// we use PBKDF2 + SHA3 to derive a key out of the entropy with a crypto/rand salt
// TODO: implement fortuna to feed the PRNG
func CTADD_Handler(acMessageCtReq *AcCipherTextMessageRequest) (acMsgResponse *AcCipherTextMessageResponse, err error) {
var responseType AcCipherTextMessageResponseAcCTRespMsgType
responseType = AcCipherTextMessageResponse_CTR_ADD
reqChan := acMessageCtReq.GetChannel()
reqNick := acMessageCtReq.GetNick()
reqServ := acMessageCtReq.GetServer()
reqBlob := acMessageCtReq.GetBlob()
acutl.DebugLog.Printf("(CALL) CTADD %s/%s from %s:'%s' (%s)\n", reqChan, reqServ, reqNick, reqBlob)
if len(reqChan) == 0 || len(reqNick) == 0 || len(reqServ) == 0 {
retErr := &acutl.AcError{Value: -1, Msg: "CTADD_Handler().args(channel|serv|mynick): 0 bytes", Err: nil}
acMsgResponse = &AcCipherTextMessageResponse{
Type: &responseType,
Bada: proto.Bool(false),
ErrorCode: proto.Int32(-1),
}
acutl.DebugLog.Printf("(RET[!]) CTADD -> (-1) ! %s\n", retErr.Error())
return acMsgResponse, retErr
}
// lets derive the key.
// randsalt := rand.Read()
// func (skgen ACSecretKeyGen) Init(input []byte, channel []byte, nick []byte, serv []byte) {
skgen := new(ackp.SecretKeyGen)
err = skgen.Init([]byte(reqBlob), []byte(reqChan), []byte(reqNick), []byte(reqServ))
if err != nil {
retErr := &acutl.AcError{Value: -2, Msg: "CTADD_Handler(): SK generator fail!", Err: err}
acMsgResponse = &AcCipherTextMessageResponse{
Type: &responseType,
Bada: proto.Bool(false),
ErrorCode: proto.Int32(-2),
}
acutl.DebugLog.Printf("(RET[!]) CTADD -> (-2) ! %s\n", retErr.Error())
return acMsgResponse, retErr
}
// XXX TODO: handle error or remove it...
acctx, _ := ackp.CreateACContext([]byte(reqChan), 0)
key := make([]byte, 32)
io.ReadFull(skgen, key)
newRnd := make([]byte, len(key))
_, err = rand.Read(newRnd)
if err != nil {
retErr := &acutl.AcError{Value: -3, Msg: "CTADD_Handler(): randomness fail!", Err: err}
acMsgResponse = &AcCipherTextMessageResponse{
Type: &responseType,
Bada: proto.Bool(false),
ErrorCode: proto.Int32(-3),
}
return acMsgResponse, retErr
}
acctx.SetKey(key)
// XOR the key...
acctx.RndKey(newRnd)
ackp.ACmap.SetSKMapEntry(reqServ, reqChan, acctx)
ackp.ACmap.SetRDMapEntry(reqServ, reqChan, newRnd)
acMsgResponse = &AcCipherTextMessageResponse{
Type: &responseType,
Bada: proto.Bool(true),
ErrorCode: proto.Int32(0),
//Blob: []byte("OK"),
Blob: [][]byte{[]byte("OK")}, // this is an array of []byte
}
acutl.DebugLog.Printf("(RET) CTADD -> (0) ! %s/%s key added (entropy: '%s')\n", reqServ, reqChan, reqBlob)
return acMsgResponse, nil
}
func OpenKXMessageNACL(peerPubkey, myPrivkey *[32]byte, cmsg, channel, myNick, peerNick []byte) (context *ackp.SecKey, SecRnd []byte, err error) {
// check that we are indeed
if peerPubkey == nil || myPrivkey == nil {
//return nil, acprotoError(-1, "OpenKXMessage().invalidPubPrivKeys(): ", err)
return nil, nil, &acutl.AcError{Value: -1, Msg: "OpenKXMessageNACL().invalidPubPrivKeys(): ", Err: err}
}
b64, err := acutl.B64DecodeData(cmsg)
if err != nil {
return nil, nil, &acutl.AcError{Value: -2, Msg: "OpenKXMessageNACL(): ", Err: err}
}
cnonce, myHdr, ciphertext, err := unpackMessageKX(b64)
if err != nil {
return nil, nil, &acutl.AcError{Value: -3, Msg: "OpenKXMessageNACL(): ", Err: err}
}
// XXX TODO: exact opposite of the one in CreateKXMessage
kx_channel := IsChannelOrPriv(channel, peerNick, myNick)
// XXX TODO: we should add the header like <ackx:peerNick> to avoid replay from
// other nickname on the channel... nonce building!
_, noncebyte, err := BuildNonceKX(cnonce, kx_channel, peerNick, myNick, myHdr)
if err != nil {
return nil, nil, &acutl.AcError{Value: -4, Msg: "OpenKXMessageNACL(): ", Err: err}
}
packed, ok := box.Open(nil, ciphertext, noncebyte, peerPubkey, myPrivkey)
if ok == false {
return nil, nil, &acutl.AcError{Value: -5, Msg: "OpenKXMessageNACL().BoxOpen(): ", Err: nil}
}
out, err := acutl.DecompressData(packed)
if err != nil {
return nil, nil, &acutl.AcError{Value: -6, Msg: "OpenKXMessageNACL(): ", Err: err}
}
//fmt.Fprintf(os.Stderr, "OPEN KX KEY: %s\n", hex.EncodeToString(out))
// XXX TODO are we at the end of the nonce value..
context, err = ackp.CreateACContext(channel, cnonce+1)
if err != nil {
return nil, nil, &acutl.AcError{Value: -7, Msg: "OpenKXMessage().CreateACContext(): ", Err: err}
}
// XXX TODO
// get RANDOMNESS bytes, return the random bytes
newRnd, err := acutl.GetRandomBytes(context.GetKeyLen())
if err != nil {
return nil, nil, &acutl.AcError{Value: -8, Msg: "OpenKXMessage() no randomness to protect the key in memory: ", Err: err}
}
/*
newRnd := make([]byte, len(context.key))
_, err = rand.Read(newRnd)
*/
// XXX TODO: check the extracted buffer size... to sure we're not copying
// too much into a restricted buffer...
//copy(context.key[:], out)
context.SetKey(out)
// Xor the key now..
context.RndKey(newRnd)
// increase nonce based on the message nonce value
context.IncNonce(cnonce)
return context, newRnd, nil
}
