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// Copyright 2018 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
package rules
import (
"encoding/json"
"fmt"
"os"
"strings"
"github.com/ethereum/go-ethereum/internal/ethapi"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/signer/core"
"github.com/ethereum/go-ethereum/signer/rules/deps"
"github.com/ethereum/go-ethereum/signer/storage"
"github.com/robertkrimen/otto"
)
var (
BigNumber_JS = deps.MustAsset("bignumber.js")
)
// consoleOutput is an override for the console.log and console.error methods to
// stream the output into the configured output stream instead of stdout.
func consoleOutput(call otto.FunctionCall) otto.Value {
output := []string{"JS:> "}
for _, argument := range call.ArgumentList {
output = append(output, fmt.Sprintf("%v", argument))
}
fmt.Fprintln(os.Stderr, strings.Join(output, " "))
return otto.Value{}
}
// rulesetUI provides an implementation of UIClientAPI that evaluates a javascript
// file for each defined UI-method
type rulesetUI struct {
next core.UIClientAPI // The next handler, for manual processing
storage storage.Storage
jsRules string // The rules to use
}
func NewRuleEvaluator(next core.UIClientAPI, jsbackend storage.Storage) (*rulesetUI, error) {
c := &rulesetUI{
next: next,
storage: jsbackend,
jsRules: "",
}
return c, nil
}
func (r *rulesetUI) RegisterUIServer(api *core.UIServerAPI) {
// TODO, make it possible to query from js
}
func (r *rulesetUI) Init(javascriptRules string) error {
r.jsRules = javascriptRules
return nil
}
func (r *rulesetUI) execute(jsfunc string, jsarg interface{}) (otto.Value, error) {
// Instantiate a fresh vm engine every time
vm := otto.New()
// Set the native callbacks
consoleObj, _ := vm.Get("console")
consoleObj.Object().Set("log", consoleOutput)
consoleObj.Object().Set("error", consoleOutput)
vm.Set("storage", struct{}{})
storageObj, _ := vm.Get("storage")
storageObj.Object().Set("put", func(call otto.FunctionCall) otto.Value {
key, val := call.Argument(0).String(), call.Argument(1).String()
if val == "" {
r.storage.Del(key)
} else {
r.storage.Put(key, val)
}
return otto.NullValue()
})
storageObj.Object().Set("get", func(call otto.FunctionCall) otto.Value {
goval, _ := r.storage.Get(call.Argument(0).String())
jsval, _ := otto.ToValue(goval)
return jsval
})
// Load bootstrap libraries
script, err := vm.Compile("bignumber.js", BigNumber_JS)
if err != nil {
log.Warn("Failed loading libraries", "err", err)
return otto.UndefinedValue(), err
}
vm.Run(script)
// Run the actual rule implementation
_, err = vm.Run(r.jsRules)
if err != nil {
log.Warn("Execution failed", "err", err)
return otto.UndefinedValue(), err
}
// And the actual call
// All calls are objects with the parameters being keys in that object.
// To provide additional insulation between js and go, we serialize it into JSON on the Go-side,
// and deserialize it on the JS side.
jsonbytes, err := json.Marshal(jsarg)
if err != nil {
log.Warn("failed marshalling data", "data", jsarg)
return otto.UndefinedValue(), err
}
// Now, we call foobar(JSON.parse(<jsondata>)).
var call string
if len(jsonbytes) > 0 {
call = fmt.Sprintf("%v(JSON.parse(%v))", jsfunc, string(jsonbytes))
} else {
call = fmt.Sprintf("%v()", jsfunc)
}
return vm.Run(call)
}
func (r *rulesetUI) checkApproval(jsfunc string, jsarg []byte, err error) (bool, error) {
if err != nil {
return false, err
}
v, err := r.execute(jsfunc, string(jsarg))
if err != nil {
log.Info("error occurred during execution", "error", err)
return false, err
}
result, err := v.ToString()
if err != nil {
log.Info("error occurred during response unmarshalling", "error", err)
return false, err
}
if result == "Approve" {
log.Info("Op approved")
return true, nil
} else if result == "Reject" {
log.Info("Op rejected")
return false, nil
}
return false, fmt.Errorf("Unknown response")
}
func (r *rulesetUI) ApproveTx(request *core.SignTxRequest) (core.SignTxResponse, error) {
jsonreq, err := json.Marshal(request)
approved, err := r.checkApproval("ApproveTx", jsonreq, err)
if err != nil {
log.Info("Rule-based approval error, going to manual", "error", err)
return r.next.ApproveTx(request)
}
if approved {
return core.SignTxResponse{
Transaction: request.Transaction,
Approved: true},
nil
}
return core.SignTxResponse{Approved: false}, err
}
func (r *rulesetUI) ApproveSignData(request *core.SignDataRequest) (core.SignDataResponse, error) {
jsonreq, err := json.Marshal(request)
approved, err := r.checkApproval("ApproveSignData", jsonreq, err)
if err != nil {
log.Info("Rule-based approval error, going to manual", "error", err)
return r.next.ApproveSignData(request)
}
if approved {
return core.SignDataResponse{Approved: true}, nil
}
return core.SignDataResponse{Approved: false}, err
}
// OnInputRequired not handled by rules
func (r *rulesetUI) OnInputRequired(info core.UserInputRequest) (core.UserInputResponse, error) {
return r.next.OnInputRequired(info)
}
func (r *rulesetUI) ApproveListing(request *core.ListRequest) (core.ListResponse, error) {
jsonreq, err := json.Marshal(request)
approved, err := r.checkApproval("ApproveListing", jsonreq, err)
if err != nil {
log.Info("Rule-based approval error, going to manual", "error", err)
return r.next.ApproveListing(request)
}
if approved {
return core.ListResponse{Accounts: request.Accounts}, nil
}
return core.ListResponse{}, err
}
func (r *rulesetUI) ApproveNewAccount(request *core.NewAccountRequest) (core.NewAccountResponse, error) {
// This cannot be handled by rules, requires setting a password
// dispatch to next
return r.next.ApproveNewAccount(request)
}
func (r *rulesetUI) ShowError(message string) {
log.Error(message)
r.next.ShowError(message)
}
func (r *rulesetUI) ShowInfo(message string) {
log.Info(message)
r.next.ShowInfo(message)
}
func (r *rulesetUI) OnSignerStartup(info core.StartupInfo) {
jsonInfo, err := json.Marshal(info)
if err != nil {
log.Warn("failed marshalling data", "data", info)
return
}
r.next.OnSignerStartup(info)
_, err = r.execute("OnSignerStartup", string(jsonInfo))
if err != nil {
log.Info("error occurred during execution", "error", err)
}
}
func (r *rulesetUI) OnApprovedTx(tx ethapi.SignTransactionResult) {
jsonTx, err := json.Marshal(tx)
if err != nil {
log.Warn("failed marshalling transaction", "tx", tx)
return
}
_, err = r.execute("OnApprovedTx", string(jsonTx))
if err != nil {
log.Info("error occurred during execution", "error", err)
}
}
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