scaffolding work towards #3712

src/include/taler_mintdb_plugin.h

@@ -24,6 +24,7 @@
 
 #include <gnunet/gnunet_util_lib.h>
 #include "taler_util.h"
+#include "taler_signatures.h"
 
 
 /**
@@ -378,7 +379,7 @@ GNUNET_NETWORK_STRUCT_BEGIN
 
 /**
  * @brief For each (old) coin being melted, we have a `struct
- * RefreshCommitLink` that allows the user to find the shared secret
+ * RefreshCommitLinkP` that allows the user to find the shared secret
  * to decrypt the respective refresh links for the new coins in the
  * `struct TALER_MINTDB_RefreshCommitCoin`.
  */
@@ -518,6 +519,44 @@ struct TALER_MINTDB_TransactionList
 };
 
 
+/**
+ * @brief All of the information from a /refresh/melt commitment.
+ */
+struct TALER_MINTDB_MeltCommitment
+{
+
+  /**
+   * Number of coins we are melting.
+   */
+  uint16_t num_oldcoins;
+
+  /**
+   * Number of new coins we are creating.
+   */
+  uint16_t num_newcoins;
+
+  /**
+   * Array of @e num_oldcoins melt operation details.
+   */
+  struct TALER_MINTDB_RefreshMelt *melts;
+
+  /**
+   * Array of @e num_newcoins denomination keys
+   */
+  struct TALER_DenominationPublicKey *denom_pubs;
+
+  /**
+   * 2D-Array of #TALER_CNC_KAPPA and @e num_newcoins commitments.
+   */
+  struct TALER_MINTDB_RefreshCommitCoin *commit_coins[TALER_CNC_KAPPA];
+
+  /**
+   * 2D-Array of #TALER_CNC_KAPPA and @e new_oldcoins links.
+   */
+  struct TALER_MINTDB_RefreshCommitLinkP *commit_links[TALER_CNC_KAPPA];
+};
+
+
 /**
  * @brief Handle for a database session (per-thread, for transactions).
  */
@@ -954,6 +993,32 @@ struct TALER_MINTDB_Plugin
                                struct TALER_MINTDB_RefreshCommitLinkP *links);
 
 
+  /**
+   * Get all of the information from the given melt commit operation.
+   *
+   * @param cls the @e cls of this struct with the plugin-specific state
+   * @param sesssion database connection to use
+   * @param session_hash hash to identify refresh session
+   * @return NULL if the @a session_hash does not correspond to any known melt
+   *         operation
+   */
+  struct TALER_MINTDB_MeltCommitment *
+  (*get_melt_commitment) (void *cls,
+                          struct TALER_MINTDB_Session *sesssion,
+                          const struct GNUNET_HashCode *session_hash);
+
+
+  /**
+   * Free information about a melt commitment.
+   *
+   * @param cls the @e cls of this struct with the plugin-specific state
+   * @param mc melt commitment data to free
+   */
+  void
+  (*free_melt_commitment) (void *cls,
+                           struct TALER_MINTDB_MeltCommitment *mc);
+
+
   /**
    * Insert signature of a new coin generated during refresh into
    * the database indexed by the refresh session and the index

src/mint/taler-mint-httpd_db.c

@@ -743,6 +743,54 @@ TMH_DB_execute_refresh_melt (struct MHD_Connection *connection,
 }
 
 
+/**
+ * Send an error response with the details of the original melt
+ * commitment and the location of the mismatch.
+ *
+ * @param connection the MHD connection to handle
+ * @param session database connection to use
+ * @param session_hash hash of session to query
+ * @param off commitment offset to check
+ * @param index index of the mismatch
+ * @param object_name name of the object with the problem
+ * @return #GNUNET_NO if we generated the error message
+ *         #GNUNET_SYSERR if we could not even generate an error message
+ */
+static int
+send_melt_commitment_error (struct MHD_Connection *connection,
+                            struct TALER_MINTDB_Session *session,
+                            const struct GNUNET_HashCode *session_hash,
+                            unsigned int off,
+                            unsigned int index,
+                            const char *object_name)
+{
+  struct TALER_MINTDB_MeltCommitment *mc;
+  int ret;
+
+  mc = TMH_plugin->get_melt_commitment (TMH_plugin->cls,
+                                        session,
+                                        session_hash);
+  if (NULL == mc)
+  {
+    GNUNET_break (0);
+    return (MHD_YES ==
+            TMH_RESPONSE_reply_internal_error (connection,
+                                               "Melt commitment assembly"))
+      ? GNUNET_NO : GNUNET_SYSERR;
+  }
+  ret = (MHD_YES ==
+         TMH_RESPONSE_reply_refresh_reveal_missmatch (connection,
+                                                      mc,
+                                                      off,
+                                                      index,
+                                                      object_name))
+    ? GNUNET_NO : GNUNET_SYSERR;
+  TMH_plugin->free_melt_commitment (TMH_plugin->cls,
+                                    mc);
+  return ret;
+}
+
+
 /**
  * Check if the given @a transfer_privs correspond to an honest
  * commitment for the given session.
@@ -811,13 +859,12 @@ check_commitment (struct MHD_Connection *connection,
       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                   "transfer keys do not match\n");
       GNUNET_free (commit_links);
-      /* FIXME: return more specific error with original signature (#3712) */
+      return send_melt_commitment_error (connection,
-      return (MHD_YES ==
+                                         session,
-	      TMH_RESPONSE_reply_refresh_reveal_missmatch (connection,
+                                         session_hash,
                                          off,
                                          j,
-                                                           "transfer key"))
+                                         "transfer key");
-        ? GNUNET_NO : GNUNET_SYSERR;
     }
 
     /* We're converting key types here, which is not very nice
@@ -858,13 +905,12 @@ check_commitment (struct MHD_Connection *connection,
       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                   "shared secrets do not match\n");
       GNUNET_free (commit_links);
-      /* FIXME: return more specific error with original signature (#3712) */
+      return send_melt_commitment_error (connection,
-      return (MHD_YES ==
+                                         session,
-              TMH_RESPONSE_reply_refresh_reveal_missmatch (connection,
+                                         session_hash,
                                          off,
                                          j,
-                                                           "transfer secret"))
+                                         "transfer secret");
-          ? GNUNET_NO : GNUNET_SYSERR;
     }
   }
   GNUNET_break (GNUNET_YES == secret_initialized);
@@ -935,14 +981,13 @@ check_commitment (struct MHD_Connection *connection,
                   "blind envelope does not match for k=%u, old=%d\n",
                   off,
                   (int) j);
-      /* FIXME: return more specific error with original signature (#3712) */
       GNUNET_free (commit_coins);
-      return (MHD_YES ==
+      return send_melt_commitment_error (connection,
-              TMH_RESPONSE_reply_refresh_reveal_missmatch (connection,
+                                         session,
+                                         session_hash,
                                          off,
                                          j,
-                                                           "envelope"))
+                                         "envelope");
-          ? GNUNET_NO : GNUNET_SYSERR;
     }
     GNUNET_free (buf);
   }

src/mint/taler-mint-httpd_refresh.c

@@ -61,7 +61,6 @@ handle_refresh_melt_binary (struct MHD_Connection *connection,
                             const struct GNUNET_HashCode *session_hash,
                             struct TALER_MINTDB_RefreshCommitCoin *const* commit_coin,
                             struct TALER_MINTDB_RefreshCommitLinkP *const* commit_link)
-
 {
   unsigned int i;
   struct TMH_KS_StateHandle *key_state;
@@ -509,6 +508,7 @@ handle_refresh_melt_json (struct MHD_Connection *connection,
         free_commit_coins (commit_coin,
                            TALER_CNC_KAPPA,
                            num_newcoins);
+        GNUNET_free (link_enc);
         return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES;
       }
       rcc->refresh_link
@@ -517,6 +517,7 @@ handle_refresh_melt_json (struct MHD_Connection *connection,
       GNUNET_CRYPTO_hash_context_read (hash_context,
                                        link_enc,
                                        link_enc_size);
+      GNUNET_free (link_enc);
     }
   }
 

src/mint/taler-mint-httpd_responses.c

@@ -776,9 +776,10 @@ TMH_RESPONSE_reply_refresh_reveal_success (struct MHD_Connection *connection,
  *
  * FIXME: should also include the client's signature over
  * the original reveal operation and the data that was signed
- * over eventually... (#3712)
+ * over eventually... (#3712) -- need to use @a mc!
  *
  * @param connection the connection to send the response to
+ * @param mc all information about the original commitment
  * @param off offset in the array of kappa-commitments where
  *            the missmatch was detected
  * @param j index of the coin for which the missmatch was
@@ -789,6 +790,7 @@ TMH_RESPONSE_reply_refresh_reveal_success (struct MHD_Connection *connection,
  */
 int
 TMH_RESPONSE_reply_refresh_reveal_missmatch (struct MHD_Connection *connection,
+                                             const struct TALER_MINTDB_MeltCommitment *mc,
                                              unsigned int off,
                                              unsigned int j,
                                              const char *missmatch_object)

src/mint/taler-mint-httpd_responses.h

@@ -316,11 +316,8 @@ TMH_RESPONSE_reply_refresh_reveal_success (struct MHD_Connection *connection,
  * Send a response for a failed "/refresh/reveal", where the
  * revealed value(s) do not match the original commitment.
  *
- * FIXME: should also include the client's signature over
- * the original reveal operation and the data that was signed
- * over eventually... (#3712)
- *
  * @param connection the connection to send the response to
+ * @param mc all information about the original commitment
  * @param off offset in the array of kappa-commitments where
  *            the missmatch was detected
  * @param j index of the coin for which the missmatch was
@@ -331,6 +328,7 @@ TMH_RESPONSE_reply_refresh_reveal_success (struct MHD_Connection *connection,
  */
 int
 TMH_RESPONSE_reply_refresh_reveal_missmatch (struct MHD_Connection *connection,
+                                             const struct TALER_MINTDB_MeltCommitment *mc,
                                              unsigned int off,
                                              unsigned int j,
                                              const char *missmatch_object);

src/mintdb/plugin_mintdb_common.c

@@ -115,4 +115,35 @@ common_free_coin_transaction_list (void *cls,
   }
 }
 
+
+/**
+ * Free melt commitment data.
+ *
+ * @param cls the @e cls of this struct with the plugin-specific state (unused)
+ * @param mc data structure to free
+ */
+static void
+common_free_melt_commitment (void *cls,
+                             struct TALER_MINTDB_MeltCommitment *mc)
+{
+  unsigned int i;
+  unsigned int k;
+
+  GNUNET_free (mc->melts);
+  for (i=0;i<mc->num_newcoins;i++)
+    GNUNET_CRYPTO_rsa_public_key_free (mc->denom_pubs[i].rsa_public_key);
+  GNUNET_free (mc->denom_pubs);
+  for (k=0;k<TALER_CNC_KAPPA;k++)
+  {
+    for (i=0;i<mc->num_newcoins;i++)
+    {
+      GNUNET_free (mc->commit_coins[k][i].refresh_link);
+      GNUNET_free (mc->commit_coins[k][i].coin_ev);
+    }
+    GNUNET_free (mc->commit_coins[k]);
+    GNUNET_free (mc->commit_links[k]);
+  }
+  GNUNET_free (mc);
+}
+
 /* end of plugin_mintdb_common.c */

src/mintdb/plugin_mintdb_postgres.c

@@ -2005,6 +2005,52 @@ postgres_get_refresh_commit_links (void *cls,
 }
 
 
+/**
+ * Get all of the information from the given melt commit operation.
+ *
+ * @param cls the @e cls of this struct with the plugin-specific state
+ * @param sesssion database connection to use
+ * @param session_hash hash to identify refresh session
+ * @return NULL if the @a session_hash does not correspond to any known melt
+ *         operation
+ */
+static struct TALER_MINTDB_MeltCommitment *
+postgres_get_melt_commitment (void *cls,
+                              struct TALER_MINTDB_Session *sesssion,
+                              const struct GNUNET_HashCode *session_hash)
+{
+  // FIXME: needs to be implemented!
+#if 0
+  struct TALER_MINTDB_MeltCommitment *mc;
+  unsigned int k;
+  unsigned int i;
+
+  mc = GNUNET_new (struct TALER_MINTDB_MeltCommitment);
+  mc->num_newcoins = ;
+  mc->num_oldcoins = ;
+  mc->denom_pubs = GNUNET_malloc (mc->num_newcoins *
+                                  sizeof (struct TALER_DenominationPublicKey));
+  mc->melts = GNUNET_malloc (mc->num_oldcoins *
+                             sizeof (struct TALER_MINTDB_RefreshMelt));
+  for (k=0;k<TALER_CNC_KAPPA;k++)
+  {
+    mc->commit_coins[k] = GNUNET_malloc (mc->num_newcoins *
+                                         sizeof (struct TALER_MINTDB_RefreshCommitCoin));
+    for (i=0;i<mc->num_newcoins;i++)
+    {
+      mc->commit_coins[k][i].refresh_link = ; // malloc...
+      mc->commit_coins[k][i].coin_ev = ; // malloc...
+    }
+    mc->commit_links[k] = GNUNET_malloc (mc->num_oldcoins *
+                                         sizeof (struct TALER_MINTDB_RefreshCommitLinkP));
+  }
+
+  return mc;
+#endif
+  return NULL;
+}
+
+
 /**
  * Insert signature of a new coin generated during refresh into
  * the database indexed by the refresh session and the index
@@ -2324,6 +2370,8 @@ libtaler_plugin_mintdb_postgres_init (void *cls)
   plugin->get_refresh_commit_coins = &postgres_get_refresh_commit_coins;
   plugin->insert_refresh_commit_links = &postgres_insert_refresh_commit_links;
   plugin->get_refresh_commit_links = &postgres_get_refresh_commit_links;
+  plugin->get_melt_commitment = &postgres_get_melt_commitment;
+  plugin->free_melt_commitment = &common_free_melt_commitment;
   plugin->insert_refresh_collectable = &postgres_insert_refresh_collectable;
   plugin->get_link_data_list = &postgres_get_link_data_list;
   plugin->free_link_data_list = &common_free_link_data_list;