diff options
| author | Yawning Angel <yawning@schwanenlied.me> | 2014-06-01 05:22:07 +0000 |
|---|---|---|
| committer | Yawning Angel <yawning@schwanenlied.me> | 2014-06-01 05:22:07 +0000 |
| commit | 36228437c43bf3fa67a4d5b8da8ddf123645e530 (patch) | |
| tree | b4772fe6a9162c543a46961dc8af053be5b1405c /handshake_ntor.go | |
| parent | 2001f0b698183b998dbf8e52f5d40a0d82aeef09 (diff) | |
Move the server keypair generation to right after Accept().
Instead of threading the code, move the keypair generation to right
after Accept() is called. This should mask the timing differential due
to the rejection sampling with the noise from the variablity in how
long it takes for the server to get around to pulling a connection out
of the backlog, and the time taken for the client to send it's portion
of the handshake.
The downside is that anyone connecting to the obfs4 port does force us
to do a bunch of math, but the obfs4 math is relatively cheap compared
to it's precursors.
Fixes #9.
Diffstat (limited to 'handshake_ntor.go')
| -rw-r--r-- | handshake_ntor.go | 15 |
1 files changed, 4 insertions, 11 deletions
diff --git a/handshake_ntor.go b/handshake_ntor.go index 92f00dc..46e2a13 100644 --- a/handshake_ntor.go +++ b/handshake_ntor.go @@ -121,7 +121,7 @@ type clientHandshake struct { serverMark []byte } -func newClientHandshake(nodeID *ntor.NodeID, serverIdentity *ntor.PublicKey, sessionKey *ntor.Keypair) (*clientHandshake, error) { +func newClientHandshake(nodeID *ntor.NodeID, serverIdentity *ntor.PublicKey, sessionKey *ntor.Keypair) *clientHandshake { hs := new(clientHandshake) hs.keypair = sessionKey hs.nodeID = nodeID @@ -129,7 +129,7 @@ func newClientHandshake(nodeID *ntor.NodeID, serverIdentity *ntor.PublicKey, ses hs.padLen = csrand.IntRange(clientMinPadLength, clientMaxPadLength) hs.mac = hmac.New(sha256.New, append(hs.serverIdentity.Bytes()[:], hs.nodeID.Bytes()[:]...)) - return hs, nil + return hs } func (hs *clientHandshake) generateHandshake() ([]byte, error) { @@ -236,8 +236,9 @@ type serverHandshake struct { clientMark []byte } -func newServerHandshake(nodeID *ntor.NodeID, serverIdentity *ntor.Keypair) *serverHandshake { +func newServerHandshake(nodeID *ntor.NodeID, serverIdentity *ntor.Keypair, sessionKey *ntor.Keypair) *serverHandshake { hs := new(serverHandshake) + hs.keypair = sessionKey hs.nodeID = nodeID hs.serverIdentity = serverIdentity hs.padLen = csrand.IntRange(serverMinPadLength, serverMaxPadLength) @@ -312,14 +313,6 @@ func (hs *serverHandshake) parseClientHandshake(filter *replayFilter, resp []byt return nil, ErrInvalidHandshake } - // At this point the client knows that we exist, so do the keypair - // generation and complete our side of the handshake. - var err error - hs.keypair, err = ntor.NewKeypair(true) - if err != nil { - return nil, err - } - clientPublic := hs.clientRepresentative.ToPublic() ok, seed, auth := ntor.ServerHandshake(clientPublic, hs.keypair, hs.serverIdentity, hs.nodeID) |