/
provisioner.go
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/
provisioner.go
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// Copyright 2015 Keybase, Inc. All rights reserved. Use of
// this source code is governed by the included BSD license.
package kex2
import (
"net"
"strings"
"time"
"golang.org/x/net/context"
keybase1 "github.com/keybase/client/go/protocol/keybase1"
"github.com/keybase/go-framed-msgpack-rpc/rpc"
)
type provisioner struct {
baseDevice
arg ProvisionerArg
helloReceived bool
}
// Provisioner is an interface that abstracts out the crypto and session
// management that a provisioner needs to do as part of the protocol.
type Provisioner interface {
GetHelloArg() (keybase1.HelloArg, error)
GetHello2Arg() (keybase1.Hello2Arg, error)
CounterSign(keybase1.HelloRes) ([]byte, error)
CounterSign2(keybase1.Hello2Res) (keybase1.DidCounterSign2Arg, error)
GetLogFactory() rpc.LogFactory
}
// ProvisionerArg provides the details that a provisioner needs in order
// to run its course
type ProvisionerArg struct {
KexBaseArg
Provisioner Provisioner
HelloTimeout time.Duration
}
func newProvisioner(arg ProvisionerArg) *provisioner {
if arg.HelloTimeout == 0 {
arg.HelloTimeout = arg.Timeout
}
ret := &provisioner{
baseDevice: baseDevice{
start: make(chan struct{}),
},
arg: arg,
}
return ret
}
func (p *provisioner) debug(fmtString string, args ...interface{}) {
if p.arg.LogCtx != nil {
p.arg.LogCtx.Debug(fmtString, args...)
}
}
// RunProvisioner runs a provisioner given the necessary arguments.
func RunProvisioner(arg ProvisionerArg) error {
p := newProvisioner(arg)
err := p.run()
p.close() // ignore any errors in closing the channel
return err
}
func (p *provisioner) close() (err error) {
if p.conn != nil {
err = p.conn.Close()
}
return err
}
func (p *provisioner) KexStart(_ context.Context) error {
close(p.start)
return nil
}
func (p *provisioner) run() (err error) {
if err = p.setDeviceID(); err != nil {
return err
}
if err = p.pickFirstConnection(); err != nil {
return err
}
return p.runProtocolWithCancel()
}
func (k KexBaseArg) getDeviceID() (ret DeviceID, err error) {
err = k.DeviceID.ToBytes([]byte(ret[:]))
return ret, err
}
func (p *provisioner) setDeviceID() (err error) {
p.deviceID, err = p.arg.getDeviceID()
return err
}
func (p *provisioner) pickFirstConnection() (err error) {
// This connection is auto-closed at the end of this function, so if
// you don't want it to close, then set it to nil. See the first
// case in the select below.
var conn net.Conn
var xp rpc.Transporter
defer func() {
if conn != nil {
conn.Close()
}
}()
// Only make a channel if we were provided a secret to start it with.
// If not, we'll just have to wait for a message on p.arg.SecretChannel
// and use the provisionee's channel.
if len(p.arg.Secret) != 0 {
if conn, err = NewConn(p.arg.Ctx, p.arg.LogCtx, p.arg.Mr, p.arg.Secret, p.deviceID, p.arg.Timeout); err != nil {
return err
}
prot := keybase1.Kex2ProvisionerProtocol(p)
xp = rpc.NewTransport(conn, p.arg.Provisioner.GetLogFactory(), nil, rpc.DefaultMaxFrameLength)
srv := rpc.NewServer(xp, nil)
if err = srv.Register(prot); err != nil {
return err
}
serverDoneCh := srv.Run()
// TODO: Do something with serverDoneCh.
_ = serverDoneCh
}
select {
case <-p.start:
p.conn = conn
conn = nil // so it's not closed in the defer()'ed close
p.xp = xp
case sec := <-p.arg.SecretChannel:
if len(sec) != SecretLen {
return ErrBadSecret
}
if p.conn, err = NewConn(p.arg.Ctx, p.arg.LogCtx, p.arg.Mr, sec, p.deviceID, p.arg.Timeout); err != nil {
return err
}
p.xp = rpc.NewTransport(p.conn, p.arg.Provisioner.GetLogFactory(), nil, rpc.DefaultMaxFrameLength)
case <-p.arg.Ctx.Done():
err = ErrCanceled
case <-time.After(p.arg.Timeout):
err = ErrTimedOut
}
return
}
func (p *provisioner) runProtocolWithCancel() (err error) {
ch := make(chan error)
go func() {
ch <- p.runProtocol()
}()
select {
case <-p.arg.Ctx.Done():
p.canceled = true
return ErrCanceled
case err = <-ch:
if err == context.Canceled && !p.helloReceived {
return ErrHelloTimeout
}
return err
}
}
func (p *provisioner) runProtocol() (err error) {
var fallback bool
p.debug("+ provisioner#runProtocol: try V2")
fallback, err = p.runProtocolV2()
p.debug("- provisioner#runProtocol -> %v, %v", fallback, err)
if fallback {
p.debug("+ provisioner#runProtocol: fallback to V1")
err = p.runProtocolV1()
p.debug("- provisioner#runProtocol V1 -> %v", err)
}
return err
}
func (p *provisioner) runProtocolV2() (fallback bool, err error) {
cli := keybase1.Kex2Provisionee2Client{Cli: rpc.NewClient(p.xp, nil, nil)}
var helloArg keybase1.Hello2Arg
helloArg, err = p.arg.Provisioner.GetHello2Arg()
if err != nil {
return false, err
}
var res keybase1.Hello2Res
if res, err = cli.Hello2(context.TODO(), helloArg); err != nil {
if strings.Contains(err.Error(), "protocol not found: keybase.1.Kex2Provisionee2") {
return true, nil
}
return false, err
}
if p.canceled {
return false, ErrCanceled
}
p.helloReceived = true
var counterSign2Arg keybase1.DidCounterSign2Arg
if counterSign2Arg, err = p.arg.Provisioner.CounterSign2(res); err != nil {
return false, err
}
if err = cli.DidCounterSign2(context.TODO(), counterSign2Arg); err != nil {
return false, err
}
return false, nil
}
func (p *provisioner) runProtocolV1() (err error) {
cli := keybase1.Kex2ProvisioneeClient{Cli: rpc.NewClient(p.xp, nil, nil)}
var helloArg keybase1.HelloArg
helloArg, err = p.arg.Provisioner.GetHelloArg()
if err != nil {
return
}
var res keybase1.HelloRes
if res, err = cli.Hello(context.TODO(), helloArg); err != nil {
return
}
if p.canceled {
return ErrCanceled
}
p.helloReceived = true
var counterSigned []byte
if counterSigned, err = p.arg.Provisioner.CounterSign(res); err != nil {
return err
}
return cli.DidCounterSign(context.TODO(), counterSigned)
}