Added TALER_age_restriction_commitment_free_inside

cleanup function for ->pub and ->priv (and zeroing keys)

src/include/taler_crypto_lib.h

@@ -2656,14 +2656,13 @@ TALER_age_commitment_hash (
   const struct TALER_AgeCommitment *commitment,
   struct TALER_AgeCommitmentHash *hash);
 
-
 /*
  * @brief Generates an age commitent for the given age.
  *
  * @param mask The age mask the defines the age groups
  * @param age The actual age for which an age commitment is generated
  * @param seed The seed that goes into the key generation.  MUST be choosen uniformly random.
- * @param commitment[out] The generated age commitment, allocated via GNUNET_malloc on success
+ * @param commitment[out] The generated age commitment, ->priv and ->pub allocated via GNUNET_malloc on success
  * @return GNUNET_OK on success, GNUNET_SYSERR otherwise
  */
 enum GNUNET_GenericReturnValue
@@ -2671,21 +2670,29 @@ TALER_age_restriction_commit (
   const struct TALER_AgeMask *mask,
   const uint8_t age,
   const uint32_t seed,
-  struct TALER_AgeCommitment **commitment);
+  struct TALER_AgeCommitment *commitment);
 
 /*
  * @brief Derives another, equivalent age commitment for a given one.
  *
  * @param orig Original age commitment
  * @param seed Used to move the points on the elliptic curve in order to generate another, equivalent commitment.
- * @param derived[out] The resulting age commitment, allocated via GNUNET_malloc on success.
+ * @param derived[out] The resulting age commitment, ->priv and ->pub allocated via GNUNET_malloc on success.
  * @return GNUNET_OK on success, GNUNET_SYSERR otherwise
  */
 enum GNUNET_GenericReturnValue
 TALER_age_restriction_derive (
   const struct TALER_AgeCommitment *orig,
   const uint32_t seed,
-  struct TALER_AgeCommitment **derived);
+  struct TALER_AgeCommitment *derived);
 
+/*
+ * @brief helper function to free memory inside a struct TALER_AgeCommitment
+ * @param cmt the commitment from which internal memory should be freed.  Note
+ * that cmt itself is NOT freed!
+ */
+void
+TALER_age_restriction_commitment_free_inside (
+  struct TALER_AgeCommitment *cmt);
 
 #endif

src/util/crypto.c

@@ -406,8 +406,10 @@ enum GNUNET_GenericReturnValue
 TALER_age_restriction_derive (
   const struct TALER_AgeCommitment *orig,
   const uint32_t seed,
-  struct TALER_AgeCommitment **derived)
+  struct TALER_AgeCommitment *new)
 {
+  struct GNUNET_CRYPTO_EccScalar val;
+
   /*
   * age commitment consists of GNUNET_CRYPTO_Eddsa{Private,Public}Key
   *
@@ -434,15 +436,11 @@ TALER_age_restriction_derive (
   * GNUNET_CRYPTO_EccScalar which is a
   *   unsigned car v[256 / 8];
   * */
-  struct GNUNET_CRYPTO_EccScalar val;
-  struct TALER_AgeCommitment *new;
 
-  GNUNET_assert (orig->num_pub == __builtin_popcount (orig->mask.mask) -1);
+  GNUNET_assert (NULL != new);
+  GNUNET_assert (orig->num_pub == __builtin_popcount (orig->mask.mask) - 1);
   GNUNET_assert (orig->num_priv <= orig->num_pub);
 
-  *derived = NULL;
-
-  new = GNUNET_malloc (sizeof(struct TALER_AgeCommitment));
   new->mask = orig->mask;
   new->num_pub = orig->num_pub;
   new->num_priv = orig->num_priv;
@@ -519,13 +517,11 @@ TALER_age_restriction_derive (
     gcry_ctx_release (ctx);
   }
 
-  *derived = new;
   return GNUNET_OK;
 
 FAIL:
   GNUNET_free (new->pub);
   GNUNET_free (new->priv);
-  GNUNET_free (new);
   return GNUNET_SYSERR;
 }
 
@@ -558,24 +554,27 @@ TALER_age_restriction_commit (
   const struct TALER_AgeMask *mask,
   const uint8_t age,
   const uint32_t seed,
-  struct TALER_AgeCommitment **commitment)
+  struct TALER_AgeCommitment *new)
 {
-  struct TALER_AgeCommitment *new;
   uint8_t num_pub = __builtin_popcount (mask->mask) - 1;
   uint8_t num_priv = get_age_group (mask, age) - 1;
   size_t i;
 
+  GNUNET_assert (NULL != new);
   GNUNET_assert (mask->mask & 1); /* fist bit must have been set */
   GNUNET_assert (0 <= num_priv);
   GNUNET_assert (31 > num_priv);
 
-  new = GNUNET_malloc (sizeof(struct TALER_AgeCommitment));
   new->mask.mask = mask->mask;
   new->num_pub = num_pub;
   new->num_priv = num_priv;
 
-  new->pub = GNUNET_new_array (num_pub, struct TALER_AgeCommitmentPublicKeyP);
-  new->priv = GNUNET_new_array (num_priv, struct TALER_AgeCommitmentPrivateKeyP);
+  new->pub = GNUNET_new_array (
+    num_pub,
+    struct TALER_AgeCommitmentPublicKeyP);
+  new->priv = GNUNET_new_array (
+    num_priv,
+    struct TALER_AgeCommitmentPrivateKeyP);
 
   /* Create as many private keys as we need */
   for (i = 0; i < num_priv; i++)
@@ -603,15 +602,40 @@ TALER_age_restriction_commit (
                                 &new->pub[i],
                                 sizeof(new->pub[i]));
 
-  *commitment = new;
   return GNUNET_OK;
 
 FAIL:
   GNUNET_free (new->pub);
   GNUNET_free (new->priv);
-  GNUNET_free (new);
   return GNUNET_SYSERR;
 }
 
 
+void
+TALER_age_restriction_commmitment_free_inside (
+  struct TALER_AgeCommitment *commitment)
+{
+  if (NULL == commitment)
+    return;
+
+  if (NULL != commitment->priv)
+  {
+    GNUNET_CRYPTO_zero_keys (
+      commitment->priv,
+      sizeof(*commitment->priv) * commitment->num_priv);
+
+    GNUNET_free (commitment->priv);
+    commitment->priv = NULL;
+  }
+
+  if (NULL != commitment->pub)
+  {
+    GNUNET_free (commitment->pub);
+    commitment->priv = NULL;
+  }
+
+  /* Caller is responsible for commitment itself */
+}
+
+
 /* end of crypto.c */