Add check for range in blockHash op

Fantom-foundation · May 14, 2024 · b2f4b5e · b2f4b5e
1 parent 4ad0e2b
commit b2f4b5e
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Showing 2 changed files with 35 additions and 5 deletions.
diff --git a/cpp/vm/evmzero/interpreter.cc b/cpp/vm/evmzero/interpreter.cc
@@ -865,7 +865,18 @@ struct Impl<OpCode::BLOCKHASH> {
 
   static OpResult Run(uint256_t* top, Context& ctx) noexcept {
     int64_t number = static_cast<int64_t>(top[0]);
-    top[0] = ToUint256(ctx.host->get_block_hash(number));
+    int64_t upper, lower;
+    upper = int64_t(ctx.host->get_tx_context().block_number);
+    if (upper < 257) {
+      lower = 0;
+    } else {
+      lower = upper - 256;
+    }
+    if (number >= lower && number < upper) {
+      top[0] = ToUint256(ctx.host->get_block_hash(number));
+    } else {
+      top[0] = 0;
+    }
     return {};
   }
 };
@@ -1701,7 +1712,6 @@ inline OpResult Invoke(uint256_t* top, const uint8_t*, int64_t gas, Context& ctx
 ///////////////////////////////////////////////////////////
 
 namespace internal {
-
 inline bool Context::CheckJumpDest(uint256_t index_u256) noexcept {
   if (index_u256[1] != 0 || index_u256[2] != 0 || index_u256[3] != 0) [[unlikely]] {
     state = RunState::kErrorJump;

diff --git a/cpp/vm/evmzero/interpreter_test.cc b/cpp/vm/evmzero/interpreter_test.cc
@@ -2834,9 +2834,12 @@ TEST(InterpreterTest, EXTCODEHASH_StackError) {
 
 ///////////////////////////////////////////////////////////
 // BLOCKHASH
-TEST(InterpreterTest, BLOCKHASH) {
+TEST(InterpreterTest, BLOCKHASH_inRange) {
   MockHost host;
-  EXPECT_CALL(host, get_block_hash(21))  //
+  EXPECT_CALL(host, get_tx_context())  //
+      .Times(1)
+      .WillOnce(Return(evmc_tx_context{.block_number = 1000}));
+  EXPECT_CALL(host, get_block_hash(900))  //
       .Times(1)
       .WillOnce(Return(evmc::bytes32(0x0a0b0c0d)));
 
@@ -2845,12 +2848,29 @@ TEST(InterpreterTest, BLOCKHASH) {
       .state_after = RunState::kDone,
       .gas_before = 40,
       .gas_after = 20,
-      .stack_before = {21},
+      .stack_before = {900},
       .stack_after = {0x0a0b0c0d},
       .host = &host,
   });
 }
 
+TEST(InterpreterTest, BLOCKHASH_outOfRange) {
+  MockHost host;
+  EXPECT_CALL(host, get_tx_context())  //
+      .Times(1)
+      .WillOnce(Return(evmc_tx_context{.block_number = 1000}));
+
+  RunInterpreterTest({
+      .code = {op::BLOCKHASH},
+      .state_after = RunState::kDone,
+      .gas_before = 40,
+      .gas_after = 20,
+      .stack_before = {500},
+      .stack_after = {0},
+      .host = &host,
+  });
+}
+
 TEST(InterpreterTest, BLOCKHASH_OutOfGas) {
   RunInterpreterTest({
       .code = {op::BLOCKHASH},