implement sm signing of key announcements

src/include/taler_crypto_lib.h

@@ -32,6 +32,44 @@
 
 GNUNET_NETWORK_STRUCT_BEGIN
 
+/**
+ * @brief Type of public keys for Taler security modules (software or hardware).
+ * Note that there are usually at least two security modules (RSA and EdDSA),
+ * each with its own private key.
+ */
+struct TALER_SecurityModulePublicKeyP
+{
+  /**
+   * Taler uses EdDSA for security modules.
+   */
+  struct GNUNET_CRYPTO_EddsaPublicKey eddsa_pub;
+};
+
+
+/**
+ * @brief Type of private keys for Taler security modules (software or hardware).
+ */
+struct TALER_SecurityModulePrivateKeyP
+{
+  /**
+   * Taler uses EdDSA for security modules.
+   */
+  struct GNUNET_CRYPTO_EddsaPrivateKey eddsa_priv;
+};
+
+
+/**
+ * @brief Type of signatures used for Taler security modules (software or hardware).
+ */
+struct TALER_SecurityModuleSignatureP
+{
+  /**
+   * Taler uses EdDSA for security modules.
+   */
+  struct GNUNET_CRYPTO_EddsaSignature eddsa_signature;
+};
+
+
 /**
  * @brief Type of public keys for Taler reserves.
  */
@@ -758,6 +796,9 @@ struct TALER_CRYPTO_DenominationHelper;
  *                 zero if the key has been revoked or purged
  * @param h_denom_pub hash of the @a denom_pub that is available (or was purged)
  * @param denom_pub the public key itself, NULL if the key was revoked or purged
+ * @param sm_pub public key of the security module, NULL if the key was revoked or purged
+ * @param sm_sig signature from the security module, NULL if the key was revoked or purged
+ *               The signature was already verified against @a sm_pub.
  */
 typedef void
 (*TALER_CRYPTO_DenominationKeyStatusCallback)(
@@ -766,7 +807,9 @@ typedef void
   struct GNUNET_TIME_Absolute start_time,
   struct GNUNET_TIME_Relative validity_duration,
   const struct GNUNET_HashCode *h_denom_pub,
-  const struct TALER_DenominationPublicKey *denom_pub);
+  const struct TALER_DenominationPublicKey *denom_pub,
+  const struct TALER_SecurityModulePublicKeyP *sm_pub,
+  const struct TALER_SecurityModuleSignatureP *sm_sig);
 
 
 /**

src/include/taler_signatures.h

@@ -210,6 +210,20 @@
 #define TALER_SIGNATURE_WALLET_COIN_LINK 1204
 
 
+/******************************/
+/* Security module signatures */
+/******************************/
+
+/**
+ * Signature on a denomination key announcement.
+ */
+#define TALER_SIGNATURE_SM_DENOMINATION_KEY 1250
+
+/**
+ * Signature on an exchange message signing key announcement.
+ */
+#define TALER_SIGNATURE_SM_SIGNING_KEY 1251
+
 /*******************/
 /* Test signatures */
 /*******************/
@@ -253,6 +267,72 @@
 
 GNUNET_NETWORK_STRUCT_BEGIN
 
+/**
+ * @brief format used by the denomination crypto helper when affirming
+ *        that it created a denomination key.
+ */
+struct TALER_DenominationKeyAnnouncementPS
+{
+
+  /**
+   * Purpose must be #TALER_SIGNATURE_SM_DENOMINATION_KEY.
+   * Used with an EdDSA signature of a `struct TALER_SecurityModulePublicKeyP`.
+   */
+  struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
+
+  /**
+   * Hash of the denomination public key.
+   */
+  struct GNUNET_HashCode h_denom_pub;
+
+  /**
+   * Hash of the section name in the configuration of this denomination.
+   */
+  struct GNUNET_HashCode h_section_name;
+
+  /**
+   * When does the key become available?
+   */
+  struct GNUNET_TIME_AbsoluteNBO anchor_time;
+
+  /**
+   * How long is the key available after @e anchor_time?
+   */
+  struct GNUNET_TIME_RelativeNBO duration_withdraw;
+
+};
+
+
+/**
+ * @brief format used by the signing crypto helper when affirming
+ *        that it created an exchange signing key.
+ */
+struct TALER_SigningKeyAnnouncementPS
+{
+
+  /**
+   * Purpose must be #TALER_SIGNATURE_SM_SIGNING_KEY.
+   * Used with an EdDSA signature of a `struct TALER_SecurityModulePublicKeyP`.
+   */
+  struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
+
+  /**
+   * Public signing key of the exchange this is about.
+   */
+  struct TALER_ExchangePublicKeyP exchange_pub;
+
+  /**
+   * When does the key become available?
+   */
+  struct GNUNET_TIME_AbsoluteNBO anchor_time;
+
+  /**
+   * How long is the key available after @e anchor_time?
+   */
+  struct GNUNET_TIME_RelativeNBO duration_withdraw;
+
+};
+
 /**
  * @brief Format used for to allow the wallet to authenticate
  * link data provided by the exchange.

src/util/crypto_helper_denom.c

@@ -20,6 +20,7 @@
  */
 #include "platform.h"
 #include "taler_util.h"
+#include "taler_signatures.h"
 #include "taler-helper-crypto-rsa.h"
 
 
@@ -276,7 +277,12 @@ handle_mt_avail (struct TALER_CRYPTO_DenominationHelper *dh,
 
   {
     struct TALER_DenominationPublicKey denom_pub;
-    struct GNUNET_HashCode h_denom_pub;
+    struct TALER_DenominationKeyAnnouncementPS dka = {
+      .purpose.purpose = htonl (TALER_SIGNATURE_SM_DENOMINATION_KEY),
+      .purpose.size = htonl (sizeof (dka)),
+      .anchor_time = kan->anchor_time,
+      .duration_withdraw = kan->duration_withdraw
+    };
 
     denom_pub.rsa_public_key
       = GNUNET_CRYPTO_rsa_public_key_decode (buf,
@@ -287,13 +293,25 @@ handle_mt_avail (struct TALER_CRYPTO_DenominationHelper *dh,
       return GNUNET_SYSERR;
     }
     GNUNET_CRYPTO_rsa_public_key_hash (denom_pub.rsa_public_key,
-                                       &h_denom_pub);
+                                       &dka.h_denom_pub);
+    if (GNUNET_OK !=
+        GNUNET_CRYPTO_eddsa_verify (TALER_SIGNATURE_SM_DENOMINATION_KEY,
+                                    &dka,
+                                    &kan->secm_sig.eddsa_signature,
+                                    &kan->secm_pub.eddsa_pub))
+    {
+      GNUNET_break_op (0);
+      GNUNET_CRYPTO_rsa_public_key_free (denom_pub.rsa_public_key);
+      return GNUNET_SYSERR;
+    }
     dh->dkc (dh->dkc_cls,
              section_name,
              GNUNET_TIME_absolute_ntoh (kan->anchor_time),
              GNUNET_TIME_relative_ntoh (kan->duration_withdraw),
-             &h_denom_pub,
+             &dka.h_denom_pub,
-             &denom_pub);
+             &denom_pub,
+             &kan->secm_pub,
+             &kan->secm_sig);
     GNUNET_CRYPTO_rsa_public_key_free (denom_pub.rsa_public_key);
   }
   return GNUNET_OK;
@@ -324,6 +342,8 @@ handle_mt_purge (struct TALER_CRYPTO_DenominationHelper *dh,
            GNUNET_TIME_UNIT_ZERO_ABS,
            GNUNET_TIME_UNIT_ZERO,
            &pn->h_denom_pub,
+           NULL,
+           NULL,
            NULL);
   return GNUNET_OK;
 }

src/util/taler-helper-crypto-eddsa.c

@@ -44,6 +44,8 @@
 #include <pthread.h>
 #include <sys/eventfd.h>
 #include "taler_error_codes.h"
+#include "taler_signatures.h"
+
 
 /**
  * One particular key.
@@ -171,6 +173,12 @@ struct WorkItem
 };
 
 
+/**
+ * Private key of this security module. Used to sign denomination key
+ * announcements.
+ */
+static struct TALER_SecurityModulePrivateKeyP smpriv;
+
 /**
  * Head of DLL of actual keys, sorted by anchor.
  */
@@ -593,6 +601,13 @@ static int
 notify_client_key_add (struct Client *client,
                        const struct Key *key)
 {
+  struct TALER_SigningKeyAnnouncementPS ska = {
+    .purpose.purpose = htonl (TALER_SIGNATURE_SM_SIGNING_KEY),
+    .purpose.size = htonl (sizeof (ska)),
+    .exchange_pub = key->exchange_pub,
+    .anchor_time = GNUNET_TIME_absolute_hton (key->anchor),
+    .duration_withdraw = GNUNET_TIME_relative_hton (duration)
+  };
   struct TALER_CRYPTO_EddsaKeyAvailableNotification an = {
     .header.size = htons (sizeof (an)),
     .header.type = htons (TALER_HELPER_EDDSA_MT_AVAIL),
@@ -601,6 +616,9 @@ notify_client_key_add (struct Client *client,
     .exchange_pub = key->exchange_pub
   };
 
+  GNUNET_CRYPTO_eddsa_sign (&smpriv.eddsa_priv,
+                            &ska,
+                            &an.secm_sig.eddsa_signature);
   if (GNUNET_OK !=
       transmit (&client->addr,
                 client->addr_size,
@@ -1363,6 +1381,38 @@ run (void *cls,
     now = GNUNET_TIME_absolute_get ();
   }
   GNUNET_TIME_round_abs (&now);
+
+  {
+    char *pfn;
+
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_filename (kcfg,
+                                                 "taler-helper-crypto-eddsa",
+                                                 "SM_PRIV_KEY",
+                                                 &pfn))
+    {
+      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
+                                 "taler-helper-crypto-eddsa",
+                                 "SM_PRIV_KEY");
+      global_ret = 1;
+      return;
+    }
+    if (GNUNET_SYSERR ==
+        GNUNET_CRYPTO_eddsa_key_from_file (pfn,
+                                           GNUNET_YES,
+                                           &smpriv.eddsa_priv))
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 "taler-helper-crypto-rsa",
+                                 "SM_PRIV_KEY",
+                                 "Could not use file to persist private key");
+      GNUNET_free (pfn);
+      global_ret = 1;
+      return;
+    }
+    GNUNET_free (pfn);
+  }
+
   if (GNUNET_OK !=
       load_durations ())
   {

src/util/taler-helper-crypto-eddsa.h

@@ -58,6 +58,17 @@ struct TALER_CRYPTO_EddsaKeyAvailableNotification
    */
   struct GNUNET_TIME_RelativeNBO duration;
 
+  /**
+   * Public key used to generate the @e sicm_sig.
+   */
+  struct TALER_SecurityModulePublicKeyP secm_pub;
+
+  /**
+   * Signature affirming the announcement, of
+   * purpose #TALER_SIGNATURE_SM_SIGNING_KEY.
+   */
+  struct TALER_SecurityModuleSignatureP secm_sig;
+
   /**
    * The public key.
    */

src/util/taler-helper-crypto-rsa.c

@@ -44,6 +44,8 @@
 #include <pthread.h>
 #include <sys/eventfd.h>
 #include "taler_error_codes.h"
+#include "taler_signatures.h"
+
 
 /**
  * Information we keep per denomination.
@@ -243,6 +245,12 @@ struct WorkItem
  */
 static int global_ret;
 
+/**
+ * Private key of this security module. Used to sign denomination key
+ * announcements.
+ */
+static struct TALER_SecurityModulePrivateKeyP smpriv;
+
 /**
  * Number of worker threads to use. Default (0) is to use one per CPU core
  * available.
@@ -693,14 +701,24 @@ static int
 notify_client_dk_add (struct Client *client,
                       const struct DenominationKey *dk)
 {
-  struct TALER_CRYPTO_RsaKeyAvailableNotification *an;
   struct Denomination *denom = dk->denom;
   size_t nlen = strlen (denom->section) + 1;
+  struct TALER_DenominationKeyAnnouncementPS dka = {
+    .purpose.purpose = htonl (TALER_SIGNATURE_SM_DENOMINATION_KEY),
+    .purpose.size = htonl (sizeof (dka)),
+    .h_denom_pub = dk->h_denom_pub,
+    .anchor_time = GNUNET_TIME_absolute_hton (dk->anchor),
+    .duration_withdraw = GNUNET_TIME_relative_hton (denom->duration_withdraw)
+  };
+  struct TALER_CRYPTO_RsaKeyAvailableNotification *an;
   size_t buf_len;
   void *buf;
   void *p;
   size_t tlen;
 
+  GNUNET_CRYPTO_hash (denom->section,
+                      nlen,
+                      &dka.h_section_name);
   buf_len = GNUNET_CRYPTO_rsa_public_key_encode (dk->denom_pub.rsa_public_key,
                                                  &buf);
   GNUNET_assert (buf_len < UINT16_MAX);
@@ -714,6 +732,9 @@ notify_client_dk_add (struct Client *client,
   an->section_name_len = htons ((uint16_t) nlen);
   an->anchor_time = GNUNET_TIME_absolute_hton (dk->anchor);
   an->duration_withdraw = GNUNET_TIME_relative_hton (denom->duration_withdraw);
+  GNUNET_CRYPTO_eddsa_sign (&smpriv.eddsa_priv,
+                            &dka,
+                            &an->secm_sig.eddsa_signature);
   p = (void *) &an[1];
   memcpy (p,
           buf,
@@ -1742,6 +1763,38 @@ run (void *cls,
     now = GNUNET_TIME_absolute_get ();
   }
   GNUNET_TIME_round_abs (&now);
+
+  {
+    char *pfn;
+
+    if (GNUNET_OK !=
+        GNUNET_CONFIGURATION_get_value_filename (kcfg,
+                                                 "taler-helper-crypto-rsa",
+                                                 "SM_PRIV_KEY",
+                                                 &pfn))
+    {
+      GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
+                                 "taler-helper-crypto-rsa",
+                                 "SM_PRIV_KEY");
+      global_ret = 1;
+      return;
+    }
+    if (GNUNET_SYSERR ==
+        GNUNET_CRYPTO_eddsa_key_from_file (pfn,
+                                           GNUNET_YES,
+                                           &smpriv.eddsa_priv))
+    {
+      GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
+                                 "taler-helper-crypto-rsa",
+                                 "SM_PRIV_KEY",
+                                 "Could not use file to persist private key");
+      GNUNET_free (pfn);
+      global_ret = 1;
+      return;
+    }
+    GNUNET_free (pfn);
+  }
+
   if (GNUNET_OK !=
       load_durations ())
   {

src/util/taler-helper-crypto-rsa.h

@@ -63,6 +63,17 @@ struct TALER_CRYPTO_RsaKeyAvailableNotification
    */
   struct GNUNET_TIME_RelativeNBO duration_withdraw;
 
+  /**
+   * Public key used to generate the @e sicm_sig.
+   */
+  struct TALER_SecurityModulePublicKeyP secm_pub;
+
+  /**
+   * Signature affirming the announcement, of
+   * purpose #TALER_SIGNATURE_SM_DENOMINATION_KEY.
+   */
+  struct TALER_SecurityModuleSignatureP secm_sig;
+
   /* followed by @e pub_size bytes of the public key */
 
   /* followed by @e section_name bytes of the configuration section name

src/util/test_helper_rsa.conf

@@ -7,3 +7,5 @@ lookahead_sign = 5 minutes
 overlap_duration = 1 s
 KEY_DIR = ${TALER_RUNTIME_DIR}/test_helper_rsa/
 UNIXPATH = ${TALER_RUNTIME_DIR}test_helper_rsa.unix
+
+SM_PRIV_KEY = ${TALER_DATA_HOME}/taler-helper-crypto-rsa/.private-key