rct: rework the verification preparation process

The whole rct data apart from the MLSAGs is now included in
the signed message, to avoid malleability issues.

Instead of passing the data that's not serialized as extra
parameters to the verification API, the transaction is modified
to fill all that information. This means the transaction can
not be const anymore, but it cleaner in other ways.

1 files changed, 13 insertions, 2 deletions

diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index b22074c57..94701608e 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -500,6 +500,7 @@ namespace cryptonote
      * validates a transaction's inputs as correctly used and not previously
      * spent.  also returns the hash and height of the most recent block
      * which contains an output that was used as an input to the transaction.
+     * The transaction's rct signatures, if any, are expanded.
      *
      * @param tx the transaction to validate
      * @param pmax_used_block_height return-by-reference block height of most recent input
@@ -509,7 +510,7 @@ namespace cryptonote
      *
      * @return false if any input is invalid, otherwise true
      */
-    bool check_tx_inputs(const transaction& tx, uint64_t& pmax_used_block_height, crypto::hash& max_used_block_id, tx_verification_context &tvc, bool kept_by_block = false);
+    bool check_tx_inputs(transaction& tx, uint64_t& pmax_used_block_height, crypto::hash& max_used_block_id, tx_verification_context &tvc, bool kept_by_block = false);
 
     /**
      * @brief check that a transaction's outputs conform to current standards
@@ -919,6 +920,7 @@ namespace cryptonote
      * This function validates transaction inputs and their keys.  Previously
      * it also performed double spend checking, but that has been moved to its
      * own function.
+     * The transaction's rct signatures, if any, are expanded.
      *
      * If pmax_related_block_height is not NULL, its value is set to the height
      * of the most recent block which contains an output used in any input set
@@ -932,7 +934,7 @@ namespace cryptonote
      *
      * @return false if any validation step fails, otherwise true
      */
-    bool check_tx_inputs(const transaction& tx, tx_verification_context &tvc, uint64_t* pmax_used_block_height = NULL);
+    bool check_tx_inputs(transaction& tx, tx_verification_context &tvc, uint64_t* pmax_used_block_height = NULL);
 
     /**
      * @brief performs a blockchain reorganization according to the longest chain rule
@@ -1211,5 +1213,14 @@ namespace cryptonote
      * a useful state.
      */
     void load_compiled_in_block_hashes();
+
+    /**
+     * @brief expands v2 transaction data from blockchain
+     *
+     * RingCT transactions do not transmit some of their data if it
+     * can be reconstituted by the receiver. This function expands
+     * that implicit data.
+     */
+    bool expand_transaction_2(transaction &tx, const crypto::hash &tx_prefix_hash, const std::vector<std::vector<rct::ctkey>> &pubkeys);
   };
 }  // namespace cryptonote