exchange

commit 6124b69ad557c5e5c97ea564a828b53596626c8b
parent fb25885342d78395295cf834a7571daf054c0b1b
Author: Christian Grothoff <christian@grothoff.org>
Date:   Mon, 12 Oct 2026 16:44:03 +0200

better place for h_planchet computation

Diffstat:
M
src/exchange/taler-exchange-httpd_post-withdraw.c
 | 
89
++++++++++++++++++++++++++++++++++++++++---------------------------------------

1 file changed, 45 insertions(+), 44 deletions(-)
diff --git a/src/exchange/taler-exchange-httpd_post-withdraw.c b/src/exchange/taler-exchange-httpd_post-withdraw.c
@@ -1080,46 +1080,6 @@ phase_check_keys (
     wc->request.withdraw.denom_serials[i] = dk->meta.serial;
   }
 
-  /* Save the hash of the batch of planchets */
-  if (! wc->request.withdraw.age_proof_required)
-  {
-    TALER_wallet_blinded_planchets_hash (
-      wc->request.withdraw.num_coins,
-      wc->request.planchets,
-      wc->request.denoms_h,
-      &wc->request.withdraw.planchets_h);
-  }
-  else
-  {
-    struct GNUNET_HashContext *ctx;
-
-    /**
-     * The age-proof-required case is a bit more involved,
-     * because we need to calculate and remember kappa hashes
-     * for each batch of coins.
-     */
-    ctx = GNUNET_CRYPTO_hash_context_start ();
-    GNUNET_assert (NULL != ctx);
-
-    for (uint8_t k = 0; k < TALER_CNC_KAPPA; k++)
-    {
-      size_t off = k * wc->request.withdraw.num_coins;
-
-      TALER_wallet_blinded_planchets_hash (
-        wc->request.withdraw.num_coins,
-        &wc->request.planchets[off],
-        wc->request.denoms_h,
-        &wc->request.kappa_planchets_h[k]);
-      GNUNET_CRYPTO_hash_context_read (
-        ctx,
-        &wc->request.kappa_planchets_h[k],
-        sizeof(wc->request.kappa_planchets_h[k]));
-    }
-    GNUNET_CRYPTO_hash_context_finish (
-      ctx,
-      &wc->request.withdraw.planchets_h.hash);
-  }
-
   /* Save the total amount including fees */
   if (0 >  TALER_amount_add (
         &wc->request.withdraw.amount_with_fee,
@@ -1703,10 +1663,10 @@ withdraw_phase_parse (
                "denoms_h must not be empty")
 
       /**
-         * The wallet had committed to more than the maximum coins allowed, the
-         * reserve has been charged, but now the user can not withdraw any money
-         * from it.  Note that the user can't get their money back in this case!
-         */
+       * The wallet had committed to more than the maximum coins allowed, the
+       * reserve has been charged, but now the user can not withdraw any money
+       * from it.  Note that the user can't get their money back in this case!
+       */
       BAIL_IF (num_coins > TALER_MAX_COINS,
                "maximum number of coins that can be withdrawn has been exceeded")
 
@@ -1813,6 +1773,47 @@ withdraw_phase_parse (
       }       /* end duplicate check */
     }       /* json_array_foreach over j_coin_evs */
   }       /* scope of j_kappa_planchets, idx */
+
+  /* Save the hash of the batch of planchets.  Needed for idempotency
+     checks. */
+  if (! wc->request.withdraw.age_proof_required)
+  {
+    TALER_wallet_blinded_planchets_hash (
+      wc->request.withdraw.num_coins,
+      wc->request.planchets,
+      wc->request.denoms_h,
+      &wc->request.withdraw.planchets_h);
+  }
+  else
+  {
+    struct GNUNET_HashContext *ctx;
+
+    /**
+     * The age-proof-required case is a bit more involved,
+     * because we need to calculate and remember kappa hashes
+     * for each batch of coins.
+     */
+    ctx = GNUNET_CRYPTO_hash_context_start ();
+    GNUNET_assert (NULL != ctx);
+
+    for (uint8_t k = 0; k < TALER_CNC_KAPPA; k++)
+    {
+      size_t off = k * wc->request.withdraw.num_coins;
+
+      TALER_wallet_blinded_planchets_hash (
+        wc->request.withdraw.num_coins,
+        &wc->request.planchets[off],
+        wc->request.denoms_h,
+        &wc->request.kappa_planchets_h[k]);
+      GNUNET_CRYPTO_hash_context_read (
+        ctx,
+        &wc->request.kappa_planchets_h[k],
+        sizeof(wc->request.kappa_planchets_h[k]));
+    }
+    GNUNET_CRYPTO_hash_context_finish (
+      ctx,
+      &wc->request.withdraw.planchets_h.hash);
+  }
   wc->phase = WITHDRAW_PHASE_CHECK_KEYS;
 }