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
50 NNCPBundlePrefix = "NNCP"
54 MagicNNCPPv2 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'P', 0, 0, 2}
55 MagicNNCPEv3 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 3}
56 BadMagic error = errors.New("Unknown magic number")
57 BadPktType error = errors.New("Unknown packet type")
68 Path *[MaxPathSize]byte
85 Sign *[ed25519.SignatureSize]byte
91 Path: new([MaxPathSize]byte),
94 n, err := xdr.Marshal(&buf, pkt)
98 PktOverhead = 8 + blake2b.Size256 + int64(n) + blake2b.Size256
101 dummyId, err := NodeIdFromString("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")
110 ExchPub: new([32]byte),
111 Sign: new([ed25519.SignatureSize]byte),
113 n, err = xdr.Marshal(&buf, pktEnc)
117 PktEncOverhead = int64(n)
120 func NewPkt(typ PktType, nice uint8, path []byte) (*Pkt, error) {
121 if len(path) > MaxPathSize {
122 return nil, errors.New("Too long path")
128 PathLen: uint8(len(path)),
129 Path: new([MaxPathSize]byte),
131 copy(pkt.Path[:], path)
135 type DevZero struct{}
137 func (d DevZero) Read(b []byte) (n int, err error) {
138 for n = 0; n < len(b); n++ {
144 func ae(keyEnc *[32]byte, r io.Reader, w io.Writer) (int, error) {
146 ciphNonce := new([16]byte)
147 ciphCtr := ciphNonce[8:]
148 buf := make([]byte, EncBlkSize)
153 n, err = io.ReadFull(r, buf)
158 if err != io.ErrUnexpectedEOF {
159 return written + n, err
164 binary.BigEndian.PutUint64(ciphCtr, blkCtr)
165 chacha20.XORKeyStream(buf[:n], buf[:n], ciphNonce, keyEnc)
166 if _, err = w.Write(buf[:n]); err != nil {
180 out io.Writer) error {
181 pubEph, prvEph, err := box.GenerateKey(rand.Reader)
185 var pktBuf bytes.Buffer
186 if _, err := xdr.Marshal(&pktBuf, pkt); err != nil {
196 var tbsBuf bytes.Buffer
197 if _, err = xdr.Marshal(&tbsBuf, &tbs); err != nil {
200 signature := new([ed25519.SignatureSize]byte)
201 copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
210 if _, err = xdr.Marshal(out, &pktEnc); err != nil {
213 sharedKey := new([32]byte)
214 curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
215 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
219 if _, err = kdf.Write(MagicNNCPEv3[:]); err != nil {
223 keyEnc := new([32]byte)
224 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
227 keyAuth := make([]byte, 64)
228 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
231 mac, err := blake2b.New256(keyAuth)
236 sizeBuf := make([]byte, 8)
237 binary.BigEndian.PutUint64(sizeBuf, uint64(size))
238 chacha20.XORKeyStream(sizeBuf, sizeBuf, new([16]byte), keyEnc)
239 if _, err = out.Write(sizeBuf); err != nil {
242 if _, err = mac.Write(sizeBuf); err != nil {
245 if _, err = out.Write(mac.Sum(nil)); err != nil {
249 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
252 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
255 mac, err = blake2b.New256(keyAuth)
259 lr := io.LimitedReader{R: data, N: size}
260 mr := io.MultiReader(&pktBuf, &lr)
261 mw := io.MultiWriter(out, mac)
262 fullSize := pktBuf.Len() + int(size)
263 written, err := ae(keyEnc, mr, mw)
267 if written != fullSize {
268 return io.ErrUnexpectedEOF
270 if _, err = out.Write(mac.Sum(nil)); err != nil {
274 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
277 lr = io.LimitedReader{R: DevZero{}, N: padSize}
278 written, err = ae(keyEnc, &lr, out)
282 if written != int(padSize) {
283 return io.ErrUnexpectedEOF
289 func TbsVerify(our *NodeOur, their *Node, pktEnc *PktEnc) (bool, error) {
295 ExchPub: pktEnc.ExchPub,
297 var tbsBuf bytes.Buffer
298 if _, err := xdr.Marshal(&tbsBuf, &tbs); err != nil {
301 return ed25519.Verify(their.SignPub, tbsBuf.Bytes(), pktEnc.Sign[:]), nil
306 nodes map[NodeId]*Node,
308 out io.Writer) (*Node, int64, error) {
310 _, err := xdr.Unmarshal(data, &pktEnc)
314 if pktEnc.Magic != MagicNNCPEv3 {
315 return nil, 0, BadMagic
317 their, known := nodes[*pktEnc.Sender]
319 return nil, 0, errors.New("Unknown sender")
321 if *pktEnc.Recipient != *our.Id {
322 return nil, 0, errors.New("Invalid recipient")
324 verified, err := TbsVerify(our, their, &pktEnc)
329 return their, 0, errors.New("Invalid signature")
331 sharedKey := new([32]byte)
332 curve25519.ScalarMult(sharedKey, our.ExchPrv, pktEnc.ExchPub)
333 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
337 if _, err = kdf.Write(MagicNNCPEv3[:]); err != nil {
341 keyEnc := new([32]byte)
342 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
345 keyAuth := make([]byte, 64)
346 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
349 mac, err := blake2b.New256(keyAuth)
354 sizeBuf := make([]byte, 8)
355 if _, err = io.ReadFull(data, sizeBuf); err != nil {
358 if _, err = mac.Write(sizeBuf); err != nil {
361 tag := make([]byte, blake2b.Size256)
362 if _, err = io.ReadFull(data, tag); err != nil {
365 if subtle.ConstantTimeCompare(mac.Sum(nil), tag) != 1 {
366 return their, 0, errors.New("Unauthenticated size")
368 chacha20.XORKeyStream(sizeBuf, sizeBuf, new([16]byte), keyEnc)
369 size := int64(binary.BigEndian.Uint64(sizeBuf))
371 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
372 return their, size, err
374 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
375 return their, size, err
377 mac, err = blake2b.New256(keyAuth)
382 fullSize := PktOverhead + size - 8 - 2*blake2b.Size256
383 lr := io.LimitedReader{R: data, N: fullSize}
384 tr := io.TeeReader(&lr, mac)
385 written, err := ae(keyEnc, tr, out)
387 return their, int64(written), err
389 if written != int(fullSize) {
390 return their, int64(written), io.ErrUnexpectedEOF
392 if _, err = io.ReadFull(data, tag); err != nil {
393 return their, size, err
395 if subtle.ConstantTimeCompare(mac.Sum(nil), tag) != 1 {
396 return their, size, errors.New("Unauthenticated payload")
398 return their, size, nil