MTH

[nncp.git] / src / pkt.go

diff --git a/src/pkt.go b/src/pkt.go
index c2715e4928d585f7fb9541af01802f87d530f337..6bc9c919e873fecba3706fc3eba711a0fdca7aa0 100644 (file)
--- a/src/pkt.go
+++ b/src/pkt.go
@@ -26,19 +26,18 @@ import (
        "io"
 
        xdr "github.com/davecgh/go-xdr/xdr2"
-       "golang.org/x/crypto/blake2b"
        "golang.org/x/crypto/chacha20poly1305"
        "golang.org/x/crypto/curve25519"
        "golang.org/x/crypto/ed25519"
        "golang.org/x/crypto/nacl/box"
        "golang.org/x/crypto/poly1305"
+       "lukechampine.com/blake3"
 )
 
 type PktType uint8
 
 const (
        EncBlkSize = 128 * (1 << 10)
-       KDFXOFSize = chacha20poly1305.KeySize * 2
 
        PktTypeFile    PktType = iota
        PktTypeFreq    PktType = iota
@@ -55,7 +54,7 @@ const (
 
 var (
        MagicNNCPPv3 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'P', 0, 0, 3}
-       MagicNNCPEv4 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 4}
+       MagicNNCPEv5 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 5}
        BadMagic     error   = errors.New("Unknown magic number")
        BadPktType   error   = errors.New("Unknown packet type")
 
@@ -103,7 +102,7 @@ func init() {
                panic(err)
        }
        pktEnc := PktEnc{
-               Magic:     MagicNNCPEv4,
+               Magic:     MagicNNCPEv5,
                Sender:    dummyId,
                Recipient: dummyId,
        }
@@ -128,6 +127,16 @@ func NewPkt(typ PktType, nice uint8, path []byte) (*Pkt, error) {
        return &pkt, nil
 }
 
+func ctrIncr(b []byte) {
+       for i := len(b) - 1; i >= 0; i-- {
+               b[i]++
+               if b[i] != 0 {
+                       return
+               }
+       }
+       panic("counter overflow")
+}
+
 func aeadProcess(
        aead cipher.AEAD,
        nonce []byte,
@@ -135,7 +144,6 @@ func aeadProcess(
        r io.Reader,
        w io.Writer,
 ) (int, error) {
-       var blkCtr uint64
        ciphCtr := nonce[len(nonce)-8:]
        buf := make([]byte, EncBlkSize+aead.Overhead())
        var toRead []byte
@@ -159,8 +167,7 @@ func aeadProcess(
                        }
                }
                readBytes += n
-               blkCtr++
-               binary.BigEndian.PutUint64(ciphCtr, blkCtr)
+               ctrIncr(ciphCtr)
                if doEncrypt {
                        toWrite = aead.Seal(buf[:0], nonce, buf[:n], nil)
                } else {
@@ -202,7 +209,7 @@ func PktEncWrite(
                return nil, err
        }
        tbs := PktTbs{
-               Magic:     MagicNNCPEv4,
+               Magic:     MagicNNCPEv5,
                Nice:      nice,
                Sender:    our.Id,
                Recipient: their.Id,
@@ -215,7 +222,7 @@ func PktEncWrite(
        signature := new([ed25519.SignatureSize]byte)
        copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
        pktEnc := PktEnc{
-               Magic:     MagicNNCPEv4,
+               Magic:     MagicNNCPEv5,
                Nice:      nice,
                Sender:    our.Id,
                Recipient: their.Id,
@@ -232,18 +239,9 @@ func PktEncWrite(
        }
        sharedKey := new([32]byte)
        curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
-       kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
-       if err != nil {
-               return nil, err
-       }
-       if _, err = kdf.Write(MagicNNCPEv4[:]); err != nil {
-               return nil, err
-       }
 
        key := make([]byte, chacha20poly1305.KeySize)
-       if _, err = io.ReadFull(kdf, key); err != nil {
-               return nil, err
-       }
+       blake3.DeriveKey(key, string(MagicNNCPEv5[:]), sharedKey[:])
        aead, err := chacha20poly1305.New(key)
        if err != nil {
                return nil, err
@@ -267,14 +265,9 @@ func PktEncWrite(
                return nil, io.ErrUnexpectedEOF
        }
        if padSize > 0 {
-               if _, err = io.ReadFull(kdf, key); err != nil {
-                       return nil, err
-               }
-               kdf, err = blake2b.NewXOF(blake2b.OutputLengthUnknown, key)
-               if err != nil {
-                       return nil, err
-               }
-               if _, err = io.CopyN(out, kdf, padSize); err != nil {
+               blake3.DeriveKey(key, string(MagicNNCPEv5[:])+" PAD", sharedKey[:])
+               xof := blake3.New(32, key).XOF()
+               if _, err = io.CopyN(out, xof, padSize); err != nil {
                        return nil, err
                }
        }
@@ -283,7 +276,7 @@ func PktEncWrite(
 
 func TbsVerify(our *NodeOur, their *Node, pktEnc *PktEnc) (bool, error) {
        tbs := PktTbs{
-               Magic:     MagicNNCPEv4,
+               Magic:     MagicNNCPEv5,
                Nice:      pktEnc.Nice,
                Sender:    their.Id,
                Recipient: our.Id,
@@ -307,7 +300,7 @@ func PktEncRead(
        if err != nil {
                return nil, 0, err
        }
-       if pktEnc.Magic != MagicNNCPEv4 {
+       if pktEnc.Magic != MagicNNCPEv5 {
                return nil, 0, BadMagic
        }
        their, known := nodes[*pktEnc.Sender]
@@ -326,18 +319,9 @@ func PktEncRead(
        }
        sharedKey := new([32]byte)
        curve25519.ScalarMult(sharedKey, our.ExchPrv, &pktEnc.ExchPub)
-       kdf, err := blake2b.NewXOF(KDFXOFSize, sharedKey[:])
-       if err != nil {
-               return their, 0, err
-       }
-       if _, err = kdf.Write(MagicNNCPEv4[:]); err != nil {
-               return their, 0, err
-       }
 
        key := make([]byte, chacha20poly1305.KeySize)
-       if _, err = io.ReadFull(kdf, key); err != nil {
-               return their, 0, err
-       }
+       blake3.DeriveKey(key, string(MagicNNCPEv5[:]), sharedKey[:])
        aead, err := chacha20poly1305.New(key)
        if err != nil {
                return their, 0, err