Stop using custom conversion function

cbeuw · Jan 13, 2019 · 735dc64 · 735dc64
1 parent 41da410
commit 735dc64
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Showing 2 changed files with 8 additions and 18 deletions.
diff --git a/internal/server/TLS.go b/internal/server/TLS.go
@@ -24,6 +24,9 @@ type ClientHello struct {
 	extensions            map[[2]byte][]byte
 }
 
+var u16 = binary.BigEndian.Uint16
+var u32 = binary.BigEndian.Uint32
+
 func parseExtensions(input []byte) (ret map[[2]byte][]byte, err error) {
 	defer func() {
 		if r := recover(); r != nil {
@@ -37,7 +40,7 @@ func parseExtensions(input []byte) (ret map[[2]byte][]byte, err error) {
 		var typ [2]byte
 		copy(typ[:], input[pointer:pointer+2])
 		pointer += 2
-		length := util.BtoInt(input[pointer : pointer+2])
+		length := int(u16(input[pointer : pointer+2]))
 		pointer += 2
 		data := input[pointer : pointer+length]
 		pointer += length
@@ -81,7 +84,7 @@ func ParseClientHello(data []byte) (ret *ClientHello, err error) {
 	}
 	pointer += 1
 	// Length
-	length := util.BtoInt(data[pointer : pointer+3])
+	length := int(u32(append([]byte{0x00}, data[pointer:pointer+3]...)))
 	pointer += 3
 	if length != len(data[pointer:]) {
 		return ret, errors.New("Hello length doesn't match")
@@ -98,7 +101,7 @@ func ParseClientHello(data []byte) (ret *ClientHello, err error) {
 	sessionId := data[pointer : pointer+sessionIdLen]
 	pointer += sessionIdLen
 	// Cipher Suites
-	cipherSuitesLen := util.BtoInt(data[pointer : pointer+2])
+	cipherSuitesLen := int(u16(data[pointer : pointer+2]))
 	pointer += 2
 	cipherSuites := data[pointer : pointer+cipherSuitesLen]
 	pointer += cipherSuitesLen
@@ -108,7 +111,7 @@ func ParseClientHello(data []byte) (ret *ClientHello, err error) {
 	compressionMethods := data[pointer : pointer+compressionMethodsLen]
 	pointer += compressionMethodsLen
 	// Extensions
-	extensionsLen := util.BtoInt(data[pointer : pointer+2])
+	extensionsLen := int(u16(data[pointer : pointer+2]))
 	pointer += 2
 	extensions, err := parseExtensions(data[pointer:])
 	ret = &ClientHello{

diff --git a/internal/util/util.go b/internal/util/util.go
@@ -28,19 +28,6 @@ func AESDecrypt(iv []byte, key []byte, ciphertext []byte) []byte {
 	return ret
 }
 
-// BtoInt converts a byte slice into int in Big Endian order
-// Uint methods from binary package can be used, but they are messy
-func BtoInt(b []byte) int {
-	var mult uint = 1
-	var sum uint
-	length := uint(len(b))
-	var i uint
-	for i = 0; i < length; i++ {
-		sum += uint(b[i]) * (mult << ((length - i - 1) * 8))
-	}
-	return int(sum)
-}
-
 // PsudoRandBytes returns a byte slice filled with psudorandom bytes generated by the seed
 func PsudoRandBytes(length int, seed int64) []byte {
 	r := prand.New(prand.NewSource(seed))
@@ -60,7 +47,7 @@ func ReadTLS(conn net.Conn, buffer []byte) (n int, err error) {
 		return
 	}
 
-	dataLength := BtoInt(buffer[3:5])
+	dataLength := int(binary.BigEndian.Uint16(buffer[3:5]))
 	if dataLength > len(buffer) {
 		err = errors.New("Reading TLS message: message size greater than buffer. message size: " + strconv.Itoa(dataLength))
 		return