diff options
Diffstat (limited to 'handshake_ntor.go')
| -rw-r--r-- | handshake_ntor.go | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/handshake_ntor.go b/handshake_ntor.go index 3a8b36e..8baa382 100644 --- a/handshake_ntor.go +++ b/handshake_ntor.go @@ -44,18 +44,18 @@ import ( ) const ( + maxHandshakeLength = 8192 + clientMinPadLength = (serverMinHandshakeLength + inlineSeedFrameLength) - clientMinHandshakeLength - clientMaxPadLength = framing.MaximumSegmentLength - clientMinHandshakeLength + clientMaxPadLength = maxHandshakeLength - clientMinHandshakeLength clientMinHandshakeLength = ntor.RepresentativeLength + markLength + macLength - clientMaxHandshakeLength = framing.MaximumSegmentLength serverMinPadLength = 0 - serverMaxPadLength = framing.MaximumSegmentLength - (serverMinHandshakeLength + + serverMaxPadLength = maxHandshakeLength - (serverMinHandshakeLength + inlineSeedFrameLength) serverMinHandshakeLength = ntor.RepresentativeLength + ntor.AuthLength + markLength + macLength - serverMaxHandshakeLength = framing.MaximumSegmentLength markLength = sha256.Size / 2 macLength = sha256.Size / 2 @@ -113,7 +113,8 @@ type clientHandshake struct { serverIdentity *ntor.PublicKey epochHour []byte - mac hash.Hash + padLen int + mac hash.Hash serverRepresentative *ntor.Representative serverAuth *ntor.Auth @@ -130,6 +131,7 @@ func newClientHandshake(nodeID *ntor.NodeID, serverIdentity *ntor.PublicKey) (*c } hs.nodeID = nodeID hs.serverIdentity = serverIdentity + hs.padLen = randRange(clientMinPadLength, clientMaxPadLength) hs.mac = hmac.New(sha256.New, append(hs.serverIdentity.Bytes()[:], hs.nodeID.Bytes()[:]...)) return hs, nil @@ -151,7 +153,7 @@ func (hs *clientHandshake) generateHandshake() ([]byte, error) { // epoch. // Generate the padding - pad, err := makePad(clientMinPadLength, clientMaxPadLength) + pad, err := makePad(hs.padLen) if err != nil { return nil, err } @@ -193,9 +195,9 @@ func (hs *clientHandshake) parseServerHandshake(resp []byte) (int, []byte, error // Attempt to find the mark + MAC. pos := findMarkMac(hs.serverMark, resp, ntor.RepresentativeLength+ntor.AuthLength+serverMinPadLength, - serverMaxHandshakeLength, false) + maxHandshakeLength, false) if pos == -1 { - if len(resp) >= serverMaxHandshakeLength { + if len(resp) >= maxHandshakeLength { return 0, nil, ErrInvalidHandshake } return 0, nil, ErrMarkNotFoundYet @@ -232,7 +234,8 @@ type serverHandshake struct { epochHour []byte serverAuth *ntor.Auth - mac hash.Hash + padLen int + mac hash.Hash clientRepresentative *ntor.Representative clientMark []byte @@ -242,6 +245,7 @@ func newServerHandshake(nodeID *ntor.NodeID, serverIdentity *ntor.Keypair) *serv hs := new(serverHandshake) hs.nodeID = nodeID hs.serverIdentity = serverIdentity + hs.padLen = randRange(serverMinPadLength, serverMaxPadLength) hs.mac = hmac.New(sha256.New, append(hs.serverIdentity.Public().Bytes()[:], hs.nodeID.Bytes()[:]...)) return hs @@ -267,9 +271,9 @@ func (hs *serverHandshake) parseClientHandshake(filter *replayFilter, resp []byt // Attempt to find the mark + MAC. pos := findMarkMac(hs.clientMark, resp, ntor.RepresentativeLength+clientMinPadLength, - clientMaxHandshakeLength, true) + maxHandshakeLength, true) if pos == -1 { - if len(resp) >= clientMaxHandshakeLength { + if len(resp) >= maxHandshakeLength { return nil, ErrInvalidHandshake } return nil, ErrMarkNotFoundYet @@ -349,7 +353,7 @@ func (hs *serverHandshake) generateHandshake() ([]byte, error) { // epoch. // Generate the padding - pad, err := makePad(serverMinPadLength, serverMaxPadLength) + pad, err := makePad(hs.padLen) if err != nil { return nil, err } @@ -422,8 +426,7 @@ func findMarkMac(mark, buf []byte, startPos, maxPos int, fromTail bool) (pos int return } -func makePad(min, max int) ([]byte, error) { - padLen := randRange(min, max) +func makePad(padLen int) ([]byte, error) { pad := make([]byte, padLen) _, err := rand.Read(pad) if err != nil { |