2 NNCP -- Node to Node copy, utilities for store-and-forward data exchange
3 Copyright (C) 2016-2021 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, version 3 of the License.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>.
28 xdr "github.com/davecgh/go-xdr/xdr2"
29 "golang.org/x/crypto/blake2b"
30 "golang.org/x/crypto/chacha20poly1305"
31 "golang.org/x/crypto/curve25519"
32 "golang.org/x/crypto/ed25519"
33 "golang.org/x/crypto/nacl/box"
34 "golang.org/x/crypto/poly1305"
40 EncBlkSize = 128 * (1 << 10)
41 KDFXOFSize = chacha20poly1305.KeySize * 2
43 PktTypeFile PktType = iota
44 PktTypeFreq PktType = iota
45 PktTypeExec PktType = iota
46 PktTypeTrns PktType = iota
48 MaxPathSize = 1<<8 - 1
50 NNCPBundlePrefix = "NNCP"
52 PktSizeOverhead = 8 + poly1305.TagSize
56 MagicNNCPPv3 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'P', 0, 0, 3}
57 MagicNNCPEv4 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 4}
58 BadMagic error = errors.New("Unknown magic number")
59 BadPktType error = errors.New("Unknown packet type")
70 Path [MaxPathSize]byte
87 Sign [ed25519.SignatureSize]byte
91 pkt := Pkt{Type: PktTypeFile}
93 n, err := xdr.Marshal(&buf, pkt)
97 PktOverhead = int64(n)
100 dummyId, err := NodeIdFromString("AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA")
109 n, err = xdr.Marshal(&buf, pktEnc)
113 PktEncOverhead = int64(n)
116 func NewPkt(typ PktType, nice uint8, path []byte) (*Pkt, error) {
117 if len(path) > MaxPathSize {
118 return nil, errors.New("Too long path")
124 PathLen: uint8(len(path)),
126 copy(pkt.Path[:], path)
138 ciphCtr := nonce[len(nonce)-8:]
139 buf := make([]byte, EncBlkSize+aead.Overhead())
146 toRead = buf[:EncBlkSize]
151 n, err = io.ReadFull(r, toRead)
156 if err != io.ErrUnexpectedEOF {
157 return readBytes + n, err
162 binary.BigEndian.PutUint64(ciphCtr, blkCtr)
164 toWrite = aead.Seal(buf[:0], nonce, buf[:n], nil)
166 toWrite, err = aead.Open(buf[:0], nonce, buf[:n], nil)
168 return readBytes, err
171 if _, err = w.Write(toWrite); err != nil {
172 return readBytes, err
175 return readBytes, nil
178 func sizeWithTags(size int64) (fullSize int64) {
179 fullSize = size + (size/EncBlkSize)*poly1305.TagSize
180 if size%EncBlkSize != 0 {
181 fullSize += poly1305.TagSize
195 pubEph, prvEph, err := box.GenerateKey(rand.Reader)
199 var pktBuf bytes.Buffer
200 if _, err := xdr.Marshal(&pktBuf, pkt); err != nil {
210 var tbsBuf bytes.Buffer
211 if _, err = xdr.Marshal(&tbsBuf, &tbs); err != nil {
214 signature := new([ed25519.SignatureSize]byte)
215 copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
224 if _, err = xdr.Marshal(out, &pktEnc); err != nil {
227 sharedKey := new([32]byte)
228 curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
229 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
233 if _, err = kdf.Write(MagicNNCPEv4[:]); err != nil {
237 key := make([]byte, chacha20poly1305.KeySize)
238 if _, err = io.ReadFull(kdf, key); err != nil {
241 aead, err := chacha20poly1305.New(key)
245 nonce := make([]byte, aead.NonceSize())
247 fullSize := pktBuf.Len() + int(size)
248 sizeBuf := make([]byte, 8+aead.Overhead())
249 binary.BigEndian.PutUint64(sizeBuf, uint64(sizeWithTags(int64(fullSize))))
250 if _, err = out.Write(aead.Seal(sizeBuf[:0], nonce, sizeBuf[:8], nil)); err != nil {
254 lr := io.LimitedReader{R: data, N: size}
255 mr := io.MultiReader(&pktBuf, &lr)
256 written, err := aeadProcess(aead, nonce, true, mr, out)
260 if written != fullSize {
261 return io.ErrUnexpectedEOF
264 if _, err = io.ReadFull(kdf, key); err != nil {
267 kdf, err = blake2b.NewXOF(blake2b.OutputLengthUnknown, key)
271 if _, err = io.CopyN(out, kdf, padSize); err != nil {
278 func TbsVerify(our *NodeOur, their *Node, pktEnc *PktEnc) (bool, error) {
284 ExchPub: pktEnc.ExchPub,
286 var tbsBuf bytes.Buffer
287 if _, err := xdr.Marshal(&tbsBuf, &tbs); err != nil {
290 return ed25519.Verify(their.SignPub, tbsBuf.Bytes(), pktEnc.Sign[:]), nil
295 nodes map[NodeId]*Node,
298 ) (*Node, int64, error) {
300 _, err := xdr.Unmarshal(data, &pktEnc)
304 if pktEnc.Magic != MagicNNCPEv4 {
305 return nil, 0, BadMagic
307 their, known := nodes[*pktEnc.Sender]
309 return nil, 0, errors.New("Unknown sender")
311 if *pktEnc.Recipient != *our.Id {
312 return nil, 0, errors.New("Invalid recipient")
314 verified, err := TbsVerify(our, their, &pktEnc)
319 return their, 0, errors.New("Invalid signature")
321 sharedKey := new([32]byte)
322 curve25519.ScalarMult(sharedKey, our.ExchPrv, &pktEnc.ExchPub)
323 kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
327 if _, err = kdf.Write(MagicNNCPEv4[:]); err != nil {
331 key := make([]byte, chacha20poly1305.KeySize)
332 if _, err = io.ReadFull(kdf, key); err != nil {
335 aead, err := chacha20poly1305.New(key)
339 nonce := make([]byte, aead.NonceSize())
341 sizeBuf := make([]byte, 8+aead.Overhead())
342 if _, err = io.ReadFull(data, sizeBuf); err != nil {
345 sizeBuf, err = aead.Open(sizeBuf[:0], nonce, sizeBuf, nil)
349 size := int64(binary.BigEndian.Uint64(sizeBuf))
351 lr := io.LimitedReader{R: data, N: size}
352 written, err := aeadProcess(aead, nonce, false, &lr, out)
354 return their, int64(written), err
356 if written != int(size) {
357 return their, int64(written), io.ErrUnexpectedEOF
359 return their, size, nil