2 NNCP -- Node to Node copy, utilities for store-and-forward data exchange
3 Copyright (C) 2016-2019 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/>.
29 "github.com/davecgh/go-xdr/xdr2"
30 "golang.org/x/crypto/blake2b"
31 "golang.org/x/crypto/chacha20poly1305"
32 "golang.org/x/crypto/curve25519"
33 "golang.org/x/crypto/ed25519"
34 "golang.org/x/crypto/nacl/box"
35 "golang.org/x/crypto/poly1305"
41 EncBlkSize = 128 * (1 << 10)
42 KDFXOFSize = chacha20poly1305.KeySize * 2
44 PktTypeFile PktType = iota
45 PktTypeFreq PktType = iota
46 PktTypeExec PktType = iota
47 PktTypeTrns PktType = iota
49 MaxPathSize = 1<<8 - 1
51 NNCPBundlePrefix = "NNCP"
55 MagicNNCPPv2 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'P', 0, 0, 2}
56 MagicNNCPEv4 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 4}
57 BadMagic error = errors.New("Unknown magic number")
58 BadPktType error = errors.New("Unknown packet type")
62 PktSizeOverhead int64 = 8 + poly1305.TagSize
70 Path *[MaxPathSize]byte
87 Sign *[ed25519.SignatureSize]byte
93 Path: new([MaxPathSize]byte),
96 n, err := xdr.Marshal(&buf, pkt)
100 PktOverhead = int64(n)
103 dummyId, err := NodeIdFromString("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")
112 ExchPub: new([32]byte),
113 Sign: new([ed25519.SignatureSize]byte),
115 n, err = xdr.Marshal(&buf, pktEnc)
119 PktEncOverhead = int64(n)
122 func NewPkt(typ PktType, nice uint8, path []byte) (*Pkt, error) {
123 if len(path) > MaxPathSize {
124 return nil, errors.New("Too long path")
130 PathLen: uint8(len(path)),
131 Path: new([MaxPathSize]byte),
133 copy(pkt.Path[:], path)
145 ciphCtr := nonce[len(nonce)-8:]
146 buf := make([]byte, EncBlkSize+aead.Overhead())
153 toRead = buf[:EncBlkSize]
158 n, err = io.ReadFull(r, toRead)
163 if err != io.ErrUnexpectedEOF {
164 return readBytes + n, err
169 binary.BigEndian.PutUint64(ciphCtr, blkCtr)
171 toWrite = aead.Seal(buf[:0], nonce, buf[:n], nil)
173 toWrite, err = aead.Open(buf[:0], nonce, buf[:n], nil)
175 return readBytes, err
178 if _, err = w.Write(toWrite); err != nil {
179 return readBytes, err
182 return readBytes, nil
185 func sizeWithTags(size int64) (fullSize int64) {
186 fullSize = size + (size/EncBlkSize)*poly1305.TagSize
187 if size%EncBlkSize != 0 {
188 fullSize += poly1305.TagSize
202 pubEph, prvEph, err := box.GenerateKey(rand.Reader)
206 var pktBuf bytes.Buffer
207 if _, err := xdr.Marshal(&pktBuf, pkt); err != nil {
217 var tbsBuf bytes.Buffer
218 if _, err = xdr.Marshal(&tbsBuf, &tbs); err != nil {
221 signature := new([ed25519.SignatureSize]byte)
222 copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
231 if _, err = xdr.Marshal(out, &pktEnc); err != nil {
234 sharedKey := new([32]byte)
235 curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
236 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
240 if _, err = kdf.Write(MagicNNCPEv4[:]); err != nil {
244 key := make([]byte, chacha20poly1305.KeySize)
245 if _, err = io.ReadFull(kdf, key); err != nil {
248 aead, err := chacha20poly1305.New(key)
252 nonce := make([]byte, aead.NonceSize())
254 fullSize := pktBuf.Len() + int(size)
255 sizeBuf := make([]byte, 8+aead.Overhead())
256 binary.BigEndian.PutUint64(sizeBuf, uint64(sizeWithTags(int64(fullSize))))
257 if _, err = out.Write(aead.Seal(sizeBuf[:0], nonce, sizeBuf[:8], nil)); err != nil {
261 lr := io.LimitedReader{R: data, N: size}
262 mr := io.MultiReader(&pktBuf, &lr)
263 written, err := aeadProcess(aead, nonce, true, mr, out)
267 if written != fullSize {
268 return io.ErrUnexpectedEOF
271 if _, err = io.ReadFull(kdf, key); err != nil {
274 kdf, err = blake2b.NewXOF(blake2b.OutputLengthUnknown, key)
278 if _, err = io.CopyN(out, kdf, padSize); err != nil {
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
302 nodes map[NodeId]*Node,
305 ) (*Node, int64, error) {
307 _, err := xdr.Unmarshal(data, &pktEnc)
311 if pktEnc.Magic != MagicNNCPEv4 {
312 return nil, 0, BadMagic
314 their, known := nodes[*pktEnc.Sender]
316 return nil, 0, errors.New("Unknown sender")
318 if *pktEnc.Recipient != *our.Id {
319 return nil, 0, errors.New("Invalid recipient")
321 verified, err := TbsVerify(our, their, &pktEnc)
326 return their, 0, errors.New("Invalid signature")
328 sharedKey := new([32]byte)
329 curve25519.ScalarMult(sharedKey, our.ExchPrv, pktEnc.ExchPub)
330 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
334 if _, err = kdf.Write(MagicNNCPEv4[:]); err != nil {
338 key := make([]byte, chacha20poly1305.KeySize)
339 if _, err = io.ReadFull(kdf, key); err != nil {
342 aead, err := chacha20poly1305.New(key)
346 nonce := make([]byte, aead.NonceSize())
348 sizeBuf := make([]byte, 8+aead.Overhead())
349 if _, err = io.ReadFull(data, sizeBuf); err != nil {
352 sizeBuf, err = aead.Open(sizeBuf[:0], nonce, sizeBuf, nil)
356 size := int64(binary.BigEndian.Uint64(sizeBuf))
358 lr := io.LimitedReader{R: data, N: size}
359 written, err := aeadProcess(aead, nonce, false, &lr, out)
361 return their, int64(written), err
363 if written != int(size) {
364 return their, int64(written), io.ErrUnexpectedEOF
366 return their, size, nil