forked from keybase/client
/
saltpack_user_keyfinder.go
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/
saltpack_user_keyfinder.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 (
"fmt"
"github.com/keybase/client/go/libkb"
keybase1 "github.com/keybase/client/go/protocol/keybase1"
)
// SaltpackUserKeyfinder is an engine to find Per User Keys (PUK). Users can also be loaded by assertions, possibly tracking them if necessary.
// This engine does not find per team keys, which capability is implemented by SaltpackRecipientKeyfinder in the saltpackKeyHelpers package.
type SaltpackUserKeyfinder struct {
Arg libkb.SaltpackRecipientKeyfinderArg
RecipientEntityKeyMap map[keybase1.UserOrTeamID]([]keybase1.KID)
RecipientDeviceAndPaperKeyMap map[keybase1.UID]([]keybase1.KID)
UsingSBS bool
SBSAssertion string
}
var _ libkb.Engine2 = (*SaltpackUserKeyfinder)(nil)
var _ libkb.SaltpackRecipientKeyfinderEngineInterface = (*SaltpackUserKeyfinder)(nil)
// NewSaltpackUserKeyfinderAsInterface creates a SaltpackUserKeyfinder engine.
func NewSaltpackUserKeyfinderAsInterface(arg libkb.SaltpackRecipientKeyfinderArg) libkb.SaltpackRecipientKeyfinderEngineInterface {
return NewSaltpackUserKeyfinder(arg)
}
func NewSaltpackUserKeyfinder(arg libkb.SaltpackRecipientKeyfinderArg) *SaltpackUserKeyfinder {
return &SaltpackUserKeyfinder{
Arg: arg,
RecipientEntityKeyMap: make(map[keybase1.UserOrTeamID]([]keybase1.KID)),
RecipientDeviceAndPaperKeyMap: make(map[keybase1.UID]([]keybase1.KID)),
}
}
// Name is the unique engine name.
func (e *SaltpackUserKeyfinder) Name() string {
return "SaltpackUserKeyfinder"
}
// Prereqs returns the engine prereqs.
func (e *SaltpackUserKeyfinder) Prereqs() Prereqs {
return Prereqs{}
}
// RequiredUIs returns the required UIs.
func (e *SaltpackUserKeyfinder) RequiredUIs() []libkb.UIKind {
return []libkb.UIKind{}
}
// SubConsumers returns the other UI consumers for this engine.
func (e *SaltpackUserKeyfinder) SubConsumers() []libkb.UIConsumer {
return []libkb.UIConsumer{}
}
func (e *SaltpackUserKeyfinder) GetPublicKIDs() []keybase1.KID {
var r []keybase1.KID
for _, keys := range e.RecipientDeviceAndPaperKeyMap {
r = append(r, keys...)
}
for _, keys := range e.RecipientEntityKeyMap {
r = append(r, keys...)
}
return r
}
func (e *SaltpackUserKeyfinder) GetSymmetricKeys() []libkb.SaltpackReceiverSymmetricKey {
return []libkb.SaltpackReceiverSymmetricKey{}
}
func (e *SaltpackUserKeyfinder) UsedUnresolvedSBSAssertion() (bool, string) {
return e.UsingSBS, e.SBSAssertion
}
func (e *SaltpackUserKeyfinder) Run(m libkb.MetaContext) (err error) {
defer m.Trace("SaltpackUserKeyfinder#Run", &err)()
if len(e.Arg.TeamRecipients) != 0 {
m.Debug("tried to use SaltpackUserKeyfinder for a team. This should never happen")
return fmt.Errorf("cannot find keys for teams")
}
err = e.AddOwnKeysIfNeeded(m)
if err != nil {
return err
}
err = e.identifyAndAddRecipients(m)
if err != nil {
return err
}
return nil
}
func (e *SaltpackUserKeyfinder) AddOwnKeysIfNeeded(m libkb.MetaContext) error {
if e.Arg.NoSelfEncrypt {
return nil
}
if !m.ActiveDevice().Valid() {
return libkb.NewLoginRequiredError("need to be logged in or use --no-self-encrypt")
}
arg := libkb.NewLoadUserArgWithMetaContext(m).WithUID(m.ActiveDevice().UID()).WithForcePoll(!e.Arg.NoForcePoll)
upak, _, err := m.G().GetUPAKLoader().LoadV2(arg)
if err != nil {
return err
}
return e.AddUserRecipient(m, &upak.Current)
}
// identifyAndAddRecipients adds the KID corresponding to each recipient to the recipientMap
func (e *SaltpackUserKeyfinder) identifyAndAddRecipients(m libkb.MetaContext) error {
for _, u := range e.Arg.Recipients {
// TODO make these lookups in parallel (maybe using sync.WaitGroup)
upk, err := e.IdentifyUser(m, u) // For existing users
switch {
case err == nil:
// nothing to do here
case libkb.IsIdentifyProofError(err):
return fmt.Errorf("Cannot encrypt for %v as their account has changed since you last followed them (it might have been compromised!): please review their identity (with `keybase follow %v`) and then try again (err = %v)", u, u, err)
case libkb.IsNotFoundError(err) || libkb.IsResolutionError(err):
return fmt.Errorf("Cannot find keys for %v: it is not an assertion for a registered user (err = %v)", u, err)
default:
return fmt.Errorf("Error while adding keys for %v: %v", u, err)
}
err = e.AddUserRecipient(m, upk)
if err != nil {
return err
}
}
return nil
}
func (e *SaltpackUserKeyfinder) IdentifyUser(m libkb.MetaContext, user string) (upk *keybase1.UserPlusKeysV2, err error) {
Arg := keybase1.Identify2Arg{
UserAssertion: user,
Reason: keybase1.IdentifyReason{
Type: keybase1.IdentifyReasonType_ENCRYPT,
},
AlwaysBlock: true,
IdentifyBehavior: keybase1.TLFIdentifyBehavior_SALTPACK,
}
eng := NewResolveThenIdentify2(m.G(), &Arg)
if err := RunEngine2(m, eng); err != nil {
return nil, err
}
engRes, err := eng.Result(m)
if err != nil {
return nil, err
}
return &engRes.Upk.Current, nil
}
func (e *SaltpackUserKeyfinder) hasRecipientDeviceOrPaperKeys(id keybase1.UID) bool {
_, ok := e.RecipientDeviceAndPaperKeyMap[id]
return ok
}
func (e *SaltpackUserKeyfinder) hasRecipientEntityKeys(id keybase1.UserOrTeamID) bool {
_, ok := e.RecipientEntityKeyMap[id]
return ok
}
func (e *SaltpackUserKeyfinder) AddUserRecipient(m libkb.MetaContext, upk *keybase1.UserPlusKeysV2) error {
err := e.AddDeviceAndPaperKeys(m, upk)
err2 := e.AddPUK(m, upk)
// If we managed to add at least one key for upk, we are happy.
if (!(e.Arg.UseDeviceKeys || e.Arg.UsePaperKeys) || err != nil) && (!e.Arg.UseEntityKeys || err2 != nil) {
return libkb.PickFirstError(err, err2)
}
return nil
}
func (e *SaltpackUserKeyfinder) isPaperEncryptionKey(key *keybase1.PublicKeyV2NaCl, deviceKeys *(map[keybase1.KID]keybase1.PublicKeyV2NaCl)) bool {
return libkb.KIDIsDeviceEncrypt(key.Base.Kid) && key.Parent != nil && (*deviceKeys)[*key.Parent].DeviceType == keybase1.DeviceTypeV2_PAPER
}
// AddPUK returns no error if it adds at least one key (or no paper keys and device keys were requested), otherwise it returns a libkb.NoNaClEncryptionKeyError
func (e *SaltpackUserKeyfinder) AddDeviceAndPaperKeys(m libkb.MetaContext, upk *keybase1.UserPlusKeysV2) error {
if !e.Arg.UsePaperKeys && !e.Arg.UseDeviceKeys {
// No need to add anything
return nil
}
if e.hasRecipientDeviceOrPaperKeys(upk.Uid) {
// This user's keys were already added
return nil
}
var keys []keybase1.KID
hasPaperKey := false
hasDeviceKey := false
hasPUK := len(upk.PerUserKeys) > 0
for KID, key := range upk.DeviceKeys {
// Note: for Nacl encryption keys, the DeviceType field is not set, so we need to look at the "parent" signing key
if e.isPaperEncryptionKey(&key, &upk.DeviceKeys) {
hasPaperKey = true
if e.Arg.UsePaperKeys {
keys = append(keys, KID)
m.Debug("adding user %v's paper key", upk.Username)
}
}
if libkb.KIDIsDeviceEncrypt(KID) && !e.isPaperEncryptionKey(&key, &upk.DeviceKeys) {
hasDeviceKey = true
if e.Arg.UseDeviceKeys {
keys = append(keys, KID)
m.Debug("adding user %v's device key", upk.Username)
}
}
}
e.RecipientDeviceAndPaperKeyMap[upk.Uid] = keys
if len(keys) == 0 {
m.Debug("did not add any device or paper keys for %v", upk.Username)
return libkb.NoNaClEncryptionKeyError{
Username: upk.Username,
HasPGPKey: len(upk.PGPKeys) > 0,
HasPUK: hasPUK,
HasDeviceKey: hasDeviceKey,
HasPaperKey: hasPaperKey,
}
}
return nil
}
// AddPUK returns no error unless the user has no PUK, in which case it returns a libkb.NoNaClEncryptionKeyError
func (e *SaltpackUserKeyfinder) AddPUK(m libkb.MetaContext, upk *keybase1.UserPlusKeysV2) error {
if !e.Arg.UseEntityKeys {
// No need to add anything
return nil
}
if e.hasRecipientEntityKeys(upk.Uid.AsUserOrTeam()) {
// This user's keys were already added
return nil
}
hasPUK := len(upk.PerUserKeys) > 0
if !hasPUK {
hasPaperKey := false
hasDeviceKey := false
for KID, key := range upk.DeviceKeys {
if e.isPaperEncryptionKey(&key, &upk.DeviceKeys) {
hasPaperKey = true
}
if libkb.KIDIsDeviceEncrypt(KID) && !e.isPaperEncryptionKey(&key, &upk.DeviceKeys) {
hasDeviceKey = true
}
}
m.Debug("did not add any per user keys for %v", upk.Username)
return libkb.NoNaClEncryptionKeyError{
Username: upk.Username,
HasPGPKey: len(upk.PGPKeys) > 0,
HasPUK: hasPUK,
HasDeviceKey: hasDeviceKey,
HasPaperKey: hasPaperKey,
}
}
// We ensured above that the user has a PUK, so the loop below will be executed at least once
maxGen := -1
var lk keybase1.KID
for _, k := range upk.PerUserKeys {
if k.Gen > maxGen {
maxGen = k.Gen
lk = k.EncKID
}
}
if lk == "" {
panic("This should never happen, user has a PUK with a nil KID")
}
m.Debug("adding user %v's latest per user key", upk.Username)
e.RecipientEntityKeyMap[upk.Uid.AsUserOrTeam()] = []keybase1.KID{lk}
return nil
}