Upgrade hevm

flake.nix

@@ -28,7 +28,8 @@
         # TODO: maybe only override it for echidna-redistributable?
         pkgsStatic = if pkgs.stdenv.hostPlatform.isLinux then pkgs.pkgsStatic else pkgs;
         # this is not perfect for development as it hardcodes solc to 0.5.7, test suite runs fine though
-        solc = solc-pkgs.mkDefault pkgs pkgs.solc_0_5_7;
+        # 0.5.7 is not available on aarch64 darwin so alternatively pick 0.8.5
+        solc = solc-pkgs.mkDefault pkgs (pkgs.solc_0_5_7 or pkgs.solc_0_8_5);
 
         secp256k1-static = pkgsStatic.secp256k1.overrideAttrs (attrs: {
           configureFlags = attrs.configureFlags ++ [ "--enable-static" ];
@@ -51,8 +52,8 @@
         hevm = pkgs: pkgs.lib.pipe ((hsPkgs pkgs).callCabal2nix "hevm" (pkgs.fetchFromGitHub {
           owner = "ethereum";
           repo = "hevm";
-          rev = "c779777d18c8ff60867f009d434b44ce08188e01";
-          sha256 = "sha256-JnJUZ9AxhxTP+TBMThksh0D4R6KFdzjgu1+fBeBERws=";
+          rev = "f1f45d3c0d9767a38df04f398d1eab8b66dbe7fc";
+          sha256 = "sha256-3zEUwcZm4uZZLecvFTgVTV5CAm4qMfKPbLdwO88LnrY=";
         }) { secp256k1 = pkgs.secp256k1; })
         ([
           pkgs.haskell.lib.compose.dontCheck

lib/Echidna/Exec.hs

@@ -20,7 +20,8 @@ import Data.Maybe (fromMaybe, fromJust)
 import Data.Text qualified as T
 import Data.Vector qualified as V
 import Data.Vector.Unboxed.Mutable qualified as VMut
-import System.Process (readProcessWithExitCode)
+import System.Environment (lookupEnv, getEnvironment)
+import System.Process qualified as P
 
 import EVM (bytecode, replaceCodeOfSelf, loadContract, exec1, vmOpIx, clearTStorages)
 import EVM.ABI
@@ -178,13 +179,21 @@ execTxWith executeTx tx = do
         runFully -- resume execution
 
       -- Execute a FFI call
-      Just (PleaseDoFFI (cmd : args) continuation) -> do
-        (_, stdout, _) <- liftIO $ readProcessWithExitCode cmd args ""
+      Just (PleaseDoFFI (cmd : args) envs continuation) -> do
+        existingEnv <- liftIO getEnvironment
+        let mergedEnv = Map.toList $ Map.union envs $ Map.fromList existingEnv
+        let process = (P.proc cmd args) { P.env = Just mergedEnv }
+        (_, stdout, _) <- liftIO $ P.readCreateProcessWithExitCode process ""
         let encodedResponse = encodeAbiValue $
               AbiTuple (V.fromList [AbiBytesDynamic . hexText . T.pack $ stdout])
         fromEVM (continuation encodedResponse)
         runFully
 
+      Just (PleaseReadEnv var continuation) -> do
+        value <- liftIO $ lookupEnv var
+        fromEVM (continuation $ fromMaybe "" value)
+        runFully -- resume execution
+
       -- No queries to answer, the tx is fully executed and the result is final
       _ -> pure vmResult
 

lib/Echidna/SymExec.hs

@@ -136,6 +136,7 @@ vmMakeSymbolic vm
   , forks          = vm.forks
   , currentFork    = vm.currentFork
   , labels         = vm.labels
+  , osEnv          = vm.osEnv
   }
 
 frameStateMakeSymbolic :: FrameState Concrete s -> FrameState Symbolic s

lib/Echidna/Test.hs

@@ -271,12 +271,12 @@ checkAssertionEvent = any (T.isPrefixOf "AssertionFailed(")
 
 checkSelfDestructedTarget :: Addr -> DappInfo -> VM Concrete RealWorld -> TestValue
 checkSelfDestructedTarget addr _ vm =
-  let selfdestructs' = vm.tx.substate.selfdestructs
+  let selfdestructs' = vm.tx.subState.selfdestructs
   in BoolValue $ LitAddr addr `notElem` selfdestructs'
 
 checkAnySelfDestructed :: DappInfo -> VM Concrete RealWorld -> TestValue
 checkAnySelfDestructed _ vm =
-  BoolValue $ null vm.tx.substate.selfdestructs
+  BoolValue $ null vm.tx.subState.selfdestructs
 
 checkPanicEvent :: T.Text -> Events -> Bool
 checkPanicEvent n = any (T.isPrefixOf ("Panic(" <> n <> ")"))

lib/Echidna/Transaction.hs

@@ -36,7 +36,7 @@ import Echidna.Types.World (World(..))
 import Echidna.Types.Campaign
 
 hasSelfdestructed :: VM Concrete s -> Addr -> Bool
-hasSelfdestructed vm addr = LitAddr addr `elem` vm.tx.substate.selfdestructs
+hasSelfdestructed vm addr = LitAddr addr `elem` vm.tx.subState.selfdestructs
 
 -- | If half a tuple is zero, make both halves zero. Useful for generating
 -- delays, since block number only goes up with timestamp

src/test/Tests/Cheat.hs

@@ -9,6 +9,10 @@ import Echidna.Types.Campaign (WorkerType(..))
 cheatTests :: TestTree
 cheatTests =
   testGroup "Cheatcodes Tests"
-    [ testContract' "cheat/ffi.sol" (Just "TestFFI") (Just (> solcV (0,6,0))) (Just "cheat/ffi.yaml") False FuzzWorker
+    [ testContract' "cheat/ffi.sol" (Just "TestFFI") (Just (> solcV (0,5,0))) (Just "cheat/ffi.yaml") False FuzzWorker
         [ ("echidna_ffi passed", solved "echidna_ffi") ]
+    , testContract' "cheat/ffi2.sol" (Just "TestFFI") (Just (> solcV (0,5,0))) (Just "cheat/ffi.yaml") False FuzzWorker
+        [ ("echidna_ffi passed", solved "echidna_ffi") ]
+    , testContract' "cheat/gas.sol" (Just "TestCheatGas") (Just (> solcV (0,5,0))) (Just "cheat/ffi.yaml") False FuzzWorker
+        [ ("echidna_gas_zero passed", solved "echidna_gas_zero") ]
     ]

stack.yaml

@@ -5,7 +5,7 @@ packages:
 
 extra-deps:
 - git: https://github.com/ethereum/hevm.git
-  commit: c779777d18c8ff60867f009d434b44ce08188e01
+  commit: f1f45d3c0d9767a38df04f398d1eab8b66dbe7fc
 
 - smt2-parser-0.1.0.1@sha256:1e1a4565915ed851c13d1e6b8bb5185cf5d454da3b43170825d53e221f753d77,1421
 - spawn-0.3@sha256:b91e01d8f2b076841410ae284b32046f91471943dc799c1af77d666c72101f02,1162

tests/solidity/cheat/ffi2.sol

@@ -0,0 +1,31 @@
+pragma experimental ABIEncoderV2;
+
+interface Hevm {
+  function setEnv(string calldata, string calldata) external;
+  function ffi(string[] calldata) external returns (bytes memory);
+}
+
+contract TestFFI {
+  address constant HEVM_ADDRESS = 0x7109709ECfa91a80626fF3989D68f67F5b1DD12D;
+
+  bytes32 hehe;
+
+  function foo(int x) external {
+    // ABI encoded "gm", as a string
+    Hevm(HEVM_ADDRESS).setEnv("ECHIDNA_FOO_BAR", "0x00000000000000000000000000000000000000000000000000000000000000200000000000000000000000000000000000000000000000000000000000000002676d000000000000000000000000000000000000000000000000000000000000");
+
+    string[] memory inputs = new string[](3);
+    inputs[0] = "sh";
+    inputs[1] = "-c";
+    inputs[2] = "printf '%s' \"$ECHIDNA_FOO_BAR\"";
+
+    bytes memory res = Hevm(HEVM_ADDRESS).ffi(inputs);
+
+    (string memory output) = abi.decode(res, (string));
+    hehe = keccak256(bytes(output));
+  }
+
+  function echidna_ffi() public returns (bool){
+    return hehe != keccak256("gm");
+  }
+}

tests/solidity/cheat/gas.sol

@@ -0,0 +1,46 @@
+pragma experimental ABIEncoderV2;
+
+interface Hevm {
+  function assume(bool) external;
+}
+
+contract C {
+  address public calledContract;
+
+  constructor() public {
+    calledContract = 0x7109709ECfa91a80626fF3989D68f67F5b1DD12D;
+  }
+
+  function foo() public returns (uint256) {
+        assembly {
+            mstore(0x80, 0x4c63e562) 
+            mstore(0xa0, 1)
+
+            let addr := sload(0 /* calledContract.slot */)
+            let beforegas := gas()
+            let success := callcode(gas(), addr, 0, 0x9c, 0x24, 0, 0)
+            let aftergas := gas()
+            mstore(0x80, sub(beforegas, aftergas))
+            return(0x80, 0x20)
+        }
+  }
+}
+
+contract TestCheatGas {
+  uint256 spent = 123456;
+  C foo;
+
+  constructor() public {
+    foo = new C();
+  }
+
+  function bar() public {
+    spent = foo.foo();
+  }
+
+  function echidna_gas_zero() public returns (bool){
+    // 0x14 as measured from opcodes, but let's leave some leeway in case solc changes
+    // GAS PUSH1 0x0 DUP1 PUSH1 0x24 PUSH1 0x9C PUSH1 0x0 DUP7 GAS CALLCODE GAS
+    return spent > 0x20;
+  }
+}