+TMH_PG_lookup_spent_tokens_by_order (void *cls,
+                                     uint64_t order_serial,
+                                     TALER_MERCHANTDB_UsedTokensCallback cb,
+                                     void *cb_cls)
+{
+  struct PostgresClosure *pg = cls;
+  struct LookupSpentTokensByOrderContext ctx = {
+    .pg = pg,
+    .cb = cb,
+    .cb_cls = cb_cls
+  };
+  struct GNUNET_PQ_QueryParam params[] = {
+    GNUNET_PQ_query_param_uint64 (&order_serial),
+    GNUNET_PQ_query_param_end
+  };
+  enum GNUNET_DB_QueryStatus qs;
+
+  check_connection (pg);
+  PREPARE (pg,
+           "lookup_spent_tokens_by_order",
+           "SELECT"
+           " spent_token_serial"
+           ",h_contract_terms"
+           ",h_pub"
+           ",token_pub"
+           ",token_sig"
+           ",blind_sig"
+           " FROM merchant_spent_tokens"
+           " JOIN merchant_contract_terms"
+           "   USING (h_contract_terms)"
+           " JOIN merchant_token_family_keys"
+           "   USING (token_family_key_serial)"
+           " WHERE order_serial=$1");
+
+  qs = GNUNET_PQ_eval_prepared_multi_select (pg->conn,
+                                             "lookup_spent_tokens_by_order",
+                                             params,
+                                             &lookup_spent_tokens_by_order_cb,
+                                             &ctx);
+
+  if (qs < 0)
+    return qs;
+  return ctx.qs;
+}
diff --git a/src/backenddb/pg_lookup_spent_tokens_by_order.h b/src/backenddb/pg_lookup_spent_tokens_by_order.h
new file mode 100644
index 00000000..d3c55676
--- /dev/null
+++ b/src/backenddb/pg_lookup_spent_tokens_by_order.h
@@ -0,0 +1,45 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2024 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 backenddb/pg_lookup_spent_tokens_by_order.h
+ * @brief implementation of the lookup_spent_tokens_by_order function for Postgres
+ * @author Christian Grothoff
+ */
+#ifndef PG_LOOKUP_SPENT_TOKENS_BY_ORDER_H
+#define PG_LOOKUP_SPENT_TOKENS_BY_ORDER_H
+
+#include <taler/taler_util.h>
+#include <taler/taler_json_lib.h>
+#include "taler_merchantdb_plugin.h"
+
+/**
+ * Retrieve details about tokens that were used for an order.
+ *
+ * @param cls closure
+ * @param order_serial identifies the order
+ * @param cb function to call for each used token
+ * @param cb_cls closure for @a cb
+ * @return transaction status
+ */
+enum GNUNET_DB_QueryStatus
+TMH_PG_lookup_spent_tokens_by_order (void *cls,
+                                     uint64_t order_serial,
+                                     TALER_MERCHANTDB_UsedTokensCallback cb,
+                                     void *cb_cls);
+
+
+
+#endif
diff --git a/src/backenddb/plugin_merchantdb_postgres.c b/src/backenddb/plugin_merchantdb_postgres.c
index 16e40ac5..a886acaf 100644
--- a/src/backenddb/plugin_merchantdb_postgres.c
+++ b/src/backenddb/plugin_merchantdb_postgres.c
@@ -142,6 +142,7 @@
 #include "pg_lookup_token_family_key.h"
 #include "pg_insert_spent_token.h"
 #include "pg_insert_issued_token.h"
+#include "pg_lookup_spent_tokens_by_order.h"
 
 
 /**
@@ -589,6 +590,8 @@ libtaler_plugin_merchantdb_postgres_init (void *cls)
     = &TMH_PG_insert_spent_token;
   plugin->insert_issued_token
     = &TMH_PG_insert_issued_token;
+  plugin->lookup_spent_tokens_by_order
+    = &TMH_PG_lookup_spent_tokens_by_order;
 
 
 
diff --git a/src/include/taler_merchantdb_plugin.h b/src/include/taler_merchantdb_plugin.h
index 329975fa..aac39d17 100644
--- a/src/include/taler_merchantdb_plugin.h
+++ b/src/include/taler_merchantdb_plugin.h
@@ -1132,6 +1132,27 @@ struct TALER_MERCHANTDB_SpentTokenDetails
 
 
 /**
+ * Function called with information about a token that was used.
+ *
+ * @param cls closure
+ * @param spent_token_serial which used token is this about
+ * @param h_contract_terms hash of the contract terms this token was used on
+ * @param h_issue_pub hash of the token issue public key
+ * @param use_pub token use public key
+ * @param use_sig token use signature
+ * @param issue_sig unblinded token issue signature
+ */
+typedef void
+(*TALER_MERCHANTDB_UsedTokensCallback)(
+  void *cls,
+  uint64_t spent_token_serial,
+  const struct TALER_PrivateContractHashP *h_contract_terms,
+  const struct TALER_TokenIssuePublicKeyHashP *h_issue_pub,
+  const struct TALER_TokenUsePublicKeyP *use_pub,
+  const struct TALER_TokenUseSignatureP *use_sig,
+  const struct TALER_TokenIssueSignatureP *issue_sig);
+
+/**
  * Handle to interact with the database.
  *
  * Functions ending with "_TR" run their OWN transaction scope
@@ -2127,6 +2148,23 @@ struct TALER_MERCHANTDB_Plugin
                     void *rc_cls);
 
 
+
+  /**
+   * Retrieve details about tokens that were used for an order.
+   *
+   * @param cls closure
+   * @param order_serial identifies the order
+   * @param cb function to call for each used token
+   * @param cb_cls closure for @a cb
+   * @return transaction status
+   */
+  enum GNUNET_DB_QueryStatus
+  (*lookup_spent_tokens_by_order) (void *cls,
+                                   uint64_t order_serial,
+                                   TALER_MERCHANTDB_UsedTokensCallback cb,
+                                   void *cb_cls);
+
+
   /**
    * Mark contract as paid and store the current @a session_id
    * for which the contract was paid. Deletes the underlying order