-ensure different HKDF is used in melt vs. withdraw

5 files changed, 136 insertions, 27 deletions

diff --git a/src/exchange/taler-exchange-httpd_csr.c b/src/exchange/taler-exchange-httpd_csr.c
index 423835979..94b55c706 100644
--- a/src/exchange/taler-exchange-httpd_csr.c
+++ b/src/exchange/taler-exchange-httpd_csr.c
@@ -179,9 +179,9 @@ TEH_handler_csr_melt (struct TEH_RequestContext *rc,
 
         /* derive r_pub */
         // FIXME: bundle all requests into one derivation request (TEH_keys_..., crypto helper, security module)
-        ec = TEH_keys_denomination_cs_r_pub (denom_pub_hash,
-                                             nonce,
-                                             r_pub);
+        ec = TEH_keys_denomination_cs_r_pub_melt (denom_pub_hash,
+                                                  nonce,
+                                                  r_pub);
         if (TALER_EC_NONE != ec)
         {
           GNUNET_break (0);
@@ -316,9 +316,9 @@ TEH_handler_csr_withdraw (struct TEH_RequestContext *rc,
   {
     enum TALER_ErrorCode ec;
 
-    ec = TEH_keys_denomination_cs_r_pub (&denom_pub_hash,
-                                         &nonce,
-                                         &ewv.details.cs_values);
+    ec = TEH_keys_denomination_cs_r_pub_withdraw (&denom_pub_hash,
+                                                  &nonce,
+                                                  &ewv.details.cs_values);
     if (TALER_EC_NONE != ec)
     {
       GNUNET_break (0);
diff --git a/src/exchange/taler-exchange-httpd_keys.c b/src/exchange/taler-exchange-httpd_keys.c
index 695ce9777..60c9c6eb0 100644
--- a/src/exchange/taler-exchange-httpd_keys.c
+++ b/src/exchange/taler-exchange-httpd_keys.c
@@ -2432,9 +2432,49 @@ TEH_keys_denomination_by_hash2 (
 
 
 enum TALER_ErrorCode
-TEH_keys_denomination_sign (const struct TALER_DenominationHash *h_denom_pub,
-                            const struct TALER_BlindedPlanchet *bp,
-                            struct TALER_BlindedDenominationSignature *bs)
+TEH_keys_denomination_sign_withdraw (
+  const struct TALER_DenominationHash *h_denom_pub,
+  const struct TALER_BlindedPlanchet *bp,
+  struct TALER_BlindedDenominationSignature *bs)
+{
+  struct TEH_KeyStateHandle *ksh;
+  struct HelperDenomination *hd;
+
+  ksh = TEH_keys_get_state ();
+  if (NULL == ksh)
+    return TALER_EC_EXCHANGE_GENERIC_KEYS_MISSING;
+  hd = GNUNET_CONTAINER_multihashmap_get (ksh->helpers->denom_keys,
+                                          &h_denom_pub->hash);
+  if (NULL == hd)
+    return TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN;
+  if (bp->cipher != hd->denom_pub.cipher)
+    return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
+  switch (hd->denom_pub.cipher)
+  {
+  case TALER_DENOMINATION_RSA:
+    return TALER_CRYPTO_helper_rsa_sign (
+      ksh->helpers->rsadh,
+      &hd->h_details.h_rsa,
+      bp->details.rsa_blinded_planchet.blinded_msg,
+      bp->details.rsa_blinded_planchet.blinded_msg_size,
+      bs);
+  case TALER_DENOMINATION_CS:
+    return TALER_CRYPTO_helper_cs_sign_withdraw (
+      ksh->helpers->csdh,
+      &hd->h_details.h_cs,
+      &bp->details.cs_blinded_planchet,
+      bs);
+  default:
+    return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
+  }
+}
+
+
+enum TALER_ErrorCode
+TEH_keys_denomination_sign_melt (
+  const struct TALER_DenominationHash *h_denom_pub,
+  const struct TALER_BlindedPlanchet *bp,
+  struct TALER_BlindedDenominationSignature *bs)
 {
   struct TEH_KeyStateHandle *ksh;
   struct HelperDenomination *hd;
@@ -2458,7 +2498,7 @@ TEH_keys_denomination_sign (const struct TALER_DenominationHash *h_denom_pub,
       bp->details.rsa_blinded_planchet.blinded_msg_size,
       bs);
   case TALER_DENOMINATION_CS:
-    return TALER_CRYPTO_helper_cs_sign (
+    return TALER_CRYPTO_helper_cs_sign_melt (
       ksh->helpers->csdh,
       &hd->h_details.h_cs,
       &bp->details.cs_blinded_planchet,
@@ -2470,10 +2510,42 @@ TEH_keys_denomination_sign (const struct TALER_DenominationHash *h_denom_pub,
 
 
 enum TALER_ErrorCode
-TEH_keys_denomination_cs_r_pub (const struct
-                                TALER_DenominationHash *h_denom_pub,
-                                const struct TALER_CsNonce *nonce,
-                                struct TALER_DenominationCSPublicRPairP *r_pub)
+TEH_keys_denomination_cs_r_pub_melt (
+  const struct TALER_DenominationHash *h_denom_pub,
+  const struct TALER_CsNonce *nonce,
+  struct TALER_DenominationCSPublicRPairP *r_pub)
+{
+  struct TEH_KeyStateHandle *ksh;
+  struct HelperDenomination *hd;
+
+  ksh = TEH_keys_get_state ();
+  if (NULL == ksh)
+  {
+    return TALER_EC_EXCHANGE_GENERIC_KEYS_MISSING;
+  }
+  hd = GNUNET_CONTAINER_multihashmap_get (ksh->helpers->denom_keys,
+                                          &h_denom_pub->hash);
+  if (NULL == hd)
+  {
+    return TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN;
+  }
+  if (TALER_DENOMINATION_CS != hd->denom_pub.cipher)
+  {
+    return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
+  }
+
+  return TALER_CRYPTO_helper_cs_r_derive_melt (ksh->helpers->csdh,
+                                               &hd->h_details.h_cs,
+                                               nonce,
+                                               r_pub);
+}
+
+
+enum TALER_ErrorCode
+TEH_keys_denomination_cs_r_pub_withdraw (
+  const struct TALER_DenominationHash *h_denom_pub,
+  const struct TALER_CsNonce *nonce,
+  struct TALER_DenominationCSPublicRPairP *r_pub)
 {
   struct TEH_KeyStateHandle *ksh;
   struct HelperDenomination *hd;
@@ -2494,10 +2566,10 @@ TEH_keys_denomination_cs_r_pub (const struct
     return TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE;
   }
 
-  return TALER_CRYPTO_helper_cs_r_derive (ksh->helpers->csdh,
-                                          &hd->h_details.h_cs,
-                                          nonce,
-                                          r_pub);
+  return TALER_CRYPTO_helper_cs_r_derive_withdraw (ksh->helpers->csdh,
+                                                   &hd->h_details.h_cs,
+                                                   nonce,
+                                                   r_pub);
 }
 
 
diff --git a/src/exchange/taler-exchange-httpd_keys.h b/src/exchange/taler-exchange-httpd_keys.h
index a329c4f12..7c6fb3e33 100644
--- a/src/exchange/taler-exchange-httpd_keys.h
+++ b/src/exchange/taler-exchange-httpd_keys.h
@@ -169,22 +169,57 @@ TEH_keys_denomination_by_hash2 (
 
 /**
  * Request to sign @a msg using the public key corresponding to
- * @a h_denom_pub.
+ * @a h_denom_pub during a withdraw operation.
  *
  * @param h_denom_pub hash of the public key to use to sign
  * @param bp blinded planchet to sign
+ * @param is_melt should we use the KDF for melting?
  * @param[out] bs set to the blind signature on success
  * @return #TALER_EC_NONE on success
  */
 enum TALER_ErrorCode
-TEH_keys_denomination_sign (const struct TALER_DenominationHash *h_denom_pub,
-                            const struct TALER_BlindedPlanchet *bp,
-                            struct TALER_BlindedDenominationSignature *bs);
+TEH_keys_denomination_sign_withdraw (
+  const struct TALER_DenominationHash *h_denom_pub,
+  const struct TALER_BlindedPlanchet *bp,
+  struct TALER_BlindedDenominationSignature *bs);
+
+
+/**
+ * Request to sign @a msg using the public key corresponding to
+ * @a h_denom_pub during a refresh operation.
+ *
+ * @param h_denom_pub hash of the public key to use to sign
+ * @param bp blinded planchet to sign
+ * @param is_melt should we use the KDF for melting?
+ * @param[out] bs set to the blind signature on success
+ * @return #TALER_EC_NONE on success
+ */
+enum TALER_ErrorCode
+TEH_keys_denomination_sign_melt (
+  const struct TALER_DenominationHash *h_denom_pub,
+  const struct TALER_BlindedPlanchet *bp,
+  struct TALER_BlindedDenominationSignature *bs);
+
+
+/**
+ * Request to derive CS @a r_pub using the denomination corresponding to @a h_denom_pub
+ * and @a nonce for withdrawing.
+ *
+ * @param h_denom_pub hash of the public key to use to derive r_pub
+ * @param nonce withdraw/refresh nonce
+ * @param[out] r_pub where to write the result
+ * @return #TALER_EC_NONE on success
+ */
+enum TALER_ErrorCode
+TEH_keys_denomination_cs_r_pub_withdraw (
+  const struct TALER_DenominationHash *h_denom_pub,
+  const struct TALER_CsNonce *nonce,
+  struct TALER_DenominationCSPublicRPairP *r_pub);
 
 
 /**
  * Request to derive CS @a r_pub using the denomination corresponding to @a h_denom_pub
- * and @a nonce.
+ * and @a nonce for melting.
  *
  * @param h_denom_pub hash of the public key to use to derive r_pub
  * @param nonce withdraw/refresh nonce
@@ -192,7 +227,7 @@ TEH_keys_denomination_sign (const struct TALER_DenominationHash *h_denom_pub,
  * @return #TALER_EC_NONE on success
  */
 enum TALER_ErrorCode
-TEH_keys_denomination_cs_r_pub (
+TEH_keys_denomination_cs_r_pub_melt (
   const struct TALER_DenominationHash *h_denom_pub,
   const struct TALER_CsNonce *nonce,
   struct TALER_DenominationCSPublicRPairP *r_pub);
diff --git a/src/exchange/taler-exchange-httpd_refreshes_reveal.c b/src/exchange/taler-exchange-httpd_refreshes_reveal.c
index 9e47f4664..0a4dd638b 100644
--- a/src/exchange/taler-exchange-httpd_refreshes_reveal.c
+++ b/src/exchange/taler-exchange-httpd_refreshes_reveal.c
@@ -216,7 +216,7 @@ check_commitment (struct RevealContext *rctx,
       {
         enum TALER_ErrorCode ec;
 
-        ec = TEH_keys_denomination_cs_r_pub (
+        ec = TEH_keys_denomination_cs_r_pub_melt (
           &rctx->rrcs[j].h_denom_pub,
           &nonces[aoff],
           &alg_values->details.cs_values);
@@ -733,7 +733,9 @@ clean_age:
   {
     enum TALER_ErrorCode ec;
 
-    ec = TEH_keys_denomination_sign (
+    // FIXME: replace with a batch call that
+    // passes all coins in once go!
+    ec = TEH_keys_denomination_sign_melt (
       &rrcs[i].h_denom_pub,
       &rcds[i].blinded_planchet,
       &rrcs[i].coin_sig);
diff --git a/src/exchange/taler-exchange-httpd_withdraw.c b/src/exchange/taler-exchange-httpd_withdraw.c
index cc6e92edf..5f159a429 100644
--- a/src/exchange/taler-exchange-httpd_withdraw.c
+++ b/src/exchange/taler-exchange-httpd_withdraw.c
@@ -505,7 +505,7 @@ TEH_handler_withdraw (struct TEH_RequestContext *rc,
   }
 
   /* Sign before transaction! */
-  ec = TEH_keys_denomination_sign (
+  ec = TEH_keys_denomination_sign_withdraw (
     &wc.collectable.denom_pub_hash,
     &wc.blinded_planchet,
     &wc.collectable.sig);