From bc173c30ea824a7dc13f07a288c84f58d562dbcb Mon Sep 17 00:00:00 2001
From: yarkin <yarkin.who@gmail.com>
Date: Wed, 9 Aug 2023 16:48:37 +0800
Subject: [PATCH] Optimze logic when processing tx with special signature.

---
 src/actions.cpp      | 49 ++++++++++++++++++++++----------------------
 tests/call_tests.cpp |  4 ++--
 2 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/src/actions.cpp b/src/actions.cpp
index 898d0602..91b792c2 100644
--- a/src/actions.cpp
+++ b/src/actions.cpp
@@ -220,39 +220,38 @@ Receipt evm_contract::execute_tx( eosio::name miner, Block& block, Transaction&
         inevm.emplace(get_self(), get_self().value);
     };
 
-    bool is_special_signature = (tx.r == intx::uint256());
+    bool is_special_signature = silkworm::is_special_signature(tx.r, tx.s);
 
     tx.from.reset();
     tx.recover_sender();
     eosio::check(tx.from.has_value(), "unable to recover sender");
     LOGTIME("EVM RECOVER SENDER");
 
-    // type 1: normal signature (normal address recovered from normal signature), required !from_self 
-    // type 2: special signature (r == 0), reserved address (stored in s), required from_self + reduce special balance
-    // type 3: special signature (r == 0), normal address (stored in s), required from_self
-    if(from_self) {
-        check(is_special_signature, "actions from self without a special signature are unexpected");
-        if (is_reserved_address(*tx.from)) {
-            const name ingress_account(*extract_reserved_address(*tx.from));
-
-            const intx::uint512 max_gas_cost = intx::uint256(tx.gas_limit) * tx.max_fee_per_gas;
-            check(max_gas_cost + tx.value < std::numeric_limits<intx::uint256>::max(), "too much gas");
-            const intx::uint256 value_with_max_gas = tx.value + (intx::uint256)max_gas_cost;
-
-            populate_bridge_accessors();
-            balance_table.modify(balance_table.get(ingress_account.value), eosio::same_payer, [&](balance& b){
-                b.balance -= value_with_max_gas;
-            });
-            inevm->set(inevm->get() += value_with_max_gas, eosio::same_payer);
+    // 1 Reject special signature NOT from self.
+    // 2 All other cases (normal signature or special signature from self) will be accepted.
+    // 3 If the from address is reserved address, the special balance needs some process.
+    check(from_self || !is_special_signature, "bridge signature used outside of bridge transaction");
+    
+    if (is_reserved_address(*tx.from)) {
+        const name ingress_account(*extract_reserved_address(*tx.from));
 
-            ep.state().set_balance(*tx.from, value_with_max_gas);
-            ep.state().set_nonce(*tx.from, tx.nonce);
-        }
+        const intx::uint512 max_gas_cost = intx::uint256(tx.gas_limit) * tx.max_fee_per_gas;
+        check(max_gas_cost + tx.value < std::numeric_limits<intx::uint256>::max(), "too much gas");
+        const intx::uint256 value_with_max_gas = tx.value + (intx::uint256)max_gas_cost;
+
+        populate_bridge_accessors();
+        balance_table.modify(balance_table.get(ingress_account.value), eosio::same_payer, [&](balance& b){
+            b.balance -= value_with_max_gas;
+        });
+        inevm->set(inevm->get() += value_with_max_gas, eosio::same_payer);
+
+        ep.state().set_balance(*tx.from, value_with_max_gas);
+        ep.state().set_nonce(*tx.from, tx.nonce);
     }
-    else if(is_special_signature)
-        check(false, "bridge signature used outside of bridge transaction");
 
-    if(enforce_chain_id && !from_self) {
+    // A tx from self with regular signature can potentially from external source. 
+    // Therefore, only tx with special signature can waive the chain_id check.
+    if(enforce_chain_id && !is_special_signature) {
         check(tx.chain_id.has_value(), "tx without chain-id");
     }
 
@@ -277,7 +276,7 @@ Receipt evm_contract::execute_tx( eosio::name miner, Block& block, Transaction&
     }
 
     if(from_self)
-        eosio::check(receipt.success, "inline actions must succeed");
+        eosio::check(receipt.success, "tx executed inline by contract must succeed");
 
     if(!ep.state().reserved_objects().empty()) {
         bool non_open_account_sent = false;
diff --git a/tests/call_tests.cpp b/tests/call_tests.cpp
index f1fd36e2..b01f8306 100644
--- a/tests/call_tests.cpp
+++ b/tests/call_tests.cpp
@@ -155,7 +155,7 @@ BOOST_FIXTURE_TEST_CASE(call_test_function, call_evm_tester) try {
   auto total_fund2 = intx::uint256(vault_balance("alice"_n)) + intx::uint256(vault_balance("evm"_n));
 
   BOOST_REQUIRE_EXCEPTION(call_test(token_addr, 0, "alice"_n, "alice"_n),
-                          eosio_assert_message_exception, eosio_assert_message_is("inline actions must succeed"));
+                          eosio_assert_message_exception, eosio_assert_message_is("tx executed inline by contract must succeed"));
 
 
   // Call and check results 
@@ -230,7 +230,7 @@ BOOST_FIXTURE_TEST_CASE(admincall_test_function, call_evm_tester) try {
 
 
   BOOST_REQUIRE_EXCEPTION(admincall_test(token_addr, 0, evm2, "evm"_n),
-                          eosio_assert_message_exception, eosio_assert_message_is("inline actions must succeed"));
+                          eosio_assert_message_exception, eosio_assert_message_is("tx executed inline by contract must succeed"));
 
   // Call and check results  
   admincall_test(token_addr, 1234, evm2, "evm"_n);