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mitm_ws.go
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mitm_ws.go
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package crep
import (
"bufio"
"context"
"fmt"
"github.com/yaklang/yaklang/common/log"
logger "github.com/yaklang/yaklang/common/log"
"github.com/yaklang/yaklang/common/minimartian"
"github.com/yaklang/yaklang/common/minimartian/proxyutil"
"github.com/yaklang/yaklang/common/netx"
"github.com/yaklang/yaklang/common/utils"
"github.com/yaklang/yaklang/common/utils/lowhttp"
"github.com/yaklang/yaklang/common/utils/lowhttp/httpctx"
"io"
"net"
"net/http"
"strings"
"time"
"github.com/pkg/errors"
)
type WebSocketModifier struct {
ProxyStr string
websocketHijackMode *utils.AtomicBool
forceTextFrame *utils.AtomicBool
websocketRequestHijackHandler func(req []byte, r *http.Request, rspIns *http.Response, startTs int64) []byte
websocketResponseHijackHandler func(rsp []byte, r *http.Request, rspIns *http.Response, startTs int64) []byte
websocketRequestMirror func(req []byte)
websocketResponseMirror func(rsp []byte)
writeExcludeHeader map[string]bool
wsCanonicalHeader []string
ProxyGetter func() *minimartian.Proxy
RequestHijackCallback func(req *http.Request) error
ResponseHijackCallback func(req *http.Request, rsp *http.Response, rspRaw []byte) []byte
}
func (w *WebSocketModifier) ModifyRequest(req *http.Request) error {
var (
err error
got bool
//webSocketKey string
)
// check if it is a websocket upgrade request
if req.Method != http.MethodGet {
return nil
}
for _, vs := range req.Header["Connection"] {
for _, v := range strings.Split(vs, ",") {
if strings.TrimSpace(strings.ToLower(v)) == "upgrade" {
got = true
}
}
}
if !got {
return nil
}
if req.Header.Get("Upgrade") != "websocket" {
return nil
}
// 如果请求存在permessage-deflate扩展则设置isDeflate
isDeflate := lowhttp.IsPermessageDeflate(req.Header)
// hijack request
if err := w.RequestHijackCallback(req); err != nil {
return err
}
ctx := minimartian.NewContext(req, w.ProxyGetter())
if ctx == nil {
return nil
}
ctx.SkipRoundTrip()
conn, brw, err := ctx.Session().Hijack()
if err != nil {
logger.Error(err)
return err
}
if err = brw.Flush(); err != nil {
logger.Error(err)
return err
}
defer conn.Close()
log.Infof("start to exec websocket hijack %v", conn.RemoteAddr())
var addr string
hostname := req.URL.Hostname()
port := req.URL.Port()
scheme := req.URL.Scheme
if port == "" {
switch scheme {
case "http", "HTTP":
port = "80"
break
case "https", "HTTPS":
port = "443"
break
default:
return utils.Errorf("unknown schema: %v", scheme)
}
}
if strings.Contains(hostname, ":") {
addr = fmt.Sprintf("[%s]:%s", hostname, port)
} else {
addr = fmt.Sprintf("%s:%s", hostname, port)
}
// dial remote
var remoteConn net.Conn
switch strings.ToLower(scheme) {
case "https", "wss":
logger.Infof("building websocket tls tunnel to %s", addr)
remoteConn, err = netx.DialX(
addr,
netx.DialX_WithProxy(w.ProxyStr),
netx.DialX_WithTimeout(30*time.Second),
netx.DialX_WithTLS(true),
)
break
default:
logger.Infof("building websocket tunnel to %s", addr)
remoteConn, err = netx.DialX(
addr,
netx.DialX_WithProxy(w.ProxyStr),
netx.DialX_WithTimeout(30*time.Second),
netx.DialX_WithTLS(false),
)
}
if err != nil {
logger.Error(err)
return err
}
defer remoteConn.Close()
req.RemoteAddr = remoteConn.RemoteAddr().String()
httpctx.SetRemoteAddr(req, remoteConn.RemoteAddr().String())
// client upgrade request to remote
remoteConnReader := bufio.NewReader(remoteConn)
remoteConnWriter := bufio.NewWriter(remoteConn)
if _, err = w.writeWSReq(req, remoteConnWriter); err != nil {
return err
}
remoteConnWriter.Flush()
rspIns, err := utils.ReadHTTPResponseFromBufioReader(remoteConnReader, req)
if err != nil {
rspIns = proxyutil.NewResponse(502, nil, req)
rspBytes, _ := utils.DumpHTTPResponse(rspIns, true)
w.ResponseHijackCallback(req, rspIns, rspBytes)
return errors.Wrap(err, "lowhttp.ReadHTTPResponseFromBufioReader")
}
rspBytes, err := utils.DumpHTTPResponse(rspIns, true)
if err != nil {
w.ResponseHijackCallback(req, rspIns, rspBytes)
return errors.Wrap(err, "lowhttp.DumpHTTPResponse")
}
fixRsp := w.ResponseHijackCallback(req, rspIns, rspBytes)
// 这里不校验,也没关系,反正本来就是为了更好兼容 "劫持部分"
//websocketAccept := rsp.Header.Get("Sec-WebSocket-Accept")
//checkSum := lowhttp.ComputeWebsocketAcceptKey(webSocketKey)
//if webSocketKey != "" && websocketAccept != checkSum {
// return utils.Errorf("Sec-WebSocket-Accept header value invalid: %s != %s", websocketAccept, checkSum)
//}
rsp, err := lowhttp.ParseBytesToHTTPResponse(fixRsp)
if err != nil {
return utils.Errorf("parse 101 response bytes to http response failed; %s", err)
}
if rsp.StatusCode != 101 {
return utils.Errorf("101 switch protocol failed: now %v", rsp.StatusCode)
}
// 如果响应中不存在permessage-deflate扩展则要反设置isDeflate
serverSupportDeflate := lowhttp.IsPermessageDeflate(rsp.Header)
// 当服务端不支持permessage-deflate扩展时,客户端也不应该使用
if !serverSupportDeflate && isDeflate {
isDeflate = false
}
if _, err = brw.Writer.Write(rspBytes); err != nil {
return err
}
if err = brw.Writer.Flush(); err != nil {
return err
}
hijackCtx, cancel := context.WithCancel(context.Background())
defer cancel()
ts := time.Now().UnixNano()
log.Infof("start to build websocket hijack tunnel: %v", conn.RemoteAddr())
// 透明模式
if w.websocketHijackMode == nil || !w.websocketHijackMode.IsSet() {
go w.copySync(lowhttp.NewFrameWriter(remoteConn, isDeflate), lowhttp.NewFrameReader(brw.Reader, isDeflate), true, req, rsp, cancel, ts)
go w.copySync(lowhttp.NewFrameWriter(brw.Writer, isDeflate), lowhttp.NewFrameReader(remoteConn, isDeflate), false, req, rsp, cancel, ts)
} else {
go w.copyHijack(remoteConnWriter, brw.Reader, true, req, rsp, cancel, ts, isDeflate)
go w.copyHijack(brw.Writer, remoteConnReader, false, req, rsp, cancel, ts, isDeflate)
}
select {
case <-hijackCtx.Done():
break
}
logger.Infof("websocket tunnel for %s closed", addr)
return nil
}
func (w *WebSocketModifier) copyHijack(writer *bufio.Writer, reader *bufio.Reader, isRequest bool, req *http.Request, rsp *http.Response, cancel context.CancelFunc, ts int64, isDeflate bool) {
defer cancel()
var (
b []byte
frame *lowhttp.Frame
err error
callbackHandler func([]byte, *http.Request, *http.Response, int64) []byte
//forceTextFrame bool = !(w.forceTextFrame == nil || !w.forceTextFrame.IsSet())
)
_ = b
// hijack
if isRequest {
callbackHandler = w.websocketRequestHijackHandler
} else {
callbackHandler = w.websocketResponseHijackHandler
}
if callbackHandler == nil {
callbackHandler = func(bytes []byte, request *http.Request, response *http.Response, i int64) []byte {
return bytes
}
}
//isDeflate = false
frameReader := lowhttp.NewFrameReaderFromBufio(reader, isDeflate)
frameWriter := lowhttp.NewFrameWriterFromBufio(writer, isDeflate)
for {
frame, err = frameReader.ReadFrame()
if err != nil {
if frame != nil {
rawData, _ := frame.Bytes()
switch frame.Type() {
case lowhttp.BinaryMessage, lowhttp.TextMessage:
callbackHandler(rawData, req, rsp, ts)
}
frameWriter.WriteRaw(rawData)
frameWriter.Flush()
}
break
}
masked := frame.GetMask()
firstByte := frame.GetFirstByte()
showData := frame.GetData()
raw := frame.GetRaw()
payload := frame.GetPayload()
switch frame.Type() {
case lowhttp.TextMessage, lowhttp.BinaryMessage:
b = callbackHandler(showData, req, rsp, ts)
newFrame, err := lowhttp.DataToWebsocketFrame(payload, firstByte, masked)
if err != nil {
frameWriter.WriteRaw(raw)
frameWriter.Flush()
continue
}
newFrame.SetData(showData)
newFrame.SetMaskingKey(frame.GetMaskingKey())
newRaw, _ := newFrame.Bytes()
frameWriter.WriteRaw(newRaw)
case lowhttp.PingMessage:
frameWriter.WritePong(showData, masked)
default:
if err = frameWriter.WriteFrame(frame); err != nil {
log.Errorf("write frame failed: %s", err)
}
}
if err = frameWriter.Flush(); err != nil {
break
}
}
if err != nil {
log.Errorf("websocket dial with hijack mode error: %v", err)
}
}
func (w *WebSocketModifier) copySync(writer *lowhttp.FrameWriter, reader *lowhttp.FrameReader, isRequest bool, req *http.Request, rsp *http.Response, cancel context.CancelFunc, ts int64) {
defer cancel()
var (
frame *lowhttp.Frame
err error
callbackHandler func([]byte)
)
if isRequest {
callbackHandler = w.websocketRequestMirror
} else {
callbackHandler = w.websocketResponseMirror
}
for {
frame, err = reader.ReadFrame()
switch frame.Type() {
case lowhttp.BinaryMessage, lowhttp.TextMessage:
case lowhttp.PingMessage:
writer.WritePong(frame.GetData(), true)
default:
continue
}
if err != nil {
if frame != nil {
rawData, _ := frame.Bytes()
if len(rawData) <= 0 {
break
}
callbackHandler(rawData)
writer.WriteRaw(rawData)
writer.Flush()
continue
}
break
}
// mirror
if callbackHandler != nil {
go callbackHandler(lowhttp.WebsocketFrameToData(frame))
}
if err = writer.WriteFrame(frame); err != nil {
break
}
if err = writer.Flush(); err != nil {
break
}
}
if err != nil {
log.Errorf("websocket dial with hijack mode error: %v", err)
cancel()
}
}
// todo: trailer
func (w *WebSocketModifier) writeWSReq(req *http.Request, bw io.Writer) (webSocketKey string, err error) {
raw, err := utils.HttpDumpWithBody(req, true)
if err != nil {
log.Warnf("dump websocket first upgrade req failed: %s", err)
}
if len(raw) > 0 {
bw.Write(raw)
return "", nil
}
// can't use req.Header.Get
if keys, ok := req.Header["Sec-WebSocket-Key"]; ok {
webSocketKey = keys[0]
}
_, err = fmt.Fprintf(bw, "GET %s HTTP/1.1\r\n", req.URL.RequestURI())
if err != nil {
return
}
var host string
if req.Host != "" {
host = req.Host
} else if req.URL.Host != "" {
host = req.Host
} else {
err = utils.Errorf("missing host")
return
}
_, err = fmt.Fprintf(bw, "Host: %s\r\n", host)
if err != nil {
return
}
if w.writeExcludeHeader == nil {
w.writeExcludeHeader = map[string]bool{
"Host": true,
"Sec-Websocket-Extensions": true,
"Sec-Websocket-Key": true,
"Sec-Websocket-Protocol": true,
"Sec-Websocket-Version": true,
}
w.wsCanonicalHeader = []string{
"Sec-WebSocket-Extensions",
"Sec-WebSocket-Key",
"Sec-WebSocket-Protocol",
"Sec-WebSocket-Version",
}
}
err = req.Header.WriteSubset(bw, w.writeExcludeHeader)
if err != nil {
return
}
// write WebSocket special headers
headers := req.Header
for _, k := range w.wsCanonicalHeader {
if values, ok := headers[k]; ok {
for _, v := range values {
if v == "" {
continue
}
_, err = fmt.Fprintf(bw, "%s: %s\r\n", k, v)
if err != nil {
return
}
}
}
}
_, err = bw.Write([]byte("\r\n"))
if err != nil {
return
}
return
}