hevm-0.50.0: src/EVM.hs
{-# Language ImplicitParams #-}
{-# Language DataKinds #-}
{-# Language GADTs #-}
{-# Language StrictData #-}
{-# Language TemplateHaskell #-}
module EVM where
import Prelude hiding (log, exponent, GT, LT)
import Data.Text (unpack)
import Data.Text.Encoding (decodeUtf8, encodeUtf8)
import EVM.ABI
import EVM.Types hiding (IllegalOverflow)
import EVM.Solidity
import EVM.Concrete (createAddress, create2Address)
import EVM.Op
import EVM.Expr (readStorage, writeStorage, readByte, readWord, writeWord, writeByte, bufLength, indexWord, litAddr, readBytes, word256At, copySlice, isLitByte)
import EVM.FeeSchedule (FeeSchedule (..))
import Options.Generic as Options
import qualified EVM.Precompiled
import qualified EVM.Expr as Expr
import Control.Lens hiding (op, (:<), (|>), (.>))
import Control.Monad.State.Strict hiding (state)
import Data.ByteString (ByteString)
import Data.ByteString.Lazy (fromStrict)
import Data.Map.Strict (Map)
import Data.Set (Set, insert, member, fromList)
import Data.Maybe (fromMaybe)
import Data.Sequence (Seq)
import Data.Vector.Storable (Vector)
import Data.Foldable (toList)
import Data.Word (Word8, Word32, Word64)
import Data.Bits (FiniteBits, countLeadingZeros, finiteBitSize)
import Data.Tree
import Data.Tuple.Curry
import Data.List (find)
import qualified Data.ByteString as BS
import qualified Data.ByteString.Lazy as LS
import qualified Data.ByteString.Char8 as Char8
import qualified Data.ByteArray as BA
import qualified Data.Map.Strict as Map
import qualified Data.Sequence as Seq
import qualified Data.Tree.Zipper as Zipper
import qualified Data.Vector as V
import qualified Data.Vector.Storable as Vector
import qualified Data.Vector.Storable.Mutable as Vector
import qualified Data.Vector as RegularVector
import Crypto.Number.ModArithmetic (expFast)
import qualified Crypto.Hash as Crypto
import Crypto.Hash (Digest, SHA256, RIPEMD160, digestFromByteString)
import Crypto.PubKey.ECC.ECDSA (signDigestWith, PrivateKey(..), Signature(..))
import Crypto.PubKey.ECC.Types (getCurveByName, CurveName(..), Point(..))
import Crypto.PubKey.ECC.Generate (generateQ)
import Data.DoubleWord (Word256(Word256), Word128 (Word128))
-- * Data types
-- | EVM failure modes
data Error
= BalanceTooLow W256 W256
| UnrecognizedOpcode Word8
| SelfDestruction
| StackUnderrun
| BadJumpDestination
| Revert (Expr Buf)
| OutOfGas Word64 Word64
| BadCheatCode (Maybe Word32)
| StackLimitExceeded
| IllegalOverflow
| Query Query
| Choose Choose
| StateChangeWhileStatic
| InvalidMemoryAccess
| CallDepthLimitReached
| MaxCodeSizeExceeded W256 W256
| InvalidFormat
| PrecompileFailure
| forall a . UnexpectedSymbolicArg Int String [Expr a]
| DeadPath
| NotUnique (Expr EWord)
| SMTTimeout
| FFI [AbiValue]
| NonceOverflow
deriving instance Show Error
-- | The possible result states of a VM
data VMResult
= VMFailure Error -- ^ An operation failed
| VMSuccess (Expr Buf) -- ^ Reached STOP, RETURN, or end-of-code
deriving instance Show VMResult
-- | The state of a stepwise EVM execution
data VM = VM
{ _result :: Maybe VMResult
, _state :: FrameState
, _frames :: [Frame]
, _env :: Env
, _block :: Block
, _tx :: TxState
, _logs :: [Expr Log]
, _traces :: Zipper.TreePos Zipper.Empty Trace
, _cache :: Cache
, _burned :: Word64
, _iterations :: Map CodeLocation Int
, _constraints :: [Prop]
, _keccakEqs :: [Prop]
, _allowFFI :: Bool
}
deriving (Show)
data Trace = Trace
{ _traceOpIx :: Int
, _traceContract :: Contract
, _traceData :: TraceData
}
deriving (Show)
data TraceData
= EventTrace (Expr EWord) (Expr Buf) [Expr EWord]
| FrameTrace FrameContext
| QueryTrace Query
| ErrorTrace Error
| EntryTrace Text
| ReturnTrace (Expr Buf) FrameContext
deriving (Show)
-- | Queries halt execution until resolved through RPC calls or SMT queries
data Query where
PleaseFetchContract :: Addr -> (Contract -> EVM ()) -> Query
--PleaseMakeUnique :: SBV a -> [SBool] -> (IsUnique a -> EVM ()) -> Query
PleaseFetchSlot :: Addr -> W256 -> (W256 -> EVM ()) -> Query
PleaseAskSMT :: Expr EWord -> [Prop] -> (BranchCondition -> EVM ()) -> Query
PleaseDoFFI :: [String] -> (ByteString -> EVM ()) -> Query
data Choose where
PleaseChoosePath :: Expr EWord -> (Bool -> EVM ()) -> Choose
instance Show Query where
showsPrec _ = \case
PleaseFetchContract addr _ ->
(("<EVM.Query: fetch contract " ++ show addr ++ ">") ++)
PleaseFetchSlot addr slot _ ->
(("<EVM.Query: fetch slot "
++ show slot ++ " for "
++ show addr ++ ">") ++)
PleaseAskSMT condition constraints _ ->
(("<EVM.Query: ask SMT about "
++ show condition ++ " in context "
++ show constraints ++ ">") ++)
-- PleaseMakeUnique val constraints _ ->
-- (("<EVM.Query: make value "
-- ++ show val ++ " unique in context "
-- ++ show constraints ++ ">") ++)
PleaseDoFFI cmd _ ->
(("<EVM.Query: do ffi: " ++ (show cmd)) ++)
instance Show Choose where
showsPrec _ = \case
PleaseChoosePath _ _ ->
(("<EVM.Choice: waiting for user to select path (0,1)") ++)
-- | Alias for the type of e.g. @exec1@.
type EVM a = State VM a
type CodeLocation = (Addr, Int)
-- | The possible return values of a SMT query
data BranchCondition = Case Bool | Unknown | Inconsistent
deriving Show
-- | The possible return values of a `is unique` SMT query
data IsUnique a = Unique a | Multiple | InconsistentU | TimeoutU
deriving Show
-- | The cache is data that can be persisted for efficiency:
-- any expensive query that is constant at least within a block.
data Cache = Cache
{ _fetchedContracts :: Map Addr Contract,
_fetchedStorage :: Map W256 (Map W256 W256),
_path :: Map (CodeLocation, Int) Bool
} deriving Show
data StorageBase = Concrete | Symbolic
deriving (Show, Eq)
-- | A way to specify an initial VM state
data VMOpts = VMOpts
{ vmoptContract :: Contract
, vmoptCalldata :: (Expr Buf, [Prop])
, vmoptStorageBase :: StorageBase
, vmoptValue :: Expr EWord
, vmoptPriorityFee :: W256
, vmoptAddress :: Addr
, vmoptCaller :: Expr EWord
, vmoptOrigin :: Addr
, vmoptGas :: Word64
, vmoptGaslimit :: Word64
, vmoptNumber :: W256
, vmoptTimestamp :: Expr EWord
, vmoptCoinbase :: Addr
, vmoptPrevRandao :: W256
, vmoptMaxCodeSize :: W256
, vmoptBlockGaslimit :: Word64
, vmoptGasprice :: W256
, vmoptBaseFee :: W256
, vmoptSchedule :: FeeSchedule Word64
, vmoptChainId :: W256
, vmoptCreate :: Bool
, vmoptTxAccessList :: Map Addr [W256]
, vmoptAllowFFI :: Bool
} deriving Show
-- | An entry in the VM's "call/create stack"
data Frame = Frame
{ _frameContext :: FrameContext
, _frameState :: FrameState
}
deriving (Show)
-- | Call/create info
data FrameContext
= CreationContext
{ creationContextAddress :: Addr
, creationContextCodehash :: Expr EWord
, creationContextReversion :: Map Addr Contract
, creationContextSubstate :: SubState
}
| CallContext
{ callContextTarget :: Addr
, callContextContext :: Addr
, callContextOffset :: W256
, callContextSize :: W256
, callContextCodehash :: Expr EWord
, callContextAbi :: Maybe W256
, callContextData :: Expr Buf
, callContextReversion :: (Map Addr Contract, Expr Storage)
, callContextSubState :: SubState
}
deriving (Show)
-- | The "registers" of the VM along with memory and data stack
data FrameState = FrameState
{ _contract :: Addr
, _codeContract :: Addr
, _code :: ContractCode
, _pc :: Int
, _stack :: [Expr EWord]
, _memory :: Expr Buf
, _memorySize :: Word64
, _calldata :: Expr Buf
, _callvalue :: Expr EWord
, _caller :: Expr EWord
, _gas :: Word64
, _returndata :: Expr Buf
, _static :: Bool
}
deriving (Show)
-- | The state that spans a whole transaction
data TxState = TxState
{ _gasprice :: W256
, _txgaslimit :: Word64
, _txPriorityFee :: W256
, _origin :: Addr
, _toAddr :: Addr
, _value :: Expr EWord
, _substate :: SubState
, _isCreate :: Bool
, _txReversion :: Map Addr Contract
}
deriving (Show)
-- | The "accrued substate" across a transaction
data SubState = SubState
{ _selfdestructs :: [Addr]
, _touchedAccounts :: [Addr]
, _accessedAddresses :: Set Addr
, _accessedStorageKeys :: Set (Addr, W256)
, _refunds :: [(Addr, Word64)]
-- in principle we should include logs here, but do not for now
}
deriving (Show)
{- |
A contract is either in creation (running its "constructor") or
post-creation, and code in these two modes is treated differently
by instructions like @EXTCODEHASH@, so we distinguish these two
code types.
The definition follows the structure of code output by solc. We need to use
some heuristics here to deal with symbolic data regions that may be present
in the bytecode since the fully abstract case is impractical:
- initcode has concrete code, followed by an abstract data "section"
- runtimecode has a fixed length, but may contain fixed size symbolic regions (due to immutable)
hopefully we do not have to deal with dynamic immutable before we get a real data section...
-}
data ContractCode
= InitCode ByteString (Expr Buf) -- ^ "Constructor" code, during contract creation
| RuntimeCode (V.Vector (Expr Byte)) -- ^ "Instance" code, after contract creation
deriving (Show)
-- runtime err when used for symbolic code
instance Eq ContractCode where
(InitCode a b) == (InitCode c d) = a == c && b == d
(RuntimeCode x) == (RuntimeCode y) = x == y
_ == _ = False
deriving instance Ord ContractCode
-- | A contract can either have concrete or symbolic storage
-- depending on what type of execution we are doing
-- data Storage
-- = Concrete (Map Word Expr EWord)
-- | Symbolic [(Expr EWord, Expr EWord)] (SArray (WordN 256) (WordN 256))
-- deriving (Show)
-- to allow for Eq Contract (which useful for debugging vmtests)
-- we mock an instance of Eq for symbolic storage.
-- It should not (cannot) be used though.
-- instance Eq Storage where
-- (==) (Concrete a) (Concrete b) = fmap forceLit a == fmap forceLit b
-- (==) (Symbolic _ _) (Concrete _) = False
-- (==) (Concrete _) (Symbolic _ _) = False
-- (==) _ _ = error "do not compare two symbolic arrays like this!"
-- | The state of a contract
data Contract = Contract
{ _contractcode :: ContractCode
, _balance :: W256
, _nonce :: W256
, _codehash :: Expr EWord
, _opIxMap :: Vector Int
, _codeOps :: RegularVector.Vector (Int, Op)
, _external :: Bool
}
deriving instance Show Contract
-- | When doing symbolic execution, we have three different
-- ways to model the storage of contracts. This determines
-- not only the initial contract storage model but also how
-- RPC or state fetched contracts will be modeled.
data StorageModel
= ConcreteS -- ^ Uses `Concrete` Storage. Reading / Writing from abstract
-- locations causes a runtime failure. Can be nicely combined with RPC.
| SymbolicS -- ^ Uses `Symbolic` Storage. Reading / Writing never reaches RPC,
-- but always done using an SMT array with no default value.
| InitialS -- ^ Uses `Symbolic` Storage. Reading / Writing never reaches RPC,
-- but always done using an SMT array with 0 as the default value.
deriving (Read, Show)
instance ParseField StorageModel
-- | Various environmental data
data Env = Env
{ _contracts :: Map Addr Contract
, _chainId :: W256
, _storage :: Expr Storage
, _origStorage :: Map W256 (Map W256 W256)
, _sha3Crack :: Map W256 ByteString
--, _keccakUsed :: [([SWord 8], SWord 256)]
}
deriving (Show)
-- | Data about the block
data Block = Block
{ _coinbase :: Addr
, _timestamp :: Expr EWord
, _number :: W256
, _prevRandao :: W256
, _gaslimit :: Word64
, _baseFee :: W256
, _maxCodeSize :: W256
, _schedule :: FeeSchedule Word64
} deriving Show
blankState :: FrameState
blankState = FrameState
{ _contract = 0
, _codeContract = 0
, _code = RuntimeCode mempty
, _pc = 0
, _stack = mempty
, _memory = mempty
, _memorySize = 0
, _calldata = mempty
, _callvalue = (Lit 0)
, _caller = (Lit 0)
, _gas = 0
, _returndata = mempty
, _static = False
}
makeLenses ''FrameState
makeLenses ''Frame
makeLenses ''Block
makeLenses ''TxState
makeLenses ''SubState
makeLenses ''Contract
makeLenses ''Env
makeLenses ''Cache
makeLenses ''Trace
makeLenses ''VM
-- | An "external" view of a contract's bytecode, appropriate for
-- e.g. @EXTCODEHASH@.
bytecode :: Getter Contract (Expr Buf)
bytecode = contractcode . to f
where f (InitCode _ _) = mempty
f (RuntimeCode ops) = Expr.fromList ops
instance Semigroup Cache where
a <> b = Cache
{ _fetchedContracts = Map.unionWith unifyCachedContract (view fetchedContracts a) (view fetchedContracts b)
, _fetchedStorage = Map.unionWith unifyCachedStorage (view fetchedStorage a) (view fetchedStorage b)
, _path = mappend (view path a) (view path b)
}
unifyCachedStorage :: Map W256 W256 -> Map W256 W256 -> Map W256 W256
unifyCachedStorage _ _ = undefined
-- only intended for use in Cache merges, where we expect
-- everything to be Concrete
unifyCachedContract :: Contract -> Contract -> Contract
unifyCachedContract _ _ = undefined
{-
unifyCachedContract a b = a & set storage merged
where merged = case (view storage a, view storage b) of
(ConcreteStore sa, ConcreteStore sb) ->
ConcreteStore (mappend sa sb)
_ ->
view storage a
-}
instance Monoid Cache where
mempty = Cache { _fetchedContracts = mempty,
_fetchedStorage = mempty,
_path = mempty
}
-- * Data accessors
currentContract :: VM -> Maybe Contract
currentContract vm =
view (env . contracts . at (view (state . codeContract) vm)) vm
-- * Data constructors
makeVm :: VMOpts -> VM
makeVm o =
let txaccessList = vmoptTxAccessList o
txorigin = vmoptOrigin o
txtoAddr = vmoptAddress o
initialAccessedAddrs = fromList $ [txorigin, txtoAddr] ++ [1..9] ++ (Map.keys txaccessList)
initialAccessedStorageKeys = fromList $ foldMap (uncurry (map . (,))) (Map.toList txaccessList)
touched = if vmoptCreate o then [txorigin] else [txorigin, txtoAddr]
in
VM
{ _result = Nothing
, _frames = mempty
, _tx = TxState
{ _gasprice = vmoptGasprice o
, _txgaslimit = vmoptGaslimit o
, _txPriorityFee = vmoptPriorityFee o
, _origin = txorigin
, _toAddr = txtoAddr
, _value = vmoptValue o
, _substate = SubState mempty touched initialAccessedAddrs initialAccessedStorageKeys mempty
--, _accessList = txaccessList
, _isCreate = vmoptCreate o
, _txReversion = Map.fromList
[(vmoptAddress o, vmoptContract o)]
}
, _logs = []
, _traces = Zipper.fromForest []
, _block = Block
{ _coinbase = vmoptCoinbase o
, _timestamp = vmoptTimestamp o
, _number = vmoptNumber o
, _prevRandao = vmoptPrevRandao o
, _maxCodeSize = vmoptMaxCodeSize o
, _gaslimit = vmoptBlockGaslimit o
, _baseFee = vmoptBaseFee o
, _schedule = vmoptSchedule o
}
, _state = FrameState
{ _pc = 0
, _stack = mempty
, _memory = mempty
, _memorySize = 0
, _code = view contractcode $ vmoptContract o
, _contract = vmoptAddress o
, _codeContract = vmoptAddress o
, _calldata = fst $ vmoptCalldata o
, _callvalue = vmoptValue o
, _caller = vmoptCaller o
, _gas = vmoptGas o
, _returndata = mempty
, _static = False
}
, _env = Env
{ _sha3Crack = mempty
, _chainId = vmoptChainId o
, _storage = if vmoptStorageBase o == Concrete then EmptyStore else AbstractStore
, _origStorage = mempty
, _contracts = Map.fromList
[(vmoptAddress o, vmoptContract o)]
--, _keccakUsed = mempty
--, _storageModel = vmoptStorageModel o
}
, _cache = Cache mempty mempty mempty
, _burned = 0
, _constraints = snd $ vmoptCalldata o
, _keccakEqs = mempty
, _iterations = mempty
, _allowFFI = vmoptAllowFFI o
}
-- | Initialize empty contract with given code
initialContract :: ContractCode -> Contract
initialContract theContractCode = Contract
{ _contractcode = theContractCode
, _codehash = hashcode theContractCode
, _balance = 0
, _nonce = if creation then 1 else 0
, _opIxMap = mkOpIxMap theContractCode
, _codeOps = mkCodeOps theContractCode
, _external = False
} where
creation = case theContractCode of
InitCode _ _ -> True
RuntimeCode _ -> False
-- * Opcode dispatch (exec1)
-- | Update program counter
next :: (?op :: Word8) => EVM ()
next = modifying (state . pc) (+ (opSize ?op))
-- | Executes the EVM one step
exec1 :: EVM ()
exec1 = do
vm <- get
let
-- Convenience function to access parts of the current VM state.
-- Arcane type signature needed to avoid monomorphism restriction.
the :: (b -> VM -> Const a VM) -> ((a -> Const a a) -> b) -> a
the f g = view (f . g) vm
-- Convenient aliases
mem = the state memory
stk = the state stack
self = the state contract
this = fromMaybe (error "internal error: state contract") (preview (ix self) (the env contracts))
fees@FeeSchedule {..} = the block schedule
doStop = finishFrame (FrameReturned mempty)
if self > 0x0 && self <= 0x9 then do
-- call to precompile
let ?op = 0x00 -- dummy value
case bufLength (the state calldata) of
(Lit calldatasize) -> do
copyBytesToMemory (the state calldata) (Lit calldatasize) (Lit 0) (Lit 0)
executePrecompile self (the state gas) 0 calldatasize 0 0 []
vmx <- get
case view (state.stack) vmx of
(x:_) -> case x of
Lit (num -> x' :: Integer) -> case x' of
0 -> do
fetchAccount self $ \_ -> do
touchAccount self
vmError PrecompileFailure
_ -> fetchAccount self $ \_ -> do
touchAccount self
out <- use (state . returndata)
finishFrame (FrameReturned out)
e -> vmError $
UnexpectedSymbolicArg (view (state . pc) vmx) "precompile returned a symbolic value" [e]
_ ->
underrun
e -> vmError $ UnexpectedSymbolicArg (the state pc) "cannot call precompiles with symbolic data" [e]
else if the state pc >= opslen (the state code)
then doStop
else do
let ?op = case (the state code) of
InitCode conc _ -> BS.index conc (the state pc)
RuntimeCode ops ->
fromMaybe (error "could not analyze symbolic code") $
unlitByte $ ops V.! the state pc
case ?op of
-- op: PUSH
x | x >= 0x60 && x <= 0x7f -> do
let !n = num x - 0x60 + 1
!xs = case the state code of
InitCode conc _ -> Lit $ word $ padRight n $ BS.take n (BS.drop (1 + the state pc) conc)
RuntimeCode ops ->
let bytes = V.take n $ V.drop (1 + the state pc) ops
in if all isLitByte bytes then -- optimize concrete path
let litBytes = V.toList $ V.catMaybes $ unlitByte <$> bytes
padded = BS.replicate (32 - length litBytes) 0 <> BS.pack litBytes
in Lit $ word padded
else readWord (Lit 0) $ Expr.fromList $ padLeft' 32 bytes
limitStack 1 $
burn g_verylow $ do
next
pushSym xs
-- op: DUP
x | x >= 0x80 && x <= 0x8f -> do
let !i = x - 0x80 + 1
case preview (ix (num i - 1)) stk of
Nothing -> underrun
Just y ->
limitStack 1 $
burn g_verylow $ do
next
pushSym y
-- op: SWAP
x | x >= 0x90 && x <= 0x9f -> do
let i = num (x - 0x90 + 1)
if length stk < i + 1
then underrun
else
burn g_verylow $ do
next
zoom (state . stack) $ do
assign (ix 0) (stk ^?! ix i)
assign (ix i) (stk ^?! ix 0)
-- op: LOG
x | x >= 0xa0 && x <= 0xa4 ->
notStatic $
let n = (num x - 0xa0) in
case stk of
(xOffset':xSize':xs) ->
if length xs < n
then underrun
else
forceConcrete2 (xOffset', xSize') "LOG" $ \(xOffset, xSize) -> do
let (topics, xs') = splitAt n xs
bytes = readMemory xOffset' xSize' vm
logs' = (LogEntry (litAddr self) bytes topics) : (view logs vm)
burn (g_log + g_logdata * (num xSize) + num n * g_logtopic) $
accessMemoryRange fees xOffset xSize $ do
traceTopLog logs'
next
assign (state . stack) xs'
assign logs logs'
_ ->
underrun
-- op: STOP
0x00 -> doStop
-- op: ADD
0x01 -> stackOp2 (const g_verylow) (uncurry Expr.add)
-- op: MUL
0x02 -> stackOp2 (const g_low) (uncurry Expr.mul)
-- op: SUB
0x03 -> stackOp2 (const g_verylow) (uncurry Expr.sub)
-- op: DIV
0x04 -> stackOp2 (const g_low) (uncurry Expr.div)
-- op: SDIV
0x05 -> stackOp2 (const g_low) (uncurry Expr.sdiv)
-- op: MOD
0x06 -> stackOp2 (const g_low) (uncurry Expr.mod)
-- op: SMOD
0x07 -> stackOp2 (const g_low) (uncurry Expr.smod)
-- op: ADDMOD
0x08 -> stackOp3 (const g_mid) (uncurryN Expr.addmod)
-- op: MULMOD
0x09 -> stackOp3 (const g_mid) (uncurryN Expr.mulmod)
-- op: LT
0x10 -> stackOp2 (const g_verylow) (uncurry Expr.lt)
-- op: GT
0x11 -> stackOp2 (const g_verylow) (uncurry Expr.gt)
-- op: SLT
0x12 -> stackOp2 (const g_verylow) (uncurry Expr.slt)
-- op: SGT
0x13 -> stackOp2 (const g_verylow) (uncurry Expr.sgt)
-- op: EQ
0x14 -> stackOp2 (const g_verylow) (uncurry Expr.eq)
-- op: ISZERO
0x15 -> stackOp1 (const g_verylow) Expr.iszero
-- op: AND
0x16 -> stackOp2 (const g_verylow) (uncurry Expr.and)
-- op: OR
0x17 -> stackOp2 (const g_verylow) (uncurry Expr.or)
-- op: XOR
0x18 -> stackOp2 (const g_verylow) (uncurry Expr.xor)
-- op: NOT
0x19 -> stackOp1 (const g_verylow) Expr.not
-- op: BYTE
0x1a -> stackOp2 (const g_verylow) (\(i, w) -> Expr.padByte $ Expr.indexWord i w)
-- op: SHL
0x1b -> stackOp2 (const g_verylow) (uncurry Expr.shl)
-- op: SHR
0x1c -> stackOp2 (const g_verylow) (uncurry Expr.shr)
-- op: SAR
0x1d -> stackOp2 (const g_verylow) (uncurry Expr.sar)
-- op: SHA3
-- more accurately refered to as KECCAK
0x20 ->
case stk of
(xOffset' : xSize' : xs) ->
forceConcrete xOffset' "sha3 offset must be concrete" $
\xOffset -> forceConcrete xSize' "sha3 size must be concrete" $ \xSize ->
burn (g_sha3 + g_sha3word * ceilDiv (num xSize) 32) $
accessMemoryRange fees xOffset xSize $ do
(hash, invMap) <- case readMemory xOffset' xSize' vm of
ConcreteBuf bs -> do
let hash' = keccak' bs
eqs <- use keccakEqs
assign keccakEqs $ PEq (Lit hash') (Keccak (ConcreteBuf bs)):eqs
pure (Lit hash', Map.singleton hash' bs)
buf -> pure (Keccak buf, mempty)
next
assign (state . stack) (hash : xs)
(env . sha3Crack) <>= invMap
_ -> underrun
-- op: ADDRESS
0x30 ->
limitStack 1 $
burn g_base (next >> push (num self))
-- op: BALANCE
0x31 ->
case stk of
(x':xs) -> forceConcrete x' "BALANCE" $ \x ->
accessAndBurn (num x) $
fetchAccount (num x) $ \c -> do
next
assign (state . stack) xs
push (num $ view balance c)
[] ->
underrun
-- op: ORIGIN
0x32 ->
limitStack 1 . burn g_base $
next >> push (num (the tx origin))
-- op: CALLER
0x33 ->
limitStack 1 . burn g_base $
next >> pushSym (the state caller)
-- op: CALLVALUE
0x34 ->
limitStack 1 . burn g_base $
next >> pushSym (the state callvalue)
-- op: CALLDATALOAD
0x35 -> stackOp1 (const g_verylow) $
\ind -> Expr.readWord ind (the state calldata)
-- op: CALLDATASIZE
0x36 ->
limitStack 1 . burn g_base $
next >> pushSym (bufLength (the state calldata))
-- op: CALLDATACOPY
0x37 ->
case stk of
(xTo' : xFrom : xSize' : xs) ->
forceConcrete2 (xTo', xSize') "CALLDATACOPY" $
\(xTo, xSize) ->
burn (g_verylow + g_copy * ceilDiv (num xSize) 32) $
accessMemoryRange fees xTo xSize $ do
next
assign (state . stack) xs
copyBytesToMemory (the state calldata) xSize' xFrom xTo'
_ -> underrun
-- op: CODESIZE
0x38 ->
limitStack 1 . burn g_base $
next >> pushSym (codelen (the state code))
-- op: CODECOPY
0x39 ->
case stk of
(memOffset' : codeOffset : n' : xs) ->
forceConcrete2 (memOffset', n') "CODECOPY" $
\(memOffset,n) -> do
case toWord64 n of
Nothing -> vmError IllegalOverflow
Just n'' ->
if n'' <= ( (maxBound :: Word64) - g_verylow ) `div` g_copy * 32 then
burn (g_verylow + g_copy * ceilDiv (num n) 32) $
accessMemoryRange fees memOffset n $ do
next
assign (state . stack) xs
copyBytesToMemory (toBuf $ the state code) n' codeOffset memOffset'
else vmError IllegalOverflow
_ -> underrun
-- op: GASPRICE
0x3a ->
limitStack 1 . burn g_base $
next >> push (the tx gasprice)
-- op: EXTCODESIZE
0x3b ->
case stk of
(x':xs) -> case x' of
(Lit x) -> if x == num cheatCode
then do
next
assign (state . stack) xs
pushSym (Lit 1)
else
accessAndBurn (num x) $
fetchAccount (num x) $ \c -> do
next
assign (state . stack) xs
pushSym (bufLength (view bytecode c))
_ -> do
assign (state . stack) xs
pushSym (CodeSize x')
[] ->
underrun
-- op: EXTCODECOPY
0x3c ->
case stk of
( extAccount'
: memOffset'
: codeOffset
: codeSize'
: xs ) ->
forceConcrete3 (extAccount', memOffset', codeSize') "EXTCODECOPY" $
\(extAccount, memOffset, codeSize) -> do
acc <- accessAccountForGas (num extAccount)
let cost = if acc then g_warm_storage_read else g_cold_account_access
burn (cost + g_copy * ceilDiv (num codeSize) 32) $
accessMemoryRange fees memOffset codeSize $
fetchAccount (num extAccount) $ \c -> do
next
assign (state . stack) xs
copyBytesToMemory (view bytecode c) codeSize' codeOffset memOffset'
_ -> underrun
-- op: RETURNDATASIZE
0x3d ->
limitStack 1 . burn g_base $
next >> pushSym (bufLength (the state returndata))
-- op: RETURNDATACOPY
0x3e ->
case stk of
(xTo' : xFrom : xSize' :xs) -> forceConcrete2 (xTo', xSize') "RETURNDATACOPY" $
\(xTo, xSize) ->
burn (g_verylow + g_copy * ceilDiv (num xSize) 32) $
accessMemoryRange fees xTo xSize $ do
next
assign (state . stack) xs
let jump True = vmError EVM.InvalidMemoryAccess
jump False = copyBytesToMemory (the state returndata) xSize' xFrom xTo'
case (xFrom, bufLength (the state returndata)) of
(Lit f, Lit l) ->
jump $ l < f + xSize || f + xSize < f
_ -> do
let oob = Expr.lt (bufLength $ the state returndata) (Expr.add xFrom xSize')
overflow = Expr.lt (Expr.add xFrom xSize') (xFrom)
loc <- codeloc
branch loc (Expr.or oob overflow) jump
_ -> underrun
-- op: EXTCODEHASH
0x3f ->
case stk of
(x':xs) -> forceConcrete x' "EXTCODEHASH" $ \x ->
accessAndBurn (num x) $ do
next
assign (state . stack) xs
fetchAccount (num x) $ \c ->
if accountEmpty c
then push (num (0 :: Int))
else pushSym $ keccak (view bytecode c)
[] ->
underrun
-- op: BLOCKHASH
0x40 -> do
-- We adopt the fake block hash scheme of the VMTests,
-- so that blockhash(i) is the hash of i as decimal ASCII.
stackOp1 (const g_blockhash) $ \case
(Lit i) -> if i + 256 < the block number || i >= the block number
then Lit 0
else (num i :: Integer) & show & Char8.pack & keccak' & Lit
i -> BlockHash i
-- op: COINBASE
0x41 ->
limitStack 1 . burn g_base $
next >> push (num (the block coinbase))
-- op: TIMESTAMP
0x42 ->
limitStack 1 . burn g_base $
next >> pushSym (the block timestamp)
-- op: NUMBER
0x43 ->
limitStack 1 . burn g_base $
next >> push (the block number)
-- op: PREVRANDAO
0x44 -> do
limitStack 1 . burn g_base $
next >> push (the block prevRandao)
-- op: GASLIMIT
0x45 ->
limitStack 1 . burn g_base $
next >> push (num $ the block gaslimit)
-- op: CHAINID
0x46 ->
limitStack 1 . burn g_base $
next >> push (the env chainId)
-- op: SELFBALANCE
0x47 ->
limitStack 1 . burn g_low $
next >> push (view balance this)
-- op: BASEFEE
0x48 ->
limitStack 1 . burn g_base $
next >> push (the block baseFee)
-- op: POP
0x50 ->
case stk of
(_:xs) -> burn g_base (next >> assign (state . stack) xs)
_ -> underrun
-- op: MLOAD
0x51 ->
case stk of
(x':xs) -> forceConcrete x' "MLOAD" $ \x ->
burn g_verylow $
accessMemoryWord fees x $ do
next
assign (state . stack) (readWord (Lit x) mem : xs)
_ -> underrun
-- op: MSTORE
0x52 ->
case stk of
(x':y:xs) -> forceConcrete x' "MSTORE index" $ \x ->
burn g_verylow $
accessMemoryWord fees x $ do
next
assign (state . memory) (writeWord (Lit x) y mem)
assign (state . stack) xs
_ -> underrun
-- op: MSTORE8
0x53 ->
case stk of
(x':y:xs) -> forceConcrete x' "MSTORE8" $ \x ->
burn g_verylow $
accessMemoryRange fees x 1 $ do
let yByte = indexWord (Lit 31) y
next
modifying (state . memory) (writeByte (Lit x) yByte)
assign (state . stack) xs
_ -> underrun
-- op: SLOAD
0x54 ->
case stk of
(x:xs) -> do
acc <- accessStorageForGas self x
let cost = if acc then g_warm_storage_read else g_cold_sload
burn cost $
accessStorage self x $ \y -> do
next
assign (state . stack) (y:xs)
_ -> underrun
-- op: SSTORE
0x55 ->
notStatic $
case stk of
(x:new:xs) ->
accessStorage self x $ \current -> do
availableGas <- use (state . gas)
if num availableGas <= g_callstipend
then finishFrame (FrameErrored (OutOfGas availableGas (num g_callstipend)))
else do
let original = case readStorage (litAddr self) x (ConcreteStore $ the env origStorage) of
Just (Lit v) -> v
_ -> 0
let storage_cost = case (maybeLitWord current, maybeLitWord new) of
(Just current', Just new') ->
if (current' == new') then g_sload
else if (current' == original) && (original == 0) then g_sset
else if (current' == original) then g_sreset
else g_sload
-- if any of the arguments are symbolic,
-- assume worst case scenario
_ -> g_sset
acc <- accessStorageForGas self x
let cold_storage_cost = if acc then 0 else g_cold_sload
burn (storage_cost + cold_storage_cost) $ do
next
assign (state . stack) xs
modifying (env . storage)
(writeStorage (litAddr self) x new)
case (maybeLitWord current, maybeLitWord new) of
(Just current', Just new') ->
unless (current' == new') $
if current' == original
then when (original /= 0 && new' == 0) $
refund (g_sreset + g_access_list_storage_key)
else do
when (original /= 0) $
if new' == 0
then refund (g_sreset + g_access_list_storage_key)
else unRefund (g_sreset + g_access_list_storage_key)
when (original == new') $
if original == 0
then refund (g_sset - g_sload)
else refund (g_sreset - g_sload)
-- if any of the arguments are symbolic,
-- don't change the refund counter
_ -> noop
_ -> underrun
-- op: JUMP
0x56 ->
case stk of
(x:xs) ->
burn g_mid $ forceConcrete x "JUMP: symbolic jumpdest" $ \x' ->
checkJump x' xs
_ -> underrun
-- op: JUMPI
0x57 -> do
case stk of
(x:y:xs) -> forceConcrete x "JUMPI: symbolic jumpdest" $ \x' ->
burn g_high $
let jump :: Bool -> EVM ()
jump False = assign (state . stack) xs >> next
jump _ = checkJump x' xs
in case maybeLitWord y of
Just y' -> jump (0 /= y')
-- if the jump condition is symbolic, we explore both sides
Nothing -> do
loc <- codeloc
branch loc y jump
_ -> underrun
-- op: PC
0x58 ->
limitStack 1 . burn g_base $
next >> push (num (the state pc))
-- op: MSIZE
0x59 ->
limitStack 1 . burn g_base $
next >> push (num (the state memorySize))
-- op: GAS
0x5a ->
limitStack 1 . burn g_base $
next >> push (num (the state gas - g_base))
-- op: JUMPDEST
0x5b -> burn g_jumpdest next
-- op: EXP
0x0a ->
-- NOTE: this can be done symbolically using unrolling like this:
-- https://hackage.haskell.org/package/sbv-9.0/docs/src/Data.SBV.Core.Model.html#.%5E
-- However, it requires symbolic gas, since the gas depends on the exponent
case stk of
(base:exponent':xs) -> forceConcrete exponent' "EXP: symbolic exponent" $ \exponent ->
let cost = if exponent == 0
then g_exp
else g_exp + g_expbyte * num (ceilDiv (1 + log2 exponent) 8)
in burn cost $ do
next
state . stack .= Expr.exp base exponent' : xs
_ -> underrun
-- op: SIGNEXTEND
0x0b -> stackOp2 (const g_low) (uncurry Expr.sex)
-- op: CREATE
0xf0 ->
notStatic $
case stk of
(xValue' : xOffset' : xSize' : xs) -> forceConcrete3 (xValue', xOffset', xSize') "CREATE" $
\(xValue, xOffset, xSize) -> do
accessMemoryRange fees xOffset xSize $ do
availableGas <- use (state . gas)
let
newAddr = createAddress self (view nonce this)
(cost, gas') = costOfCreate fees availableGas 0
_ <- accessAccountForGas newAddr
burn (cost - gas') $ do
-- unfortunately we have to apply some (pretty hacky)
-- heuristics here to parse the unstructured buffer read
-- from memory into a code and data section
let initCode = readMemory xOffset' xSize' vm
create self this (num gas') xValue xs newAddr initCode
_ -> underrun
-- op: CALL
0xf1 ->
case stk of
( xGas'
: xTo
: xValue'
: xInOffset'
: xInSize'
: xOutOffset'
: xOutSize'
: xs
) -> forceConcrete6 (xGas', xValue', xInOffset', xInSize', xOutOffset', xOutSize') "CALL" $
\(xGas, xValue, xInOffset, xInSize, xOutOffset, xOutSize) ->
(if xValue > 0 then notStatic else id) $
delegateCall this (num xGas) xTo xTo xValue xInOffset xInSize xOutOffset xOutSize xs $ \callee -> do
zoom state $ do
assign callvalue (Lit xValue)
assign caller (litAddr self)
assign contract callee
transfer self callee xValue
touchAccount self
touchAccount callee
_ ->
underrun
-- op: CALLCODE
0xf2 ->
case stk of
( xGas'
: xTo
: xValue'
: xInOffset'
: xInSize'
: xOutOffset'
: xOutSize'
: xs
) -> forceConcrete6 (xGas', xValue', xInOffset', xInSize', xOutOffset', xOutSize') "CALLCODE" $
\(xGas, xValue, xInOffset, xInSize, xOutOffset, xOutSize) ->
delegateCall this (num xGas) xTo (litAddr self) xValue xInOffset xInSize xOutOffset xOutSize xs $ \_ -> do
zoom state $ do
assign callvalue (Lit xValue)
assign caller (litAddr self)
touchAccount self
_ ->
underrun
-- op: RETURN
0xf3 ->
case stk of
(xOffset' : xSize' :_) -> forceConcrete2 (xOffset', xSize') "RETURN" $ \(xOffset, xSize) ->
accessMemoryRange fees xOffset xSize $ do
let
output = readMemory xOffset' xSize' vm
codesize = fromMaybe (error "RETURN: cannot return dynamically sized abstract data")
. unlit . bufLength $ output
maxsize = the block maxCodeSize
creation = case view frames vm of
[] -> the tx isCreate
frame:_ -> case view frameContext frame of
CreationContext {} -> True
CallContext {} -> False
if creation
then
if codesize > maxsize
then
finishFrame (FrameErrored (MaxCodeSizeExceeded maxsize codesize))
else do
let frameReturned = burn (g_codedeposit * num codesize) $
finishFrame (FrameReturned output)
frameErrored = finishFrame $ FrameErrored InvalidFormat
case readByte (Lit 0) output of
LitByte 0xef -> frameErrored
LitByte _ -> frameReturned
y -> do
loc <- codeloc
branch loc (Expr.eqByte y (LitByte 0xef)) $ \case
True -> frameErrored
False -> frameReturned
else
finishFrame (FrameReturned output)
_ -> underrun
-- op: DELEGATECALL
0xf4 ->
case stk of
(xGas'
:xTo
:xInOffset'
:xInSize'
:xOutOffset'
:xOutSize'
:xs) -> forceConcrete5 (xGas', xInOffset', xInSize', xOutOffset', xOutSize') "DELEGATECALL" $
\(xGas, xInOffset, xInSize, xOutOffset, xOutSize) ->
delegateCall this (num xGas) xTo (litAddr self) 0 xInOffset xInSize xOutOffset xOutSize xs $ \_ -> do
touchAccount self
_ -> underrun
-- op: CREATE2
0xf5 -> notStatic $
case stk of
(xValue'
:xOffset'
:xSize'
:xSalt'
:xs) -> forceConcrete4 (xValue', xOffset', xSize', xSalt') "CREATE2" $
\(xValue, xOffset, xSize, xSalt) ->
accessMemoryRange fees xOffset xSize $ do
availableGas <- use (state . gas)
forceConcreteBuf (readMemory xOffset' xSize' vm) "CREATE2" $
\initCode -> do
let
newAddr = create2Address self xSalt initCode
(cost, gas') = costOfCreate fees availableGas xSize
_ <- accessAccountForGas newAddr
burn (cost - gas') $ create self this gas' xValue xs newAddr (ConcreteBuf initCode)
_ -> underrun
-- op: STATICCALL
0xfa ->
case stk of
(xGas'
:xTo
:xInOffset'
:xInSize'
:xOutOffset'
:xOutSize'
:xs) -> forceConcrete5 (xGas', xInOffset', xInSize', xOutOffset', xOutSize') "STATICCALL" $
\(xGas, xInOffset, xInSize, xOutOffset, xOutSize) -> do
delegateCall this (num xGas) xTo xTo 0 xInOffset xInSize xOutOffset xOutSize xs $ \callee -> do
zoom state $ do
assign callvalue (Lit 0)
assign caller (litAddr self)
assign contract callee
assign static True
touchAccount self
touchAccount callee
_ ->
underrun
-- op: SELFDESTRUCT
0xff ->
notStatic $
case stk of
[] -> underrun
(xTo':_) -> forceConcrete xTo' "SELFDESTRUCT" $ \(num -> xTo) -> do
acc <- accessAccountForGas (num xTo)
let cost = if acc then 0 else g_cold_account_access
funds = view balance this
recipientExists = accountExists xTo vm
c_new = if not recipientExists && funds /= 0
then g_selfdestruct_newaccount
else 0
burn (g_selfdestruct + c_new + cost) $ do
selfdestruct self
touchAccount xTo
if funds /= 0
then fetchAccount xTo $ \_ -> do
env . contracts . ix xTo . balance += funds
assign (env . contracts . ix self . balance) 0
doStop
else doStop
-- op: REVERT
0xfd ->
case stk of
(xOffset':xSize':_) -> forceConcrete2 (xOffset', xSize') "REVERT" $ \(xOffset, xSize) ->
accessMemoryRange fees xOffset xSize $ do
let output = readMemory xOffset' xSize' vm
finishFrame (FrameReverted output)
_ -> underrun
xxx ->
vmError (UnrecognizedOpcode xxx)
transfer :: Addr -> Addr -> W256 -> EVM ()
transfer xFrom xTo xValue =
zoom (env . contracts) $ do
ix xFrom . balance -= xValue
ix xTo . balance += xValue
-- | Checks a *CALL for failure; OOG, too many callframes, memory access etc.
callChecks
:: (?op :: Word8)
=> Contract -> Word64 -> Addr -> Addr -> W256 -> W256 -> W256 -> W256 -> W256 -> [Expr EWord]
-- continuation with gas available for call
-> (Word64 -> EVM ())
-> EVM ()
callChecks this xGas xContext xTo xValue xInOffset xInSize xOutOffset xOutSize xs continue = do
vm <- get
let fees = view (block . schedule) vm
accessMemoryRange fees xInOffset xInSize $
accessMemoryRange fees xOutOffset xOutSize $ do
availableGas <- use (state . gas)
let recipientExists = accountExists xContext vm
(cost, gas') <- costOfCall fees recipientExists xValue availableGas xGas xTo
burn (cost - gas') $ do
if xValue > num (view balance this)
then do
assign (state . stack) (Lit 0 : xs)
assign (state . returndata) mempty
pushTrace $ ErrorTrace $ BalanceTooLow xValue (view balance this)
next
else if length (view frames vm) >= 1024
then do
assign (state . stack) (Lit 0 : xs)
assign (state . returndata) mempty
pushTrace $ ErrorTrace CallDepthLimitReached
next
else continue gas'
precompiledContract
:: (?op :: Word8)
=> Contract
-> Word64
-> Addr
-> Addr
-> W256
-> W256 -> W256 -> W256 -> W256
-> [Expr EWord]
-> EVM ()
precompiledContract this xGas precompileAddr recipient xValue inOffset inSize outOffset outSize xs =
callChecks this xGas recipient precompileAddr xValue inOffset inSize outOffset outSize xs $ \gas' ->
do
executePrecompile precompileAddr gas' inOffset inSize outOffset outSize xs
self <- use (state . contract)
stk <- use (state . stack)
pc' <- use (state . pc)
case stk of
(x:_) -> case maybeLitWord x of
Just 0 ->
return ()
Just 1 ->
fetchAccount recipient $ \_ -> do
transfer self recipient xValue
touchAccount self
touchAccount recipient
_ -> vmError $ UnexpectedSymbolicArg pc' "symbolic return value from precompile" [x]
_ -> underrun
executePrecompile
:: (?op :: Word8)
=> Addr
-> Word64 -> W256 -> W256 -> W256 -> W256 -> [Expr EWord]
-> EVM ()
executePrecompile preCompileAddr gasCap inOffset inSize outOffset outSize xs = do
vm <- get
let input = readMemory (Lit inOffset) (Lit inSize) vm
fees = view (block . schedule) vm
cost = costOfPrecompile fees preCompileAddr input
notImplemented = error $ "precompile at address " <> show preCompileAddr <> " not yet implemented"
precompileFail = burn (gasCap - cost) $ do
assign (state . stack) (Lit 0 : xs)
pushTrace $ ErrorTrace PrecompileFailure
next
if cost > gasCap then
burn gasCap $ do
assign (state . stack) (Lit 0 : xs)
next
else
burn cost $
case preCompileAddr of
-- ECRECOVER
0x1 ->
-- TODO: support symbolic variant
forceConcreteBuf input "ECRECOVER" $ \input' ->
case EVM.Precompiled.execute 0x1 (truncpadlit 128 input') 32 of
Nothing -> do
-- return no output for invalid signature
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) mempty
next
Just output -> do
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) (ConcreteBuf output)
copyBytesToMemory (ConcreteBuf output) (Lit outSize) (Lit 0) (Lit outOffset)
next
-- SHA2-256
0x2 ->
let
hash = case input of
ConcreteBuf input' -> sha256Buf input'
_ -> WriteWord (Lit 0) (SHA256 input) mempty
sha256Buf x = ConcreteBuf $ BA.convert (Crypto.hash x :: Digest SHA256)
in do
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) hash
copyBytesToMemory hash (Lit outSize) (Lit 0) (Lit outOffset)
next
-- RIPEMD-160
0x3 ->
-- TODO: support symbolic variant
forceConcreteBuf input "RIPEMD160" $ \input' ->
let
padding = BS.pack $ replicate 12 0
hash' = BA.convert (Crypto.hash input' :: Digest RIPEMD160)
hash = ConcreteBuf $ padding <> hash'
in do
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) hash
copyBytesToMemory hash (Lit outSize) (Lit 0) (Lit outOffset)
next
-- IDENTITY
0x4 -> do
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) input
copyCallBytesToMemory input (Lit outSize) (Lit 0) (Lit outOffset)
next
-- MODEXP
0x5 ->
-- TODO: support symbolic variant
forceConcreteBuf input "MODEXP" $ \input' ->
let
(lenb, lene, lenm) = parseModexpLength input'
output = ConcreteBuf $
if isZero (96 + lenb + lene) lenm input'
then truncpadlit (num lenm) (asBE (0 :: Int))
else
let
b = asInteger $ lazySlice 96 lenb input'
e = asInteger $ lazySlice (96 + lenb) lene input'
m = asInteger $ lazySlice (96 + lenb + lene) lenm input'
in
padLeft (num lenm) (asBE (expFast b e m))
in do
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) output
copyBytesToMemory output (Lit outSize) (Lit 0) (Lit outOffset)
next
-- ECADD
0x6 ->
-- TODO: support symbolic variant
forceConcreteBuf input "ECADD" $ \input' ->
case EVM.Precompiled.execute 0x6 (truncpadlit 128 input') 64 of
Nothing -> precompileFail
Just output -> do
let truncpaddedOutput = ConcreteBuf $ truncpadlit 64 output
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) truncpaddedOutput
copyBytesToMemory truncpaddedOutput (Lit outSize) (Lit 0) (Lit outOffset)
next
-- ECMUL
0x7 ->
-- TODO: support symbolic variant
forceConcreteBuf input "ECMUL" $ \input' ->
case EVM.Precompiled.execute 0x7 (truncpadlit 96 input') 64 of
Nothing -> precompileFail
Just output -> do
let truncpaddedOutput = ConcreteBuf $ truncpadlit 64 output
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) truncpaddedOutput
copyBytesToMemory truncpaddedOutput (Lit outSize) (Lit 0) (Lit outOffset)
next
-- ECPAIRING
0x8 ->
-- TODO: support symbolic variant
forceConcreteBuf input "ECPAIR" $ \input' ->
case EVM.Precompiled.execute 0x8 input' 32 of
Nothing -> precompileFail
Just output -> do
let truncpaddedOutput = ConcreteBuf $ truncpadlit 32 output
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) truncpaddedOutput
copyBytesToMemory truncpaddedOutput (Lit outSize) (Lit 0) (Lit outOffset)
next
-- BLAKE2
0x9 ->
-- TODO: support symbolic variant
forceConcreteBuf input "BLAKE2" $ \input' -> do
case (BS.length input', 1 >= BS.last input') of
(213, True) -> case EVM.Precompiled.execute 0x9 input' 64 of
Just output -> do
let truncpaddedOutput = ConcreteBuf $ truncpadlit 64 output
assign (state . stack) (Lit 1 : xs)
assign (state . returndata) truncpaddedOutput
copyBytesToMemory truncpaddedOutput (Lit outSize) (Lit 0) (Lit outOffset)
next
Nothing -> precompileFail
_ -> precompileFail
_ -> notImplemented
truncpadlit :: Int -> ByteString -> ByteString
truncpadlit n xs = if m > n then BS.take n xs
else BS.append xs (BS.replicate (n - m) 0)
where m = BS.length xs
lazySlice :: W256 -> W256 -> ByteString -> LS.ByteString
lazySlice offset size bs =
let bs' = LS.take (num size) (LS.drop (num offset) (fromStrict bs))
in bs' <> LS.replicate ((num size) - LS.length bs') 0
parseModexpLength :: ByteString -> (W256, W256, W256)
parseModexpLength input =
let lenb = word $ LS.toStrict $ lazySlice 0 32 input
lene = word $ LS.toStrict $ lazySlice 32 64 input
lenm = word $ LS.toStrict $ lazySlice 64 96 input
in (lenb, lene, lenm)
--- checks if a range of ByteString bs starting at offset and length size is all zeros.
isZero :: W256 -> W256 -> ByteString -> Bool
isZero offset size bs =
LS.all (== 0) $
LS.take (num size) $
LS.drop (num offset) $
fromStrict bs
asInteger :: LS.ByteString -> Integer
asInteger xs = if xs == mempty then 0
else 256 * asInteger (LS.init xs)
+ num (LS.last xs)
-- * Opcode helper actions
noop :: Monad m => m ()
noop = pure ()
pushTo :: MonadState s m => ASetter s s [a] [a] -> a -> m ()
pushTo f x = f %= (x :)
pushToSequence :: MonadState s m => ASetter s s (Seq a) (Seq a) -> a -> m ()
pushToSequence f x = f %= (Seq.|> x)
getCodeLocation :: VM -> CodeLocation
getCodeLocation vm = (view (state . contract) vm, view (state . pc) vm)
branch :: CodeLocation -> Expr EWord -> (Bool -> EVM ()) -> EVM ()
branch loc cond continue = do
pathconds <- use constraints
assign result . Just . VMFailure . Query $ PleaseAskSMT cond pathconds choosePath
where
choosePath (Case v) = do assign result Nothing
pushTo constraints $ if v then (cond ./= (Lit 0)) else (cond .== (Lit 0))
iteration <- use (iterations . at loc . non 0)
assign (cache . path . at (loc, iteration)) (Just v)
assign (iterations . at loc) (Just (iteration + 1))
continue v
-- Both paths are possible; we ask for more input
choosePath Unknown = assign result . Just . VMFailure . Choose . PleaseChoosePath cond $ choosePath . Case
-- None of the paths are possible; fail this branch
choosePath Inconsistent = vmError DeadPath
-- | Construct RPC Query and halt execution until resolved
fetchAccount :: Addr -> (Contract -> EVM ()) -> EVM ()
fetchAccount addr continue =
use (env . contracts . at addr) >>= \case
Just c -> continue c
Nothing ->
use (cache . fetchedContracts . at addr) >>= \case
Just c -> do
assign (env . contracts . at addr) (Just c)
continue c
Nothing -> do
assign result . Just . VMFailure $ Query $
PleaseFetchContract addr
(\c -> do assign (cache . fetchedContracts . at addr) (Just c)
assign (env . contracts . at addr) (Just c)
assign result Nothing
continue c)
accessStorage
:: Addr -- ^ Contract address
-> Expr EWord -- ^ Storage slot key
-> (Expr EWord -> EVM ()) -- ^ Continuation
-> EVM ()
accessStorage addr slot continue = do
store <- use (env . storage)
use (env . contracts . at addr) >>= \case
Just c ->
case readStorage (litAddr addr) slot store of
-- Notice that if storage is symbolic, we always continue straight away
Just x ->
continue x
Nothing ->
if view external c
then
-- check if the slot is cached
use (cache . fetchedContracts . at addr) >>= \case
Nothing -> forceConcrete slot "cannot read symbolic slots via RPC" mkQuery
Just _ -> forceConcrete slot "cannot read symbolic slots via rpc" $
\s -> maybe (mkQuery s) continue (readStorage (litAddr addr) slot store)
else do
modifying (env . storage) (writeStorage (litAddr addr) slot (Lit 0))
continue $ Lit 0
Nothing ->
fetchAccount addr $ \_ ->
accessStorage addr slot continue
where
mkQuery s = assign result . Just . VMFailure . Query $
PleaseFetchSlot addr s
(\x -> do
modifying (cache . fetchedStorage . ix (num addr)) (Map.insert s x)
modifying (env . storage) (writeStorage (litAddr addr) slot (Lit x))
assign result Nothing
continue (Lit x))
accountExists :: Addr -> VM -> Bool
accountExists addr vm =
case view (env . contracts . at addr) vm of
Just c -> not (accountEmpty c)
Nothing -> False
-- EIP 161
accountEmpty :: Contract -> Bool
accountEmpty c =
case view contractcode c of
RuntimeCode b -> null b
_ -> False
&& (view nonce c == 0)
&& (view balance c == 0)
-- * How to finalize a transaction
finalize :: EVM ()
finalize = do
let
revertContracts = use (tx . txReversion) >>= assign (env . contracts)
revertSubstate = assign (tx . substate) (SubState mempty mempty mempty mempty mempty)
use result >>= \case
Nothing ->
error "Finalising an unfinished tx."
Just (VMFailure (EVM.Revert _)) -> do
revertContracts
revertSubstate
Just (VMFailure _) -> do
-- burn remaining gas
assign (state . gas) 0
revertContracts
revertSubstate
Just (VMSuccess output) -> do
-- deposit the code from a creation tx
pc' <- use (state . pc)
creation <- use (tx . isCreate)
createe <- use (state . contract)
createeExists <- (Map.member createe) <$> use (env . contracts)
case Expr.toList output of
Nothing -> vmError $ UnexpectedSymbolicArg pc' "runtime code cannot have an abstract lentgh" [output]
Just ops ->
when (creation && createeExists) $ replaceCode createe (RuntimeCode ops)
-- compute and pay the refund to the caller and the
-- corresponding payment to the miner
txOrigin <- use (tx . origin)
sumRefunds <- (sum . (snd <$>)) <$> (use (tx . substate . refunds))
miner <- use (block . coinbase)
blockReward <- num . r_block <$> (use (block . schedule))
gasPrice <- use (tx . gasprice)
priorityFee <- use (tx . txPriorityFee)
gasLimit <- use (tx . txgaslimit)
gasRemaining <- use (state . gas)
let
gasUsed = gasLimit - gasRemaining
cappedRefund = min (quot gasUsed 5) (num sumRefunds)
originPay = (num $ gasRemaining + cappedRefund) * gasPrice
minerPay = priorityFee * (num gasUsed)
modifying (env . contracts)
(Map.adjust (over balance (+ originPay)) txOrigin)
modifying (env . contracts)
(Map.adjust (over balance (+ minerPay)) miner)
touchAccount miner
-- pay out the block reward, recreating the miner if necessary
preuse (env . contracts . ix miner) >>= \case
Nothing -> modifying (env . contracts)
(Map.insert miner (initialContract (EVM.RuntimeCode mempty)))
Just _ -> noop
modifying (env . contracts)
(Map.adjust (over balance (+ blockReward)) miner)
-- perform state trie clearing (EIP 161), of selfdestructs
-- and touched accounts. addresses are cleared if they have
-- a) selfdestructed, or
-- b) been touched and
-- c) are empty.
-- (see Yellow Paper "Accrued Substate")
--
-- remove any destructed addresses
destroyedAddresses <- use (tx . substate . selfdestructs)
modifying (env . contracts)
(Map.filterWithKey (\k _ -> (k `notElem` destroyedAddresses)))
-- then, clear any remaining empty and touched addresses
touchedAddresses <- use (tx . substate . touchedAccounts)
modifying (env . contracts)
(Map.filterWithKey
(\k a -> not ((k `elem` touchedAddresses) && accountEmpty a)))
-- | Loads the selected contract as the current contract to execute
loadContract :: Addr -> EVM ()
loadContract target =
preuse (env . contracts . ix target . contractcode) >>=
\case
Nothing ->
error "Call target doesn't exist"
Just targetCode -> do
assign (state . contract) target
assign (state . code) targetCode
assign (state . codeContract) target
limitStack :: Int -> EVM () -> EVM ()
limitStack n continue = do
stk <- use (state . stack)
if length stk + n > 1024
then vmError EVM.StackLimitExceeded
else continue
notStatic :: EVM () -> EVM ()
notStatic continue = do
bad <- use (state . static)
if bad
then vmError StateChangeWhileStatic
else continue
-- | Burn gas, failing if insufficient gas is available
burn :: Word64 -> EVM () -> EVM ()
burn n continue = do
available <- use (state . gas)
if n <= available
then do
state . gas -= n
burned += n
continue
else
vmError (OutOfGas available n)
--forceConcreteAddr :: SAddr -> (Addr -> EVM ()) -> EVM ()
--forceConcreteAddr n continue = case maybeLitAddr n of
--Nothing -> vmError UnexpectedSymbolicArg
--Just c -> continue c
forceConcrete :: Expr EWord -> String -> (W256 -> EVM ()) -> EVM ()
forceConcrete n msg continue = case maybeLitWord n of
Nothing -> do
vm <- get
vmError $ UnexpectedSymbolicArg (view (state . pc) vm) msg [n]
Just c -> continue c
forceConcrete2 :: (Expr EWord, Expr EWord) -> String -> ((W256, W256) -> EVM ()) -> EVM ()
forceConcrete2 (n,m) msg continue = case (maybeLitWord n, maybeLitWord m) of
(Just c, Just d) -> continue (c, d)
_ -> do
vm <- get
vmError $ UnexpectedSymbolicArg (view (state . pc) vm) msg [n, m]
forceConcrete3 :: (Expr EWord, Expr EWord, Expr EWord) -> String -> ((W256, W256, W256) -> EVM ()) -> EVM ()
forceConcrete3 (k,n,m) msg continue = case (maybeLitWord k, maybeLitWord n, maybeLitWord m) of
(Just c, Just d, Just f) -> continue (c, d, f)
_ -> do
vm <- get
vmError $ UnexpectedSymbolicArg (view (state . pc) vm) msg [k, n, m]
forceConcrete4 :: (Expr EWord, Expr EWord, Expr EWord, Expr EWord) -> String -> ((W256, W256, W256, W256) -> EVM ()) -> EVM ()
forceConcrete4 (k,l,n,m) msg continue = case (maybeLitWord k, maybeLitWord l, maybeLitWord n, maybeLitWord m) of
(Just b, Just c, Just d, Just f) -> continue (b, c, d, f)
_ -> do
vm <- get
vmError $ UnexpectedSymbolicArg (view (state . pc) vm) msg [k, l, n, m]
forceConcrete5 :: (Expr EWord, Expr EWord, Expr EWord, Expr EWord, Expr EWord) -> String -> ((W256, W256, W256, W256, W256) -> EVM ()) -> EVM ()
forceConcrete5 (k,l,m,n,o) msg continue = case (maybeLitWord k, maybeLitWord l, maybeLitWord m, maybeLitWord n, maybeLitWord o) of
(Just a, Just b, Just c, Just d, Just e) -> continue (a, b, c, d, e)
_ -> do
vm <- get
vmError $ UnexpectedSymbolicArg (view (state . pc) vm) msg [k, l, m, n, o]
forceConcrete6 :: (Expr EWord, Expr EWord, Expr EWord, Expr EWord, Expr EWord, Expr EWord) -> String -> ((W256, W256, W256, W256, W256, W256) -> EVM ()) -> EVM ()
forceConcrete6 (k,l,m,n,o,p) msg continue = case (maybeLitWord k, maybeLitWord l, maybeLitWord m, maybeLitWord n, maybeLitWord o, maybeLitWord p) of
(Just a, Just b, Just c, Just d, Just e, Just f) -> continue (a, b, c, d, e, f)
_ -> do
vm <- get
vmError $ UnexpectedSymbolicArg (view (state . pc) vm) msg [k, l, m, n, o, p]
forceConcreteBuf :: Expr Buf -> String -> (ByteString -> EVM ()) -> EVM ()
forceConcreteBuf (ConcreteBuf b) _ continue = continue b
forceConcreteBuf b msg _ = do
vm <- get
vmError $ UnexpectedSymbolicArg (view (state . pc) vm) msg [b]
-- * Substate manipulation
refund :: Word64 -> EVM ()
refund n = do
self <- use (state . contract)
pushTo (tx . substate . refunds) (self, n)
unRefund :: Word64 -> EVM ()
unRefund n = do
self <- use (state . contract)
refs <- use (tx . substate . refunds)
assign (tx . substate . refunds)
(filter (\(a,b) -> not (a == self && b == n)) refs)
touchAccount :: Addr -> EVM()
touchAccount = pushTo ((tx . substate) . touchedAccounts)
selfdestruct :: Addr -> EVM()
selfdestruct = pushTo ((tx . substate) . selfdestructs)
accessAndBurn :: Addr -> EVM () -> EVM ()
accessAndBurn x cont = do
FeeSchedule {..} <- use ( block . schedule )
acc <- accessAccountForGas x
let cost = if acc then g_warm_storage_read else g_cold_account_access
burn cost cont
-- | returns a wrapped boolean- if true, this address has been touched before in the txn (warm gas cost as in EIP 2929)
-- otherwise cold
accessAccountForGas :: Addr -> EVM Bool
accessAccountForGas addr = do
accessedAddrs <- use (tx . substate . accessedAddresses)
let accessed = member addr accessedAddrs
assign (tx . substate . accessedAddresses) (insert addr accessedAddrs)
return accessed
-- | returns a wrapped boolean- if true, this slot has been touched before in the txn (warm gas cost as in EIP 2929)
-- otherwise cold
accessStorageForGas :: Addr -> Expr EWord -> EVM Bool
accessStorageForGas addr key = do
accessedStrkeys <- use (tx . substate . accessedStorageKeys)
case maybeLitWord key of
Just litword -> do
let accessed = member (addr, litword) accessedStrkeys
assign (tx . substate . accessedStorageKeys) (insert (addr, litword) accessedStrkeys)
return accessed
_ -> return False
-- * Cheat codes
-- The cheat code is 7109709ecfa91a80626ff3989d68f67f5b1dd12d.
-- Call this address using one of the cheatActions below to do
-- special things, e.g. changing the block timestamp. Beware that
-- these are necessarily hevm specific.
cheatCode :: Addr
cheatCode = num (keccak' "hevm cheat code")
cheat
:: (?op :: Word8)
=> (W256, W256) -> (W256, W256)
-> EVM ()
cheat (inOffset, inSize) (outOffset, outSize) = do
mem <- use (state . memory)
vm <- get
let
abi = readBytes 4 (Lit inOffset) mem
input = readMemory (Lit $ inOffset + 4) (Lit $ inSize - 4) vm
case maybeLitWord abi of
Nothing -> vmError $ UnexpectedSymbolicArg (view (state . pc) vm) "symbolic cheatcode selector" [abi]
Just (fromIntegral -> abi') ->
case Map.lookup abi' cheatActions of
Nothing ->
vmError (BadCheatCode (Just abi'))
Just action -> do
action (Lit outOffset) (Lit outSize) input
next
push 1
type CheatAction = Expr EWord -> Expr EWord -> Expr Buf -> EVM ()
cheatActions :: Map Word32 CheatAction
cheatActions =
Map.fromList
[ action "ffi(string[])" $
\sig outOffset outSize input -> do
vm <- get
if view EVM.allowFFI vm then
case decodeBuf [AbiArrayDynamicType AbiStringType] input of
CAbi valsArr -> case valsArr of
[AbiArrayDynamic AbiStringType strsV] ->
let
cmd = fmap
(\case
(AbiString a) -> unpack $ decodeUtf8 a
_ -> "")
(V.toList strsV)
cont bs = do
let encoded = ConcreteBuf bs
assign (state . returndata) encoded
copyBytesToMemory encoded outSize (Lit 0) outOffset
assign result Nothing
in assign result (Just . VMFailure . Query $ (PleaseDoFFI cmd cont))
_ -> vmError (BadCheatCode sig)
_ -> vmError (BadCheatCode sig)
else
let msg = encodeUtf8 "ffi disabled: run again with --ffi if you want to allow tests to call external scripts"
in vmError . EVM.Revert . ConcreteBuf $
abiMethod "Error(string)" (AbiTuple . V.fromList $ [AbiString msg]),
action "warp(uint256)" $
\sig _ _ input -> case decodeStaticArgs 0 1 input of
[x] -> assign (block . timestamp) x
_ -> vmError (BadCheatCode sig),
action "roll(uint256)" $
\sig _ _ input -> case decodeStaticArgs 0 1 input of
[x] -> forceConcrete x "cannot roll to a symbolic block number" (assign (block . number))
_ -> vmError (BadCheatCode sig),
action "store(address,bytes32,bytes32)" $
\sig _ _ input -> case decodeStaticArgs 0 3 input of
[a, slot, new] ->
forceConcrete a "cannot store at a symbolic address" $ \(num -> a') ->
fetchAccount a' $ \_ -> do
modifying (env . storage) (writeStorage (litAddr a') slot new)
_ -> vmError (BadCheatCode sig),
action "load(address,bytes32)" $
\sig outOffset _ input -> case decodeStaticArgs 0 2 input of
[a, slot] ->
forceConcrete a "cannot load from a symbolic address" $ \(num -> a') ->
accessStorage a' slot $ \res -> do
assign (state . returndata . word256At (Lit 0)) res
assign (state . memory . word256At outOffset) res
_ -> vmError (BadCheatCode sig),
action "sign(uint256,bytes32)" $
\sig outOffset _ input -> case decodeStaticArgs 0 2 input of
[sk, hash] ->
forceConcrete2 (sk, hash) "cannot sign symbolic data" $ \(sk', hash') -> let
curve = getCurveByName SEC_p256k1
priv = PrivateKey curve (num sk')
digest = digestFromByteString (word256Bytes hash')
in do
case digest of
Nothing -> vmError (BadCheatCode sig)
Just digest' -> do
let s = ethsign priv digest'
-- calculating the V value is pretty annoying if you
-- don't have access to the full X/Y coords of the
-- signature (which we don't get back from cryptonite).
-- Luckily since we use a fixed nonce (to avoid the
-- overhead of bringing randomness into the core EVM
-- semantics), it would appear that every signature we
-- produce has v == 28. Definitely a hack, and also bad
-- for code that somehow depends on the value of v, but
-- that seems acceptable for now.
v = 28
encoded = encodeAbiValue $
AbiTuple (RegularVector.fromList
[ AbiUInt 8 v
, AbiBytes 32 (word256Bytes . fromInteger $ sign_r s)
, AbiBytes 32 (word256Bytes . fromInteger $ sign_s s)
])
assign (state . returndata) (ConcreteBuf encoded)
copyBytesToMemory (ConcreteBuf encoded) (Lit . num . BS.length $ encoded) (Lit 0) outOffset
_ -> vmError (BadCheatCode sig),
action "addr(uint256)" $
\sig outOffset _ input -> case decodeStaticArgs 0 1 input of
[sk] -> forceConcrete sk "cannot derive address for a symbolic key" $ \sk' -> let
curve = getCurveByName SEC_p256k1
pubPoint = generateQ curve (num sk')
encodeInt = encodeAbiValue . AbiUInt 256 . fromInteger
in do
case pubPoint of
PointO -> do vmError (BadCheatCode sig)
Point x y -> do
-- See yellow paper #286
let
pub = BS.concat [ encodeInt x, encodeInt y ]
addr = Lit . W256 . word256 . BS.drop 12 . BS.take 32 . keccakBytes $ pub
assign (state . returndata . word256At (Lit 0)) addr
assign (state . memory . word256At outOffset) addr
_ -> vmError (BadCheatCode sig)
]
where
action s f = (abiKeccak s, f (Just $ abiKeccak s))
-- | We don't wanna introduce the machinery needed to sign with a random nonce,
-- so we just use the same nonce every time (420). This is obviusly very
-- insecure, but fine for testing purposes.
ethsign :: PrivateKey -> Digest Crypto.Keccak_256 -> Signature
ethsign sk digest = go 420
where
go k = case signDigestWith k sk digest of
Nothing -> go (k + 1)
Just sig -> sig
-- * General call implementation ("delegateCall")
-- note that the continuation is ignored in the precompile case
delegateCall
:: (?op :: Word8)
=> Contract -> Word64 -> Expr EWord -> Expr EWord -> W256 -> W256 -> W256 -> W256 -> W256
-> [Expr EWord]
-> (Addr -> EVM ())
-> EVM ()
delegateCall this gasGiven xTo xContext xValue xInOffset xInSize xOutOffset xOutSize xs continue =
forceConcrete2 (xTo, xContext) "cannot delegateCall with symbolic target or context" $
\((num -> xTo'), (num -> xContext')) ->
if xTo' > 0 && xTo' <= 9
then precompiledContract this gasGiven xTo' xContext' xValue xInOffset xInSize xOutOffset xOutSize xs
else if xTo' == cheatCode then
do
assign (state . stack) xs
cheat (xInOffset, xInSize) (xOutOffset, xOutSize)
else
callChecks this gasGiven xContext' xTo' xValue xInOffset xInSize xOutOffset xOutSize xs $
\xGas -> do
vm0 <- get
fetchAccount xTo' $ \target ->
burn xGas $ do
let newContext = CallContext
{ callContextTarget = xTo'
, callContextContext = xContext'
, callContextOffset = xOutOffset
, callContextSize = xOutSize
, callContextCodehash = view codehash target
, callContextReversion = (view (env . contracts) vm0, view (env . storage) vm0)
, callContextSubState = view (tx . substate) vm0
, callContextAbi =
if xInSize >= 4
then case unlit $ readBytes 4 (Lit xInOffset) (view (state . memory) vm0)
of Nothing -> Nothing
Just abi -> Just $ num abi
else Nothing
, callContextData = (readMemory (Lit xInOffset) (Lit xInSize) vm0)
}
pushTrace (FrameTrace newContext)
next
vm1 <- get
pushTo frames $ Frame
{ _frameState = (set stack xs) (view state vm1)
, _frameContext = newContext
}
let clearInitCode = \case
(InitCode _ _) -> InitCode mempty mempty
a -> a
zoom state $ do
assign gas (num xGas)
assign pc 0
assign code (clearInitCode (view contractcode target))
assign codeContract xTo'
assign stack mempty
assign memory mempty
assign memorySize 0
assign returndata mempty
assign calldata (copySlice (Lit xInOffset) (Lit 0) (Lit xInSize) (view (state . memory) vm0) mempty)
continue xTo'
-- -- * Contract creation
-- EIP 684
collision :: Maybe Contract -> Bool
collision c' = case c' of
Just c -> (view nonce c /= 0) || case view contractcode c of
RuntimeCode b -> not $ null b
_ -> True
Nothing -> False
create :: (?op :: Word8)
=> Addr -> Contract
-> Word64 -> W256 -> [Expr EWord] -> Addr -> Expr Buf -> EVM ()
create self this xGas' xValue xs newAddr initCode = do
vm0 <- get
let xGas = num xGas'
if view nonce this == num (maxBound :: Word64)
then do
assign (state . stack) (Lit 0 : xs)
assign (state . returndata) mempty
pushTrace $ ErrorTrace NonceOverflow
next
else if xValue > view balance this
then do
assign (state . stack) (Lit 0 : xs)
assign (state . returndata) mempty
pushTrace $ ErrorTrace $ BalanceTooLow xValue (view balance this)
next
else if length (view frames vm0) >= 1024
then do
assign (state . stack) (Lit 0 : xs)
assign (state . returndata) mempty
pushTrace $ ErrorTrace CallDepthLimitReached
next
else if collision $ view (env . contracts . at newAddr) vm0
then burn xGas $ do
assign (state . stack) (Lit 0 : xs)
assign (state . returndata) mempty
modifying (env . contracts . ix self . nonce) succ
next
else burn xGas $ do
touchAccount self
touchAccount newAddr
let
-- unfortunately we have to apply some (pretty hacky)
-- heuristics here to parse the unstructured buffer read
-- from memory into a code and data section
-- TODO: comment explaining whats going on here
let contract' = do
prefixLen <- Expr.concPrefix initCode
prefix <- Expr.toList $ Expr.take (num prefixLen) initCode
let sym = Expr.drop (num prefixLen) initCode
conc <- mapM unlitByte prefix
pure $ InitCode (BS.pack $ V.toList conc) sym
case contract' of
Nothing ->
vmError $ UnexpectedSymbolicArg (view (state . pc) vm0) "initcode must have a concrete prefix" []
Just c -> do
let
newContract = initialContract c
newContext =
CreationContext { creationContextAddress = newAddr
, creationContextCodehash = view codehash newContract
, creationContextReversion = view (env . contracts) vm0
, creationContextSubstate = view (tx . substate) vm0
}
zoom (env . contracts) $ do
oldAcc <- use (at newAddr)
let oldBal = maybe 0 (view balance) oldAcc
assign (at newAddr) (Just (newContract & balance .~ oldBal))
modifying (ix self . nonce) succ
let resetStorage = \case
ConcreteStore s -> ConcreteStore (Map.delete (num newAddr) s)
AbstractStore -> AbstractStore
EmptyStore -> EmptyStore
SStore {} -> error "trying to reset symbolic storage with writes in create"
GVar _ -> error "unexpected global variable"
modifying (env . storage) resetStorage
modifying (env . origStorage) (Map.delete (num newAddr))
transfer self newAddr xValue
pushTrace (FrameTrace newContext)
next
vm1 <- get
pushTo frames $ Frame
{ _frameContext = newContext
, _frameState = (set stack xs) (view state vm1)
}
assign state $
blankState
& set contract newAddr
& set codeContract newAddr
& set code c
& set callvalue (Lit xValue)
& set caller (litAddr self)
& set gas xGas'
-- | Replace a contract's code, like when CREATE returns
-- from the constructor code.
replaceCode :: Addr -> ContractCode -> EVM ()
replaceCode target newCode =
zoom (env . contracts . at target) $
get >>= \case
Just now -> case (view contractcode now) of
InitCode _ _ ->
put . Just $
initialContract newCode
& set balance (view balance now)
& set nonce (view nonce now)
RuntimeCode _ ->
error ("internal error: can't replace code of deployed contract " <> show target)
Nothing ->
error "internal error: can't replace code of nonexistent contract"
replaceCodeOfSelf :: ContractCode -> EVM ()
replaceCodeOfSelf newCode = do
vm <- get
replaceCode (view (state . contract) vm) newCode
resetState :: EVM ()
resetState = do
assign result Nothing
assign frames []
assign state blankState
-- * VM error implementation
vmError :: Error -> EVM ()
vmError e = finishFrame (FrameErrored e)
underrun :: EVM ()
underrun = vmError StackUnderrun
-- | A stack frame can be popped in three ways.
data FrameResult
= FrameReturned (Expr Buf) -- ^ STOP, RETURN, or no more code
| FrameReverted (Expr Buf) -- ^ REVERT
| FrameErrored Error -- ^ Any other error
deriving Show
-- | This function defines how to pop the current stack frame in either of
-- the ways specified by 'FrameResult'.
--
-- It also handles the case when the current stack frame is the only one;
-- in this case, we set the final '_result' of the VM execution.
finishFrame :: FrameResult -> EVM ()
finishFrame how = do
oldVm <- get
case view frames oldVm of
-- Is the current frame the only one?
[] -> do
case how of
FrameReturned output -> assign result . Just $ VMSuccess output
FrameReverted buffer -> assign result . Just $ VMFailure (EVM.Revert buffer)
FrameErrored e -> assign result . Just $ VMFailure e
finalize
-- Are there some remaining frames?
nextFrame : remainingFrames -> do
-- Insert a debug trace.
insertTrace $
case how of
FrameErrored e ->
ErrorTrace e
FrameReverted e ->
ErrorTrace (EVM.Revert e)
FrameReturned output ->
ReturnTrace output (view frameContext nextFrame)
-- Pop to the previous level of the debug trace stack.
popTrace
-- Pop the top frame.
assign frames remainingFrames
-- Install the state of the frame to which we shall return.
assign state (view frameState nextFrame)
-- When entering a call, the gas allowance is counted as burned
-- in advance; this unburns the remainder and adds it to the
-- parent frame.
let remainingGas = view (state . gas) oldVm
reclaimRemainingGasAllowance = do
modifying burned (subtract remainingGas)
modifying (state . gas) (+ remainingGas)
-- Now dispatch on whether we were creating or calling,
-- and whether we shall return, revert, or error (six cases).
case view frameContext nextFrame of
-- Were we calling?
CallContext _ _ (Lit -> outOffset) (Lit -> outSize) _ _ _ reversion substate' -> do
-- Excerpt K.1. from the yellow paper:
-- K.1. Deletion of an Account Despite Out-of-gas.
-- At block 2675119, in the transaction 0xcf416c536ec1a19ed1fb89e4ec7ffb3cf73aa413b3aa9b77d60e4fd81a4296ba,
-- an account at address 0x03 was called and an out-of-gas occurred during the call.
-- Against the equation (197), this added 0x03 in the set of touched addresses, and this transaction turned σ[0x03] into ∅.
-- In other words, we special case address 0x03 and keep it in the set of touched accounts during revert
touched <- use (tx . substate . touchedAccounts)
let
substate'' = over touchedAccounts (maybe id cons (find (3 ==) touched)) substate'
(contractsReversion, storageReversion) = reversion
revertContracts = assign (env . contracts) contractsReversion
revertStorage = assign (env . storage) storageReversion
revertSubstate = assign (tx . substate) substate''
case how of
-- Case 1: Returning from a call?
FrameReturned output -> do
assign (state . returndata) output
copyCallBytesToMemory output outSize (Lit 0) outOffset
reclaimRemainingGasAllowance
push 1
-- Case 2: Reverting during a call?
FrameReverted output -> do
revertContracts
revertStorage
revertSubstate
assign (state . returndata) output
copyCallBytesToMemory output outSize (Lit 0) outOffset
reclaimRemainingGasAllowance
push 0
-- Case 3: Error during a call?
FrameErrored _ -> do
revertContracts
revertStorage
revertSubstate
assign (state . returndata) mempty
push 0
-- Or were we creating?
CreationContext _ _ reversion substate' -> do
creator <- use (state . contract)
let
createe = view (state . contract) oldVm
revertContracts = assign (env . contracts) reversion'
revertSubstate = assign (tx . substate) substate'
-- persist the nonce through the reversion
reversion' = (Map.adjust (over nonce (+ 1)) creator) reversion
case how of
-- Case 4: Returning during a creation?
FrameReturned output -> do
case Expr.toList output of
Nothing -> vmError $
UnexpectedSymbolicArg
(view (state . pc) oldVm)
"runtime code cannot have an abstract length"
[output]
Just newCode -> do
replaceCode createe (RuntimeCode newCode)
assign (state . returndata) mempty
reclaimRemainingGasAllowance
push (num createe)
-- Case 5: Reverting during a creation?
FrameReverted output -> do
revertContracts
revertSubstate
assign (state . returndata) output
reclaimRemainingGasAllowance
push 0
-- Case 6: Error during a creation?
FrameErrored _ -> do
revertContracts
revertSubstate
assign (state . returndata) mempty
push 0
-- * Memory helpers
accessUnboundedMemoryRange
:: FeeSchedule Word64
-> Word64
-> Word64
-> EVM ()
-> EVM ()
accessUnboundedMemoryRange _ _ 0 continue = continue
accessUnboundedMemoryRange fees f l continue = do
m0 <- num <$> use (state . memorySize)
do
let m1 = 32 * ceilDiv (max m0 (f + l)) 32
burn (memoryCost fees m1 - memoryCost fees m0) $ do
assign (state . memorySize) m1
continue
accessMemoryRange
:: FeeSchedule Word64
-> W256
-> W256
-> EVM ()
-> EVM ()
accessMemoryRange _ _ 0 continue = continue
accessMemoryRange fees f l continue =
case (,) <$> toWord64 f <*> toWord64 l of
Nothing -> vmError IllegalOverflow
Just (f64, l64) ->
if f64 + l64 < l64
then vmError IllegalOverflow
else accessUnboundedMemoryRange fees f64 l64 continue
accessMemoryWord
:: FeeSchedule Word64 -> W256 -> EVM () -> EVM ()
accessMemoryWord fees x = accessMemoryRange fees x 32
copyBytesToMemory
:: Expr Buf -> Expr EWord -> Expr EWord -> Expr EWord -> EVM ()
copyBytesToMemory bs size xOffset yOffset =
if size == (Lit 0) then noop
else do
mem <- use (state . memory)
assign (state . memory) $
copySlice xOffset yOffset size bs mem
copyCallBytesToMemory
:: Expr Buf -> Expr EWord -> Expr EWord -> Expr EWord -> EVM ()
copyCallBytesToMemory bs size xOffset yOffset =
if size == (Lit 0) then noop
else do
mem <- use (state . memory)
assign (state . memory) $
copySlice xOffset yOffset (Expr.min size (bufLength bs)) bs mem
readMemory :: Expr EWord -> Expr EWord -> VM -> Expr Buf
readMemory offset size vm = copySlice offset (Lit 0) size (view (state . memory) vm) mempty
-- * Tracing
withTraceLocation
:: (MonadState VM m) => TraceData -> m Trace
withTraceLocation x = do
vm <- get
let
Just this =
currentContract vm
pure Trace
{ _traceData = x
, _traceContract = this
, _traceOpIx = fromMaybe 0 $ (view opIxMap this) Vector.!? (view (state . pc) vm)
}
pushTrace :: TraceData -> EVM ()
pushTrace x = do
trace <- withTraceLocation x
modifying traces $
\t -> Zipper.children $ Zipper.insert (Node trace []) t
insertTrace :: TraceData -> EVM ()
insertTrace x = do
trace <- withTraceLocation x
modifying traces $
\t -> Zipper.nextSpace $ Zipper.insert (Node trace []) t
popTrace :: EVM ()
popTrace =
modifying traces $
\t -> case Zipper.parent t of
Nothing -> error "internal error (trace root)"
Just t' -> Zipper.nextSpace t'
zipperRootForest :: Zipper.TreePos Zipper.Empty a -> Forest a
zipperRootForest z =
case Zipper.parent z of
Nothing -> Zipper.toForest z
Just z' -> zipperRootForest (Zipper.nextSpace z')
traceForest :: VM -> Forest Trace
traceForest = view (traces . to zipperRootForest)
traceTopLog :: (MonadState VM m) => [Expr Log] -> m ()
traceTopLog [] = noop
traceTopLog ((LogEntry addr bytes topics) : _) = do
trace <- withTraceLocation (EventTrace addr bytes topics)
modifying traces $
\t -> Zipper.nextSpace (Zipper.insert (Node trace []) t)
traceTopLog ((GVar _) : _) = error "unexpected global variable"
-- * Stack manipulation
push :: W256 -> EVM ()
push = pushSym . Lit
pushSym :: Expr EWord -> EVM ()
pushSym x = state . stack %= (x :)
stackOp1
:: (?op :: Word8)
=> ((Expr EWord) -> Word64)
-> ((Expr EWord) -> (Expr EWord))
-> EVM ()
stackOp1 cost f =
use (state . stack) >>= \case
(x:xs) ->
burn (cost x) $ do
next
let !y = f x
state . stack .= y : xs
_ ->
underrun
stackOp2
:: (?op :: Word8)
=> (((Expr EWord), (Expr EWord)) -> Word64)
-> (((Expr EWord), (Expr EWord)) -> (Expr EWord))
-> EVM ()
stackOp2 cost f =
use (state . stack) >>= \case
(x:y:xs) ->
burn (cost (x, y)) $ do
next
state . stack .= f (x, y) : xs
_ ->
underrun
stackOp3
:: (?op :: Word8)
=> (((Expr EWord), (Expr EWord), (Expr EWord)) -> Word64)
-> (((Expr EWord), (Expr EWord), (Expr EWord)) -> (Expr EWord))
-> EVM ()
stackOp3 cost f =
use (state . stack) >>= \case
(x:y:z:xs) ->
burn (cost (x, y, z)) $ do
next
state . stack .= f (x, y, z) : xs
_ ->
underrun
-- * Bytecode data functions
checkJump :: (Integral n) => n -> [Expr EWord] -> EVM ()
checkJump x xs = do
theCode <- use (state . code)
self <- use (state . codeContract)
theCodeOps <- use (env . contracts . ix self . codeOps)
theOpIxMap <- use (env . contracts . ix self . opIxMap)
let ops = case theCode of
InitCode ops' _ -> V.fromList $ LitByte <$> BS.unpack ops'
RuntimeCode ops' -> ops'
op = do
-- TODO: not a big fan of how bounds are checked, change this
b <- if x < num (length ops) then ops V.!? num x else Nothing
unlitByte b
case op of
Nothing -> vmError EVM.BadJumpDestination
Just b ->
if 0x5b == b && OpJumpdest == snd (theCodeOps RegularVector.! (theOpIxMap Vector.! num x))
then do
state . stack .= xs
state . pc .= num x
else
vmError EVM.BadJumpDestination
opSize :: Word8 -> Int
opSize x | x >= 0x60 && x <= 0x7f = num x - 0x60 + 2
opSize _ = 1
-- i of the resulting vector contains the operation index for
-- the program counter value i. This is needed because source map
-- entries are per operation, not per byte.
mkOpIxMap :: ContractCode -> Vector Int
mkOpIxMap (InitCode conc _)
= Vector.create $ Vector.new (BS.length conc) >>= \v ->
-- Loop over the byte string accumulating a vector-mutating action.
-- This is somewhat obfuscated, but should be fast.
let (_, _, _, m) = BS.foldl' (go v) (0 :: Word8, 0, 0, return ()) conc
in m >> return v
where
-- concrete case
go v (0, !i, !j, !m) x | x >= 0x60 && x <= 0x7f =
{- Start of PUSH op. -} (x - 0x60 + 1, i + 1, j, m >> Vector.write v i j)
go v (1, !i, !j, !m) _ =
{- End of PUSH op. -} (0, i + 1, j + 1, m >> Vector.write v i j)
go v (0, !i, !j, !m) _ =
{- Other op. -} (0, i + 1, j + 1, m >> Vector.write v i j)
go v (n, !i, !j, !m) _ =
{- PUSH data. -} (n - 1, i + 1, j, m >> Vector.write v i j)
mkOpIxMap (RuntimeCode ops)
= Vector.create $ Vector.new (length ops) >>= \v ->
let (_, _, _, m) = foldl (go v) (0, 0, 0, return ()) (stripBytecodeMetadataSym $ V.toList ops)
in m >> return v
where
go v (0, !i, !j, !m) x = case unlitByte x of
Just x' -> if x' >= 0x60 && x' <= 0x7f
-- start of PUSH op --
then (x' - 0x60 + 1, i + 1, j, m >> Vector.write v i j)
-- other data --
else (0, i + 1, j + 1, m >> Vector.write v i j)
_ -> error $ "cannot analyze symbolic code:\nx: " <> show x <> " i: " <> show i <> " j: " <> show j
go v (1, !i, !j, !m) _ =
{- End of PUSH op. -} (0, i + 1, j + 1, m >> Vector.write v i j)
go v (n, !i, !j, !m) _ =
{- PUSH data. -} (n - 1, i + 1, j, m >> Vector.write v i j)
vmOp :: VM -> Maybe Op
vmOp vm =
let i = vm ^. state . pc
code' = vm ^. state . code
(op, pushdata) = case code' of
InitCode xs' _ ->
(BS.index xs' i, fmap LitByte $ BS.unpack $ BS.drop i xs')
RuntimeCode xs' ->
( fromMaybe (error "unexpected symbolic code") . unlitByte $ xs' V.! i , V.toList $ V.drop i xs')
in if (opslen code' < i)
then Nothing
else Just (readOp op pushdata)
vmOpIx :: VM -> Maybe Int
vmOpIx vm =
do self <- currentContract vm
(view opIxMap self) Vector.!? (view (state . pc) vm)
opParams :: VM -> Map String (Expr EWord)
opParams vm =
case vmOp vm of
Just OpCreate ->
params $ words "value offset size"
Just OpCall ->
params $ words "gas to value in-offset in-size out-offset out-size"
Just OpSstore ->
params $ words "index value"
Just OpCodecopy ->
params $ words "mem-offset code-offset code-size"
Just OpSha3 ->
params $ words "offset size"
Just OpCalldatacopy ->
params $ words "to from size"
Just OpExtcodecopy ->
params $ words "account mem-offset code-offset code-size"
Just OpReturn ->
params $ words "offset size"
Just OpJumpi ->
params $ words "destination condition"
_ -> mempty
where
params xs =
if length (vm ^. state . stack) >= length xs
then Map.fromList (zip xs (vm ^. state . stack))
else mempty
-- | Reads
readOp :: Word8 -> [Expr Byte] -> Op
readOp x _ | x >= 0x80 && x <= 0x8f = OpDup (x - 0x80 + 1)
readOp x _ | x >= 0x90 && x <= 0x9f = OpSwap (x - 0x90 + 1)
readOp x _ | x >= 0xa0 && x <= 0xa4 = OpLog (x - 0xa0)
readOp x xs | x >= 0x60 && x <= 0x7f =
let n = num $ x - 0x60 + 1
in OpPush (readBytes n (Lit 0) (Expr.fromList $ V.fromList xs))
readOp x _ = case x of
0x00 -> OpStop
0x01 -> OpAdd
0x02 -> OpMul
0x03 -> OpSub
0x04 -> OpDiv
0x05 -> OpSdiv
0x06 -> OpMod
0x07 -> OpSmod
0x08 -> OpAddmod
0x09 -> OpMulmod
0x0a -> OpExp
0x0b -> OpSignextend
0x10 -> OpLt
0x11 -> OpGt
0x12 -> OpSlt
0x13 -> OpSgt
0x14 -> OpEq
0x15 -> OpIszero
0x16 -> OpAnd
0x17 -> OpOr
0x18 -> OpXor
0x19 -> OpNot
0x1a -> OpByte
0x1b -> OpShl
0x1c -> OpShr
0x1d -> OpSar
0x20 -> OpSha3
0x30 -> OpAddress
0x31 -> OpBalance
0x32 -> OpOrigin
0x33 -> OpCaller
0x34 -> OpCallvalue
0x35 -> OpCalldataload
0x36 -> OpCalldatasize
0x37 -> OpCalldatacopy
0x38 -> OpCodesize
0x39 -> OpCodecopy
0x3a -> OpGasprice
0x3b -> OpExtcodesize
0x3c -> OpExtcodecopy
0x3d -> OpReturndatasize
0x3e -> OpReturndatacopy
0x3f -> OpExtcodehash
0x40 -> OpBlockhash
0x41 -> OpCoinbase
0x42 -> OpTimestamp
0x43 -> OpNumber
0x44 -> OpPrevRandao
0x45 -> OpGaslimit
0x46 -> OpChainid
0x47 -> OpSelfbalance
0x50 -> OpPop
0x51 -> OpMload
0x52 -> OpMstore
0x53 -> OpMstore8
0x54 -> OpSload
0x55 -> OpSstore
0x56 -> OpJump
0x57 -> OpJumpi
0x58 -> OpPc
0x59 -> OpMsize
0x5a -> OpGas
0x5b -> OpJumpdest
0xf0 -> OpCreate
0xf1 -> OpCall
0xf2 -> OpCallcode
0xf3 -> OpReturn
0xf4 -> OpDelegatecall
0xf5 -> OpCreate2
0xfd -> OpRevert
0xfa -> OpStaticcall
0xff -> OpSelfdestruct
_ -> OpUnknown x
-- Maps operation indicies into a pair of (bytecode index, operation)
mkCodeOps :: ContractCode -> RegularVector.Vector (Int, Op)
mkCodeOps (InitCode bytes _) = RegularVector.fromList . toList $ go 0 bytes
where
go !i !xs =
case BS.uncons xs of
Nothing ->
mempty
Just (x, xs') ->
let j = opSize x
in (i, readOp x (fmap LitByte $ BS.unpack xs')) Seq.<| go (i + j) (BS.drop j xs)
mkCodeOps (RuntimeCode ops) = RegularVector.fromList . toList $ go' 0 (stripBytecodeMetadataSym $ V.toList ops)
where
go' !i !xs =
case uncons xs of
Nothing ->
mempty
Just (x, xs') ->
let x' = fromMaybe (error "unexpected symbolic code argument") $ unlitByte x
j = opSize x'
in (i, readOp x' xs') Seq.<| go' (i + j) (drop j xs)
-- * Gas cost calculation helpers
-- Gas cost function for CALL, transliterated from the Yellow Paper.
costOfCall
:: FeeSchedule Word64
-> Bool -> W256 -> Word64 -> Word64 -> Addr
-> EVM (Word64, Word64)
costOfCall (FeeSchedule {..}) recipientExists xValue availableGas xGas target = do
acc <- accessAccountForGas target
let call_base_gas = if acc then g_warm_storage_read else g_cold_account_access
c_new = if not recipientExists && xValue /= 0
then g_newaccount
else 0
c_xfer = if xValue /= 0 then num g_callvalue else 0
c_extra = call_base_gas + c_xfer + c_new
c_gascap = if availableGas >= c_extra
then min xGas (allButOne64th (availableGas - c_extra))
else xGas
c_callgas = if xValue /= 0 then c_gascap + g_callstipend else c_gascap
return (c_gascap + c_extra, c_callgas)
-- Gas cost of create, including hash cost if needed
costOfCreate
:: FeeSchedule Word64
-> Word64 -> W256 -> (Word64, Word64)
costOfCreate (FeeSchedule {..}) availableGas hashSize =
(createCost + initGas, initGas)
where
createCost = g_create + hashCost
hashCost = g_sha3word * ceilDiv (num hashSize) 32
initGas = allButOne64th (availableGas - createCost)
concreteModexpGasFee :: ByteString -> Word64
concreteModexpGasFee input =
if lenb < num (maxBound :: Word32) &&
(lene < num (maxBound :: Word32) || (lenb == 0 && lenm == 0)) &&
lenm < num (maxBound :: Word64)
then
max 200 ((multiplicationComplexity * iterCount) `div` 3)
else
maxBound -- TODO: this is not 100% correct, return Nothing on overflow
where (lenb, lene, lenm) = parseModexpLength input
ez = isZero (96 + lenb) lene input
e' = word $ LS.toStrict $
lazySlice (96 + lenb) (min 32 lene) input
nwords :: Word64
nwords = ceilDiv (num $ max lenb lenm) 8
multiplicationComplexity = nwords * nwords
iterCount' :: Word64
iterCount' | lene <= 32 && ez = 0
| lene <= 32 = num (log2 e')
| e' == 0 = 8 * (num lene - 32)
| otherwise = num (log2 e') + 8 * (num lene - 32)
iterCount = max iterCount' 1
-- Gas cost of precompiles
costOfPrecompile :: FeeSchedule Word64 -> Addr -> Expr Buf -> Word64
costOfPrecompile (FeeSchedule {..}) precompileAddr input =
let errorDynamicSize = error "precompile input cannot have a dynamic size"
inputLen = case input of
ConcreteBuf bs -> fromIntegral $ BS.length bs
AbstractBuf _ -> errorDynamicSize
buf -> case bufLength buf of
Lit l -> num l -- TODO: overflow
_ -> errorDynamicSize
in case precompileAddr of
-- ECRECOVER
0x1 -> 3000
-- SHA2-256
0x2 -> num $ (((inputLen + 31) `div` 32) * 12) + 60
-- RIPEMD-160
0x3 -> num $ (((inputLen + 31) `div` 32) * 120) + 600
-- IDENTITY
0x4 -> num $ (((inputLen + 31) `div` 32) * 3) + 15
-- MODEXP
0x5 -> case input of
ConcreteBuf i -> concreteModexpGasFee i
_ -> error "Unsupported symbolic modexp gas calc "
-- ECADD
0x6 -> g_ecadd
-- ECMUL
0x7 -> g_ecmul
-- ECPAIRING
0x8 -> (inputLen `div` 192) * g_pairing_point + g_pairing_base
-- BLAKE2
0x9 -> case input of
ConcreteBuf i -> g_fround * (num $ asInteger $ lazySlice 0 4 i)
_ -> error "Unsupported symbolic blake2 gas calc"
_ -> error ("unimplemented precompiled contract " ++ show precompileAddr)
-- Gas cost of memory expansion
memoryCost :: FeeSchedule Word64 -> Word64 -> Word64
memoryCost FeeSchedule{..} byteCount =
let
wordCount = ceilDiv byteCount 32
linearCost = g_memory * wordCount
quadraticCost = div (wordCount * wordCount) 512
in
linearCost + quadraticCost
-- * Arithmetic
ceilDiv :: (Num a, Integral a) => a -> a -> a
ceilDiv m n = div (m + n - 1) n
allButOne64th :: (Num a, Integral a) => a -> a
allButOne64th n = n - div n 64
log2 :: FiniteBits b => b -> Int
log2 x = finiteBitSize x - 1 - countLeadingZeros x
hashcode :: ContractCode -> Expr EWord
hashcode (InitCode ops args) = keccak $ (ConcreteBuf ops) <> args
hashcode (RuntimeCode ops) = keccak . Expr.fromList $ ops
-- | The length of the code ignoring any constructor args.
-- This represents the region that can contain executable opcodes
opslen :: ContractCode -> Int
opslen (InitCode ops _) = BS.length ops
opslen (RuntimeCode ops) = length ops
-- | The length of the code including any constructor args.
-- This can return an abstract value
codelen :: ContractCode -> Expr EWord
codelen c@(InitCode {}) = bufLength $ toBuf c
codelen (RuntimeCode ops) = Lit . num $ length ops
toBuf :: ContractCode -> Expr Buf
toBuf (InitCode ops args) = ConcreteBuf ops <> args
toBuf (RuntimeCode ops) = Expr.fromList ops
codeloc :: EVM CodeLocation
codeloc = do
vm <- get
let self = view (state . contract) vm
loc = view (state . pc) vm
pure (self, loc)
toWord64 :: W256 -> Maybe Word64
toWord64 n =
if n <= num (maxBound :: Word64)
then let (W256 (Word256 _ (Word128 _ n'))) = n in Just n'
else Nothing
-- * Emacs setup
-- Local Variables:
-- outline-regexp: "-- \\*+\\|data \\|newtype \\|type \\| +-- op: "
-- outline-heading-alist:
-- (("-- *" . 1) ("data " . 2) ("newtype " . 2) ("type " . 2))
-- compile-command: "make"
-- End: