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 PktTypeMail 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 string) (*Pkt, error) {
126 if len(pb) > MaxPathSize {
127 return nil, errors.New("Too long path")
133 PathLen: uint8(len(pb)),
134 Path: new([MaxPathSize]byte),
136 copy(pkt.Path[:], pb)
140 type DevZero struct{}
142 func (d DevZero) Read(b []byte) (n int, err error) {
143 for n = 0; n < len(b); n++ {
149 func ae(keyEnc *[32]byte, r io.Reader, w io.Writer) (int, error) {
151 ciphNonce := new([16]byte)
152 ciphCtr := ciphNonce[8:]
153 buf := make([]byte, EncBlkSize)
158 n, err = io.ReadFull(r, buf)
163 if err != io.ErrUnexpectedEOF {
164 return written + n, err
169 binary.BigEndian.PutUint64(ciphCtr, blkCtr)
170 chacha20.XORKeyStream(buf[:n], buf[:n], ciphNonce, keyEnc)
171 if _, err = w.Write(buf[:n]); err != nil {
178 func PktEncWrite(our *NodeOur, their *Node, pkt *Pkt, nice uint8, size, padSize int64, data io.Reader, out io.Writer) error {
179 pubEph, prvEph, err := box.GenerateKey(rand.Reader)
183 var pktBuf bytes.Buffer
184 if _, err := xdr.Marshal(&pktBuf, pkt); err != nil {
194 var tbsBuf bytes.Buffer
195 if _, err = xdr.Marshal(&tbsBuf, &tbs); err != nil {
198 signature := new([ed25519.SignatureSize]byte)
199 copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
208 if _, err = xdr.Marshal(out, &pktEnc); err != nil {
211 sharedKey := new([32]byte)
212 curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
213 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
217 if _, err = kdf.Write(MagicNNCPEv3[:]); err != nil {
221 keyEnc := new([32]byte)
222 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
225 keyAuth := make([]byte, 64)
226 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
229 mac, err := blake2b.New256(keyAuth)
234 sizeBuf := make([]byte, 8)
235 binary.BigEndian.PutUint64(sizeBuf, uint64(size))
236 chacha20.XORKeyStream(sizeBuf, sizeBuf, new([16]byte), keyEnc)
237 if _, err = out.Write(sizeBuf); err != nil {
240 if _, err = mac.Write(sizeBuf); err != nil {
243 if _, err = out.Write(mac.Sum(nil)); err != nil {
247 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
250 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
253 mac, err = blake2b.New256(keyAuth)
257 lr := io.LimitedReader{data, size}
258 mr := io.MultiReader(&pktBuf, &lr)
259 mw := io.MultiWriter(out, mac)
260 fullSize := pktBuf.Len() + int(size)
261 written, err := ae(keyEnc, mr, mw)
265 if written != fullSize {
266 return io.ErrUnexpectedEOF
268 if _, err = out.Write(mac.Sum(nil)); err != nil {
272 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
275 lr = io.LimitedReader{DevZero{}, padSize}
276 written, err = ae(keyEnc, &lr, out)
280 if written != int(padSize) {
281 return io.ErrUnexpectedEOF
287 func TbsVerify(our *NodeOur, their *Node, pktEnc *PktEnc) (bool, error) {
293 ExchPub: pktEnc.ExchPub,
295 var tbsBuf bytes.Buffer
296 if _, err := xdr.Marshal(&tbsBuf, &tbs); err != nil {
299 return ed25519.Verify(their.SignPub, tbsBuf.Bytes(), pktEnc.Sign[:]), nil
302 func PktEncRead(our *NodeOur, nodes map[NodeId]*Node, data io.Reader, out io.Writer) (*Node, int64, error) {
304 _, err := xdr.Unmarshal(data, &pktEnc)
308 if pktEnc.Magic != MagicNNCPEv3 {
309 return nil, 0, BadMagic
311 their, known := nodes[*pktEnc.Sender]
313 return nil, 0, errors.New("Unknown sender")
315 if *pktEnc.Recipient != *our.Id {
316 return nil, 0, errors.New("Invalid recipient")
318 verified, err := TbsVerify(our, their, &pktEnc)
323 return their, 0, errors.New("Invalid signature")
325 sharedKey := new([32]byte)
326 curve25519.ScalarMult(sharedKey, our.ExchPrv, pktEnc.ExchPub)
327 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
331 if _, err = kdf.Write(MagicNNCPEv3[:]); err != nil {
335 keyEnc := new([32]byte)
336 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
339 keyAuth := make([]byte, 64)
340 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
343 mac, err := blake2b.New256(keyAuth)
348 sizeBuf := make([]byte, 8)
349 if _, err = io.ReadFull(data, sizeBuf); err != nil {
352 if _, err = mac.Write(sizeBuf); err != nil {
355 tag := make([]byte, blake2b.Size256)
356 if _, err = io.ReadFull(data, tag); err != nil {
359 if subtle.ConstantTimeCompare(mac.Sum(nil), tag) != 1 {
360 return their, 0, errors.New("Unauthenticated size")
362 chacha20.XORKeyStream(sizeBuf, sizeBuf, new([16]byte), keyEnc)
363 size := int64(binary.BigEndian.Uint64(sizeBuf))
365 if _, err = io.ReadFull(kdf, keyEnc[:]); err != nil {
366 return their, size, err
368 if _, err = io.ReadFull(kdf, keyAuth); err != nil {
369 return their, size, err
371 mac, err = blake2b.New256(keyAuth)
376 fullSize := PktOverhead + size - 8 - 2*blake2b.Size256
377 lr := io.LimitedReader{data, fullSize}
378 tr := io.TeeReader(&lr, mac)
379 written, err := ae(keyEnc, tr, out)
381 return their, int64(written), err
383 if written != int(fullSize) {
384 return their, int64(written), io.ErrUnexpectedEOF
386 if _, err = io.ReadFull(data, tag); err != nil {
387 return their, size, err
389 if subtle.ConstantTimeCompare(mac.Sum(nil), tag) != 1 {
390 return their, size, errors.New("Unauthenticated payload")
392 return their, size, nil