[age restriction] progress 14/n - withdraw and deposit

Age restriction support for
  - withdraw is done and tested
  - deposit is done and tested

TODOs:
  - melt/refresh/reveal
  - link

------

Added functions
 - TALER_age_restriction_commit
 - TALER_age_commitment_derive
 - TALER_age_commitment_hash
 - TALER_age_restriction_commitment_free_inside
 - Hash of age commitment passed around API boundaries

Exchangedb adjustments for denominations
 - all prepared statements re: denominations now handle age_mask
 - signature parameters adjusted

Hash and signature verification of /keys adjusted
 - Hashes of (normal) denominations and age-restricted denominations are
   calculated seperately
 - The hash of the age-restricted ones will then be added to the other
   hash
 - The total hash is signed/verified

Tests for withdraw with age restriction added
 - TALER_EXCHANGE_DenomPublickey now carries age_mask
 - TALER_TESTING_cmd_withdraw_amount* takes age parameter
 - TALER_TESTING_find_pk takes boolean age_restricted
 - WithdrawState carries age_commitment and its hash
 - withdraw_run derives new age commitment, if applicable
 - Added age parameter to testing (13 as example)

Various Fixes and changes
 - Fixes of post handler for /management/extensions
 - Fixes for offline tool extensions signing
 - Slight refactoring of extensions
 - Age restriction extension simplified
   - config is now global to extension
   - added global TEH_age_restriction_enabled and TEH_age_mask in
     taler-exchange-httpd
   - helper functions and macros introduced

1 files changed, 10 insertions, 3 deletions

diff --git a/src/testing/testing_api_helpers_exchange.c b/src/testing/testing_api_helpers_exchange.c
index 8e0e0298f..1eecbfeb3 100644
--- a/src/testing/testing_api_helpers_exchange.c
+++ b/src/testing/testing_api_helpers_exchange.c
@@ -27,6 +27,7 @@
 #include "taler_json_lib.h"
 #include <gnunet/gnunet_curl_lib.h>
 #include "taler_signatures.h"
+#include "taler_extensions.h"
 #include "taler_testing_lib.h"
 
 /**
@@ -312,6 +313,9 @@ sign_keys_for_exchange (void *cls,
   char *exchange_master_pub;
   int ret;
 
+  /* Load the age restriction mask from the configuration */
+  TALER_extensions_load_taler_config (cfg);
+
   if (GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_string (cfg,
                                              "exchange",
@@ -402,7 +406,8 @@ TALER_TESTING_prepare_exchange (const char *config_filename,
 
 const struct TALER_EXCHANGE_DenomPublicKey *
 TALER_TESTING_find_pk (const struct TALER_EXCHANGE_Keys *keys,
-                       const struct TALER_Amount *amount)
+                       const struct TALER_Amount *amount,
+                       bool age_restricted)
 {
   struct GNUNET_TIME_Timestamp now;
   struct TALER_EXCHANGE_DenomPublicKey *pk;
@@ -419,7 +424,8 @@ TALER_TESTING_find_pk (const struct TALER_EXCHANGE_Keys *keys,
                                      pk->valid_from)) &&
          (GNUNET_TIME_timestamp_cmp (now,
                                      <,
-                                     pk->withdraw_valid_until)) )
+                                     pk->withdraw_valid_until)) &&
+         (age_restricted == (0 != pk->key.age_mask.mask)) )
       return pk;
   }
   /* do 2nd pass to check if expiration times are to blame for
@@ -435,7 +441,8 @@ TALER_TESTING_find_pk (const struct TALER_EXCHANGE_Keys *keys,
                                      pk->valid_from) ||
           GNUNET_TIME_timestamp_cmp (now,
                                      >,
-                                     pk->withdraw_valid_until) ) )
+                                     pk->withdraw_valid_until) ) &&
+         (age_restricted == (0 != pk->key.age_mask.mask)) )
     {
       GNUNET_log
         (GNUNET_ERROR_TYPE_WARNING,