2 NNCP -- Node to Node copy, utilities for store-and-forward data exchange
3 Copyright (C) 2016-2017 Sergey Matveev <stargrave@stargrave.org>
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
30 "github.com/davecgh/go-xdr/xdr2"
31 "golang.org/x/crypto/blake2b"
32 "golang.org/x/crypto/curve25519"
33 "golang.org/x/crypto/ed25519"
34 "golang.org/x/crypto/nacl/box"
40 EncBlkSize = 128 * (1 << 10)
41 KDFXOFSize = 2*(32+64) + 32
43 PktTypeFile PktType = iota
44 PktTypeFreq PktType = iota
45 PktTypeMail PktType = iota
46 PktTypeTrns PktType = iota
48 MaxPathSize = 1<<8 - 1
54 NNCPBundlePrefix = "NNCP"
58 MagicNNCPPv1 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'P', 0, 0, 1}
59 MagicNNCPEv3 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 3}
60 BadMagic error = errors.New("Unknown magic number")
61 BadPktType error = errors.New("Unknown packet type")
71 Path *[MaxPathSize]byte
88 Sign *[ed25519.SignatureSize]byte
94 Path: new([MaxPathSize]byte),
97 n, err := xdr.Marshal(&buf, pkt)
101 PktOverhead = 8 + blake2b.Size256 + int64(n) + blake2b.Size256
104 dummyId, err := NodeIdFromString("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")
113 ExchPub: new([32]byte),
114 Sign: new([ed25519.SignatureSize]byte),
116 n, err = xdr.Marshal(&buf, pktEnc)
120 PktEncOverhead = int64(n)
123 func NewPkt(typ PktType, path string) (*Pkt, error) {
125 if len(pb) > MaxPathSize {
126 return nil, errors.New("Too long path")
131 PathLen: uint8(len(pb)),
132 Path: new([MaxPathSize]byte),
134 copy(pkt.Path[:], pb)
138 type DevZero struct{}
140 func (d DevZero) Read(b []byte) (n int, err error) {
141 for n = 0; n < len(b); n++ {
147 func ae(keyEnc *[32]byte, r io.Reader, w io.Writer) (int, error) {
149 ciphNonce := new([16]byte)
150 ciphCtr := ciphNonce[8:]
151 buf := make([]byte, EncBlkSize)
156 n, err = io.ReadFull(r, buf)
161 if err != io.ErrUnexpectedEOF {
162 return written + n, err
167 binary.BigEndian.PutUint64(ciphCtr, blkCtr)
168 chacha20.XORKeyStream(buf[:n], buf[:n], ciphNonce, keyEnc)
169 if _, err = w.Write(buf[:n]); err != nil {
176 func PktEncWrite(our *NodeOur, their *Node, pkt *Pkt, nice uint8, size, padSize int64, data io.Reader, out io.Writer) error {
177 pubEph, prvEph, err := box.GenerateKey(rand.Reader)
181 var pktBuf bytes.Buffer
182 if _, err := xdr.Marshal(&pktBuf, pkt); err != nil {
192 var tbsBuf bytes.Buffer
193 if _, err = xdr.Marshal(&tbsBuf, &tbs); err != nil {
196 signature := new([ed25519.SignatureSize]byte)
197 copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
206 if _, err = xdr.Marshal(out, &pktEnc); err != nil {
209 sharedKey := new([32]byte)
210 curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
211 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
215 if _, err = kdf.Write(MagicNNCPEv3[:]); err != nil {
219 keyEnc := new([32]byte)
220 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
223 keyAuth := make([]byte, 64)
224 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
227 mac, err := blake2b.New256(keyAuth)
232 sizeBuf := make([]byte, 8)
233 binary.BigEndian.PutUint64(sizeBuf, uint64(size))
234 chacha20.XORKeyStream(sizeBuf, sizeBuf, new([16]byte), keyEnc)
235 if _, err = out.Write(sizeBuf); err != nil {
238 if _, err = mac.Write(sizeBuf); err != nil {
241 if _, err = out.Write(mac.Sum(nil)); err != nil {
245 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
248 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
251 mac, err = blake2b.New256(keyAuth)
255 lr := io.LimitedReader{data, size}
256 mr := io.MultiReader(&pktBuf, &lr)
257 mw := io.MultiWriter(out, mac)
258 fullSize := pktBuf.Len() + int(size)
259 written, err := ae(keyEnc, mr, mw)
263 if written != fullSize {
264 return io.ErrUnexpectedEOF
266 if _, err = out.Write(mac.Sum(nil)); err != nil {
270 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
273 lr = io.LimitedReader{DevZero{}, padSize}
274 written, err = ae(keyEnc, &lr, out)
278 if written != int(padSize) {
279 return io.ErrUnexpectedEOF
285 func TbsVerify(our *NodeOur, their *Node, pktEnc *PktEnc) (bool, error) {
291 ExchPub: pktEnc.ExchPub,
293 var tbsBuf bytes.Buffer
294 if _, err := xdr.Marshal(&tbsBuf, &tbs); err != nil {
297 return ed25519.Verify(their.SignPub, tbsBuf.Bytes(), pktEnc.Sign[:]), nil
300 func PktEncRead(our *NodeOur, nodes map[NodeId]*Node, data io.Reader, out io.Writer) (*Node, int64, error) {
302 _, err := xdr.Unmarshal(data, &pktEnc)
306 if pktEnc.Magic != MagicNNCPEv3 {
307 return nil, 0, BadMagic
309 their, known := nodes[*pktEnc.Sender]
311 return nil, 0, errors.New("Unknown sender")
313 if *pktEnc.Recipient != *our.Id {
314 return nil, 0, errors.New("Invalid recipient")
316 verified, err := TbsVerify(our, their, &pktEnc)
321 return their, 0, errors.New("Invalid signature")
323 sharedKey := new([32]byte)
324 curve25519.ScalarMult(sharedKey, our.ExchPrv, pktEnc.ExchPub)
325 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
329 if _, err = kdf.Write(MagicNNCPEv3[:]); err != nil {
333 keyEnc := new([32]byte)
334 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
337 keyAuth := make([]byte, 64)
338 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
341 mac, err := blake2b.New256(keyAuth)
346 sizeBuf := make([]byte, 8)
347 if _, err = io.ReadFull(data, sizeBuf); err != nil {
350 if _, err = mac.Write(sizeBuf); err != nil {
353 tag := make([]byte, blake2b.Size256)
354 if _, err = io.ReadFull(data, tag); err != nil {
357 if subtle.ConstantTimeCompare(mac.Sum(nil), tag) != 1 {
358 return their, 0, errors.New("Unauthenticated size")
360 chacha20.XORKeyStream(sizeBuf, sizeBuf, new([16]byte), keyEnc)
361 size := int64(binary.BigEndian.Uint64(sizeBuf))
363 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
364 return their, size, err
366 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
367 return their, size, err
369 mac, err = blake2b.New256(keyAuth)
374 fullSize := PktOverhead + size - 8 - 2*blake2b.Size256
375 lr := io.LimitedReader{data, fullSize}
376 tr := io.TeeReader(&lr, mac)
377 written, err := ae(keyEnc, tr, out)
379 return their, int64(written), err
381 if written != int(fullSize) {
382 return their, int64(written), io.ErrUnexpectedEOF
384 if _, err = io.ReadFull(data, tag); err != nil {
385 return their, size, err
387 if subtle.ConstantTimeCompare(mac.Sum(nil), tag) != 1 {
388 return their, size, errors.New("Unauthenticated payload")
390 return their, size, nil