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re-compute refresh session hash in reveal step

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This commit is contained in:
Christian Grothoff 2016-08-11 22:19:12 +02:00
parent 1f39f7e92b
commit 0bfc7bcbf9
2 changed files with 155 additions and 23 deletions
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4
src/exchange-lib/exchange_api_refresh.c
View File

@ -794,8 +794,8 @@ TALER_EXCHANGE_refresh_prepare (const struct TALER_CoinSpendPrivateKeyP *melt_pr
return NULL;
}
/* now compute melt session hash */
/* next, add all of the hashes from the denomination keys to the
hash_context */
for (i=0;i<fresh_pks_len;i++)
{
char *buf;

174
src/exchange/taler-exchange-httpd_db.c
View File

@ -1166,6 +1166,8 @@ send_melt_commitment_error (struct MHD_Connection *connection,
* @param melt information about the melted coin
* @param num_newcoins number of newcoins being generated
* @param denom_pubs array of @a num_newcoins keys for the new coins
* @param hash_context hash context to update by hashing in the data
* from this offset
* @return #GNUNET_OK if the committment was honest,
* #GNUNET_NO if there was a problem and we generated an error message
* #GNUNET_SYSERR if we could not even generate an error message
@ -1178,7 +1180,8 @@ check_commitment (struct MHD_Connection *connection,
const struct TALER_TransferPrivateKeyP *transfer_priv,
const struct TALER_EXCHANGEDB_RefreshMelt *melt,
unsigned int num_newcoins,
const struct TALER_DenominationPublicKey *denom_pubs)
const struct TALER_DenominationPublicKey *denom_pubs,
struct GNUNET_HashContext *hash_context)
{
struct TALER_TransferPublicKeyP transfer_pub;
struct TALER_TransferSecretP transfer_secret;
@ -1187,6 +1190,8 @@ check_commitment (struct MHD_Connection *connection,
unsigned int j;
int ret;
/* FIXME: instead of consulting DB, reconstruct everything
from transfer_priv here! */
if (GNUNET_OK !=
TMH_plugin->get_refresh_transfer_public_key (TMH_plugin->cls,
session,
@ -1206,8 +1211,7 @@ check_commitment (struct MHD_Connection *connection,
&transfer_pub,
sizeof (struct TALER_TransferPublicKeyP)))
{
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"transfer keys do not match\n");
GNUNET_break_op (0);
return send_melt_commitment_error (connection,
session,
session_hash,
@ -1275,6 +1279,7 @@ check_commitment (struct MHD_Connection *connection,
commit_coins[j].coin_ev,
buf_len)) )
{
GNUNET_break_op (0);
GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
"blind envelope does not match for k=%u, old=%d\n",
off,
@ -1289,6 +1294,9 @@ check_commitment (struct MHD_Connection *connection,
"envelope");
goto cleanup;
}
GNUNET_CRYPTO_hash_context_read (hash_context,
commit_coins[j].coin_ev,
commit_coins[j].coin_ev_size);
GNUNET_free (buf);
}
ret = GNUNET_OK;
@ -1391,17 +1399,6 @@ execute_refresh_reveal_transaction (struct MHD_Connection *connection,
int ret;
START_TRANSACTION (session, connection);
if (GNUNET_OK !=
TMH_plugin->get_refresh_commit_coins (TMH_plugin->cls,
session,
session_hash,
refresh_session->noreveal_index,
refresh_session->num_newcoins,
commit_coins))
{
GNUNET_break (0);
return TMH_RESPONSE_reply_internal_db_error (connection);
}
key_state = TMH_KS_acquire ();
for (j=0;j<refresh_session->num_newcoins;j++)
{
@ -1456,6 +1453,8 @@ TMH_DB_execute_refresh_reveal (struct MHD_Connection *connection,
unsigned int i;
unsigned int j;
unsigned int off;
struct GNUNET_HashContext *hash_context;
struct GNUNET_HashCode sh_check;
if (NULL == (session = TMH_plugin->get_session (TMH_plugin->cls)))
{
@ -1489,34 +1488,167 @@ TMH_DB_execute_refresh_reveal (struct MHD_Connection *connection,
? GNUNET_NO : GNUNET_SYSERR;
}
hash_context = GNUNET_CRYPTO_hash_context_start ();
/* first, iterate over transfer public keys for hash_context */
off = 0;
for (i=0;i<TALER_CNC_KAPPA - 1;i++)
for (i=0;i<TALER_CNC_KAPPA;i++)
{
struct TALER_TransferPublicKeyP tp;
if (i == refresh_session.noreveal_index)
{
off = 1;
/* obtain tp from db */
if (GNUNET_OK !=
TMH_plugin->get_refresh_transfer_public_key (TMH_plugin->cls,
session,
session_hash,
i,
&tp))
{
GNUNET_break (0);
GNUNET_free (denom_pubs);
GNUNET_CRYPTO_rsa_signature_free (refresh_session.melt.coin.denom_sig.rsa_signature);
GNUNET_CRYPTO_rsa_public_key_free (refresh_session.melt.coin.denom_pub.rsa_public_key);
GNUNET_CRYPTO_hash_context_abort (hash_context);
return (MHD_YES == TMH_RESPONSE_reply_internal_db_error (connection))
? GNUNET_NO : GNUNET_SYSERR;
}
}
else
{
/* compute tp from private key */
GNUNET_CRYPTO_ecdhe_key_get_public (&transfer_privs[i - off].ecdhe_priv,
&tp.ecdhe_pub);
}
GNUNET_CRYPTO_hash_context_read (hash_context,
&tp,
sizeof (struct TALER_TransferPublicKeyP));
}
/* next, add all of the hashes from the denomination keys to the
hash_context */
{
struct TALER_DenominationPublicKey denom_pubs[refresh_session.num_newcoins];
if (GNUNET_OK !=
TMH_plugin->get_refresh_order (TMH_plugin->cls,
session,
session_hash,
refresh_session.num_newcoins,
denom_pubs))
{
GNUNET_break (0);
GNUNET_free (denom_pubs);
GNUNET_CRYPTO_rsa_signature_free (refresh_session.melt.coin.denom_sig.rsa_signature);
GNUNET_CRYPTO_rsa_public_key_free (refresh_session.melt.coin.denom_pub.rsa_public_key);
GNUNET_CRYPTO_hash_context_abort (hash_context);
return (MHD_YES == TMH_RESPONSE_reply_internal_db_error (connection))
? GNUNET_NO : GNUNET_SYSERR;
}
for (i=0;i<refresh_session.num_newcoins;i++)
{
char *buf;
size_t buf_size;
buf_size = GNUNET_CRYPTO_rsa_public_key_encode (denom_pubs[i].rsa_public_key,
&buf);
GNUNET_CRYPTO_hash_context_read (hash_context,
buf,
buf_size);
GNUNET_free (buf);
GNUNET_CRYPTO_rsa_public_key_free (denom_pubs[i].rsa_public_key);
}
}
/* next, add public key of coin and amount being refreshed */
{
struct TALER_AmountNBO melt_amountn;
GNUNET_CRYPTO_hash_context_read (hash_context,
&refresh_session.melt.coin.coin_pub,
sizeof (struct TALER_CoinSpendPublicKeyP));
TALER_amount_hton (&melt_amountn,
&refresh_session.melt.amount_with_fee);
GNUNET_CRYPTO_hash_context_read (hash_context,
&melt_amountn,
sizeof (struct TALER_AmountNBO));
}
commit_coins = GNUNET_new_array (refresh_session.num_newcoins,
struct TALER_EXCHANGEDB_RefreshCommitCoin);
off = 0;
for (i=0;i<TALER_CNC_KAPPA;i++)
{
if (i == refresh_session.noreveal_index)
{
off = 1;
/* obtain commit_coins for the selected gamma value from DB */
if (GNUNET_OK !=
TMH_plugin->get_refresh_commit_coins (TMH_plugin->cls,
session,
session_hash,
i,
refresh_session.num_newcoins,
commit_coins))
{
GNUNET_break (0);
GNUNET_free (denom_pubs);
GNUNET_CRYPTO_rsa_signature_free (refresh_session.melt.coin.denom_sig.rsa_signature);
GNUNET_CRYPTO_rsa_public_key_free (refresh_session.melt.coin.denom_pub.rsa_public_key);
GNUNET_CRYPTO_hash_context_abort (hash_context);
return TMH_RESPONSE_reply_internal_db_error (connection);
}
/* add envelopes to hash_context */
for (j=0;j<refresh_session.num_newcoins;j++)
{
GNUNET_CRYPTO_hash_context_read (hash_context,
commit_coins[j].coin_ev,
commit_coins[j].coin_ev_size);
}
continue;
}
if (GNUNET_OK !=
(res = check_commitment (connection,
session,
session_hash,
i + off,
&transfer_privs[i],
i,
&transfer_privs[i - off],
&refresh_session.melt,
refresh_session.num_newcoins,
denom_pubs)))
denom_pubs,
hash_context)))
{
GNUNET_break_op (0);
for (j=0;j<refresh_session.num_newcoins;j++)
GNUNET_CRYPTO_rsa_public_key_free (denom_pubs[j].rsa_public_key);
GNUNET_free (denom_pubs);
GNUNET_CRYPTO_rsa_signature_free (refresh_session.melt.coin.denom_sig.rsa_signature);
GNUNET_CRYPTO_rsa_public_key_free (refresh_session.melt.coin.denom_pub.rsa_public_key);
GNUNET_CRYPTO_hash_context_abort (hash_context);
return (GNUNET_NO == res) ? MHD_YES : MHD_NO;
}
}
/* Check session hash matches */
GNUNET_CRYPTO_hash_context_finish (hash_context,
&sh_check);
if (0 != memcmp (&sh_check,
session_hash,
sizeof (struct GNUNET_HashCode)))
{
GNUNET_break_op (0);
for (j=0;j<refresh_session.num_newcoins;j++)
GNUNET_CRYPTO_rsa_public_key_free (denom_pubs[j].rsa_public_key);
GNUNET_free (denom_pubs);
GNUNET_CRYPTO_rsa_signature_free (refresh_session.melt.coin.denom_sig.rsa_signature);
GNUNET_CRYPTO_rsa_public_key_free (refresh_session.melt.coin.denom_pub.rsa_public_key);
return (MHD_YES == TMH_RESPONSE_reply_external_error (connection,
"session hash does not match"))
? GNUNET_NO : GNUNET_SYSERR;
}
/* Client request OK, start transaction */
commit_coins = GNUNET_new_array (refresh_session.num_newcoins,
struct TALER_EXCHANGEDB_RefreshCommitCoin);
ev_sigs = GNUNET_new_array (refresh_session.num_newcoins,
struct TALER_DenominationSignature);
res = execute_refresh_reveal_transaction (connection,