addressing #4803: nicer error messages for invalid wire formats

14 files changed, 259 insertions, 116 deletions

diff --git a/src/exchange-lib/exchange_api_wire.c b/src/exchange-lib/exchange_api_wire.c
index 7401e66d4..fe60d664c 100644
--- a/src/exchange-lib/exchange_api_wire.c
+++ b/src/exchange-lib/exchange_api_wire.c
@@ -95,7 +95,8 @@ verify_wire_method_signature_ok (const struct TALER_EXCHANGE_WireHandle *wh,
   const struct TALER_EXCHANGE_Keys *key_state;
   struct TALER_WIRE_Plugin *plugin;
   char *lib_name;
-  int ret;
+  char *emsg;
+  enum TALER_ErrorCode ec;
 
   key_state = TALER_EXCHANGE_get_keys (wh->exchange);
   (void) GNUNET_asprintf (&lib_name,
@@ -112,13 +113,15 @@ verify_wire_method_signature_ok (const struct TALER_EXCHANGE_WireHandle *wh,
     return GNUNET_NO;
   }
   plugin->library_name = lib_name;
-  ret = plugin->wire_validate (plugin->cls,
-                               json,
-                               &key_state->master_pub);
+  ec = plugin->wire_validate (plugin->cls,
+                              json,
+                              &key_state->master_pub,
+                              &emsg);
+  GNUNET_free_non_null (emsg);
   GNUNET_PLUGIN_unload (lib_name,
                         plugin);
   GNUNET_free (lib_name);
-  return (GNUNET_YES == ret) ? GNUNET_OK : GNUNET_SYSERR;
+  return (TALER_EC_NONE == ec) ? GNUNET_OK : GNUNET_SYSERR;
 }
 
 
diff --git a/src/exchange-lib/test_exchange_api.c b/src/exchange-lib/test_exchange_api.c
index 8c5e17d15..7f6e86a4a 100644
--- a/src/exchange-lib/test_exchange_api.c
+++ b/src/exchange-lib/test_exchange_api.c
@@ -1596,6 +1596,7 @@ deposit_wtid_cb (void *cls,
     }
     break;
   default:
+    GNUNET_break (0);
     break;
   }
   next_command (is);
@@ -2427,6 +2428,10 @@ do_shutdown (void *cls)
   struct Command *cmd;
   unsigned int i;
 
+  fprintf (stderr,
+           "Executing shutdown at `%s'\n",
+           is->commands[is->ip].label);
+
   for (i=0;OC_END != (cmd = &is->commands[i])->oc;i++)
   {
     switch (cmd->oc)
@@ -3084,6 +3089,9 @@ main (int argc,
   /* These might get in the way... */
   unsetenv ("XDG_DATA_HOME");
   unsetenv ("XDG_CONFIG_HOME");
+  GNUNET_log_setup ("test-exchange-api",
+                    "INFO",
+                    NULL);
   proc = GNUNET_OS_start_process (GNUNET_NO,
                                   GNUNET_OS_INHERIT_STD_ALL,
                                   NULL, NULL, NULL,
@@ -3145,6 +3153,7 @@ main (int argc,
   result = GNUNET_SYSERR;
   sigpipe = GNUNET_DISK_pipe (GNUNET_NO, GNUNET_NO, GNUNET_NO, GNUNET_NO);
   GNUNET_assert (NULL != sigpipe);
+  sleep (30);
   shc_chld = GNUNET_SIGNAL_handler_install (GNUNET_SIGCHLD,
                                             &sighandler_child_death);
   GNUNET_SCHEDULER_run (&run, NULL);
diff --git a/src/exchange/taler-exchange-httpd_admin.c b/src/exchange/taler-exchange-httpd_admin.c
index 72cdcb7d6..8bb4b4988 100644
--- a/src/exchange/taler-exchange-httpd_admin.c
+++ b/src/exchange/taler-exchange-httpd_admin.c
@@ -50,6 +50,8 @@ TEH_ADMIN_handler_admin_add_incoming (struct TEH_RequestHandler *rh,
   struct TALER_ReservePublicKeyP reserve_pub;
   struct TALER_Amount amount;
   struct GNUNET_TIME_Absolute at;
+  enum TALER_ErrorCode ec;
+  char *emsg;
   json_t *sender_account_details;
   json_t *transfer_details;
   json_t *root;
@@ -82,15 +84,17 @@ TEH_ADMIN_handler_admin_add_incoming (struct TEH_RequestHandler *rh,
     json_decref (root);
     return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES;
   }
-  if (GNUNET_YES !=
-      TEH_json_validate_wireformat (sender_account_details,
-                                    GNUNET_NO))
+  if (TALER_EC_NONE !=
+      (ec = TEH_json_validate_wireformat (sender_account_details,
+                                          GNUNET_NO,
+                                          &emsg)))
   {
-    GNUNET_break_op (0);
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_arg_unknown (connection,
-					   TALER_EC_ADMIN_ADD_INCOMING_WIREFORMAT_UNSUPPORTED,
-                                           "sender_account_details");
+    res = TEH_RESPONSE_reply_external_error (connection,
+                                             ec,
+                                             emsg);
+    GNUNET_free (emsg);
+    return res;
   }
   if (0 != strcasecmp (amount.currency,
                        TEH_exchange_currency_string))
diff --git a/src/exchange/taler-exchange-httpd_deposit.c b/src/exchange/taler-exchange-httpd_deposit.c
index b0ab42e7f..d3b4d031f 100644
--- a/src/exchange/taler-exchange-httpd_deposit.c
+++ b/src/exchange/taler-exchange-httpd_deposit.c
@@ -106,6 +106,8 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
   json_t *json;
   int res;
   json_t *wire;
+  char *emsg;
+  enum TALER_ErrorCode ec;
   struct TALER_EXCHANGEDB_Deposit deposit;
   struct TALER_EXCHANGEDB_DenominationKeyIssueInformation *dki;
   struct TEH_KS_StateHandle *key_state;
@@ -156,14 +158,17 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
                                            "refund_deadline");
   }
 
-  if (GNUNET_YES !=
-      TEH_json_validate_wireformat (wire,
-                                    GNUNET_NO))
+  if (TALER_EC_NONE !=
+      (ec = TEH_json_validate_wireformat (wire,
+                                          GNUNET_NO,
+                                          &emsg)))
   {
     GNUNET_JSON_parse_free (spec);
-    return TEH_RESPONSE_reply_arg_unknown (connection,
-					   TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT,
-                                           "wire");
+    res = TEH_RESPONSE_reply_external_error (connection,
+                                             ec,
+                                             emsg);
+    GNUNET_free (emsg);
+    return res;
   }
   if (GNUNET_OK !=
       TALER_JSON_hash (wire,
@@ -223,7 +228,7 @@ TEH_DEPOSIT_handler_deposit (struct TEH_RequestHandler *rh,
 					      TALER_EC_DEPOSIT_NEGATIVE_VALUE_AFTER_FEE,
                                               "deposited amount smaller than depositing fee");
   }
-  
+
   res = verify_and_execute_deposit (connection,
                                     &deposit);
   GNUNET_JSON_parse_free (spec);
diff --git a/src/exchange/taler-exchange-httpd_validation.c b/src/exchange/taler-exchange-httpd_validation.c
index 9d7b4ffcb..f5221feb7 100644
--- a/src/exchange/taler-exchange-httpd_validation.c
+++ b/src/exchange/taler-exchange-httpd_validation.c
@@ -144,23 +144,27 @@ TEH_VALIDATION_done ()
  *
  * @param wire the JSON wire format object
  * @param ours #GNUNET_YES if the signature should match our master key
- * @return #GNUNET_YES if correctly formatted; #GNUNET_NO if not
+ * @param[OUT] emsg set to error message if we return an error code
+ * @return #TALER_EC_NONE if correctly formatted; otherwise error code
  */
-int
+enum TALER_ErrorCode
 TEH_json_validate_wireformat (const json_t *wire,
-                              int ours)
+                              int ours,
+                              char **emsg)
 {
   const char *stype;
   json_error_t error;
   struct Plugin *p;
 
+  *emsg = NULL;
   if (0 != json_unpack_ex ((json_t *) wire,
                            &error, 0,
                            "{s:s}",
                            "type", &stype))
   {
-    GNUNET_break (0);
-    return GNUNET_SYSERR;
+    GNUNET_asprintf (emsg,
+                     "No `type' specified in the wire details\n");
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_TYPE_MISSING;
   }
   for (p=wire_head; NULL != p; p = p->next)
     if (0 == strcasecmp (p->type,
@@ -169,8 +173,12 @@ TEH_json_validate_wireformat (const json_t *wire,
                                        wire,
                                        (GNUNET_YES == ours)
                                        ? &TEH_master_public_key
-                                       : NULL);
-  return GNUNET_NO;
+                                       : NULL,
+                                       emsg);
+  GNUNET_asprintf (emsg,
+                   "Wire format type `%s' is not supported by this exchange\n",
+                   stype);
+  return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_TYPE_UNSUPPORTED;
 }
 
 
@@ -190,6 +198,8 @@ TEH_VALIDATION_get_wire_methods (const char *prefix)
   struct Plugin *p;
   struct TALER_WIRE_Plugin *plugin;
   char *account_name;
+  char *emsg;
+  enum TALER_ErrorCode ec;
 
   methods = json_object ();
   for (p=wire_head;NULL != p;p = p->next)
@@ -202,13 +212,17 @@ TEH_VALIDATION_get_wire_methods (const char *prefix)
     method = plugin->get_wire_details (plugin->cls,
                                        cfg,
                                        account_name);
-    if (GNUNET_YES !=
-        TEH_json_validate_wireformat (method,
-                                      GNUNET_YES))
+    if (TALER_EC_NONE !=
+        (ec = TEH_json_validate_wireformat (method,
+                                            GNUNET_YES,
+                                            &emsg)))
     {
       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                  "Account details for method `%s' ill-formed. Disabling method\n",
-                  p->type);
+                  "Disabling method `%s' as details are ill-formed: %s (%d)\n",
+                  p->type,
+                  emsg,
+                  ec);
+      GNUNET_free (emsg);
       json_decref (method);
       method = NULL;
     }
diff --git a/src/exchange/taler-exchange-httpd_validation.h b/src/exchange/taler-exchange-httpd_validation.h
index 7722460b7..7f2393279 100644
--- a/src/exchange/taler-exchange-httpd_validation.h
+++ b/src/exchange/taler-exchange-httpd_validation.h
@@ -48,11 +48,13 @@ TEH_VALIDATION_done (void);
  *
  * @param wire the JSON wire format object
  * @param ours #GNUNET_YES if the signature should match our master key
- * @return #GNUNET_YES if correctly formatted; #GNUNET_NO if not
+ * @param[OUT] emsg set to error message if we return an error code
+ * @return #TALER_EC_NONE if correctly formatted; otherwise error code
  */
-int
+enum TALER_ErrorCode
 TEH_json_validate_wireformat (const json_t *wire,
-                              int ours);
+                              int ours,
+                              char **emsg);
 
 
 /**
diff --git a/src/include/taler_error_codes.h b/src/include/taler_error_codes.h
index dd8a14972..6e6614579 100644
--- a/src/include/taler_error_codes.h
+++ b/src/include/taler_error_codes.h
@@ -48,6 +48,10 @@ enum TALER_ErrorCode
    */
   TALER_EC_INVALID_RESPONSE = 2,
 
+  /**
+   * Generic implementation error: this function was not yet implemented.
+   */
+  TALER_EC_NOT_IMPLEMENTED = 3,
 
   /* ********** generic error codes ************* */
 
@@ -324,10 +328,11 @@ enum TALER_ErrorCode
 
   /**
    * The exchange does not recognize the validity of or support the
-   * given wire (bank account) address.  This response is provided
+   * given wire format type.
+   * This response is provided
    * with HTTP status code MHD_HTTP_BAD_REQUEST.
    */
-  TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT = 1209,
+  TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_TYPE = 1209,
 
   /**
    * The exchange failed to canonicalize and hash the given wire format.
@@ -354,6 +359,46 @@ enum TALER_ErrorCode
   TALER_EC_DEPOSIT_HISTORY_DB_ERROR_INSUFFICIENT_FUNDS = 1212,
 
   /**
+   * The exchange detected that the given account number
+   * is invalid for the selected wire format type.
+   * This response is provided
+   * with HTTP status code MHD_HTTP_BAD_REQUEST.
+   */
+  TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_ACCOUNT_NUMBER = 1213,
+
+  /**
+   * The signature over the given wire details is invalid.
+   * This response is provided
+   * with HTTP status code MHD_HTTP_BAD_REQUEST.
+   */
+  TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_SIGNATURE = 1214,
+
+  /**
+   * The bank specified in the wire transfer format is not supported
+   * by this exchange.
+   * This response is provided
+   * with HTTP status code MHD_HTTP_BAD_REQUEST.
+   */
+  TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_BANK = 1215,
+
+  /**
+   * No wire format type was specified in the JSON wire format
+   * details.
+   * This response is provided
+   * with HTTP status code MHD_HTTP_BAD_REQUEST.
+   */
+  TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_TYPE_MISSING = 1216,
+
+  /**
+   * The given wire format type is not supported by this
+   * exchange.
+   * This response is provided
+   * with HTTP status code MHD_HTTP_BAD_REQUEST.
+   */
+  TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_TYPE_UNSUPPORTED = 1217,
+
+
+  /**
    * The respective coin did not have sufficient residual value
    * for the /refresh/melt operation.  The "history" in this
    * response provdes the "residual_value" of the coin, which may
diff --git a/src/include/taler_wire_plugin.h b/src/include/taler_wire_plugin.h
index c3c9c3a54..6c06e8247 100644
--- a/src/include/taler_wire_plugin.h
+++ b/src/include/taler_wire_plugin.h
@@ -24,6 +24,7 @@
 #include <gnunet/gnunet_util_lib.h>
 #include <jansson.h>
 #include "taler_util.h"
+#include "taler_error_codes.h"
 
 
 /**
@@ -137,12 +138,15 @@ struct TALER_WIRE_Plugin
    * @param cls the @e cls of this struct with the plugin-specific state
    * @param wire the JSON wire format object
    * @param master_pub public key of the exchange to verify against
-   * @return #GNUNET_YES if correctly formatted; #GNUNET_NO if not
+   * @param[OUT] emsg set to an error message, unless we return #TALER_EC_NONE;
+   *             error message must be freed by the caller using GNUNET_free()
+   * @return #TALER_EC_NONE if correctly formatted
    */
-  int
+  enum TALER_ErrorCode
   (*wire_validate) (void *cls,
                     const json_t *wire,
-                    const struct TALER_MasterPublicKeyP *master_pub);
+                    const struct TALER_MasterPublicKeyP *master_pub,
+                    char **emsg);
 
 
   /**
diff --git a/src/util/Makefile.am b/src/util/Makefile.am
index ec6c11a7a..eb9ffe475 100644
--- a/src/util/Makefile.am
+++ b/src/util/Makefile.am
@@ -9,7 +9,6 @@ endif
 
 pkgcfgdir = $(prefix)/share/taler/config.d/
 
-
 pkgcfg_DATA = \
   paths.conf
 
diff --git a/src/wire/plugin_wire_sepa.c b/src/wire/plugin_wire_sepa.c
index 61b30259a..cc00bcad7 100644
--- a/src/wire/plugin_wire_sepa.c
+++ b/src/wire/plugin_wire_sepa.c
@@ -451,12 +451,15 @@ verify_wire_sepa_signature_ok (const json_t *json,
  * @param cls the @e cls of this struct with the plugin-specific state
  * @param wire the JSON wire format object
  * @param master_pub public key of the exchange to verify against
- * @return #GNUNET_YES if correctly formatted; #GNUNET_NO if not
+ * @param[OUT] emsg set to an error message, unless we return #TALER_EC_NONE;
+ *             error message must be freed by the caller using GNUNET_free()
+ * @return #TALER_EC_NONE if correctly formatted
  */
-static int
+static enum TALER_ErrorCode
 sepa_wire_validate (void *cls,
                     const json_t *wire,
-                    const struct TALER_MasterPublicKeyP *master_pub)
+                    const struct TALER_MasterPublicKeyP *master_pub,
+                    char **emsg)
 {
   json_error_t error;
   const char *type;
@@ -464,6 +467,7 @@ sepa_wire_validate (void *cls,
   const char *name;
   const char *bic;
 
+  *emsg = NULL;
   if (0 != json_unpack_ex
       ((json_t *) wire,
        &error, 0,
@@ -478,39 +482,44 @@ sepa_wire_validate (void *cls,
        "name", &name,
        "bic", &bic))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                "JSON parsing failed at %s:%u: %s (%s)\n",
-                __FILE__, __LINE__,
-                error.text, error.source);
-    json_dumpf (wire, stderr, 0);
-    fprintf (stderr, "\n");
-    return GNUNET_SYSERR;
+    char *dump;
+
+    dump = json_dumps (wire, 0);
+    GNUNET_asprintf (emsg,
+                     "JSON parsing failed at %s:%u: %s (%s): %s\n",
+                     __FILE__, __LINE__,
+                     error.text,
+                     error.source,
+                     dump);
+    free (dump);
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_JSON;
   }
   if (0 != strcasecmp (type,
                        "sepa"))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-		"Transfer type `%s' invalid\n",
-		type);
-    return GNUNET_SYSERR;
+    GNUNET_asprintf (emsg,
+                     "Transfer type `%s' invalid for SEPA wire plugin\n",
+                     type);
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_TYPE;
   }
   if (1 != validate_iban (iban))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-		"IBAN `%s' invalid\n",
-		iban);
-    return GNUNET_NO;
+    GNUNET_asprintf (emsg,
+                     "IBAN `%s' invalid\n",
+                     iban);
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_ACCOUNT_NUMBER;
   }
   /* FIXME: don't parse again, integrate properly... */
   if (GNUNET_OK !=
       verify_wire_sepa_signature_ok (wire,
                                      master_pub))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                "Signature invalid\n");
-    return GNUNET_NO;
+    GNUNET_asprintf (emsg,
+                     "Signature using public key `%s' invalid\n",
+                     TALER_B2S (master_pub));
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_SIGNATURE;
   }
-  return GNUNET_YES;
+  return TALER_EC_NONE;
 }
 
 
@@ -531,6 +540,7 @@ sepa_get_wire_details (void *cls,
   char *sepa_wire_file;
   json_error_t err;
   json_t *ret;
+  char *emsg;
 
   /* Fetch reply */
   if (GNUNET_OK !=
@@ -558,13 +568,17 @@ sepa_get_wire_details (void *cls,
     GNUNET_free (sepa_wire_file);
     return NULL;
   }
-  if (GNUNET_YES != sepa_wire_validate (cls,
-                                        ret,
-                                        NULL))
-  {
+  if (TALER_EC_NONE !=
+      sepa_wire_validate (cls,
+                          ret,
+                          NULL,
+                          &emsg))
+    {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Failed to validate SEPA data in %s\n",
-                sepa_wire_file);
+                "Failed to validate SEPA data in %s: %s\n",
+                sepa_wire_file,
+                emsg);
+    GNUNET_free (emsg);
     GNUNET_free (sepa_wire_file);
     json_decref (ret);
     return NULL;
diff --git a/src/wire/plugin_wire_template.c b/src/wire/plugin_wire_template.c
index 2bc2a2abf..416eb9c58 100644
--- a/src/wire/plugin_wire_template.c
+++ b/src/wire/plugin_wire_template.c
@@ -98,15 +98,19 @@ template_get_wire_details (void *cls,
  * @param cls the @e cls of this struct with the plugin-specific state
  * @param wire the JSON wire format object
  * @param master_pub public key of the exchange to verify against
- * @return #GNUNET_YES if correctly formatted; #GNUNET_NO if not
+ * @param[OUT] emsg set to an error message, unless we return #TALER_EC_NONE;
+ *             error message must be freed by the caller using GNUNET_free()
+ * @return #TALER_EC_NONE if correctly formatted
  */
-static int
+static enum TALER_ErrorCode
 template_wire_validate (void *cls,
                         const json_t *wire,
-                        const struct TALER_MasterPublicKeyP *master_pub)
+                        const struct TALER_MasterPublicKeyP *master_pub,
+                        char **emsg)
 {
-  GNUNET_break (0);
-  return GNUNET_SYSERR;
+  GNUNET_asprintf (emsg,
+                   "Not implemented");
+  return TALER_EC_NOT_IMPLEMENTED;
 }
 
 
diff --git a/src/wire/plugin_wire_test.c b/src/wire/plugin_wire_test.c
index bdcf78058..7b52dee40 100644
--- a/src/wire/plugin_wire_test.c
+++ b/src/wire/plugin_wire_test.c
@@ -213,12 +213,15 @@ compute_purpose (uint64_t account,
  * @param cls the @e cls of this struct with the plugin-specific state
  * @param wire the JSON wire format object
  * @param master_pub public key of the exchange to verify against
- * @return #GNUNET_YES if correctly formatted; #GNUNET_NO if not
+ * @param[OUT] emsg set to an error message, unless we return #TALER_EC_NONE;
+ *             error message must be freed by the caller using GNUNET_free()
+ * @return #TALER_EC_NONE if correctly formatted
  */
-static int
+static enum TALER_ErrorCode
 test_wire_validate (void *cls,
                     const json_t *wire,
-                    const struct TALER_MasterPublicKeyP *master_pub)
+                    const struct TALER_MasterPublicKeyP *master_pub,
+                    char **emsg)
 {
   struct TestClosure *tc = cls;
   json_error_t error;
@@ -228,6 +231,7 @@ test_wire_validate (void *cls,
   struct TALER_MasterWireDetailsPS wsd;
   struct TALER_MasterSignatureP sig;
 
+  *emsg = NULL;
   if (0 !=
       json_unpack_ex ((json_t *) wire,
 		      &error,
@@ -236,30 +240,41 @@ test_wire_validate (void *cls,
 		      "account_number", &account_no,
                       "bank_uri", &bank_uri))
   {
-    GNUNET_break_op (0);
-    return GNUNET_SYSERR;
+    char *dump;
+
+    dump = json_dumps (wire, 0);
+    GNUNET_asprintf (emsg,
+                     "JSON parsing failed at %s:%u: %s (%s): %s\n",
+                     __FILE__, __LINE__,
+                     error.text,
+                     error.source,
+                     dump);
+    free (dump);
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_JSON;
   }
   if ( (account_no < 0) ||
        (account_no > (1LL << 53)) )
   {
-    GNUNET_break (0);
-    return GNUNET_SYSERR;
+    GNUNET_asprintf (emsg,
+                     "Account number %llu outside of permitted range\n",
+                     account_no);
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_ACCOUNT_NUMBER;
   }
   if ( (NULL != tc->bank_uri) &&
        (0 != strcmp (bank_uri,
                      tc->bank_uri)) )
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Wire specifies bank URI %s, but this exchange only supports %s\n",
-                bank_uri,
-                tc->bank_uri);
-    return GNUNET_NO;
+    GNUNET_asprintf (emsg,
+                     "Wire specifies bank URI `%s', but this exchange only supports `%s'\n",
+                     bank_uri,
+                     tc->bank_uri);
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_BANK;
   }
   if (NULL == master_pub)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Skipping signature check as master public key not given\n");
-    return GNUNET_OK;
+    return TALER_EC_NONE;
   }
   if (0 !=
       json_unpack_ex ((json_t *) wire,
@@ -268,9 +283,9 @@ test_wire_validate (void *cls,
 		      "{s:s}",
                       "sig", &sig_s))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Signature check required, but signature is missing\n");
-    return GNUNET_NO;
+    GNUNET_asprintf (emsg,
+                     "Signature check required, but signature is missing\n");
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_SIGNATURE;
   }
   compute_purpose (account_no,
                    bank_uri,
@@ -290,10 +305,12 @@ test_wire_validate (void *cls,
                                   &sig.eddsa_signature,
                                   &master_pub->eddsa_pub))
   {
-    GNUNET_break (0);
-    return GNUNET_SYSERR;
+    GNUNET_asprintf (emsg,
+                     "Signature using public key `%s' invalid\n",
+                     TALER_B2S (master_pub));
+    return TALER_EC_DEPOSIT_INVALID_WIRE_FORMAT_SIGNATURE;
   }
-  return GNUNET_YES;
+  return TALER_EC_NONE;
 }
 
 
@@ -315,6 +332,7 @@ test_get_wire_details (void *cls,
   char *test_wire_file;
   json_error_t err;
   json_t *ret;
+  char *emsg;
 
   /* Fetch reply */
   if (GNUNET_OK !=
@@ -342,13 +360,17 @@ test_get_wire_details (void *cls,
     GNUNET_free (test_wire_file);
     return NULL;
   }
-  if (GNUNET_YES != test_wire_validate (tc,
-                                        ret,
-                                        NULL))
+  if (TALER_EC_NONE !=
+      test_wire_validate (tc,
+                          ret,
+                          NULL,
+                          &emsg))
   {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Failed to validate TEST wire data in %s\n",
-                test_wire_file);
+                "Failed to validate TEST wire data in %s: %s\n",
+                test_wire_file,
+                emsg);
+    GNUNET_free (emsg);
     GNUNET_free (test_wire_file);
     json_decref (ret);
     return NULL;
@@ -478,13 +500,16 @@ test_prepare_wire_transfer (void *cls,
 {
   struct TestClosure *tc = cls;
   struct TALER_WIRE_PrepareHandle *pth;
+  char *emsg;
 
-  if (GNUNET_YES !=
+  if (TALER_EC_NONE !=
       test_wire_validate (tc,
                           wire,
-                          NULL))
+                          NULL,
+                          &emsg))
   {
     GNUNET_break_op (0);
+    GNUNET_free (emsg);
     return NULL;
   }
   pth = GNUNET_new (struct TALER_WIRE_PrepareHandle);
@@ -624,6 +649,7 @@ test_execute_wire_transfer (void *cls,
   struct TALER_Amount amount;
   json_int_t account_no;
   struct BufFormatP bf;
+  char *emsg;
 
   if (NULL == tc->ctx)
   {
@@ -650,10 +676,11 @@ test_execute_wire_transfer (void *cls,
     GNUNET_break (0);
     return NULL;
   }
-  GNUNET_assert (GNUNET_YES ==
+  GNUNET_assert (TALER_EC_NONE ==
                  test_wire_validate (tc,
                                      wire,
-                                     NULL));
+                                     NULL,
+                                     &emsg));
   if (0 !=
       json_unpack_ex (wire,
 		      &error,
diff --git a/src/wire/test_sepa_wireformat.c b/src/wire/test_sepa_wireformat.c
index 43bd51a32..07a3784c6 100644
--- a/src/wire/test_sepa_wireformat.c
+++ b/src/wire/test_sepa_wireformat.c
@@ -67,6 +67,7 @@ main(int argc,
      const char *const argv[])
 {
   json_t *wire;
+  char *emsg;
   json_error_t error;
   int ret;
   struct GNUNET_CONFIGURATION_Handle *cfg;
@@ -85,28 +86,35 @@ main(int argc,
   GNUNET_assert (NULL != plugin);
   (void) memset(&error, 0, sizeof(error));
   GNUNET_assert (NULL != (wire = json_loads (unsupported_wire_str, 0, NULL)));
-  GNUNET_assert (GNUNET_YES != plugin->wire_validate (NULL,
-                                                      wire,
-                                                      NULL));
+  GNUNET_assert (TALER_EC_NONE != plugin->wire_validate (NULL,
+                                                         wire,
+                                                         NULL,
+                                                         &emsg));
+  GNUNET_free (emsg);
   json_decref (wire);
   GNUNET_assert (NULL != (wire = json_loads (invalid_wire_str, 0, NULL)));
-  GNUNET_assert (GNUNET_NO == plugin->wire_validate (NULL,
-                                                     wire,
-                                                     NULL));
+  GNUNET_assert (TALER_EC_NONE != plugin->wire_validate (NULL,
+                                                         wire,
+                                                         NULL,
+                                                         &emsg));
+  GNUNET_free (emsg);
   json_decref (wire);
   GNUNET_assert (NULL != (wire = json_loads (invalid_wire_str2, 0, NULL)));
-  GNUNET_assert (GNUNET_NO == plugin->wire_validate (NULL,
-                                                     wire,
-                                                     NULL));
+  GNUNET_assert (TALER_EC_NONE != plugin->wire_validate (NULL,
+                                                         wire,
+                                                         NULL,
+                                                         &emsg));
+  GNUNET_free (emsg);
   json_decref (wire);
   GNUNET_assert (NULL != (wire = json_loads (valid_wire_str, 0, &error)));
   ret = plugin->wire_validate (NULL,
                                wire,
-                               NULL);
+                               NULL,
+                               &emsg);
   json_decref (wire);
   TALER_WIRE_plugin_unload (plugin);
   GNUNET_CONFIGURATION_destroy (cfg);
-  if (GNUNET_NO == ret)
+  if (TALER_EC_NONE != ret)
     return 1;
   return 0;
 }
diff --git a/src/wire/test_wire_plugin.c b/src/wire/test_wire_plugin.c
index c465302f1..0828a06b7 100644
--- a/src/wire/test_wire_plugin.c
+++ b/src/wire/test_wire_plugin.c
@@ -112,6 +112,7 @@ run_test (const struct TestBlock *test,
   json_t *lwire;
   struct TALER_Amount in;
   struct TALER_Amount expect;
+  char *emsg;
 
   GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE,
                               &salt,
@@ -134,12 +135,14 @@ run_test (const struct TestBlock *test,
                        "sig",
                        GNUNET_JSON_from_data (&sig,
                                               sizeof (sig)));
-  if (GNUNET_OK !=
+  if (TALER_EC_NONE !=
       plugin->wire_validate (plugin->cls,
                              wire,
-                             &pub_key))
+                             &pub_key,
+                             &emsg))
   {
     GNUNET_break (0);
+    GNUNET_free (emsg);
     return GNUNET_SYSERR;
   }
   /* load wire details from file */
@@ -151,12 +154,14 @@ run_test (const struct TestBlock *test,
     GNUNET_break (0);
     return GNUNET_SYSERR;
   }
-  if (GNUNET_OK !=
+  if (TALER_EC_NONE !=
       plugin->wire_validate (plugin->cls,
                              lwire,
-                             &pub_key))
+                             &pub_key,
+                             &emsg))
   {
     GNUNET_break (0);
+    GNUNET_free (emsg);
     json_decref (lwire);
     return GNUNET_SYSERR;
   }