// ServerFactory returns a new obfs4ServerFactory instance. func (t *Transport) ServerFactory(stateDir string, args *pt.Args) (base.ServerFactory, error) { st, err := serverStateFromArgs(stateDir, args) if err != nil { return nil, err } var iatSeed *drbg.Seed if st.iatMode != iatNone { iatSeedSrc := sha256.Sum256(st.drbgSeed.Bytes()[:]) var err error iatSeed, err = drbg.SeedFromBytes(iatSeedSrc[:]) if err != nil { return nil, err } } // Store the arguments that should appear in our descriptor for the clients. ptArgs := pt.Args{} ptArgs.Add(certArg, st.cert.String()) ptArgs.Add(iatArg, strconv.Itoa(st.iatMode)) // Initialize the replay filter. filter, err := replayfilter.New(replayTTL) if err != nil { return nil, err } // Initialize the close thresholds for failed connections. drbg, err := drbg.NewHashDrbg(st.drbgSeed) if err != nil { return nil, err } rng := rand.New(drbg) sf := &obfs4ServerFactory{t, &ptArgs, st.nodeID, st.identityKey, st.drbgSeed, iatSeed, st.iatMode, filter, rng.Intn(maxCloseDelayBytes), rng.Intn(maxCloseDelay)} return sf, nil }
func TestHandshakeNtorClient(t *testing.T) { // Generate the server node id and id keypair, and ephemeral session keys. nodeID, _ := ntor.NewNodeID([]byte("\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13")) idKeypair, _ := ntor.NewKeypair(false) serverFilter, _ := replayfilter.New(replayTTL) clientKeypair, err := ntor.NewKeypair(true) if err != nil { t.Fatalf("client: ntor.NewKeypair failed: %s", err) } serverKeypair, err := ntor.NewKeypair(true) if err != nil { t.Fatalf("server: ntor.NewKeypair failed: %s", err) } // Test client handshake padding. for l := clientMinPadLength; l <= clientMaxPadLength; l++ { // Generate the client state and override the pad length. clientHs := newClientHandshake(nodeID, idKeypair.Public(), clientKeypair) clientHs.padLen = l // Generate what the client will send to the server. clientBlob, err := clientHs.generateHandshake() if err != nil { t.Fatalf("[%d:0] clientHandshake.generateHandshake() failed: %s", l, err) } if len(clientBlob) > maxHandshakeLength { t.Fatalf("[%d:0] Generated client body is oversized: %d", l, len(clientBlob)) } if len(clientBlob) < clientMinHandshakeLength { t.Fatalf("[%d:0] Generated client body is undersized: %d", l, len(clientBlob)) } if len(clientBlob) != clientMinHandshakeLength+l { t.Fatalf("[%d:0] Generated client body incorrect size: %d", l, len(clientBlob)) } // Generate the server state and override the pad length. serverHs := newServerHandshake(nodeID, idKeypair, serverKeypair) serverHs.padLen = serverMinPadLength // Parse the client handshake message. serverSeed, err := serverHs.parseClientHandshake(serverFilter, clientBlob) if err != nil { t.Fatalf("[%d:0] serverHandshake.parseClientHandshake() failed: %s", l, err) } // Genrate what the server will send to the client. serverBlob, err := serverHs.generateHandshake() if err != nil { t.Fatalf("[%d:0]: serverHandshake.generateHandshake() failed: %s", l, err) } // Parse the server handshake message. clientHs.serverRepresentative = nil n, clientSeed, err := clientHs.parseServerHandshake(serverBlob) if err != nil { t.Fatalf("[%d:0] clientHandshake.parseServerHandshake() failed: %s", l, err) } if n != len(serverBlob) { t.Fatalf("[%d:0] clientHandshake.parseServerHandshake() has bytes remaining: %d", l, n) } // Ensure the derived shared secret is the same. if 0 != bytes.Compare(clientSeed, serverSeed) { t.Fatalf("[%d:0] client/server seed mismatch", l) } } // Test oversized client padding. clientHs := newClientHandshake(nodeID, idKeypair.Public(), clientKeypair) if err != nil { t.Fatalf("newClientHandshake failed: %s", err) } clientHs.padLen = clientMaxPadLength + 1 clientBlob, err := clientHs.generateHandshake() if err != nil { t.Fatalf("clientHandshake.generateHandshake() (forced oversize) failed: %s", err) } serverHs := newServerHandshake(nodeID, idKeypair, serverKeypair) _, err = serverHs.parseClientHandshake(serverFilter, clientBlob) if err == nil { t.Fatalf("serverHandshake.parseClientHandshake() succeded (oversized)") } // Test undersized client padding. clientHs.padLen = clientMinPadLength - 1 clientBlob, err = clientHs.generateHandshake() if err != nil { t.Fatalf("clientHandshake.generateHandshake() (forced undersize) failed: %s", err) } serverHs = newServerHandshake(nodeID, idKeypair, serverKeypair) _, err = serverHs.parseClientHandshake(serverFilter, clientBlob) if err == nil { t.Fatalf("serverHandshake.parseClientHandshake() succeded (undersized)") } }
func TestHandshakeNtorServer(t *testing.T) { // Generate the server node id and id keypair, and ephemeral session keys. nodeID, _ := ntor.NewNodeID([]byte("\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f\x10\x11\x12\x13")) idKeypair, _ := ntor.NewKeypair(false) serverFilter, _ := replayfilter.New(replayTTL) clientKeypair, err := ntor.NewKeypair(true) if err != nil { t.Fatalf("client: ntor.NewKeypair failed: %s", err) } serverKeypair, err := ntor.NewKeypair(true) if err != nil { t.Fatalf("server: ntor.NewKeypair failed: %s", err) } // Test server handshake padding. for l := serverMinPadLength; l <= serverMaxPadLength+inlineSeedFrameLength; l++ { // Generate the client state and override the pad length. clientHs := newClientHandshake(nodeID, idKeypair.Public(), clientKeypair) clientHs.padLen = clientMinPadLength // Generate what the client will send to the server. clientBlob, err := clientHs.generateHandshake() if err != nil { t.Fatalf("[%d:1] clientHandshake.generateHandshake() failed: %s", l, err) } if len(clientBlob) > maxHandshakeLength { t.Fatalf("[%d:1] Generated client body is oversized: %d", l, len(clientBlob)) } // Generate the server state and override the pad length. serverHs := newServerHandshake(nodeID, idKeypair, serverKeypair) serverHs.padLen = l // Parse the client handshake message. serverSeed, err := serverHs.parseClientHandshake(serverFilter, clientBlob) if err != nil { t.Fatalf("[%d:1] serverHandshake.parseClientHandshake() failed: %s", l, err) } // Genrate what the server will send to the client. serverBlob, err := serverHs.generateHandshake() if err != nil { t.Fatalf("[%d:1]: serverHandshake.generateHandshake() failed: %s", l, err) } // Parse the server handshake message. n, clientSeed, err := clientHs.parseServerHandshake(serverBlob) if err != nil { t.Fatalf("[%d:1] clientHandshake.parseServerHandshake() failed: %s", l, err) } if n != len(serverBlob) { t.Fatalf("[%d:1] clientHandshake.parseServerHandshake() has bytes remaining: %d", l, n) } // Ensure the derived shared secret is the same. if 0 != bytes.Compare(clientSeed, serverSeed) { t.Fatalf("[%d:1] client/server seed mismatch", l) } } // Test oversized client padding. clientHs := newClientHandshake(nodeID, idKeypair.Public(), clientKeypair) if err != nil { t.Fatalf("newClientHandshake failed: %s", err) } clientHs.padLen = clientMaxPadLength + 1 clientBlob, err := clientHs.generateHandshake() if err != nil { t.Fatalf("clientHandshake.generateHandshake() (forced oversize) failed: %s", err) } serverHs := newServerHandshake(nodeID, idKeypair, serverKeypair) _, err = serverHs.parseClientHandshake(serverFilter, clientBlob) if err == nil { t.Fatalf("serverHandshake.parseClientHandshake() succeded (oversized)") } // Test undersized client padding. clientHs.padLen = clientMinPadLength - 1 clientBlob, err = clientHs.generateHandshake() if err != nil { t.Fatalf("clientHandshake.generateHandshake() (forced undersize) failed: %s", err) } serverHs = newServerHandshake(nodeID, idKeypair, serverKeypair) _, err = serverHs.parseClientHandshake(serverFilter, clientBlob) if err == nil { t.Fatalf("serverHandshake.parseClientHandshake() succeded (undersized)") } // Test oversized server padding. // // NB: serverMaxPadLength isn't the real maxPadLength that triggers client // rejection, because the implementation is written with the asusmption // that the PRNG_SEED is also inlined with the response. Thus the client // actually accepts longer padding. The server handshake test and this // test adjust around that. clientHs.padLen = clientMinPadLength clientBlob, err = clientHs.generateHandshake() if err != nil { t.Fatalf("clientHandshake.generateHandshake() failed: %s", err) } serverHs = newServerHandshake(nodeID, idKeypair, serverKeypair) serverHs.padLen = serverMaxPadLength + inlineSeedFrameLength + 1 _, err = serverHs.parseClientHandshake(serverFilter, clientBlob) if err != nil { t.Fatalf("serverHandshake.parseClientHandshake() failed: %s", err) } serverBlob, err := serverHs.generateHandshake() if err != nil { t.Fatalf("serverHandshake.generateHandshake() (forced oversize) failed: %s", err) } _, _, err = clientHs.parseServerHandshake(serverBlob) if err == nil { t.Fatalf("clientHandshake.parseServerHandshake() succeded (oversized)") } }