Feature: MITM rewrite

2022-04-10 03:59:27 +08:00
parent 5a27ebd1b3
commit f036e06f6f
40 changed files with 2144 additions and 71 deletions
--- a/rewrite/handler.go
+++ b/rewrite/handler.go
@@ -0,0 +1,202 @@
+package rewrites
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/textproto"
+	"strconv"
+	"strings"
+
+	C "github.com/Dreamacro/clash/constant"
+	"github.com/Dreamacro/clash/listener/mitm"
+	"github.com/Dreamacro/clash/tunnel"
+)
+
+var _ mitm.Handler = (*RewriteHandler)(nil)
+
+type RewriteHandler struct{}
+
+func (*RewriteHandler) HandleRequest(session *mitm.Session) (*http.Request, *http.Response) {
+	var (
+		request  = session.Request()
+		response *http.Response
+	)
+
+	rule, sub, found := matchRewriteRule(request.URL.String(), true)
+	if !found {
+		return nil, nil
+	}
+
+	switch rule.RuleType() {
+	case C.MitmReject:
+		response = session.NewResponse(http.StatusNotFound, nil)
+		response.Header.Set("Content-Type", "text/html; charset=utf-8")
+	case C.MitmReject200:
+		response = session.NewResponse(http.StatusOK, nil)
+		response.Header.Set("Content-Type", "text/html; charset=utf-8")
+	case C.MitmRejectImg:
+		response = session.NewResponse(http.StatusOK, OnePixelPNG.Body())
+		response.Header.Set("Content-Type", "image/png")
+		response.ContentLength = OnePixelPNG.ContentLength()
+	case C.MitmRejectDict:
+		response = session.NewResponse(http.StatusOK, EmptyDict.Body())
+		response.Header.Set("Content-Type", "application/json; charset=utf-8")
+		response.ContentLength = EmptyDict.ContentLength()
+	case C.MitmRejectArray:
+		response = session.NewResponse(http.StatusOK, EmptyArray.Body())
+		response.Header.Set("Content-Type", "application/json; charset=utf-8")
+		response.ContentLength = EmptyArray.ContentLength()
+	case C.Mitm302:
+		response = session.NewResponse(http.StatusFound, nil)
+		response.Header.Set("Location", rule.ReplaceURLPayload(sub))
+	case C.Mitm307:
+		response = session.NewResponse(http.StatusTemporaryRedirect, nil)
+		response.Header.Set("Location", rule.ReplaceURLPayload(sub))
+	case C.MitmRequestHeader:
+		if len(request.Header) == 0 {
+			return nil, nil
+		}
+
+		rawHeader := &bytes.Buffer{}
+		oldHeader := request.Header
+		if err := oldHeader.Write(rawHeader); err != nil {
+			return nil, nil
+		}
+
+		newRawHeader := rule.ReplaceSubPayload(rawHeader.String())
+		tb := textproto.NewReader(bufio.NewReader(strings.NewReader(newRawHeader)))
+		newHeader, err := tb.ReadMIMEHeader()
+		if err != nil && !errors.Is(err, io.EOF) {
+			return nil, nil
+		}
+		request.Header = http.Header(newHeader)
+	case C.MitmRequestBody:
+		if !CanRewriteBody(request.ContentLength, request.Header.Get("Content-Type")) {
+			return nil, nil
+		}
+
+		buf := make([]byte, request.ContentLength)
+		_, err := io.ReadFull(request.Body, buf)
+		if err != nil {
+			return nil, nil
+		}
+
+		newBody := rule.ReplaceSubPayload(string(buf))
+		request.Body = io.NopCloser(strings.NewReader(newBody))
+		request.ContentLength = int64(len(newBody))
+	default:
+		found = false
+	}
+
+	if found {
+		if response != nil {
+			response.Close = true
+		}
+		return request, response
+	}
+	return nil, nil
+}
+
+func (*RewriteHandler) HandleResponse(session *mitm.Session) *http.Response {
+	var (
+		request  = session.Request()
+		response = session.Response()
+	)
+
+	rule, _, found := matchRewriteRule(request.URL.String(), false)
+	found = found && rule.RuleRegx() != nil
+	if !found {
+		return nil
+	}
+
+	switch rule.RuleType() {
+	case C.MitmResponseHeader:
+		if len(response.Header) == 0 {
+			return nil
+		}
+
+		rawHeader := &bytes.Buffer{}
+		oldHeader := response.Header
+		if err := oldHeader.Write(rawHeader); err != nil {
+			return nil
+		}
+
+		newRawHeader := rule.ReplaceSubPayload(rawHeader.String())
+		tb := textproto.NewReader(bufio.NewReader(strings.NewReader(newRawHeader)))
+		newHeader, err := tb.ReadMIMEHeader()
+		if err != nil && !errors.Is(err, io.EOF) {
+			return nil
+		}
+
+		response.Header = http.Header(newHeader)
+		response.Header.Set("Content-Length", strconv.FormatInt(response.ContentLength, 10))
+	case C.MitmResponseBody:
+		if !CanRewriteBody(response.ContentLength, response.Header.Get("Content-Type")) {
+			return nil
+		}
+
+		b, err := mitm.ReadDecompressedBody(response)
+		_ = response.Body.Close()
+		if err != nil {
+			return nil
+		}
+
+		body, err := mitm.DecodeLatin1(bytes.NewReader(b))
+		if err != nil {
+			return nil
+		}
+
+		newBody := rule.ReplaceSubPayload(body)
+
+		modifiedBody, err := mitm.EncodeLatin1(newBody)
+		if err != nil {
+			return nil
+		}
+
+		response.Body = ioutil.NopCloser(bytes.NewReader(modifiedBody))
+		response.Header.Del("Content-Encoding")
+		response.ContentLength = int64(len(modifiedBody))
+	default:
+		found = false
+	}
+
+	if found {
+		return response
+	}
+	return nil
+}
+
+func (h *RewriteHandler) HandleApiRequest(*mitm.Session) bool {
+	return false
+}
+
+// HandleError session maybe nil
+func (h *RewriteHandler) HandleError(*mitm.Session, error) {}
+
+func matchRewriteRule(url string, isRequest bool) (rr C.Rewrite, sub []string, found bool) {
+	rewrites := tunnel.Rewrites()
+	if isRequest {
+		found = rewrites.SearchInRequest(func(r C.Rewrite) bool {
+			sub = r.URLRegx().FindStringSubmatch(url)
+			if len(sub) != 0 {
+				rr = r
+				return true
+			}
+			return false
+		})
+	} else {
+		found = rewrites.SearchInResponse(func(r C.Rewrite) bool {
+			if r.URLRegx().FindString(url) != "" {
+				rr = r
+				return true
+			}
+			return false
+		})
+	}
+
+	return
+}