// Check that the content of the UID message is consistent with it's version.
func (msg *Message) Check() error {
// we only support version 1.0 at this stage
if msg.UIDContent.VERSION != "1.0" {
return log.Errorf("uid: unknown UIDContent.VERSION: %s",
msg.UIDContent.VERSION)
}
// generic checks
optional := Optional.String()
if msg.UIDContent.PREFERENCES.FORWARDSEC != optional {
if msg.UIDContent.MIXADDRESS != "" {
return log.Errorf("uid: MIXADDRESS must be null, if FORWARDSEC is not %q",
optional)
}
if msg.UIDContent.NYMADDRESS != "" {
return log.Errorf("uid: NYMADDRESS must be null, if FORWARDSEC is not %q",
optional)
}
}
if err := identity.IsMapped(msg.UIDContent.IDENTITY); err != nil {
return log.Error(err)
}
// check SIGKEY
if msg.UIDContent.SIGKEY.CIPHERSUITE != DefaultCiphersuite {
return log.Error("uid: UIDContent.SIGKEY.CIPHERSUITE != DefaultCiphersuite")
}
if msg.UIDContent.SIGKEY.FUNCTION != "ED25519" {
return log.Error("uid: UIDContent.SIGKEY.FUNCTION != \"ED25519\"")
}
// make sure LASTENTRY is parseable for a non-keyserver localpart.
// For keyservers the LASTENTRY can be empty, iff this is the first entry
// in the hashchain.
lp, _, _ := identity.Split(msg.UIDContent.IDENTITY)
if lp != "keyserver" {
_, _, _, _, _, _, err := hashchain.SplitEntry(msg.UIDContent.LASTENTRY)
if err != nil {
return err
}
}
// make sure ESCROWSIGNATURE and USERSIGNATURE are not set at the same time
if msg.ESCROWSIGNATURE != "" && msg.USERSIGNATURE != "" {
return log.Error("uid: USERSIGNATURE and ESCROWSIGNATURE cannot be set at the same time")
}
// version 1.0 specific checks
return msg.checkV1_0()
}
// Create creates a new UID message for the given userID and self-signs it.
// It automatically creates all necessary keys. If sigescrow is true, an
// escrow key is included in the created UID message.
// Necessary randomness is read from rand.
func Create(
userID string,
sigescrow bool,
mixaddress, nymaddress string,
pfsPreference PFSPreference,
lastEntry string,
rand io.Reader,
) (*Message, error) {
var msg Message
var err error
// check user ID (identity)
if err := identity.IsMapped(userID); err != nil {
return nil, log.Error(err)
}
msg.UIDContent.VERSION = ProtocolVersion
msg.UIDContent.MSGCOUNT = 0 // this is the first UIDMessage
msg.UIDContent.NOTAFTER = uint64(times.OneYearLater()) // TODO: make this settable!
msg.UIDContent.NOTBEFORE = 0 // TODO: make this settable
if pfsPreference == Optional {
msg.UIDContent.MIXADDRESS = mixaddress
msg.UIDContent.NYMADDRESS = nymaddress
} else {
msg.UIDContent.MIXADDRESS = ""
msg.UIDContent.NYMADDRESS = ""
}
msg.UIDContent.IDENTITY = userID
if err = msg.UIDContent.SIGKEY.initSigKey(rand); err != nil {
return nil, err
}
msg.UIDContent.PUBKEYS = make([]KeyEntry, 1)
if err := msg.UIDContent.PUBKEYS[0].InitDHKey(rand); err != nil {
return nil, err
}
if sigescrow {
msg.UIDContent.SIGESCROW = new(KeyEntry)
if err = msg.UIDContent.SIGESCROW.initSigKey(rand); err != nil {
return nil, err
}
}
// make sure LASTENTRY is parseable for a non-keyserver localpart.
// For keyservers the LASTENTRY can be empty, iff this is the first entry
// in the hashchain.
lp, domain, _ := identity.Split(msg.UIDContent.IDENTITY)
if lp != "keyserver" {
if _, _, _, _, _, _, err := hashchain.SplitEntry(lastEntry); err != nil {
return nil, err
}
}
msg.UIDContent.LASTENTRY = lastEntry
// set REPOURIS to the domain of UIDContent.IDENTITY
// TODO: support different KeyInit repository configurations
msg.UIDContent.REPOURIS = []string{domain}
msg.UIDContent.PREFERENCES.FORWARDSEC = pfsPreference.String()
msg.UIDContent.PREFERENCES.CIPHERSUITES = []string{DefaultCiphersuite}
// TODO: CHAINLINK (later protocol version)
// theses signatures are always empty for messages the first UIDMessage
msg.ESCROWSIGNATURE = ""
msg.USERSIGNATURE = ""
selfsig := msg.UIDContent.SIGKEY.ed25519Key.Sign(msg.UIDContent.JSON())
msg.SELFSIGNATURE = base64.Encode(selfsig)
// TODO: LINKAUTHORITY
return &msg, nil
}
// searchHashChain searches the local hash chain corresponding to the given id
// for the id. It talks to the corresponding key server to retrieve necessary
// UIDMessageReplys and stores found UIDMessages in the local keyDB.
func (ce *CryptEngine) searchHashChain(id string, searchOnly bool) error {
// map identity
mappedID, domain, err := identity.MapPlus(id)
if err != nil {
return err
}
// make sure we have a hashchain for the given domain
max, found, err := ce.keyDB.GetLastHashChainPos(domain)
if err != nil {
return err
}
if !found {
return log.Errorf("no hash chain entries found for domain '%s'", domain)
}
var TYPE, NONCE, HashID, CrUID, UIDIndex []byte
var matchFound bool
for i := uint64(0); i <= max; i++ {
hcEntry, err := ce.keyDB.GetHashChainEntry(domain, i)
if err != nil {
return err
}
log.Debugf("cryptengine: search hash chain entry %d: %s", i, hcEntry)
_, TYPE, NONCE, HashID, CrUID, UIDIndex, err = hashchain.SplitEntry(hcEntry)
if err != nil {
return err
}
if !bytes.Equal(TYPE, hashchain.Type) {
return log.Error("cryptengine: invalid hash chain entry type")
}
// Compute k1, k2 = CKDF(NONCE)
k1, k2 := cipher.CKDF(NONCE)
// Compute: HashIDTest = HASH(k1 | Identity)
tmp := make([]byte, len(k1)+len(mappedID))
copy(tmp, k1)
copy(tmp[len(k1):], mappedID)
HashIDTest := cipher.SHA256(tmp)
// If NOT: HashID == HashIDTest: Continue
if !bytes.Equal(HashID, HashIDTest) {
continue
}
if searchOnly {
return nil
}
log.Debugf("cryptengine: UIDIndex=%s", base64.Encode(UIDIndex))
// Check UID already exists in keyDB
_, pos, found, err := ce.keyDB.GetPublicUID(mappedID, i)
if err != nil {
return err
}
if found && pos == i {
// UID exists already -> skip entry
matchFound = true
continue
}
// Compute: IDKEY = HASH(k2 | Identity)
tmp = make([]byte, len(k2)+len(mappedID))
copy(tmp, k2)
copy(tmp[len(k2):], mappedID)
IDKEY := cipher.SHA256(tmp)
// Fetch from Key Repository: UIDMessageReply = GET(UIDIndex)
msgReply, err := ce.fetchUID(domain, UIDIndex)
if err != nil {
return err
}
// Decrypt UIDHash = AES_256_CBC_Decrypt( IDKEY, CrUID)
UIDHash := cipher.AES256CBCDecrypt(IDKEY, CrUID)
log.Debugf("cryptengine: UIDHash=%s", base64.Encode(UIDHash))
// Decrypt UIDMessageReply.UIDMessage with UIDHash
index, uid, err := msgReply.Decrypt(UIDHash)
if err != nil {
return err
}
log.Debugf("cryptengine: UIDMessage=%s", uid.JSON())
// Check index
if !bytes.Equal(index, UIDIndex) {
return log.Errorf("cryptengine: index != UIDIndex")
}
// Verify self signature
if err := uid.VerifySelfSig(); err != nil {
return log.Error(err)
}
// Verify server signature
if err := ce.verifyServerSig(uid, msgReply, i); err != nil {
return err
}
// TODO: make sure the whole chain of UIDMessages is valid
// Store UIDMessage
if err := ce.keyDB.AddPublicUID(uid, i); err != nil {
return err
}
matchFound = true
// If no further entry can be found, the latest UIDMessage entry has been found
}
if matchFound {
return nil
}
return log.Errorf("no hash chain entry found of id '%s'", id)
}
func (ce *CryptEngine) lookupHashChain(id string) error {
// map identity
mappedID, domain, err := identity.MapPlus(id)
if err != nil {
return err
}
// get JSON-RPC client
client, _, err := ce.cache.Get(domain, ce.keydPort, ce.keydHost, ce.homedir,
"KeyHashchain.LookupUID")
if err != nil {
return err
}
// Call KeyHashchain.LookupUID
content := make(map[string]interface{})
content["Identity"] = mappedID
reply, err := client.JSONRPCRequest("KeyHashchain.LookupUID", content)
if err != nil {
return err
}
hcPositions, ok := reply["HCPositions"].([]interface{})
if !ok {
if _, ok := reply["HCPositions"].(interface{}); !ok {
return log.Errorf("lookup found no entry of id '%s'", id)
}
return log.Error("cryptengine: lookup ID reply has the wrong type")
}
var TYPE, NONCE, HashID, CrUID, UIDIndex []byte
var matchFound bool
for k, v := range hcPositions {
hcPosFloat, ok := v.(float64)
if !ok {
return log.Errorf("cryptengine: lookup ID reply position entry %d has the wrong type", k)
}
hcPos := uint64(hcPosFloat)
hcEntry, err := ce.keyDB.GetHashChainEntry(domain, hcPos)
if err != nil {
return err
}
_, TYPE, NONCE, HashID, CrUID, UIDIndex, err = hashchain.SplitEntry(hcEntry)
if err != nil {
return err
}
if !bytes.Equal(TYPE, hashchain.Type) {
return log.Error("cryptengine: invalid entry type")
}
// Compute k1, k2 = CKDF(NONCE)
k1, k2 := cipher.CKDF(NONCE)
// Compute: HashIDTest = HASH(k1 | Identity)
tmp := make([]byte, len(k1)+len(mappedID))
copy(tmp, k1)
copy(tmp[len(k1):], mappedID)
HashIDTest := cipher.SHA256(tmp)
// If NOT: HashID == HashIDTest: Continue
if !bytes.Equal(HashID, HashIDTest) {
return log.Error("cryptengine: lookup ID returned bogus position")
}
log.Debugf("cryptengine: UIDIndex=%s", base64.Encode(UIDIndex))
// Check UID already exists in keyDB
_, pos, found, err := ce.keyDB.GetPublicUID(mappedID, hcPos)
if err != nil {
return err
}
if found && pos == hcPos {
// UID exists already -> skip entry
matchFound = true
continue
}
// Compute: IDKEY = HASH(k2 | Identity)
tmp = make([]byte, len(k2)+len(mappedID))
copy(tmp, k2)
copy(tmp[len(k2):], mappedID)
IDKEY := cipher.SHA256(tmp)
// Fetch from Key Repository: UIDMessageReply = GET(UIDIndex)
msgReply, err := ce.fetchUID(domain, UIDIndex)
if err != nil {
return err
}
// Decrypt UIDHash = AES_256_CBC_Decrypt( IDKEY, CrUID)
UIDHash := cipher.AES256CBCDecrypt(IDKEY, CrUID)
log.Debugf("cryptengine: UIDHash=%s", base64.Encode(UIDHash))
// Decrypt UIDMessageReply.UIDMessage with UIDHash
index, uid, err := msgReply.Decrypt(UIDHash)
if err != nil {
return err
}
log.Debugf("cryptengine: UIDMessage=%s", uid.JSON())
// Check index
if !bytes.Equal(index, UIDIndex) {
return log.Errorf("cryptengine: index != UIDIndex")
}
// Verify self signature
if err := uid.VerifySelfSig(); err != nil {
return log.Error(err)
}
// Verify server signature
if err := ce.verifyServerSig(uid, msgReply, hcPos); err != nil {
return err
}
// TODO: make sure the whole chain of UIDMessages is valid
// Store UIDMessage
if err := ce.keyDB.AddPublicUID(uid, hcPos); err != nil {
return err
}
matchFound = true
// If no further entry can be found, the latest UIDMessage entry has been found
}
if matchFound {
return nil
}
return log.Errorf("lookup found no entry of id '%s'", id)
}
// validateHashChain validates the local hash chain for the given domain.
// That is, it checks that each entry has the correct length and the links are
// valid.
func (ce *CryptEngine) validateHashChain(domain string) error {
// make sure we have a hashchain for the given domain
max, found, err := ce.keyDB.GetLastHashChainPos(domain)
if err != nil {
return err
}
if !found {
return log.Errorf("no hash chain entries found for domain '%s'", domain)
}
var hashEntryN, TYPE, NONCE, HashID, CrUID, UIDIndex, hashEntryNminus1 []byte
for i := uint64(0); i <= max; i++ {
entry, err := ce.keyDB.GetHashChainEntry(domain, i)
if err != nil {
return err
}
log.Debugf("cryptengine: validate entry %d: %s", i, entry)
if i == 0 {
hashEntryNminus1 = make([]byte, sha256.Size)
} else {
hashEntryNminus1 = hashEntryN
}
hashEntryN, TYPE, NONCE, HashID, CrUID, UIDIndex, err = hashchain.SplitEntry(entry)
if err != nil {
return err
}
if !bytes.Equal(TYPE, hashchain.Type) {
return log.Error("cryptengine: invalid hash chain entry type")
}
entryN := make([]byte, 153)
copy(entryN, TYPE)
copy(entryN[1:], NONCE)
copy(entryN[9:], HashID)
copy(entryN[41:], CrUID)
copy(entryN[89:], UIDIndex)
copy(entryN[121:], hashEntryNminus1)
if !bytes.Equal(hashEntryN, cipher.SHA256(entryN)) {
return log.Errorf("cryptengine: hash chain entry %d invalid", i)
}
}
// get all private identities for the given domain
ids, err := ce.keyDB.GetPrivateIdentitiesForDomain(domain)
if err != nil {
return err
}
// make sure UIDMessageReplies are recorded in hash chain
for _, id := range ids {
_, msgReply, err := ce.keyDB.GetPrivateUID(id, false)
if err != nil {
return err
}
if msgReply != nil && msgReply.ENTRY.HASHCHAINPOS <= max {
entry, err := ce.keyDB.GetHashChainEntry(domain, msgReply.ENTRY.HASHCHAINPOS)
if err != nil {
return err
}
if entry != msgReply.ENTRY.HASHCHAINENTRY {
return log.Errorf("cryptengine: hash chain entry differs from UIDMessageReply (%s)", id)
}
}
}
return nil
}