cmd/clef, signer: initial poc of the standalone signer (#16154)

* signer: introduce external signer command

* cmd/signer, rpc: Implement new signer. Add info about remote user to Context

* signer: refactored request/response, made use of urfave.cli

* cmd/signer: Use common flags

* cmd/signer: methods to validate calldata against abi

* cmd/signer: work on abi parser

* signer: add mutex around UI

* cmd/signer: add json 4byte directory, remove passwords from api

* cmd/signer: minor changes

* cmd/signer: Use ErrRequestDenied, enable lightkdf

* cmd/signer: implement tests

* cmd/signer: made possible for UI to modify tx parameters

* cmd/signer: refactors, removed channels in ui comms, added UI-api via stdin/out

* cmd/signer: Made lowercase json-definitions, added UI-signer test functionality

* cmd/signer: update documentation

* cmd/signer: fix bugs, improve abi detection, abi argument display

* cmd/signer: minor change in json format

* cmd/signer: rework json communication

* cmd/signer: implement mixcase addresses in API, fix json id bug

* cmd/signer: rename fromaccount, update pythonpoc with new json encoding format

* cmd/signer: make use of new abi interface

* signer: documentation

* signer/main: remove redundant  option

* signer: implement audit logging

* signer: create package 'signer', minor changes

* common: add 0x-prefix to mixcaseaddress in json marshalling + validation

* signer, rules, storage: implement rules + ephemeral storage for signer rules

* signer: implement OnApprovedTx, change signing response (API BREAKAGE)

* signer: refactoring + documentation

* signer/rules: implement dispatching to next handler

* signer: docs

* signer/rules: hide json-conversion from users, ensure context is cleaned

* signer: docs

* signer: implement validation rules, change signature of call_info

* signer: fix log flaw with string pointer

* signer: implement custom 4byte databsae that saves submitted signatures

* signer/storage: implement aes-gcm-backed credential storage

* accounts: implement json unmarshalling of url

* signer: fix listresponse, fix gas->uint64

* node: make http/ipc start methods public

* signer: add ipc capability+review concerns

* accounts: correct docstring

* signer: address review concerns

* rpc: go fmt -s

* signer: review concerns+ baptize Clef

* signer,node: move Start-functions to separate file

* signer: formatting

common/types.go

@@ -23,8 +23,10 @@ import (
 	"math/rand"
 	"reflect"
 
+	"encoding/json"
 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/ethereum/go-ethereum/crypto/sha3"
+	"strings"
 )
 
 const (
@@ -238,3 +240,63 @@ func (a *UnprefixedAddress) UnmarshalText(input []byte) error {
 func (a UnprefixedAddress) MarshalText() ([]byte, error) {
 	return []byte(hex.EncodeToString(a[:])), nil
 }
+
+// MixedcaseAddress retains the original string, which may or may not be
+// correctly checksummed
+type MixedcaseAddress struct {
+	addr     Address
+	original string
+}
+
+// NewMixedcaseAddress constructor (mainly for testing)
+func NewMixedcaseAddress(addr Address) MixedcaseAddress {
+	return MixedcaseAddress{addr: addr, original: addr.Hex()}
+}
+
+// NewMixedcaseAddressFromString is mainly meant for unit-testing
+func NewMixedcaseAddressFromString(hexaddr string) (*MixedcaseAddress, error) {
+	if !IsHexAddress(hexaddr) {
+		return nil, fmt.Errorf("Invalid address")
+	}
+	a := FromHex(hexaddr)
+	return &MixedcaseAddress{addr: BytesToAddress(a), original: hexaddr}, nil
+}
+
+// UnmarshalJSON parses MixedcaseAddress
+func (ma *MixedcaseAddress) UnmarshalJSON(input []byte) error {
+	if err := hexutil.UnmarshalFixedJSON(addressT, input, ma.addr[:]); err != nil {
+		return err
+	}
+	return json.Unmarshal(input, &ma.original)
+}
+
+// MarshalJSON marshals the original value
+func (ma *MixedcaseAddress) MarshalJSON() ([]byte, error) {
+	if strings.HasPrefix(ma.original, "0x") || strings.HasPrefix(ma.original, "0X") {
+		return json.Marshal(fmt.Sprintf("0x%s", ma.original[2:]))
+	}
+	return json.Marshal(fmt.Sprintf("0x%s", ma.original))
+}
+
+// Address returns the address
+func (ma *MixedcaseAddress) Address() Address {
+	return ma.addr
+}
+
+// String implements fmt.Stringer
+func (ma *MixedcaseAddress) String() string {
+	if ma.ValidChecksum() {
+		return fmt.Sprintf("%s [chksum ok]", ma.original)
+	}
+	return fmt.Sprintf("%s [chksum INVALID]", ma.original)
+}
+
+// ValidChecksum returns true if the address has valid checksum
+func (ma *MixedcaseAddress) ValidChecksum() bool {
+	return ma.original == ma.addr.Hex()
+}
+
+// Original returns the mixed-case input string
+func (ma *MixedcaseAddress) Original() string {
+	return ma.original
+}