2 NNCP -- Node to Node copy, utilities for store-and-forward data exchange
3 Copyright (C) 2016-2018 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 PktTypeExec PktType = iota
46 PktTypeTrns PktType = iota
48 MaxPathSize = 1<<8 - 1
54 NNCPBundlePrefix = "NNCP"
58 MagicNNCPPv2 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'P', 0, 0, 2}
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")
72 Path *[MaxPathSize]byte
89 Sign *[ed25519.SignatureSize]byte
95 Path: new([MaxPathSize]byte),
98 n, err := xdr.Marshal(&buf, pkt)
102 PktOverhead = 8 + blake2b.Size256 + int64(n) + blake2b.Size256
105 dummyId, err := NodeIdFromString("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")
114 ExchPub: new([32]byte),
115 Sign: new([ed25519.SignatureSize]byte),
117 n, err = xdr.Marshal(&buf, pktEnc)
121 PktEncOverhead = int64(n)
124 func NewPkt(typ PktType, nice uint8, path []byte) (*Pkt, error) {
125 if len(path) > MaxPathSize {
126 return nil, errors.New("Too long path")
132 PathLen: uint8(len(path)),
133 Path: new([MaxPathSize]byte),
135 copy(pkt.Path[:], path)
139 type DevZero struct{}
141 func (d DevZero) Read(b []byte) (n int, err error) {
142 for n = 0; n < len(b); n++ {
148 func ae(keyEnc *[32]byte, r io.Reader, w io.Writer) (int, error) {
150 ciphNonce := new([16]byte)
151 ciphCtr := ciphNonce[8:]
152 buf := make([]byte, EncBlkSize)
157 n, err = io.ReadFull(r, buf)
162 if err != io.ErrUnexpectedEOF {
163 return written + n, err
168 binary.BigEndian.PutUint64(ciphCtr, blkCtr)
169 chacha20.XORKeyStream(buf[:n], buf[:n], ciphNonce, keyEnc)
170 if _, err = w.Write(buf[:n]); err != nil {
184 out io.Writer) error {
185 pubEph, prvEph, err := box.GenerateKey(rand.Reader)
189 var pktBuf bytes.Buffer
190 if _, err := xdr.Marshal(&pktBuf, pkt); err != nil {
200 var tbsBuf bytes.Buffer
201 if _, err = xdr.Marshal(&tbsBuf, &tbs); err != nil {
204 signature := new([ed25519.SignatureSize]byte)
205 copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
214 if _, err = xdr.Marshal(out, &pktEnc); err != nil {
217 sharedKey := new([32]byte)
218 curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
219 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
223 if _, err = kdf.Write(MagicNNCPEv3[:]); err != nil {
227 keyEnc := new([32]byte)
228 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
231 keyAuth := make([]byte, 64)
232 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
235 mac, err := blake2b.New256(keyAuth)
240 sizeBuf := make([]byte, 8)
241 binary.BigEndian.PutUint64(sizeBuf, uint64(size))
242 chacha20.XORKeyStream(sizeBuf, sizeBuf, new([16]byte), keyEnc)
243 if _, err = out.Write(sizeBuf); err != nil {
246 if _, err = mac.Write(sizeBuf); err != nil {
249 if _, err = out.Write(mac.Sum(nil)); err != nil {
253 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
256 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
259 mac, err = blake2b.New256(keyAuth)
263 lr := io.LimitedReader{R: data, N: size}
264 mr := io.MultiReader(&pktBuf, &lr)
265 mw := io.MultiWriter(out, mac)
266 fullSize := pktBuf.Len() + int(size)
267 written, err := ae(keyEnc, mr, mw)
271 if written != fullSize {
272 return io.ErrUnexpectedEOF
274 if _, err = out.Write(mac.Sum(nil)); err != nil {
278 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
281 lr = io.LimitedReader{R: DevZero{}, N: padSize}
282 written, err = ae(keyEnc, &lr, out)
286 if written != int(padSize) {
287 return io.ErrUnexpectedEOF
293 func TbsVerify(our *NodeOur, their *Node, pktEnc *PktEnc) (bool, error) {
299 ExchPub: pktEnc.ExchPub,
301 var tbsBuf bytes.Buffer
302 if _, err := xdr.Marshal(&tbsBuf, &tbs); err != nil {
305 return ed25519.Verify(their.SignPub, tbsBuf.Bytes(), pktEnc.Sign[:]), nil
310 nodes map[NodeId]*Node,
312 out io.Writer) (*Node, int64, error) {
314 _, err := xdr.Unmarshal(data, &pktEnc)
318 if pktEnc.Magic != MagicNNCPEv3 {
319 return nil, 0, BadMagic
321 their, known := nodes[*pktEnc.Sender]
323 return nil, 0, errors.New("Unknown sender")
325 if *pktEnc.Recipient != *our.Id {
326 return nil, 0, errors.New("Invalid recipient")
328 verified, err := TbsVerify(our, their, &pktEnc)
333 return their, 0, errors.New("Invalid signature")
335 sharedKey := new([32]byte)
336 curve25519.ScalarMult(sharedKey, our.ExchPrv, pktEnc.ExchPub)
337 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
341 if _, err = kdf.Write(MagicNNCPEv3[:]); err != nil {
345 keyEnc := new([32]byte)
346 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
349 keyAuth := make([]byte, 64)
350 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
353 mac, err := blake2b.New256(keyAuth)
358 sizeBuf := make([]byte, 8)
359 if _, err = io.ReadFull(data, sizeBuf); err != nil {
362 if _, err = mac.Write(sizeBuf); err != nil {
365 tag := make([]byte, blake2b.Size256)
366 if _, err = io.ReadFull(data, tag); err != nil {
369 if subtle.ConstantTimeCompare(mac.Sum(nil), tag) != 1 {
370 return their, 0, errors.New("Unauthenticated size")
372 chacha20.XORKeyStream(sizeBuf, sizeBuf, new([16]byte), keyEnc)
373 size := int64(binary.BigEndian.Uint64(sizeBuf))
375 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
376 return their, size, err
378 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
379 return their, size, err
381 mac, err = blake2b.New256(keyAuth)
386 fullSize := PktOverhead + size - 8 - 2*blake2b.Size256
387 lr := io.LimitedReader{R: data, N: fullSize}
388 tr := io.TeeReader(&lr, mac)
389 written, err := ae(keyEnc, tr, out)
391 return their, int64(written), err
393 if written != int(fullSize) {
394 return their, int64(written), io.ErrUnexpectedEOF
396 if _, err = io.ReadFull(data, tag); err != nil {
397 return their, size, err
399 if subtle.ConstantTimeCompare(mac.Sum(nil), tag) != 1 {
400 return their, size, errors.New("Unauthenticated payload")
402 return their, size, nil