forked from keybase/client
/
kex2_provisioner.go
346 lines (297 loc) · 8.78 KB
/
kex2_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 engine
import (
"time"
"github.com/keybase/client/go/kex2"
"github.com/keybase/client/go/libkb"
keybase1 "github.com/keybase/client/go/protocol/keybase1"
"github.com/keybase/go-framed-msgpack-rpc/rpc"
jsonw "github.com/keybase/go-jsonw"
"golang.org/x/net/context"
)
// Kex2Provisioner is an engine.
type Kex2Provisioner struct {
libkb.Contextified
secret kex2.Secret
secretCh chan kex2.Secret
me *libkb.User
signingKey libkb.GenericKey
pps keybase1.PassphraseStream
provisioneeDeviceName string
provisioneeDeviceType string
ctx *Context
}
// Kex2Provisioner implements kex2.Provisioner interface.
var _ kex2.Provisioner = (*Kex2Provisioner)(nil)
// NewKex2Provisioner creates a Kex2Provisioner engine.
func NewKex2Provisioner(g *libkb.GlobalContext, secret kex2.Secret, pps *libkb.PassphraseStream) *Kex2Provisioner {
e := &Kex2Provisioner{
Contextified: libkb.NewContextified(g),
secret: secret,
secretCh: make(chan kex2.Secret),
}
if pps != nil {
e.pps = pps.Export()
}
return e
}
// Name is the unique engine name.
func (e *Kex2Provisioner) Name() string {
return "Kex2Provisioner"
}
// GetPrereqs returns the engine prereqs.
func (e *Kex2Provisioner) Prereqs() Prereqs {
return Prereqs{Device: true}
}
// RequiredUIs returns the required UIs.
func (e *Kex2Provisioner) RequiredUIs() []libkb.UIKind {
return []libkb.UIKind{
libkb.SecretUIKind,
libkb.ProvisionUIKind,
}
}
// SubConsumers returns the other UI consumers for this engine.
func (e *Kex2Provisioner) SubConsumers() []libkb.UIConsumer {
return nil
}
// Run starts the provisioner engine.
func (e *Kex2Provisioner) Run(ctx *Context) error {
// before starting provisioning, need to load some information:
// load self:
var err error
e.me, err = libkb.LoadMe(libkb.NewLoadUserArg(e.G()))
if err != nil {
return err
}
// get signing key (including secret key):
ska := libkb.SecretKeyArg{
Me: e.me,
KeyType: libkb.DeviceSigningKeyType,
}
e.signingKey, err = e.G().Keyrings.GetSecretKeyWithPrompt(ctx.SecretKeyPromptArg(ska, "new device install"))
if err != nil {
return err
}
// get current passphrase stream if necessary:
if e.pps.PassphraseStream == nil {
e.G().Log.Debug("kex2 provisioner needs passphrase stream, getting it from LoginState")
pps, err := e.G().LoginState().GetPassphraseStreamStored(ctx.SecretUI)
if err != nil {
return err
}
e.pps = pps.Export()
}
// ctx needed by some kex2 functions
e.ctx = ctx
deviceID := e.G().Env.GetDeviceID()
nctx := ctx.NetContext
if nctx == nil {
e.G().Log.Debug("no NetContext in engine.Context, using context.Background()")
nctx = context.Background()
}
// all set: start provisioner
karg := kex2.KexBaseArg{
Ctx: nctx,
ProvisionCtx: e.G(),
Mr: libkb.NewKexRouter(e.G()),
DeviceID: deviceID,
Secret: e.secret,
SecretChannel: e.secretCh,
Timeout: 5 * time.Minute,
}
parg := kex2.ProvisionerArg{
KexBaseArg: karg,
Provisioner: e,
HelloTimeout: 15 * time.Second,
}
if err := kex2.RunProvisioner(parg); err != nil {
return err
}
// successfully provisioned the other device
sarg := keybase1.ProvisionerSuccessArg{
DeviceName: e.provisioneeDeviceName,
DeviceType: e.provisioneeDeviceType,
}
if err := ctx.ProvisionUI.ProvisionerSuccess(context.TODO(), sarg); err != nil {
return err
}
return nil
}
// AddSecret inserts a received secret into the provisioner's
// secret channel.
func (e *Kex2Provisioner) AddSecret(s kex2.Secret) {
e.secretCh <- s
}
// GetLogFactory implements GetLogFactory in kex2.Provisioner.
func (e *Kex2Provisioner) GetLogFactory() rpc.LogFactory {
return rpc.NewSimpleLogFactory(e.G().Log, nil)
}
// GetHelloArg implements GetHelloArg in kex2.Provisioner.
func (e *Kex2Provisioner) GetHelloArg() (arg keybase1.HelloArg, err error) {
e.G().Log.Debug("+ GetHelloArg()")
defer func() { e.G().Log.Debug("- GetHelloArg() -> %s", libkb.ErrToOk(err)) }()
e.ctx.ProvisionUI.DisplaySecretExchanged(context.TODO(), 0)
// get a session token that device Y can use
token, csrf, err := e.sessionForY()
if err != nil {
return arg, err
}
// generate a skeleton key proof
sigBody, err := e.skeletonProof()
if err != nil {
return arg, err
}
// return the HelloArg
arg = keybase1.HelloArg{
Uid: e.me.GetUID(),
Pps: e.pps,
Token: keybase1.SessionToken(token),
Csrf: keybase1.CsrfToken(csrf),
SigBody: sigBody,
}
return arg, nil
}
// GetHello2Arg implements GetHello2Arg in kex2.Provisioner.
func (e *Kex2Provisioner) GetHello2Arg() (arg2 keybase1.Hello2Arg, err error) {
e.G().Log.Debug("+ GetHello2Arg()")
defer func() { e.G().Log.Debug("- GetHello2Arg() -> %s", libkb.ErrToOk(err)) }()
var arg1 keybase1.HelloArg
arg1, err = e.GetHelloArg()
arg2 = keybase1.Hello2Arg{
Uid: arg1.Uid,
Token: arg1.Token,
Csrf: arg1.Csrf,
SigBody: arg1.SigBody,
}
return arg2, nil
}
// CounterSign implements CounterSign in kex2.Provisioner.
func (e *Kex2Provisioner) CounterSign(input keybase1.HelloRes) (sig []byte, err error) {
e.G().Log.Debug("+ CounterSign()")
defer func() { e.G().Log.Debug("- CounterSign() -> %s", libkb.ErrToOk(err)) }()
jw, err := jsonw.Unmarshal([]byte(input))
if err != nil {
return nil, err
}
// check the reverse signature
if err = e.checkReverseSig(jw); err != nil {
e.G().Log.Debug("provisioner failed to verify reverse sig: %s", err)
return nil, err
}
e.G().Log.Debug("provisioner verified reverse sig")
// remember some device information for ProvisionUI.ProvisionerSuccess()
if err = e.rememberDeviceInfo(jw); err != nil {
return nil, err
}
// sign the whole thing with provisioner's signing key
s, _, _, err := libkb.SignJSON(jw, e.signingKey)
if err != nil {
return nil, err
}
return []byte(s), nil
}
// CounterSign2 implements CounterSign in kex2.Provisioner.
func (e *Kex2Provisioner) CounterSign2(input keybase1.Hello2Res) (output keybase1.DidCounterSign2Arg, err error) {
defer e.G().Trace("CounterSign2()", func() error { return err })()
var key libkb.GenericKey
key, err = libkb.ImportKeypairFromKID(input.EncryptionKey)
if err != nil {
return output, err
}
output.Sig, err = e.CounterSign(input.SigPayload)
if err != nil {
return output, err
}
var ppsPacked []byte
ppsPacked, err = libkb.MsgpackEncode(e.pps)
if err != nil {
return output, err
}
output.PpsEncrypted, err = key.EncryptToString(ppsPacked, nil)
return output, err
}
// sessionForY gets session tokens that Y can use to interact with
// API server.
func (e *Kex2Provisioner) sessionForY() (token, csrf string, err error) {
resp, err := e.G().API.Post(libkb.APIArg{
Endpoint: "new_session",
NeedSession: true,
})
if err != nil {
return "", "", err
}
token, err = resp.Body.AtKey("session").GetString()
if err != nil {
return "", "", err
}
csrf, err = resp.Body.AtKey("csrf_token").GetString()
if err != nil {
return "", "", err
}
return token, csrf, nil
}
// skeletonProof generates a partial key proof structure that
// device Y can fill in.
func (e *Kex2Provisioner) skeletonProof() (string, error) {
delg := libkb.Delegator{
ExistingKey: e.signingKey,
Me: e.me,
DelegationType: libkb.SibkeyType,
Expire: libkb.NaclEdDSAExpireIn,
Contextified: libkb.NewContextified(e.G()),
}
jw, err := libkb.KeyProof(delg)
if err != nil {
return "", err
}
body, err := jw.Marshal()
if err != nil {
return "", err
}
return string(body), nil
}
// checkReverseSig verifies that the reverse sig in jw is valid
// and matches jw.
func (e *Kex2Provisioner) checkReverseSig(jw *jsonw.Wrapper) error {
kid, err := jw.AtPath("body.sibkey.kid").GetString()
if err != nil {
return err
}
keypair, err := libkb.ImportKeypairFromKID(keybase1.KIDFromString(kid))
if err != nil {
return err
}
revsig, err := jw.AtPath("body.sibkey.reverse_sig").GetString()
if err != nil {
return err
}
// set reverse_sig to nil to verify it:
jw.SetValueAtPath("body.sibkey.reverse_sig", jsonw.NewNil())
msg, err := jw.Marshal()
if err != nil {
return err
}
_, err = keypair.VerifyString(e.G().Log, revsig, msg)
if err != nil {
return err
}
// put reverse_sig back in
jw.SetValueAtPath("body.sibkey.reverse_sig", jsonw.NewString(revsig))
return nil
}
// rememberDeviceInfo saves the device name and type in
// Kex2Provisioner for later use.
func (e *Kex2Provisioner) rememberDeviceInfo(jw *jsonw.Wrapper) error {
name, err := jw.AtPath("body.device.name").GetString()
if err != nil {
return err
}
e.provisioneeDeviceName = name
dtype, err := jw.AtPath("body.device.type").GetString()
if err != nil {
return err
}
e.provisioneeDeviceType = dtype
return nil
}