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/chacha20poly1305"
30 "golang.org/x/crypto/curve25519"
31 "golang.org/x/crypto/ed25519"
32 "golang.org/x/crypto/nacl/box"
33 "golang.org/x/crypto/poly1305"
34 "lukechampine.com/blake3"
40 EncBlkSize = 128 * (1 << 10)
42 PktTypeFile PktType = iota
43 PktTypeFreq PktType = iota
44 PktTypeExec PktType = iota
45 PktTypeTrns PktType = iota
46 PktTypeExecFat 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 MagicNNCPEv5 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 5}
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)
130 func ctrIncr(b []byte) {
131 for i := len(b) - 1; i >= 0; i-- {
137 panic("counter overflow")
147 ciphCtr := nonce[len(nonce)-8:]
148 buf := make([]byte, EncBlkSize+aead.Overhead())
155 toRead = buf[:EncBlkSize]
160 n, err = io.ReadFull(r, toRead)
165 if err != io.ErrUnexpectedEOF {
166 return readBytes + n, err
172 toWrite = aead.Seal(buf[:0], nonce, buf[:n], ad)
174 toWrite, err = aead.Open(buf[:0], nonce, buf[:n], ad)
176 return readBytes, err
179 if _, err = w.Write(toWrite); err != nil {
180 return readBytes, err
183 return readBytes, nil
186 func sizeWithTags(size int64) (fullSize int64) {
187 fullSize = size + (size/EncBlkSize)*poly1305.TagSize
188 if size%EncBlkSize != 0 {
189 fullSize += poly1305.TagSize
203 pubEph, prvEph, err := box.GenerateKey(rand.Reader)
207 var pktBuf bytes.Buffer
208 if _, err := xdr.Marshal(&pktBuf, pkt); err != nil {
218 var tbsBuf bytes.Buffer
219 if _, err = xdr.Marshal(&tbsBuf, &tbs); err != nil {
222 signature := new([ed25519.SignatureSize]byte)
223 copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
232 ad := blake3.Sum256(tbsBuf.Bytes())
234 if _, err = xdr.Marshal(&tbsBuf, &pktEnc); err != nil {
237 pktEncRaw := tbsBuf.Bytes()
238 if _, err = out.Write(pktEncRaw); err != nil {
241 sharedKey := new([32]byte)
242 curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
244 key := make([]byte, chacha20poly1305.KeySize)
245 blake3.DeriveKey(key, string(MagicNNCPEv5[:]), sharedKey[:])
246 aead, err := chacha20poly1305.New(key)
250 nonce := make([]byte, aead.NonceSize())
252 fullSize := pktBuf.Len() + int(size)
253 sizeBuf := make([]byte, 8+aead.Overhead())
254 binary.BigEndian.PutUint64(sizeBuf, uint64(sizeWithTags(int64(fullSize))))
255 if _, err = out.Write(aead.Seal(sizeBuf[:0], nonce, sizeBuf[:8], ad[:])); err != nil {
259 lr := io.LimitedReader{R: data, N: size}
260 mr := io.MultiReader(&pktBuf, &lr)
261 written, err := aeadProcess(aead, nonce, ad[:], true, mr, out)
265 if written != fullSize {
266 return nil, io.ErrUnexpectedEOF
269 blake3.DeriveKey(key, string(MagicNNCPEv5[:])+" PAD", sharedKey[:])
270 xof := blake3.New(32, key).XOF()
271 if _, err = io.CopyN(out, xof, padSize); err != nil {
275 return pktEncRaw, nil
278 func TbsVerify(our *NodeOur, their *Node, pktEnc *PktEnc) ([]byte, bool, error) {
284 ExchPub: pktEnc.ExchPub,
286 var tbsBuf bytes.Buffer
287 if _, err := xdr.Marshal(&tbsBuf, &tbs); err != nil {
288 return nil, false, err
290 return tbsBuf.Bytes(), 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 != MagicNNCPEv5 {
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 tbsRaw, verified, err := TbsVerify(our, their, &pktEnc)
319 return their, 0, errors.New("Invalid signature")
321 ad := blake3.Sum256(tbsRaw)
322 sharedKey := new([32]byte)
323 curve25519.ScalarMult(sharedKey, our.ExchPrv, &pktEnc.ExchPub)
325 key := make([]byte, chacha20poly1305.KeySize)
326 blake3.DeriveKey(key, string(MagicNNCPEv5[:]), sharedKey[:])
327 aead, err := chacha20poly1305.New(key)
331 nonce := make([]byte, aead.NonceSize())
333 sizeBuf := make([]byte, 8+aead.Overhead())
334 if _, err = io.ReadFull(data, sizeBuf); err != nil {
337 sizeBuf, err = aead.Open(sizeBuf[:0], nonce, sizeBuf, ad[:])
341 size := int64(binary.BigEndian.Uint64(sizeBuf))
343 lr := io.LimitedReader{R: data, N: size}
344 written, err := aeadProcess(aead, nonce, ad[:], false, &lr, out)
346 return their, int64(written), err
348 if written != int(size) {
349 return their, int64(written), io.ErrUnexpectedEOF
351 return their, size, nil