Merge pull request #6 from matter-labs/vb-keccak-precompile

keccak precompile

Author: vladbochok

contracts/Keccak256.sol

@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+pragma solidity ^0.8.0;
+
+import './SystemContractHelper.sol';
+
+/**
+ * @author Matter Labs
+ */
+contract Keccak256 {
+    uint256 constant PERMANENT_ERGS_COST = 100;
+    uint256 constant INTERNAL_KECCAK_ROUND_ERGS_COST = 100;
+    uint256 constant MAX_PREIMAGE_BYTES_LENGTH = 1024;
+    uint256 constant BLOCK_SIZE = 136;
+    uint32 constant INPUT_OFFSET_IN_WORDS = 0;
+    uint32 constant OUTPUT_OFFSET_IN_WORDS = 0;
+    uint32 constant OUTPUT_LENGTH_IN_WORDS = 1;
+
+    fallback() external {
+		address codeAddress = SystemContractHelper.getCodeAddress();
+		// Check that we are NOT in delegatecall
+		require(codeAddress == address(this));
+
+        uint256 bytesSize;
+
+        assembly {
+            bytesSize := calldatasize()
+        }
+
+        require(bytesSize <= MAX_PREIMAGE_BYTES_LENGTH);
+
+        uint256 padLen = BLOCK_SIZE - bytesSize % BLOCK_SIZE;
+        uint256 paddedByteSize = bytesSize + padLen;
+        assert(paddedByteSize % BLOCK_SIZE == 0); // can deleted later one
+        uint64 numRounds = uint64(paddedByteSize / BLOCK_SIZE);
+
+        // manual memory copy and management, as we do not care about Solidity allocations
+        uint32 inputLengthInWords = uint32(paddedByteSize / 32);
+        if (paddedByteSize % 32 != 0) {
+			unchecked {
+				inputLengthInWords += 1;
+			}
+        }
+
+    
+        assembly {
+            calldatacopy(0x00, 0x00, bytesSize)
+        }
+
+        if (padLen == 1) {
+            // write 0x81 at the end
+            assembly {
+                mstore(add(bytesSize, 1), 0x8100000000000000000000000000000000000000000000000000000000000000) // we do not care about what is after
+            }
+        } else {
+            assembly {
+                mstore(add(bytesSize, 1), 0x0100000000000000000000000000000000000000000000000000000000000000)
+                mstore(sub(paddedByteSize, 1), 0x8000000000000000000000000000000000000000000000000000000000000000)
+            }
+        }
+
+        uint256 precompileParams = SystemContractHelper.packPrecompileParams(
+            INPUT_OFFSET_IN_WORDS,
+            inputLengthInWords,
+            OUTPUT_OFFSET_IN_WORDS,
+            OUTPUT_LENGTH_IN_WORDS,
+            numRounds
+        );
+
+        uint256 ergsToPay = PERMANENT_ERGS_COST + INTERNAL_KECCAK_ROUND_ERGS_COST * uint256(numRounds);
+        bool success = SystemContractHelper.precompileCall(precompileParams, uint32(ergsToPay));
+        require(success);
+
+        assembly {
+            return(0, 32)
+        }
+    }
+}

contracts/SystemContractHelper.sol

@@ -58,24 +58,34 @@ library SystemContractHelper {
         }
     }
 
-    // Call precompile with given parameters.
-    // The list of currently available precompiles sha256, keccak256, ecrecover, deployer.
-    // NOTE: The precompile type depends on `this` which calls precompile, which means that only
-    // system contracts corresponding to the list of precompiles above can do `precompileCall`.
-    function precompileCall(PrecompileCall memory _params, uint32 _ergsToBurn) internal view {
-        address callAddr = PRECOMPILE_CALL_ADDRESS;
-        uint256 rawParams = _params.inputMemoryOffset;
-        rawParams |= uint256(_params.inputMemoryLength) << 32;
-        rawParams |= uint256(_params.outputMemoryOffset) << 64;
-        rawParams |= uint256(_params.outputMemoryLength) << 96;
-        
-        // After `precompileCall` ergs will be burned down to 0 if there are not enough of them,
-        // thats why it should be checked before the call.
-        require(gasleft() >= _ergsToBurn);
-        assembly {
-            let success := staticcall(rawParams, callAddr, _ergsToBurn, 0, 0, 0)
-        }
-    }
+	function packPrecompileParams(
+		uint32 inputMemoryOffset,
+		uint32 inputMemoryLength,
+		uint32 outputMemoryOffset,
+		uint32 outputMemoryLength,
+        uint64 perPrecompileInterpreted
+	) external pure returns (uint256 rawParams) {
+		rawParams = inputMemoryOffset;
+		rawParams |= uint256(inputMemoryLength) << 32;
+		rawParams |= uint256(outputMemoryOffset) << 64;
+		rawParams |= uint256(outputMemoryLength) << 96;
+        rawParams |= uint256(perPrecompileInterpreted) << 192;
+	}
+
+	// Call precompile with given parameters.
+	// The list of currently available precompiles sha256, keccak256, ecrecover, deployer.
+	// NOTE: The precompile type depends on `this` which calls precompile, which means that only
+	// system contracts corresponding to the list of precompiles above can do `precompileCall`.
+	function precompileCall(uint256 _rawParams, uint32 _ergsToBurn) internal view returns (bool success) {
+		address callAddr = PRECOMPILE_CALL_ADDRESS;
+
+		// After `precompileCall` ergs will be burned down to 0 if there are not enough of them,
+		// thats why it should be checked before the call.
+		require(gasleft() >= _ergsToBurn);
+		assembly {
+			success := staticcall(_rawParams, callAddr, _ergsToBurn, 0, 0, 0)
+		}
+	}
 
     // Allows to perform a call with a custom `msg.sender`.
     function mimicCall(