1 files changed, 248 insertions, 0 deletions
diff --git a/signer/rules/rules.go b/signer/rules/rules.go
new file mode 100644
index 000000000..fa270436d
--- /dev/null
+++ b/signer/rules/rules.go
@@ -0,0 +1,248 @@
+// 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/common"
+	"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.Stdout, strings.Join(output, " "))
+	return otto.Value{}
+}
+
+// rulesetUi provides an implementation of SignerUI that evaluates a javascript
+// file for each defined UI-method
+type rulesetUi struct {
+	next        core.SignerUI // The next handler, for manual processing
+	storage     storage.Storage
+	credentials storage.Storage
+	jsRules     string // The rules to use
+}
+
+func NewRuleEvaluator(next core.SignerUI, jsbackend, credentialsBackend storage.Storage) (*rulesetUi, error) {
+	c := &rulesetUi{
+		next:        next,
+		storage:     jsbackend,
+		credentials: credentialsBackend,
+		jsRules:     "",
+	}
+
+	return c, nil
+}
+
+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", r.storage)
+
+	// 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,
+				Password:    r.lookupPassword(request.Transaction.From.Address()),
+			},
+			nil
+	}
+	return core.SignTxResponse{Approved: false}, err
+}
+
+func (r *rulesetUi) lookupPassword(address common.Address) string {
+	return r.credentials.Get(strings.ToLower(address.String()))
+}
+
+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, Password: r.lookupPassword(request.Address.Address())}, nil
+	}
+	return core.SignDataResponse{Approved: false, Password: ""}, err
+}
+
+func (r *rulesetUi) ApproveExport(request *core.ExportRequest) (core.ExportResponse, error) {
+	jsonreq, err := json.Marshal(request)
+	approved, err := r.checkApproval("ApproveExport", jsonreq, err)
+	if err != nil {
+		log.Info("Rule-based approval error, going to manual", "error", err)
+		return r.next.ApproveExport(request)
+	}
+	if approved {
+		return core.ExportResponse{Approved: true}, nil
+	}
+	return core.ExportResponse{Approved: false}, err
+}
+
+func (r *rulesetUi) ApproveImport(request *core.ImportRequest) (core.ImportResponse, error) {
+	// This cannot be handled by rules, requires setting a password
+	// dispatch to next
+	return r.next.ApproveImport(request)
+}
+
+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)
+	}
+}