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[taler-exchange] 02/04: WiP: age-withdraw implementation, part 3/n
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gnunet |
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Subject: |
[taler-exchange] 02/04: WiP: age-withdraw implementation, part 3/n |
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Date: |
Mon, 06 Mar 2023 20:51:27 +0100 |
This is an automated email from the git hooks/post-receive script.
oec pushed a commit to branch master
in repository exchange.
commit 262b470878a4e14cb9aa8ce43ea51e4fba60c6cb
Author: Özgür Kesim <oec-taler@kesim.org>
AuthorDate: Mon Mar 6 20:42:48 2023 +0100
WiP: age-withdraw implementation, part 3/n
- retrieval of previous commitment
- validity check of all denominations
- comparison of accumulated values and fees with commited value and fee.
- update gana
---
contrib/gana | 2 +-
.../taler-exchange-httpd_age-withdraw_reveal.c | 358 +++++++++++++++++----
2 files changed, 300 insertions(+), 60 deletions(-)
diff --git a/contrib/gana b/contrib/gana
index 214bc664..02132ede 160000
--- a/contrib/gana
+++ b/contrib/gana
@@ -1 +1 @@
-Subproject commit 214bc664476333a2c042ae57911558d1325e725f
+Subproject commit 02132ededc12a0a1cfd81f0ca76c384304e15259
diff --git a/src/exchange/taler-exchange-httpd_age-withdraw_reveal.c
b/src/exchange/taler-exchange-httpd_age-withdraw_reveal.c
index 0cbad661..daefca4c 100644
--- a/src/exchange/taler-exchange-httpd_age-withdraw_reveal.c
+++ b/src/exchange/taler-exchange-httpd_age-withdraw_reveal.c
@@ -42,7 +42,7 @@ struct AgeRevealContext
/**
* Public key of the reserve for with the age-withdraw commitment was
* originally made. This parameter is provided by the client again
- * during the call to reveal in order to save a database-lookup .
+ * during the call to reveal in order to save a database-lookup.
*/
struct TALER_ReservePublicKeyP reserve_pub;
@@ -52,20 +52,41 @@ struct AgeRevealContext
uint32_t num_coins;
/**
- * TODO:oec num_coins denoms
+ * #num_coins hashes of the denominations from which the coins are withdrawn.
+ * Those must support age restriction.
*/
struct TALER_DenominationHashP *denoms_h;
/**
- * TODO:oec num_coins blinded coins
+ * #num_coins denomination keys, found in the system, according to denoms_h;
+ */
+ struct TEH_DenominationKey *denom_keys;
+
+ /**
+ * #num_coins hases of blinded coins.
*/
struct TALER_BlindedCoinHashP *coin_evs;
/**
- * TODO:oec num_coins*(kappa - 1) disclosed coins
+ * Total sum of all denominations' values
+ **/
+ struct TALER_Amount total_amount;
+
+ /**
+ * Total sum of all denominations' fees
+ */
+ struct TALER_Amount total_fee;
+
+ /**
+ * #num_coins*(kappa - 1) disclosed coins.
*/
struct GNUNET_CRYPTO_EddsaPrivateKey *disclosed_coins;
+ /**
+ * The data from the original age-withdraw. Will be retrieved from
+ * the DB via @a ach.
+ */
+ struct TALER_EXCHANGEDB_AgeWithdrawCommitment commitment;
};
/**
@@ -75,30 +96,35 @@ void
age_reveal_context_free (struct AgeRevealContext *actx)
{
GNUNET_free (actx->denoms_h);
+ GNUNET_free (actx->denom_keys);
GNUNET_free (actx->coin_evs);
GNUNET_free (actx->disclosed_coins);
}
/**
- * Handle a "/age-withdraw/$ACH/reveal request. Parses the given JSON
- * ... TODO:oec:description
+ * Parse the json body of an '/age-withdraw/$ACH/reveal' request. It extracts
+ * the denomination hashes, blinded coins and disclosed coins and allocates
+ * memory for those.
*
* @param connection The MHD connection to handle
- * @param actx The context of the operation, only partially built at call time
* @param j_denoms_h Array of hashes of the denominations for the withdrawal,
in JSON format
* @param j_coin_evs The blinded envelopes in JSON format for the coins that
are not revealed and will be signed on success
* @param j_disclosed_coins The n*(kappa-1) disclosed coins' private keys in
JSON format, from which all other attributes (age restriction, blinding, nonce)
will be derived from
+ * @param[out] actx The context of the operation, only partially built at call
time
+ * @param[out] mhd_mret The result if a reply is queued for MHD
+ * @return true on success, false on failure, with a reply already queued for
MHD.
*/
-MHD_RESULT
-handle_age_withdraw_reveal_json (
+static enum GNUNET_GenericReturnValue
+parse_age_withdraw_reveal_json (
struct MHD_Connection *connection,
- struct AgeRevealContext *actx,
const json_t *j_denoms_h,
const json_t *j_coin_evs,
- const json_t *j_disclosed_coins)
+ const json_t *j_disclosed_coins,
+ struct AgeRevealContext *actx,
+ MHD_RESULT *mhd_ret)
{
- MHD_RESULT mhd_ret = MHD_NO;
+ enum GNUNET_GenericReturnValue result = GNUNET_SYSERR;
/* Verify JSON-structure consistency */
{
@@ -129,10 +155,13 @@ handle_age_withdraw_reveal_json (
TALER_CNC_KAPPA_MINUS_ONE_STR " times the size of denoms_h";
if (NULL != error)
- return TALER_MHD_reply_with_error (connection,
- MHD_HTTP_BAD_REQUEST,
- TALER_EC_GENERIC_PARAMETER_MALFORMED,
- error);
+ {
+ *mhd_ret = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_BAD_REQUEST,
+
TALER_EC_GENERIC_PARAMETER_MALFORMED,
+ error);
+ return GNUNET_SYSERR;
+ }
}
/* Continue parsing the parts */
@@ -158,11 +187,11 @@ handle_age_withdraw_reveal_json (
sizeof(msg),
"couldn't parse entry no. %d in array denoms_h",
idx + 1);
- mhd_ret = TALER_MHD_reply_with_error (connection,
- MHD_HTTP_BAD_REQUEST,
-
TALER_EC_GENERIC_PARAMETER_MALFORMED,
- msg);
- goto CLEANUP;
+ *mhd_ret = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_BAD_REQUEST,
+
TALER_EC_GENERIC_PARAMETER_MALFORMED,
+ msg);
+ goto EXIT;
}
};
@@ -184,11 +213,11 @@ handle_age_withdraw_reveal_json (
sizeof(msg),
"couldn't parse entry no. %d in array coin_evs",
idx + 1);
- mhd_ret = TALER_MHD_reply_with_error (connection,
- MHD_HTTP_BAD_REQUEST,
-
TALER_EC_GENERIC_PARAMETER_MALFORMED,
- msg);
- goto CLEANUP;
+ *mhd_ret = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_BAD_REQUEST,
+
TALER_EC_GENERIC_PARAMETER_MALFORMED,
+ msg);
+ goto EXIT;
}
};
@@ -211,28 +240,211 @@ handle_age_withdraw_reveal_json (
sizeof(msg),
"couldn't parse entry no. %d in array
disclosed_coins",
idx + 1);
- mhd_ret = TALER_MHD_reply_with_error (connection,
- MHD_HTTP_BAD_REQUEST,
-
TALER_EC_GENERIC_PARAMETER_MALFORMED,
- msg);
- goto CLEANUP;
+ *mhd_ret = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_BAD_REQUEST,
+
TALER_EC_GENERIC_PARAMETER_MALFORMED,
+ msg);
+ goto EXIT;
}
};
}
- /* TODO:oec: find commitment */
- /* TODO:oec: check validity of denoms */
- /* TODO:oec: check amount total against denoms */
- /* TODO:oec: compute the disclosed blinded coins */
- /* TODO:oec: generate h_commitment_comp */
- /* TODO:oec: compare h_commitment_comp against h_commitment */
- /* TODO:oec: sign the coins */
- /* TODO:oec: send response */
+ result = GNUNET_OK;
+ *mhd_ret = MHD_YES;
+
+
+EXIT:
+ return result;
+}
+
+
+/**
+ * Check if the request belongs to an existing age-withdraw request.
+ * If so, sets the age_withdraw object with the request data.
+ * Otherwise, it queues an appropriate MHD response.
+ *
+ * @param connection The HTTP connection to the client
+ * @param h_commitment Original commitment value sent with the age-withdraw
request
+ * @param reserve_pub Reserve public key used in the original age-withdraw
request
+ * @param[out] commitment Data from the original age-withdraw request
+ * @param[out] result In the error cases, a response will be queued with MHD
and this will be the result.
+ * @return GNUNET_OK if the withdraw request has been found,
+ * GNUNET_SYSERROR if we did not find the request in the DB
+ */
+static enum GNUNET_GenericReturnValue
+retrieve_original_commitment (
+ struct MHD_Connection *connection,
+ const struct TALER_AgeWithdrawCommitmentHashP *h_commitment,
+ const struct TALER_ReservePublicKeyP *reserve_pub,
+ struct TALER_EXCHANGEDB_AgeWithdrawCommitment *commitment,
+ MHD_RESULT *result)
+{
+ enum GNUNET_DB_QueryStatus qs;
+
+ qs = TEH_plugin->get_age_withdraw_info (TEH_plugin->cls,
+ reserve_pub,
+ h_commitment,
+ commitment);
+ switch (qs)
+ {
+ case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
+ return GNUNET_OK; /* Only happy case */
+
+ case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
+ *result = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_NOT_FOUND,
+
TALER_EC_EXCHANGE_AGE_WITHDRAW_COMMITMENT_UNKNOWN,
+ NULL);
+ break;
+
+ case GNUNET_DB_STATUS_HARD_ERROR:
+ *result = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_INTERNAL_SERVER_ERROR,
+ TALER_EC_GENERIC_DB_FETCH_FAILED,
+ "get_age_withdraw_info");
+ break;
+
+ case GNUNET_DB_STATUS_SOFT_ERROR:
+ /* FIXME: Do we queue a result in this case or retry? */
+ default:
+ GNUNET_break (0); /* should be impossible */
+ *result = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_INTERNAL_SERVER_ERROR,
+
TALER_EC_GENERIC_INTERNAL_INVARIANT_FAILURE,
+ NULL);
+ }
+
+ return GNUNET_SYSERR;
+}
+
+
+/**
+ * Check if the given array of hashes of denomination_keys a) belong
+ * to valid denominations and b) those are marked as age restricted.
+ *
+ * @param connection The HTTP connection to the client
+ * @param len The lengths of the array @a denoms_h
+ * @param denoms_h array of hashes of denomination public keys
+ * @param[out] dks On success, will be filled with the denomination keys.
Caller must deallocate.
+ * @param amount_with_fee The commited amount including fees
+ * @param[out] total_sum On success, will contain the total sum of all
denominations
+ * @param[out] total_fee On success, will contain the total sum of all fees
+ * @param[out] result In the error cases, a response will be queued with MHD
and this will be the result.
+ * @return GNUNET_OK if the denominations are valid and support age-restriction
+ * GNUNET_SYSERR otherwise
+ */
+static enum GNUNET_GenericReturnValue
+all_denominations_valid (
+ struct MHD_Connection *connection,
+ uint32_t len,
+ const struct TALER_DenominationHashP *denoms_h,
+ struct TEH_DenominationKey **dks,
+ const struct TALER_Amount *amount_with_fee,
+ struct TALER_Amount *total_amount,
+ struct TALER_Amount *total_fee,
+ MHD_RESULT *result)
+{
+ struct TEH_KeyStateHandle *ksh;
+
+ GNUNET_assert (*dks == NULL);
+
+ ksh = TEH_keys_get_state ();
+ if (NULL == ksh)
+ {
+ *result = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_INTERNAL_SERVER_ERROR,
+
TALER_EC_EXCHANGE_GENERIC_KEYS_MISSING,
+ NULL);
+ return GNUNET_SYSERR;
+ }
+
+ *dks = GNUNET_new_array (len, struct TEH_DenominationKey);
+ TALER_amount_set_zero (TEH_currency, total_amount);
+ TALER_amount_set_zero (TEH_currency, total_fee);
+
+ for (uint32_t i = 0; i < len; i++)
+ {
+ dks[i] = TEH_keys_denomination_by_hash2 (
+ ksh,
+ &denoms_h[i],
+ connection,
+ result);
+
+ /* Does the denomination exist? */
+ if (NULL == dks[i])
+ {
+ GNUNET_assert (result != NULL);
+ /* Note: a HTTP-response has been queued and result has been set by
+ * TEH_keys_denominations_by_hash2 */
+ return GNUNET_SYSERR;
+ }
+
+ /* Does the denomation support age restriction ? */
+ if (0 == dks[i]->denom_pub.age_mask.bits)
+ {
+ char msg[256] = {0};
+ GNUNET_snprintf (msg,
+ sizeof(msg),
+ "denomination key no. %d does not support age
restriction",
+ i + 1);
+
+ *result = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_BAD_REQUEST,
+
TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN,
+ msg);
+ return GNUNET_SYSERR;
+ }
+
+ /* Accumulate the values */
+ if (0 > TALER_amount_add (
+ total_amount,
+ total_amount,
+ &dks[i]->meta.value))
+ {
+ GNUNET_break (0);
+ *result = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_INTERNAL_SERVER_ERROR,
+
TALER_EC_EXCHANGE_AGE_WITHDRAW_AMOUNT_OVERFLOW,
+ "amount");
+ return GNUNET_SYSERR;
+ }
+ /* Accumulate the withdraw fees */
+ if (0 > TALER_amount_add (
+ total_fee,
+ total_fee,
+ &dks[i]->meta.fees.withdraw))
+ {
+ GNUNET_break (0);
+ *result = TALER_MHD_reply_with_error (connection,
+ MHD_HTTP_INTERNAL_SERVER_ERROR,
+
TALER_EC_EXCHANGE_AGE_WITHDRAW_AMOUNT_OVERFLOW,
+ "fee");
+ return GNUNET_SYSERR;
+ }
+ }
+
+ /* Compare the commited amount against the totals */
+ {
+ struct TALER_Amount sum;
+ TALER_amount_set_zero (TEH_currency, &sum);
+
+ GNUNET_assert (0 < TALER_amount_add (
+ &sum,
+ total_amount,
+ total_fee));
+
+ if (0 != TALER_amount_cmp (&sum, amount_with_fee))
+ {
+ GNUNET_break (0);
+ *result = TALER_MHD_reply_with_ec (connection,
+
TALER_EC_EXCHANGE_AGE_WITHDRAW_AMOUNT_INCORRECT,
+ NULL);
+ return GNUNET_SYSERR;
+ }
+ }
-CLEANUP:
- age_reveal_context_free (actx);
- return mhd_ret;
+ return GNUNET_OK;
}
@@ -242,6 +454,8 @@ TEH_handler_age_withdraw_reveal (
const struct TALER_AgeWithdrawCommitmentHashP *ach,
const json_t *root)
{
+ MHD_RESULT result = MHD_NO;
+ enum GNUNET_GenericReturnValue ret = GNUNET_SYSERR;
struct AgeRevealContext actx = {0};
json_t *j_denoms_h;
json_t *j_coin_evs;
@@ -258,33 +472,59 @@ TEH_handler_age_withdraw_reveal (
/* Parse JSON body*/
{
- enum GNUNET_GenericReturnValue res;
-
- res = TALER_MHD_parse_json_data (rc->connection,
+ ret = TALER_MHD_parse_json_data (rc->connection,
root,
spec);
- if (GNUNET_OK != res)
+ if (GNUNET_OK != ret)
{
GNUNET_break_op (0);
- return (GNUNET_SYSERR == res) ? MHD_NO : MHD_YES;
+ return (GNUNET_SYSERR == ret) ? MHD_NO : MHD_YES;
}
}
- /* handle reveal request */
- {
- MHD_RESULT res;
-
- res = handle_age_withdraw_reveal_json (rc->connection,
- &actx,
- j_denoms_h,
- j_coin_evs,
- j_disclosed_coins);
+ do {
+ /* Extract denominations, blinded and disclosed coins */
+ if (GNUNET_OK != parse_age_withdraw_reveal_json (rc->connection,
+ j_denoms_h,
+ j_coin_evs,
+ j_disclosed_coins,
+ &actx,
+ &result))
+ break;
+
+ /* Find original commitment */
+ if (GNUNET_OK != retrieve_original_commitment (rc->connection,
+ &actx.ach,
+ &actx.reserve_pub,
+ &actx.commitment,
+ &result))
+ break;
+
+ /* Ensure validity of denoms and the sum of amounts and fees */
+ if (GNUNET_OK != all_denominations_valid (
+ rc->connection,
+ actx.num_coins,
+ actx.denoms_h,
+ &actx.denom_keys,
+ &actx.commitment.amount_with_fee,
+ &actx.total_amount,
+ &actx.total_fee,
+ &result))
+ break;
+
+
+ } while(0);
- GNUNET_JSON_parse_free (spec);
- return res;
- }
+ /* TODO:oec: compute the disclosed blinded coins */
+ /* TODO:oec: generate h_commitment_comp */
+ /* TODO:oec: compare h_commitment_comp against h_commitment */
+ /* TODO:oec: sign the coins */
+ /* TODO:oec: send response */
+ age_reveal_context_free (&actx);
+ GNUNET_JSON_parse_free (spec);
+ return result;
}
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