Refactor makeAuthenticationPayload to allow easier tests

internal/client/TLS.go

@@ -1,6 +1,7 @@
 package client
 
 import (
+	"crypto/rand"
 	"encoding/binary"
 	"github.com/cbeuw/Cloak/internal/util"
 	"net"
@@ -45,6 +46,8 @@ func addExtRec(typ []byte, data []byte) []byte {
 }
 
 func unmarshalAuthenticationInfo(ai authenticationPayload, serverName string) (ret clientHelloFields) {
+	// random is marshalled ephemeral pub key 32 bytes
+	// The authentication ciphertext and its tag are then distributed among SessionId and X25519KeyShare
 	ret.random = ai.randPubKey[:]
 	ret.sessionId = ai.ciphertextWithTag[0:32]
 	ret.x25519KeyShare = ai.ciphertextWithTag[32:64]
@@ -63,7 +66,7 @@ func (DirectTLS) UnitReadFunc() func(net.Conn, []byte) (int, error) { return uti
 // if the server proceed with Cloak authentication
 func (DirectTLS) PrepareConnection(sta *State, conn net.Conn) (preparedConn net.Conn, sessionKey []byte, err error) {
 	preparedConn = conn
-	payload, sharedSecret := makeAuthenticationPayload(sta)
+	payload, sharedSecret := makeAuthenticationPayload(sta, rand.Reader)
 	chOnly := sta.browser.composeClientHello(unmarshalAuthenticationInfo(payload, sta.ServerName))
 	chWithRecordLayer := util.AddRecordLayer(chOnly, []byte{0x16}, []byte{0x03, 0x01})
 	_, err = preparedConn.Write(chWithRecordLayer)

internal/client/auth.go

@@ -1,12 +1,10 @@
 package client
 
 import (
-	"crypto/rand"
 	"encoding/binary"
-	"encoding/hex"
 	"github.com/cbeuw/Cloak/internal/ecdh"
 	"github.com/cbeuw/Cloak/internal/util"
-	"log"
+	"io"
 	"sync/atomic"
 )
 
@@ -20,9 +18,8 @@ type authenticationPayload struct {
 }
 
 // makeAuthenticationPayload generates the ephemeral key pair, calculates the shared secret, and then compose and
-// encrypt the Authentication data. It also composes SNI extension.
-func makeAuthenticationPayload(sta *State) (ret authenticationPayload, sharedSecret []byte) {
-	// random is marshalled ephemeral pub key 32 bytes
+// encrypt the authenticationPayload
+func makeAuthenticationPayload(sta *State, randReader io.Reader) (ret authenticationPayload, sharedSecret []byte) {
 	/*
 		Authentication data:
 		+----------+----------------+---------------------+-------------+--------------+--------+------------+
@@ -31,8 +28,7 @@ func makeAuthenticationPayload(sta *State) (ret authenticationPayload, sharedSec
 		| 16 bytes | 12 bytes       | 1 byte              | 8 bytes     | 4 bytes      | 1 byte | 6 bytes    |
 		+----------+----------------+---------------------+-------------+--------------+--------+------------+
 	*/
-	// The authentication ciphertext and its tag are then distributed among SessionId and X25519KeyShare
-	ephPv, ephPub, _ := ecdh.GenerateKey(rand.Reader)
+	ephPv, ephPub, _ := ecdh.GenerateKey(randReader)
 	copy(ret.randPubKey[:], ecdh.Marshal(ephPub))
 
 	plaintext := make([]byte, 48)
@@ -48,7 +44,6 @@ func makeAuthenticationPayload(sta *State) (ret authenticationPayload, sharedSec
 
 	sharedSecret = ecdh.GenerateSharedSecret(ephPv, sta.staticPub)
 	ciphertextWithTag, _ := util.AESGCMEncrypt(ret.randPubKey[:12], sharedSecret, plaintext)
-	log.Print(hex.EncodeToString(sharedSecret))
 	copy(ret.ciphertextWithTag[:], ciphertextWithTag[:])
 	return
 }

internal/client/auth_test.go

@@ -0,0 +1,74 @@
+package client
+
+import (
+	"bytes"
+	"github.com/cbeuw/Cloak/internal/multiplex"
+	"io"
+	"testing"
+	"time"
+)
+
+func TestMakeAuthenticationPayload(t *testing.T) {
+	tests := []struct {
+		state      *State
+		seed       io.Reader
+		expPayload authenticationPayload
+		expSecret  []byte
+	}{
+		{
+			&State{
+				Unordered: false,
+				SessionID: 3421516597,
+				UID: []byte{
+					0x4c, 0xd8, 0xcc, 0x15, 0x60, 0x0d, 0x7e,
+					0xb6, 0x81, 0x31, 0xfd, 0x80, 0x97, 0x67, 0x37, 0x46},
+				staticPub: &[32]byte{
+					0x21, 0x8a, 0x14, 0xce, 0x49, 0x5e, 0xfd, 0x3f,
+					0xe4, 0xae, 0x21, 0x3e, 0x51, 0xf7, 0x66, 0xec,
+					0x01, 0xd0, 0xb4, 0x87, 0x86, 0x9c, 0x15, 0x9b,
+					0x86, 0x19, 0x53, 0x6e, 0x60, 0xe9, 0x51, 0x42},
+				Now:              func() time.Time { return time.Unix(1579908372, 0) },
+				ProxyMethod:      "shadowsocks",
+				EncryptionMethod: multiplex.E_METHOD_PLAIN,
+				ServerName:       "d2jkinvisak5y9.cloudfront.net",
+			},
+			bytes.NewBuffer([]byte{
+				0xf1, 0x1e, 0x42, 0xe1, 0x84, 0x22, 0x07, 0xc5,
+				0xc3, 0x5c, 0x0f, 0x7b, 0x01, 0xf3, 0x65, 0x2d,
+				0xd7, 0x9b, 0xad, 0xb0, 0xb2, 0x77, 0xa2, 0x06,
+				0x6b, 0x78, 0x1b, 0x74, 0x1f, 0x43, 0xc9, 0x80}),
+			authenticationPayload{
+				randPubKey: [32]byte{
+					0xee, 0x9e, 0x41, 0x4e, 0xb3, 0x3b, 0x85, 0x03,
+					0x6d, 0x85, 0xba, 0x30, 0x11, 0x31, 0x10, 0x24,
+					0x4f, 0x7b, 0xd5, 0x38, 0x50, 0x0f, 0xf2, 0x4d,
+					0xa3, 0xdf, 0xba, 0x76, 0x0a, 0xe9, 0x19, 0x19},
+				ciphertextWithTag: [64]byte{
+					0x71, 0xb1, 0x6c, 0x5a, 0x60, 0x46, 0x90, 0x12,
+					0x36, 0x3b, 0x1b, 0xc4, 0x79, 0x3c, 0xab, 0xdd,
+					0x5a, 0x53, 0xc5, 0xed, 0xaf, 0xdb, 0x10, 0x98,
+					0x83, 0x96, 0x81, 0xa6, 0xfc, 0xa2, 0x1e, 0xb0,
+					0x89, 0xb2, 0x29, 0x71, 0x7e, 0x45, 0x97, 0x54,
+					0x11, 0x7d, 0x9b, 0x92, 0xbb, 0xd6, 0xce, 0x37,
+					0x3b, 0xb8, 0x8b, 0xfb, 0xb6, 0x40, 0xf0, 0x2c,
+					0x6c, 0x55, 0xb9, 0xfc, 0x5d, 0x34, 0x89, 0x41},
+			},
+			[]byte{
+				0xc7, 0xc6, 0x9b, 0xbe, 0xec, 0xf8, 0x35, 0x55,
+				0x67, 0x20, 0xcd, 0xeb, 0x74, 0x16, 0xc5, 0x60,
+				0xee, 0x9d, 0x63, 0x1a, 0x44, 0xc5, 0x09, 0xf6,
+				0xe0, 0x24, 0xad, 0xd2, 0x10, 0xe3, 0x4a, 0x11},
+		},
+	}
+	for _, tc := range tests {
+		func() {
+			payload, sharedSecret := makeAuthenticationPayload(tc.state, tc.seed)
+			if payload != tc.expPayload {
+				t.Errorf("payload doesn't match:\nexp %v\ngot %v", tc.expPayload, payload)
+			}
+			if !bytes.Equal(sharedSecret, tc.expSecret) {
+				t.Errorf("secret doesn't match:\nexp %x\ngot %x", tc.expPayload, payload)
+			}
+		}()
+	}
+}

internal/client/websocket.go

@@ -1,6 +1,7 @@
 package client
 
 import (
+	"crypto/rand"
 	"encoding/base64"
 	"errors"
 	"fmt"
@@ -37,7 +38,7 @@ func (WSOverTLS) PrepareConnection(sta *State, conn net.Conn) (preparedConn net.
 		return preparedConn, nil, fmt.Errorf("failed to parse ws url: %v", err)
 	}
 
-	payload, sharedSecret := makeAuthenticationPayload(sta)
+	payload, sharedSecret := makeAuthenticationPayload(sta, rand.Reader)
 	header := http.Header{}
 	header.Add("hidden", base64.StdEncoding.EncodeToString(append(payload.randPubKey[:], payload.ciphertextWithTag[:]...)))
 	c, _, err := websocket.NewClient(preparedConn, u, header, 16480, 16480)