Recipient in encrypted packet is needed for future changes

[nncp.git] / src / cypherpunks.ru / nncp / pkt.go

diff --git a/src/cypherpunks.ru/nncp/pkt.go b/src/cypherpunks.ru/nncp/pkt.go
index b35f83e3ee969f6fdaad031ae3972b83b8cf04bb..fa46282c3b9354d5ea8382ec57d46096cd3a53e9 100644 (file)
--- a/src/cypherpunks.ru/nncp/pkt.go
+++ b/src/cypherpunks.ru/nncp/pkt.go
@@ -53,7 +53,7 @@ const (
 
 var (
        MagicNNCPPv1 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'P', 0, 0, 1}
-       MagicNNCPEv1 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 1}
+       MagicNNCPEv2 [8]byte = [8]byte{'N', 'N', 'C', 'P', 'E', 0, 0, 2}
        BadMagic     error   = errors.New("Unknown magic number")
        BadPktType   error   = errors.New("Unknown packet type")
 
@@ -71,17 +71,18 @@ type Pkt struct {
 type PktTbs struct {
        Magic     [8]byte
        Nice      uint8
-       Recipient *NodeId
        Sender    *NodeId
+       Recipient *NodeId
        ExchPub   *[32]byte
 }
 
 type PktEnc struct {
-       Magic   [8]byte
-       Nice    uint8
-       Sender  *NodeId
-       ExchPub *[32]byte
-       Sign    *[ed25519.SignatureSize]byte
+       Magic     [8]byte
+       Nice      uint8
+       Sender    *NodeId
+       Recipient *NodeId
+       ExchPub   *[32]byte
+       Sign      *[ed25519.SignatureSize]byte
 }
 
 func init() {
@@ -102,11 +103,12 @@ func init() {
                panic(err)
        }
        pktEnc := PktEnc{
-               Magic:   MagicNNCPEv1,
-               Nice:    123,
-               Sender:  dummyId,
-               ExchPub: new([32]byte),
-               Sign:    new([ed25519.SignatureSize]byte),
+               Magic:     MagicNNCPEv2,
+               Nice:      123,
+               Sender:    dummyId,
+               Recipient: dummyId,
+               ExchPub:   new([32]byte),
+               Sign:      new([ed25519.SignatureSize]byte),
        }
        n, err = xdr.Marshal(&buf, pktEnc)
        if err != nil {
@@ -157,10 +159,10 @@ func PktEncWrite(our *NodeOur, their *Node, pkt *Pkt, nice uint8, size, padSize
                return err
        }
        tbs := PktTbs{
-               Magic:     MagicNNCPEv1,
+               Magic:     MagicNNCPEv2,
                Nice:      nice,
-               Recipient: their.Id,
                Sender:    our.Id,
+               Recipient: their.Id,
                ExchPub:   pubEph,
        }
        var tbsBuf bytes.Buffer
@@ -170,18 +172,19 @@ func PktEncWrite(our *NodeOur, their *Node, pkt *Pkt, nice uint8, size, padSize
        signature := new([ed25519.SignatureSize]byte)
        copy(signature[:], ed25519.Sign(our.SignPrv, tbsBuf.Bytes()))
        pktEnc := PktEnc{
-               Magic:   MagicNNCPEv1,
-               Nice:    nice,
-               Sender:  our.Id,
-               ExchPub: pubEph,
-               Sign:    signature,
+               Magic:     MagicNNCPEv2,
+               Nice:      nice,
+               Sender:    our.Id,
+               Recipient: their.Id,
+               ExchPub:   pubEph,
+               Sign:      signature,
        }
        if _, err = xdr.Marshal(out, &pktEnc); err != nil {
                return err
        }
        sharedKey := new([32]byte)
        curve25519.ScalarMult(sharedKey, prvEph, their.ExchPub)
-       kdf := hkdf.New(blake256, sharedKey[:], nil, MagicNNCPEv1[:])
+       kdf := hkdf.New(blake256, sharedKey[:], nil, MagicNNCPEv2[:])
 
        keyEnc := make([]byte, 32)
        if _, err = io.ReadFull(kdf, keyEnc); err != nil {
@@ -257,10 +260,10 @@ func PktEncWrite(our *NodeOur, their *Node, pkt *Pkt, nice uint8, size, padSize
 
 func TbsVerify(our *NodeOur, their *Node, pktEnc *PktEnc) (bool, error) {
        tbs := PktTbs{
-               Magic:     MagicNNCPEv1,
+               Magic:     MagicNNCPEv2,
                Nice:      pktEnc.Nice,
-               Recipient: our.Id,
                Sender:    their.Id,
+               Recipient: our.Id,
                ExchPub:   pktEnc.ExchPub,
        }
        var tbsBuf bytes.Buffer
@@ -276,13 +279,16 @@ func PktEncRead(our *NodeOur, nodes map[NodeId]*Node, data io.Reader, out io.Wri
        if err != nil {
                return nil, 0, err
        }
-       if pktEnc.Magic != MagicNNCPEv1 {
+       if pktEnc.Magic != MagicNNCPEv2 {
                return nil, 0, BadMagic
        }
        their, known := nodes[*pktEnc.Sender]
        if !known {
                return nil, 0, errors.New("Unknown sender")
        }
+       if *pktEnc.Recipient != *our.Id {
+               return nil, 0, errors.New("Invalid recipient")
+       }
        verified, err := TbsVerify(our, their, &pktEnc)
        if err != nil {
                return nil, 0, err
@@ -292,7 +298,7 @@ func PktEncRead(our *NodeOur, nodes map[NodeId]*Node, data io.Reader, out io.Wri
        }
        sharedKey := new([32]byte)
        curve25519.ScalarMult(sharedKey, our.ExchPrv, pktEnc.ExchPub)
-       kdf := hkdf.New(blake256, sharedKey[:], nil, MagicNNCPEv1[:])
+       kdf := hkdf.New(blake256, sharedKey[:], nil, MagicNNCPEv2[:])
 
        keyEnc := make([]byte, 32)
        if _, err = io.ReadFull(kdf, keyEnc); err != nil {