forked from keybase/client
/
passphrase_change.go
456 lines (382 loc) · 12.2 KB
/
passphrase_change.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 (
"errors"
"fmt"
"github.com/keybase/client/go/libkb"
keybase1 "github.com/keybase/client/go/protocol/keybase1"
triplesec "github.com/keybase/go-triplesec"
)
// PassphraseChange engine is used for changing the user's passphrase, either
// by replacement or by force.
type PassphraseChange struct {
arg *keybase1.PassphraseChangeArg
me *libkb.User
ppStream *libkb.PassphraseStream
usingPaper bool
libkb.Contextified
}
// NewPassphraseChange creates a new engine for changing user passphrases,
// either if the current passphrase is known, or in "force" mode
func NewPassphraseChange(a *keybase1.PassphraseChangeArg, g *libkb.GlobalContext) *PassphraseChange {
return &PassphraseChange{
arg: a,
Contextified: libkb.NewContextified(g),
}
}
// Name provides the name of the engine for the engine interface
func (c *PassphraseChange) Name() string {
return "PassphraseChange"
}
// Prereqs returns engine prereqs
func (c *PassphraseChange) Prereqs() Prereqs {
if c.arg.Force {
return Prereqs{}
}
return Prereqs{Session: true}
}
// RequiredUIs returns the required UIs.
func (c *PassphraseChange) RequiredUIs() []libkb.UIKind {
return []libkb.UIKind{
libkb.SecretUIKind,
}
}
// SubConsumers requires the other UI consumers of this engine
func (c *PassphraseChange) SubConsumers() []libkb.UIConsumer {
return []libkb.UIConsumer{
&PaperKeyGen{},
}
}
// Run the engine
func (c *PassphraseChange) Run(ctx *Context) (err error) {
c.G().Log.Debug("+ PassphraseChange.Run")
defer func() {
c.G().Log.Debug("- PassphraseChange.Run -> %s", libkb.ErrToOk(err))
c.G().SKBKeyringMu.Unlock()
}()
c.G().SKBKeyringMu.Lock()
c.G().Log.Debug("| Acquired SKBKeyringMu mutex")
if len(c.arg.Passphrase) < libkb.MinPassphraseLength {
return libkb.PassphraseError{Msg: "too short"}
}
if err = c.loadMe(); err != nil {
return
}
c.G().LoginState().RunSecretSyncer(c.me.GetUID())
if c.arg.Force {
err = c.runForcedUpdate(ctx)
} else {
err = c.runStandardUpdate(ctx)
}
if err == nil {
c.G().LoginState().RunSecretSyncer(c.me.GetUID())
}
return
}
// findDeviceKeys looks for device keys and unlocks them.
func (c *PassphraseChange) findDeviceKeys(ctx *Context) (*keypair, error) {
return findDeviceKeys(ctx, c, c.me)
}
// findPaperKeys checks if the user has paper keys. If he/she
// does, it prompts for a paper key phrase. This is used to
// regenerate paper keys, which are then matched against the
// paper keys found in the keyfamily.
func (c *PassphraseChange) findPaperKeys(ctx *Context) (*keypair, error) {
kp, err := findPaperKeys(ctx, c.G(), c.me)
if err != nil {
c.G().Log.Debug("findPaperKeys error: %s", err)
return nil, err
}
c.G().Log.Debug("findPaperKeys success")
c.usingPaper = true
return kp, nil
}
// findUpdateKeys looks for keys to perform the passphrase update.
// The first choice is device keys. If that fails, it will look
// for backup keys. If backup keys are necessary, then it will
// also log the user in with the backup keys.
func (c *PassphraseChange) findUpdateKeys(ctx *Context) (*keypair, error) {
kp, err := c.findDeviceKeys(ctx)
if err == nil {
return kp, nil
}
kp, err = c.findPaperKeys(ctx)
if err != nil {
return nil, err
}
// log in with backup keys
err = c.G().LoginState().LoginWithKey(ctx.LoginContext, c.me, kp.sigKey, nil)
if err != nil {
return nil, err
}
return kp, nil
}
func (c *PassphraseChange) forceUpdatePassphrase(ctx *Context, sigKey libkb.GenericKey, ppGen libkb.PassphraseGeneration, oldClientHalf libkb.LKSecClientHalf) error {
// Don't update server-synced pgp keys when recovering.
// This will render any server-synced pgp keys unrecoverable from the server.
// TODO would it responsible to ask the server to delete them?
pgpKeys, nPgpKeysLost, err := c.findAndDecryptPrivatePGPKeysLossy(ctx)
if err != nil {
return err
}
if nPgpKeysLost > 0 {
c.G().Log.Debug("PassphraseChange.runForcedUpdate: Losing %v synced keys", nPgpKeysLost)
}
var acctErr error
c.G().LoginState().Account(func(a *libkb.Account) {
// Ready the update argument; almost done, but we need some more stuff.
payload, err := c.commonArgs(a, oldClientHalf, pgpKeys, ppGen)
if err != nil {
acctErr = err
return
}
// get the new passphrase hash out of the args
pwh, ok := payload["pwh"].(string)
if !ok || len(pwh) == 0 {
acctErr = errors.New("no pwh found in common args")
return
}
// get the new PDPKA5 KID out of the args
pdpka5kid, ok := payload["pdpka5_kid"].(string)
if !ok || len(pdpka5kid) == 0 {
acctErr = errors.New("no pdpka5kid found in common args")
return
}
// Generate a signature with our unlocked sibling key from device.
proof, err := c.me.UpdatePassphraseProof(sigKey, pwh, ppGen+1, pdpka5kid)
if err != nil {
acctErr = err
return
}
sig, _, _, err := libkb.SignJSON(proof, sigKey)
if err != nil {
acctErr = err
return
}
payload["sig"] = sig
payload["signing_kid"] = sigKey.GetKID()
postArg := libkb.APIArg{
Endpoint: "passphrase/sign",
SessionType: libkb.APISessionTypeREQUIRED,
JSONPayload: payload,
SessionR: a.LocalSession(),
}
_, err = c.G().API.PostJSON(postArg)
if err != nil {
acctErr = fmt.Errorf("api post to passphrase/sign error: %s", err)
return
}
// Reset passphrase stream cache so that subsequent updates go through
// without a problem (seee CORE-3933)
a.ClearStreamCache()
}, "PassphraseChange.runForcedUpdate")
if acctErr != nil {
return acctErr
}
return nil
}
// 1. Get keys for decryption and signing
// 2. If necessary, log in with backup keys
// 3. Get lks client half from server
// 4. Post an update passphrase proof
func (c *PassphraseChange) runForcedUpdate(ctx *Context) (err error) {
c.G().Log.Debug("+ PassphraseChange.runForcedUpdate")
defer func() {
c.G().Log.Debug("- PassphraseChange.runForcedUpdate -> %s", libkb.ErrToOk(err))
}()
kp, err := c.findUpdateKeys(ctx)
if err != nil {
return
}
if kp == nil {
return libkb.NoSecretKeyError{}
}
ppGen, oldClientHalf, err := fetchLKS(ctx, c.G(), kp.encKey)
if err != nil {
return
}
return c.forceUpdatePassphrase(ctx, kp.sigKey, ppGen, oldClientHalf)
}
// runStandardUpdate is for when the user knows the current password.
func (c *PassphraseChange) runStandardUpdate(ctx *Context) (err error) {
c.G().Log.Debug("+ PassphraseChange.runStandardUpdate")
defer func() {
c.G().Log.Debug("- PassphraseChange.runStandardUpdate -> %s", libkb.ErrToOk(err))
}()
if len(c.arg.OldPassphrase) == 0 {
err = c.getVerifiedPassphraseHash(ctx)
} else {
err = c.verifySuppliedPassphrase(ctx)
}
if err != nil {
return err
}
pgpKeys, err := c.findAndDecryptPrivatePGPKeys(ctx)
if err != nil {
return err
}
var acctErr error
c.G().LoginState().Account(func(a *libkb.Account) {
gen := a.PassphraseStreamCache().PassphraseStream().Generation()
oldClientHalf := a.PassphraseStreamCache().PassphraseStream().LksClientHalf()
payload, err := c.commonArgs(a, oldClientHalf, pgpKeys, gen)
if err != nil {
acctErr = err
return
}
lp, err := libkb.ComputeLoginPackage(a, "")
if err != nil {
acctErr = err
return
}
payload["ppgen"] = gen
payload["old_pdpka4"] = lp.PDPKA4()
payload["old_pdpka5"] = lp.PDPKA5()
postArg := libkb.APIArg{
Endpoint: "passphrase/replace",
SessionType: libkb.APISessionTypeREQUIRED,
JSONPayload: payload,
SessionR: a.LocalSession(),
}
_, err = c.G().API.PostJSON(postArg)
if err != nil {
acctErr = err
return
}
// Reset passphrase stream cache so that subsequent updates go through
// without a problem (seee CORE-3933)
a.ClearStreamCache()
}, "PassphraseChange.runStandardUpdate")
if acctErr != nil {
err = acctErr
return err
}
return nil
}
// commonArgs must be called inside a LoginState().Account(...)
// closure
func (c *PassphraseChange) commonArgs(a *libkb.Account, oldClientHalf libkb.LKSecClientHalf, pgpKeys []libkb.GenericKey, existingGen libkb.PassphraseGeneration) (libkb.JSONPayload, error) {
// ensure that the login session is loaded
if err := a.LoadLoginSession(c.me.GetName()); err != nil {
return nil, err
}
salt, err := a.LoginSession().Salt()
if err != nil {
return nil, err
}
tsec, newPPStream, err := libkb.StretchPassphrase(c.G(), c.arg.Passphrase, salt)
if err != nil {
return nil, err
}
newPWH := newPPStream.PWHash()
newClientHalf := newPPStream.LksClientHalf()
pdpka5kid, err := newPPStream.PDPKA5KID()
if err != nil {
return nil, err
}
mask := oldClientHalf.ComputeMask(newClientHalf)
lksch := make(map[keybase1.KID]string)
devices := c.me.GetComputedKeyFamily().GetAllDevices()
for _, dev := range devices {
if !dev.IsActive() {
continue
}
key, err := c.me.GetComputedKeyFamily().GetEncryptionSubkeyForDevice(dev.ID)
if err != nil {
return nil, err
}
ctext, err := key.EncryptToString(newClientHalf.Bytes(), nil)
if err != nil {
return nil, err
}
lksch[key.GetKID()] = ctext
}
payload := make(libkb.JSONPayload)
payload["pwh"] = libkb.HexArg(newPWH).String()
payload["pwh_version"] = triplesec.Version
payload["lks_mask"] = mask.EncodeToHex()
payload["lks_client_halves"] = lksch
payload["pdpka5_kid"] = pdpka5kid.String()
var encodedKeys []string
for _, key := range pgpKeys {
encoded, err := c.encodePrivatePGPKey(key, tsec, existingGen+1)
if err != nil {
return nil, err
}
encodedKeys = append(encodedKeys, encoded)
}
payload["private_keys"] = encodedKeys
return payload, nil
}
func (c *PassphraseChange) loadMe() (err error) {
c.me, err = libkb.LoadMe(libkb.NewLoadUserForceArg(c.G()))
return
}
func (c *PassphraseChange) getVerifiedPassphraseHash(ctx *Context) (err error) {
c.ppStream, err = c.G().LoginState().GetPassphraseStream(ctx.SecretUI)
return
}
func (c *PassphraseChange) verifySuppliedPassphrase(ctx *Context) (err error) {
c.ppStream, err = c.G().LoginState().VerifyPlaintextPassphrase(c.arg.OldPassphrase)
return
}
// findAndDecryptPrivatePGPKeys gets the user's private pgp keys if any exist and decrypts them.
func (c *PassphraseChange) findAndDecryptPrivatePGPKeys(ctx *Context) ([]libkb.GenericKey, error) {
var keyList []libkb.GenericKey
// Using a paper key makes TripleSec-synced keys unrecoverable
if c.usingPaper {
c.G().Log.Debug("using a paper key, thus TripleSec-synced keys are unrecoverable")
return keyList, nil
}
// Only use the synced secret keys:
blocks, err := c.me.AllSyncedSecretKeys(ctx.LoginContext)
if err != nil {
return nil, err
}
secretRetriever := libkb.NewSecretStore(c.G(), c.me.GetNormalizedName())
for _, block := range blocks {
parg := ctx.SecretKeyPromptArg(libkb.SecretKeyArg{}, "passphrase change")
key, err := block.PromptAndUnlock(parg, secretRetriever, c.me)
if err != nil {
return nil, err
}
keyList = append(keyList, key)
}
return keyList, nil
}
// findAndDecryptPrivatePGPKeysLossy gets the user's private pgp keys if any exist and attempts
// to decrypt them without prompting the user. If any fail to decrypt, they are silently not returned.
// The second return value is the number of keys which were not decrypted.
func (c *PassphraseChange) findAndDecryptPrivatePGPKeysLossy(ctx *Context) ([]libkb.GenericKey, int, error) {
var keyList []libkb.GenericKey
nLost := 0
// Only use the synced secret keys:
blocks, err := c.me.AllSyncedSecretKeys(ctx.LoginContext)
if err != nil {
return nil, 0, err
}
secretRetriever := libkb.NewSecretStore(c.G(), c.me.GetNormalizedName())
for _, block := range blocks {
key, err := block.UnlockNoPrompt(ctx.LoginContext, secretRetriever)
if err == nil {
keyList = append(keyList, key)
} else {
if err != libkb.ErrUnlockNotPossible {
return nil, 0, err
}
nLost++
c.G().Log.Debug("findAndDecryptPrivatePGPKeysLossy: ignoring failure to decrypt key without prompt")
}
}
return keyList, nLost, nil
}
// encodePrivatePGPKey encrypts key with tsec and armor-encodes it.
// It includes the passphrase generation in the data.
func (c *PassphraseChange) encodePrivatePGPKey(key libkb.GenericKey, tsec libkb.Triplesec, gen libkb.PassphraseGeneration) (string, error) {
skb, err := libkb.ToServerSKB(c.G(), key, tsec, gen)
if err != nil {
return "", err
}
return skb.ArmoredEncode()
}