lotus/node/impl/full/eth_trace.go
Steven Allen cff785fa37
fix: eth: correctly encode and simplify native input/output encoding ()
* chore: eth: move & rename input/output encoding functions

These are shared functions, so I'm moving them to the utils library.

* fix: eth: correctly encode and simplify native input/output encoding

When generating eth traces, we encode "native" message inputs/outputs
to "solidity ABI" by formatting the inputs/outputs the same way we do in
FEVM's "handle_native_method". However, we had quite a few bugs with the
implementation:

1. We were right-aligning 64bit values in 256bit words, instead of
left-aligning (as we should given that these values are big-endian).
2. The return-value encoding wasn't correctly handling lengths.

This patch:

1. Fixes those bugs.
2. Deduplicates the logic (we're doing _basically_ the same thing in
both cases).
3. Removes all error paths (these functions can't fail).
2023-11-06 09:41:22 -08:00

250 lines
9.1 KiB
Go

package full
import (
"bytes"
"context"
"github.com/multiformats/go-multicodec"
cbg "github.com/whyrusleeping/cbor-gen"
"golang.org/x/xerrors"
"github.com/filecoin-project/go-state-types/builtin"
"github.com/filecoin-project/go-state-types/builtin/v10/evm"
builtinactors "github.com/filecoin-project/lotus/chain/actors/builtin"
"github.com/filecoin-project/lotus/chain/types"
"github.com/filecoin-project/lotus/chain/types/ethtypes"
)
// decodePayload is a utility function which decodes the payload using the given codec
func decodePayload(payload []byte, codec uint64) (ethtypes.EthBytes, error) {
if len(payload) == 0 {
return nil, nil
}
switch multicodec.Code(codec) {
case multicodec.Identity:
return nil, nil
case multicodec.DagCbor, multicodec.Cbor:
buf, err := cbg.ReadByteArray(bytes.NewReader(payload), uint64(len(payload)))
if err != nil {
return nil, xerrors.Errorf("decodePayload: failed to decode cbor payload: %w", err)
}
return buf, nil
case multicodec.Raw:
return ethtypes.EthBytes(payload), nil
}
return nil, xerrors.Errorf("decodePayload: unsupported codec: %d", codec)
}
// buildTraces recursively builds the traces for a given ExecutionTrace by walking the subcalls
func buildTraces(ctx context.Context, traces *[]*ethtypes.EthTrace, parent *ethtypes.EthTrace, addr []int, et types.ExecutionTrace, height int64, sa StateAPI) error {
// lookup the eth address from the from/to addresses. Note that this may fail but to support
// this we need to include the ActorID in the trace. For now, just log a warning and skip
// this trace.
//
// TODO: Add ActorID in trace, see https://github.com/filecoin-project/lotus/pull/11100#discussion_r1302442288
from, err := lookupEthAddress(ctx, et.Msg.From, sa)
if err != nil {
log.Warnf("buildTraces: failed to lookup from address %s: %v", et.Msg.From, err)
return nil
}
to, err := lookupEthAddress(ctx, et.Msg.To, sa)
if err != nil {
log.Warnf("buildTraces: failed to lookup to address %s: %w", et.Msg.To, err)
return nil
}
trace := &ethtypes.EthTrace{
Action: ethtypes.EthTraceAction{
From: from,
To: to,
Gas: ethtypes.EthUint64(et.Msg.GasLimit),
Input: nil,
Value: ethtypes.EthBigInt(et.Msg.Value),
FilecoinFrom: et.Msg.From,
FilecoinTo: et.Msg.To,
FilecoinMethod: et.Msg.Method,
FilecoinCodeCid: et.Msg.CodeCid,
},
Result: ethtypes.EthTraceResult{
GasUsed: ethtypes.EthUint64(et.SumGas().TotalGas),
Output: nil,
},
Subtraces: 0, // will be updated by the children once they are added to the trace
TraceAddress: addr,
Parent: parent,
LastByteCode: nil,
}
trace.SetCallType("call")
if et.Msg.Method == builtin.MethodsEVM.InvokeContract {
log.Debugf("COND1 found InvokeContract call at height: %d", height)
// TODO: ignore return errors since actors can send gibberish and we don't want
// to fail the whole trace in that case
trace.Action.Input, err = decodePayload(et.Msg.Params, et.Msg.ParamsCodec)
if err != nil {
return xerrors.Errorf("buildTraces: %w", err)
}
trace.Result.Output, err = decodePayload(et.MsgRct.Return, et.MsgRct.ReturnCodec)
if err != nil {
return xerrors.Errorf("buildTraces: %w", err)
}
} else if et.Msg.To == builtin.EthereumAddressManagerActorAddr &&
et.Msg.Method == builtin.MethodsEAM.CreateExternal {
log.Debugf("COND2 found CreateExternal call at height: %d", height)
trace.Action.Input, err = decodePayload(et.Msg.Params, et.Msg.ParamsCodec)
if err != nil {
return xerrors.Errorf("buildTraces: %w", err)
}
if et.MsgRct.ExitCode.IsSuccess() {
// ignore return value
trace.Result.Output = nil
} else {
// return value is the error message
trace.Result.Output, err = decodePayload(et.MsgRct.Return, et.MsgRct.ReturnCodec)
if err != nil {
return xerrors.Errorf("buildTraces: %w", err)
}
}
// treat this as a contract creation
trace.SetCallType("create")
} else {
// we are going to assume a native method, but we may change it in one of the edge cases below
// TODO: only do this if we know it's a native method (optimization)
trace.Action.Input = encodeFilecoinParamsAsABI(et.Msg.Method, et.Msg.ParamsCodec, et.Msg.Params)
trace.Result.Output = encodeFilecoinReturnAsABI(et.MsgRct.ExitCode, et.MsgRct.ReturnCodec, et.MsgRct.Return)
}
// TODO: is it OK to check this here or is this only specific to certain edge case (evm to evm)?
if et.Msg.ReadOnly {
trace.SetCallType("staticcall")
}
// there are several edge cases that require special handling when displaying the traces. Note that while iterating over
// the traces we update the trace backwards (through the parent pointer)
if parent != nil {
// Handle Native actor creation
//
// Actor A calls to the init actor on method 2 and The init actor creates the target actor B then calls it on method 1
if parent.Action.FilecoinTo == builtin.InitActorAddr &&
parent.Action.FilecoinMethod == builtin.MethodsInit.Exec &&
et.Msg.Method == builtin.MethodConstructor {
log.Debugf("COND3 Native actor creation! method:%d, code:%s, height:%d", et.Msg.Method, et.Msg.CodeCid.String(), height)
parent.SetCallType("create")
parent.Action.To = to
parent.Action.Input = []byte{0xFE}
parent.Result.Output = nil
// there should never be any subcalls when creating a native actor
//
// TODO: add support for native actors calling another when created
return nil
}
// Handle EVM contract creation
//
// To detect EVM contract creation we need to check for the following sequence of events:
//
// 1) EVM contract A calls the EAM (Ethereum Address Manager) on method 2 (create) or 3 (create2).
// 2) The EAM calls the init actor on method 3 (Exec4).
// 3) The init actor creates the target actor B then calls it on method 1.
if parent.Parent != nil {
calledCreateOnEAM := parent.Parent.Action.FilecoinTo == builtin.EthereumAddressManagerActorAddr &&
(parent.Parent.Action.FilecoinMethod == builtin.MethodsEAM.Create || parent.Parent.Action.FilecoinMethod == builtin.MethodsEAM.Create2)
eamCalledInitOnExec4 := parent.Action.FilecoinTo == builtin.InitActorAddr &&
parent.Action.FilecoinMethod == builtin.MethodsInit.Exec4
initCreatedActor := trace.Action.FilecoinMethod == builtin.MethodConstructor
// TODO: We need to handle failures in contract creations and support resurrections on an existing but dead EVM actor)
if calledCreateOnEAM && eamCalledInitOnExec4 && initCreatedActor {
log.Debugf("COND4 EVM contract creation method:%d, code:%s, height:%d", et.Msg.Method, et.Msg.CodeCid.String(), height)
if parent.Parent.Action.FilecoinMethod == builtin.MethodsEAM.Create {
parent.Parent.SetCallType("create")
} else {
parent.Parent.SetCallType("create2")
}
// update the parent.parent to make this
parent.Parent.Action.To = trace.Action.To
parent.Parent.Subtraces = 0
// delete the parent (the EAM) and skip the current trace (init)
*traces = (*traces)[:len(*traces)-1]
return nil
}
}
if builtinactors.IsEvmActor(parent.Action.FilecoinCodeCid) {
// Handle delegate calls
//
// 1) Look for trace from an EVM actor to itself on InvokeContractDelegate, method 6.
// 2) Check that the previous trace calls another actor on method 3 (GetByteCode) and they are at the same level (same parent)
// 3) Treat this as a delegate call to actor A.
if parent.LastByteCode != nil && trace.Action.From == trace.Action.To &&
trace.Action.FilecoinMethod == builtin.MethodsEVM.InvokeContractDelegate {
log.Debugf("COND7 found delegate call, height: %d", height)
prev := parent.LastByteCode
if prev.Action.From == trace.Action.From && prev.Action.FilecoinMethod == builtin.MethodsEVM.GetBytecode && prev.Parent == trace.Parent {
trace.SetCallType("delegatecall")
trace.Action.To = prev.Action.To
var dp evm.DelegateCallParams
err := dp.UnmarshalCBOR(bytes.NewReader(et.Msg.Params))
if err != nil {
return xerrors.Errorf("failed UnmarshalCBOR: %w", err)
}
trace.Action.Input = dp.Input
trace.Result.Output, err = decodePayload(et.MsgRct.Return, et.MsgRct.ReturnCodec)
if err != nil {
return xerrors.Errorf("failed decodePayload: %w", err)
}
}
} else {
// Handle EVM call special casing
//
// Any outbound call from an EVM actor on methods 1-1023 are side-effects from EVM instructions
// and should be dropped from the trace.
if et.Msg.Method > 0 &&
et.Msg.Method <= 1023 {
log.Debugf("Infof found outbound call from an EVM actor on method 1-1023 method:%d, code:%s, height:%d", et.Msg.Method, parent.Action.FilecoinCodeCid.String(), height)
if et.Msg.Method == builtin.MethodsEVM.GetBytecode {
// save the last bytecode trace to handle delegate calls
parent.LastByteCode = trace
}
return nil
}
}
}
}
// we are adding trace to the traces so update the parent subtraces count as it was originally set to zero
if parent != nil {
parent.Subtraces++
}
*traces = append(*traces, trace)
for i, call := range et.Subcalls {
err := buildTraces(ctx, traces, trace, append(addr, i), call, height, sa)
if err != nil {
return err
}
}
return nil
}