From 124efa26686efc937f0ab0ee3b7645ca232aae1f Mon Sep 17 00:00:00 2001
From: Andrew Chow <achow101-github@achow101.com>
Date: Wed, 9 Dec 2020 12:31:29 -0500
Subject: [PATCH] Return better errors for BlindingStatus

---
 src/blindpsbt.cpp        | 21 +++++++++++++++++++++
 src/blindpsbt.h          |  2 ++
 src/wallet/rpcwallet.cpp | 10 ++++++----
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/src/blindpsbt.cpp b/src/blindpsbt.cpp
index 800aeab0e6..55ad807710 100644
--- a/src/blindpsbt.cpp
+++ b/src/blindpsbt.cpp
@@ -12,6 +12,27 @@
 #include <random.h>
 #include <util/system.h>
 
+std::string GetBlindingStatusError(const BlindingStatus& status)
+{
+    switch(status) {
+    case BlindingStatus::OK:
+        return "No error";
+    case BlindingStatus::NEEDS_UTXOS:
+        return "Inputs are missing UTXOs (or peg-in data for peg-in inputs)";
+    case BlindingStatus::INVALID_ASSET:
+        return "Provided asset tag is invalid";
+    case BlindingStatus::INVALID_ASSET_COMMITMENT:
+        return "Provided asset commitment is invalid";
+    case BlindingStatus::SCALAR_UNABLE:
+        return "Unable to compute the scalars for the final blinder";
+    case BlindingStatus::INVALID_BLINDER:
+        return "Computed blinding factor is invalid";
+    case BlindingStatus::ASP_UNABLE:
+        return "Unable to create an asset surjection proof";
+    }
+    assert(false);
+}
+
 // Create surjection proof
 bool CreateAssetSurjectionProof(std::vector<unsigned char>& output_proof, const std::vector<secp256k1_fixed_asset_tag>& fixed_input_tags, const std::vector<secp256k1_generator>& ephemeral_input_tags, const std::vector<uint256>& input_asset_blinders, const uint256& output_asset_blinder, const secp256k1_generator& output_asset_tag, const CAsset& asset)
 {
diff --git a/src/blindpsbt.h b/src/blindpsbt.h
index aa62663450..8e08e9a719 100644
--- a/src/blindpsbt.h
+++ b/src/blindpsbt.h
@@ -28,6 +28,8 @@ enum class BlindingStatus
     ASP_UNABLE,
 };
 
+std::string GetBlindingStatusError(const BlindingStatus& status);
+
 bool CreateAssetSurjectionProof(std::vector<unsigned char>& output_proof, const std::vector<secp256k1_fixed_asset_tag>& fixed_input_tags, const std::vector<secp256k1_generator>& ephemeral_input_tags, const std::vector<uint256>& input_asset_blinders, const uint256& output_asset_blinder, const secp256k1_generator& output_asset_tag, const CAsset& asset);
 uint256 GenerateRangeproofECDHKey(CPubKey& ephemeral_pubkey, const CPubKey blinding_pubkey);
 bool CreateValueRangeProof(std::vector<unsigned char>& rangeproof, const uint256& value_blinder, const uint256& nonce, const CAmount amount, const CScript& scriptPubKey, const secp256k1_pedersen_commitment& value_commit, const secp256k1_generator& gen, const CAsset& asset, const uint256& asset_blinder);
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 0ca0813e48..34a78f0701 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -4813,8 +4813,9 @@ static RPCHelpMan walletprocesspsbt()
         }
     }
     if (needs_blinding) {
-        if (pwallet->WalletBlindPSBT(psbtx) != BlindingStatus::OK) {
-            throw JSONRPCError(RPC_WALLET_ERROR, "Something went wrong");
+        BlindingStatus status = pwallet->WalletBlindPSBT(psbtx);
+        if (status != BlindingStatus::OK) {
+            throw JSONRPCError(RPC_WALLET_ERROR, GetBlindingStatusError(status));
         }
     }
 
@@ -4873,8 +4874,9 @@ static RPCHelpMan walletblindpsbt()
         throw JSONRPCError(RPC_DESERIALIZATION_ERROR, strprintf("TX decode failed %s", error));
     }
 
-    if (pwallet->WalletBlindPSBT(psbtx) != BlindingStatus::OK) {
-        throw JSONRPCError(RPC_WALLET_ERROR, "Something went wrong");
+    BlindingStatus status = pwallet->WalletBlindPSBT(psbtx);
+    if (status != BlindingStatus::OK) {
+        throw JSONRPCError(RPC_WALLET_ERROR, GetBlindingStatusError(status));
     }
 
     UniValue result(UniValue::VOBJ);