From 6bead9bdc2d1409d82bcae2785c5e3122c74769d Mon Sep 17 00:00:00 2001
From: Andrei Maiboroda <andrei@ethereum.org>
Date: Wed, 4 Sep 2019 12:04:08 +0200
Subject: [PATCH] EIP-2200 implementation: throw OOG for SSTORE with gas below
 stipend

---
 lib/evmone/analysis.cpp           |  1 +
 lib/evmone/instructions.cpp       |  8 ++++++++
 test/unittests/evm_state_test.cpp | 20 ++++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/lib/evmone/analysis.cpp b/lib/evmone/analysis.cpp
index 4b6c202aa7..40a1a3fbd3 100644
--- a/lib/evmone/analysis.cpp
+++ b/lib/evmone/analysis.cpp
@@ -160,6 +160,7 @@ code_analysis analyze(
             break;
 
         case OP_GAS:
+        case OP_SSTORE:
             instr.arg.p.number = block->gas_cost;
             break;
 
diff --git a/lib/evmone/instructions.cpp b/lib/evmone/instructions.cpp
index 351c713262..051d5930ec 100644
--- a/lib/evmone/instructions.cpp
+++ b/lib/evmone/instructions.cpp
@@ -491,6 +491,14 @@ const instr_info* op_sstore(const instr_info* instr, execution_state& state) noe
     if (state.msg->flags & EVMC_STATIC)
         return state.exit(EVMC_STATIC_MODE_VIOLATION);
 
+    if (state.rev >= EVMC_ISTANBUL)
+    {
+        const auto correction = state.current_block_cost - instr->arg.p.number;
+        const auto gas_left = state.gas_left + correction;
+        if (gas_left <= 2300)
+            return state.exit(EVMC_OUT_OF_GAS);
+    }
+
     const auto key = intx::be::store<evmc::bytes32>(state.stack.pop());
     const auto value = intx::be::store<evmc::bytes32>(state.stack.pop());
     auto status = state.host.set_storage(state.msg->destination, key, value);
diff --git a/test/unittests/evm_state_test.cpp b/test/unittests/evm_state_test.cpp
index 8550175f18..0cfa0c2059 100644
--- a/test/unittests/evm_state_test.cpp
+++ b/test/unittests/evm_state_test.cpp
@@ -164,6 +164,26 @@ TEST_F(evm_state, sstore_cost)
     }
 }
 
+TEST_F(evm_state, sstore_below_stipend)
+{
+    const auto code = sstore(0, 0);
+
+    rev = EVMC_HOMESTEAD;
+    execute(2306, code);
+    EXPECT_EQ(result.status_code, EVMC_OUT_OF_GAS);
+
+    rev = EVMC_CONSTANTINOPLE;
+    execute(2306, code);
+    EXPECT_EQ(result.status_code, EVMC_SUCCESS);
+
+    rev = EVMC_ISTANBUL;
+    execute(2306, code);
+    EXPECT_EQ(result.status_code, EVMC_OUT_OF_GAS);
+
+    execute(2307, code);
+    EXPECT_EQ(result.status_code, EVMC_SUCCESS);
+}
+
 TEST_F(evm_state, tx_context)
 {
     host.tx_context.block_timestamp = 0xdd;