sing-box/common/badtls/badtls.go
2022-10-01 11:29:46 +08:00

207 lines
6.3 KiB
Go

//go:build go1.19 && !go1.20
package badtls
import (
"crypto/cipher"
"crypto/rand"
"crypto/tls"
"encoding/binary"
"io"
"net"
"reflect"
"sync"
"sync/atomic"
"unsafe"
"github.com/sagernet/sing/common"
"github.com/sagernet/sing/common/buf"
"github.com/sagernet/sing/common/bufio"
E "github.com/sagernet/sing/common/exceptions"
N "github.com/sagernet/sing/common/network"
)
type Conn struct {
*tls.Conn
writer N.ExtendedWriter
activeCall *int32
closeNotifySent *bool
version *uint16
rand io.Reader
halfAccess *sync.Mutex
halfError *error
cipher cipher.AEAD
explicitNonceLen int
halfPtr uintptr
halfSeq []byte
halfScratchBuf []byte
}
func Create(conn *tls.Conn) (TLSConn, error) {
if !handshakeComplete(conn) {
return nil, E.New("handshake not finished")
}
rawConn := reflect.Indirect(reflect.ValueOf(conn))
rawActiveCall := rawConn.FieldByName("activeCall")
if !rawActiveCall.IsValid() || rawActiveCall.Kind() != reflect.Int32 {
return nil, E.New("badtls: invalid active call")
}
activeCall := (*int32)(unsafe.Pointer(rawActiveCall.UnsafeAddr()))
rawHalfConn := rawConn.FieldByName("out")
if !rawHalfConn.IsValid() || rawHalfConn.Kind() != reflect.Struct {
return nil, E.New("badtls: invalid half conn")
}
rawVersion := rawConn.FieldByName("vers")
if !rawVersion.IsValid() || rawVersion.Kind() != reflect.Uint16 {
return nil, E.New("badtls: invalid version")
}
version := (*uint16)(unsafe.Pointer(rawVersion.UnsafeAddr()))
rawCloseNotifySent := rawConn.FieldByName("closeNotifySent")
if !rawCloseNotifySent.IsValid() || rawCloseNotifySent.Kind() != reflect.Bool {
return nil, E.New("badtls: invalid notify")
}
closeNotifySent := (*bool)(unsafe.Pointer(rawCloseNotifySent.UnsafeAddr()))
rawConfig := reflect.Indirect(rawConn.FieldByName("config"))
if !rawConfig.IsValid() || rawConfig.Kind() != reflect.Struct {
return nil, E.New("badtls: bad config")
}
config := (*tls.Config)(unsafe.Pointer(rawConfig.UnsafeAddr()))
randReader := config.Rand
if randReader == nil {
randReader = rand.Reader
}
rawHalfMutex := rawHalfConn.FieldByName("Mutex")
if !rawHalfMutex.IsValid() || rawHalfMutex.Kind() != reflect.Struct {
return nil, E.New("badtls: invalid half mutex")
}
halfAccess := (*sync.Mutex)(unsafe.Pointer(rawHalfMutex.UnsafeAddr()))
rawHalfError := rawHalfConn.FieldByName("err")
if !rawHalfError.IsValid() || rawHalfError.Kind() != reflect.Interface {
return nil, E.New("badtls: invalid half error")
}
halfError := (*error)(unsafe.Pointer(rawHalfError.UnsafeAddr()))
rawHalfCipherInterface := rawHalfConn.FieldByName("cipher")
if !rawHalfCipherInterface.IsValid() || rawHalfCipherInterface.Kind() != reflect.Interface {
return nil, E.New("badtls: invalid cipher interface")
}
rawHalfCipher := rawHalfCipherInterface.Elem()
aeadCipher, loaded := valueInterface(rawHalfCipher, false).(cipher.AEAD)
if !loaded {
return nil, E.New("badtls: invalid AEAD cipher")
}
var explicitNonceLen int
switch cipherName := reflect.Indirect(rawHalfCipher).Type().String(); cipherName {
case "tls.prefixNonceAEAD":
explicitNonceLen = aeadCipher.NonceSize()
case "tls.xorNonceAEAD":
default:
return nil, E.New("badtls: unknown cipher type: ", cipherName)
}
rawHalfSeq := rawHalfConn.FieldByName("seq")
if !rawHalfSeq.IsValid() || rawHalfSeq.Kind() != reflect.Array {
return nil, E.New("badtls: invalid seq")
}
halfSeq := rawHalfSeq.Bytes()
rawHalfScratchBuf := rawHalfConn.FieldByName("scratchBuf")
if !rawHalfScratchBuf.IsValid() || rawHalfScratchBuf.Kind() != reflect.Array {
return nil, E.New("badtls: invalid scratchBuf")
}
halfScratchBuf := rawHalfScratchBuf.Bytes()
return &Conn{
Conn: conn,
writer: bufio.NewExtendedWriter(conn.NetConn()),
activeCall: activeCall,
closeNotifySent: closeNotifySent,
version: version,
halfAccess: halfAccess,
halfError: halfError,
cipher: aeadCipher,
explicitNonceLen: explicitNonceLen,
rand: randReader,
halfPtr: rawHalfConn.UnsafeAddr(),
halfSeq: halfSeq,
halfScratchBuf: halfScratchBuf,
}, nil
}
func (c *Conn) WriteBuffer(buffer *buf.Buffer) error {
if buffer.Len() > maxPlaintext {
defer buffer.Release()
return common.Error(c.Write(buffer.Bytes()))
}
for {
x := atomic.LoadInt32(c.activeCall)
if x&1 != 0 {
return net.ErrClosed
}
if atomic.CompareAndSwapInt32(c.activeCall, x, x+2) {
break
}
}
defer atomic.AddInt32(c.activeCall, -2)
c.halfAccess.Lock()
defer c.halfAccess.Unlock()
if err := *c.halfError; err != nil {
return err
}
if *c.closeNotifySent {
return errShutdown
}
dataLen := buffer.Len()
dataBytes := buffer.Bytes()
outBuf := buffer.ExtendHeader(recordHeaderLen + c.explicitNonceLen)
outBuf[0] = 23
version := *c.version
if version == 0 {
version = tls.VersionTLS10
} else if version == tls.VersionTLS13 {
version = tls.VersionTLS12
}
binary.BigEndian.PutUint16(outBuf[1:], version)
var nonce []byte
if c.explicitNonceLen > 0 {
nonce = outBuf[5 : 5+c.explicitNonceLen]
if c.explicitNonceLen < 16 {
copy(nonce, c.halfSeq)
} else {
if _, err := io.ReadFull(c.rand, nonce); err != nil {
return err
}
}
}
if len(nonce) == 0 {
nonce = c.halfSeq
}
if *c.version == tls.VersionTLS13 {
buffer.FreeBytes()[0] = 23
binary.BigEndian.PutUint16(outBuf[3:], uint16(dataLen+1+c.cipher.Overhead()))
c.cipher.Seal(outBuf, nonce, outBuf[recordHeaderLen:recordHeaderLen+c.explicitNonceLen+dataLen+1], outBuf[:recordHeaderLen])
buffer.Extend(1 + c.cipher.Overhead())
} else {
binary.BigEndian.PutUint16(outBuf[3:], uint16(dataLen))
additionalData := append(c.halfScratchBuf[:0], c.halfSeq...)
additionalData = append(additionalData, outBuf[:recordHeaderLen]...)
c.cipher.Seal(outBuf, nonce, dataBytes, additionalData)
buffer.Extend(c.cipher.Overhead())
binary.BigEndian.PutUint16(outBuf[3:], uint16(dataLen+c.explicitNonceLen+c.cipher.Overhead()))
}
incSeq(c.halfPtr)
return c.writer.WriteBuffer(buffer)
}
func (c *Conn) FrontHeadroom() int {
return recordHeaderLen + c.explicitNonceLen
}
func (c *Conn) RearHeadroom() int {
return 1 + c.cipher.Overhead()
}
func (c *Conn) WriterMTU() int {
return maxPlaintext
}
func (c *Conn) Upstream() any {
return c.NetConn()
}