mirror of
https://github.com/RuoJi6/ARTEX.git
synced 2026-10-27 17:03:49 +08:00
410 lines
12 KiB
Go
410 lines
12 KiB
Go
package server
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import (
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"bytes"
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"context"
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"crypto/tls"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"net"
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"net/http"
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"net/url"
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"os"
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"strconv"
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"strings"
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"syscall"
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"time"
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)
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const (
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repeaterMaxBody = 2 << 20 // 2 MiB, for both the JSON request and response preview
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repeaterDefaultTimeout = 30_000
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repeaterMinTimeout = 1_000
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repeaterMaxTimeout = 120_000
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repeaterAllowLocalEnv = "ARTEX_REPEATER_ALLOW_LOCAL"
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)
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var repeaterHopByHop = map[string]struct{}{
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"Connection": {}, "Keep-Alive": {}, "Proxy-Connection": {}, "Transfer-Encoding": {},
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"Te": {}, "Trailer": {}, "Upgrade": {}, "Content-Length": {}, "Proxy-Authorization": {},
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}
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type repeaterSendRequest struct {
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Method *string `json:"method"`
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URL string `json:"url"`
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Headers map[string]string `json:"headers"`
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Body string `json:"body"`
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TimeoutMs int `json:"timeout_ms"`
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InsecureSkipVerify bool `json:"insecure_skip_verify"`
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UseRecordingProxy *bool `json:"use_recording_proxy"`
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}
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type repeaterSendResponse struct {
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Status int `json:"status"`
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StatusText string `json:"status_text"`
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Proto string `json:"proto"`
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Headers map[string][]string `json:"headers"`
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Body string `json:"body"`
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BodyTruncated bool `json:"body_truncated"`
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BodyBytes int `json:"body_bytes"`
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ElapsedMs int64 `json:"elapsed_ms"`
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URL string `json:"url"`
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Error string `json:"error,omitempty"`
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}
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func (s *Server) registerRepeater(mux *http.ServeMux) {
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mux.HandleFunc("POST /api/repeater/send", s.sendRepeater)
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}
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func (s *Server) sendRepeater(w http.ResponseWriter, r *http.Request) {
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var in repeaterSendRequest
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dec := json.NewDecoder(http.MaxBytesReader(w, r.Body, repeaterMaxBody))
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if err := dec.Decode(&in); err != nil {
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writeErr(w, http.StatusBadRequest, "请求体无效")
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return
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}
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// Reject a second JSON value (or oversized trailing data) instead of silently
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// accepting bytes beyond the documented 2 MiB request limit.
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var extra any
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if err := dec.Decode(&extra); err != io.EOF {
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writeErr(w, http.StatusBadRequest, "请求体无效")
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return
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}
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method := http.MethodGet
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if in.Method != nil {
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method = strings.ToUpper(strings.TrimSpace(*in.Method))
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}
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if method == "" {
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writeErr(w, http.StatusBadRequest, "HTTP 方法不能为空")
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return
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}
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switch method {
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case http.MethodGet, http.MethodPost, http.MethodPut, http.MethodPatch,
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http.MethodDelete, http.MethodHead, http.MethodOptions:
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default:
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writeErr(w, http.StatusBadRequest, "不支持的 HTTP 方法")
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return
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}
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rawURL := strings.TrimSpace(in.URL)
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if rawURL == "" {
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writeErr(w, http.StatusBadRequest, "url 必填")
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return
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}
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u, err := url.Parse(rawURL)
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if err != nil || u.Host == "" || u.Hostname() == "" ||
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!strings.EqualFold(u.Scheme, "http") && !strings.EqualFold(u.Scheme, "https") {
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writeErr(w, http.StatusBadRequest, "仅支持绝对 http/https URL")
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return
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}
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// This check is needed even when a proxy is used: the proxy must remain usable
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// for normal targets, while obvious literal metadata/loopback URLs stay blocked.
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if err := repeaterCheckURL(u); err != nil {
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writeErr(w, http.StatusBadRequest, err.Error())
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return
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}
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timeoutMs := in.TimeoutMs
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if timeoutMs <= 0 {
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timeoutMs = repeaterDefaultTimeout
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}
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if timeoutMs < repeaterMinTimeout {
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timeoutMs = repeaterMinTimeout
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}
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if timeoutMs > repeaterMaxTimeout {
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timeoutMs = repeaterMaxTimeout
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}
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useRecordingProxy := true
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if in.UseRecordingProxy != nil {
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useRecordingProxy = *in.UseRecordingProxy
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}
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var body io.Reader
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if in.Body != "" && method != http.MethodHead {
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body = strings.NewReader(in.Body)
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}
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ctx, cancel := context.WithTimeout(r.Context(), time.Duration(timeoutMs)*time.Millisecond)
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defer cancel()
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req, err := http.NewRequestWithContext(ctx, method, u.String(), body)
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if err != nil {
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writeErr(w, http.StatusBadRequest, "构造请求失败")
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return
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}
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for key, value := range in.Headers {
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name := strings.TrimSpace(key)
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if name == "" {
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continue
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}
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if _, blocked := repeaterHopByHop[http.CanonicalHeaderKey(name)]; blocked {
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continue
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}
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if strings.EqualFold(name, "Host") {
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// Host is a special Request field, but retaining it in Header too makes
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// the editor semantics explicit; net/http uses req.Host on the wire.
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req.Host = strings.TrimSpace(value)
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req.Header.Set("Host", strings.TrimSpace(value))
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continue
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}
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req.Header.Set(name, value)
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}
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client := &http.Client{
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Timeout: time.Duration(timeoutMs) * time.Millisecond,
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Transport: s.repeaterTransport(useRecordingProxy, in.InsecureSkipVerify),
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CheckRedirect: func(next *http.Request, via []*http.Request) error {
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if len(via) >= 10 {
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return errors.New("重定向次数过多")
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}
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if err := repeaterCheckURL(next.URL); err != nil {
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return err
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}
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if len(via) > 0 && !strings.EqualFold(next.URL.Host, via[0].URL.Host) {
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return fmt.Errorf("拒绝跨主机重定向（%s → %s）", via[0].URL.Host, next.URL.Host)
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}
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return nil
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},
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}
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started := time.Now()
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resp, err := client.Do(req)
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if err != nil {
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writeJSON(w, http.StatusOK, repeaterSendResponse{
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Headers: map[string][]string{}, URL: u.String(),
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ElapsedMs: time.Since(started).Milliseconds(), Error: repeaterRedactError(err),
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})
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return
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}
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defer resp.Body.Close()
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out := repeaterSendResponse{
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Status: resp.StatusCode, StatusText: resp.Status, Proto: resp.Proto,
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Headers: resp.Header.Clone(), URL: resp.Request.URL.String(),
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}
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if method != http.MethodHead {
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// Read one byte beyond the cap so truncation is exact. The MVP keeps the
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// preview as UTF-8 text; invalid bytes are replaced instead of base64.
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data, readErr := io.ReadAll(io.LimitReader(resp.Body, repeaterMaxBody+1))
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if len(data) > repeaterMaxBody {
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out.BodyTruncated = true
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data = data[:repeaterMaxBody]
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}
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out.Body = repeaterBodyText(data)
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out.BodyBytes = len(data)
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if readErr != nil && !errors.Is(readErr, io.EOF) {
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out.Error = "读取响应失败: " + readErr.Error()
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}
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}
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out.ElapsedMs = time.Since(started).Milliseconds()
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writeJSON(w, http.StatusOK, out)
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}
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// repeaterBodyText keeps the response preview as text for the MVP. Invalid
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// UTF-8 and NUL bytes are replaced so a binary response cannot inject control
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// characters into the JSON/UI raw view; the original bytes are not base64
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// encoded and the preview remains bounded by repeaterMaxBody.
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func repeaterBodyText(data []byte) string {
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text := string(bytes.ToValidUTF8(data, []byte("�")))
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return strings.ReplaceAll(text, "\x00", "�")
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}
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func (s *Server) repeaterTransport(useRecordingProxy, insecure bool) http.RoundTripper {
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var transport *http.Transport
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proxied := false
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if useRecordingProxy && s != nil && s.m != nil {
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transport = s.httpProxyTransport(httpExec{UseRecordingProxy: true})
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proxied = transport != nil
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}
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if transport == nil && s != nil && s.m != nil && strings.TrimSpace(s.m.GlobalProxy()) != "" {
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transport = s.httpProxyTransport(httpExec{Proxy: s.m.GlobalProxy()})
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proxied = transport != nil
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}
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if transport == nil {
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if base, ok := http.DefaultTransport.(*http.Transport); ok {
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transport = base.Clone()
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} else {
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transport = &http.Transport{}
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}
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// "Direct" means direct even if the process inherited HTTP_PROXY. The
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// configured recording/global proxy paths are handled above explicitly.
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transport.Proxy = nil
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}
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transport = transport.Clone()
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// Keep response bytes faithful and make body_bytes match what was received;
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// transparent gzip decompression would otherwise obscure both values.
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transport.DisableCompression = true
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if !proxied {
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// Clear a custom TLS dialer before installing the guarded dialer; when
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// DialTLSContext is set, net/http bypasses DialContext entirely.
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transport.DialTLSContext = nil
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transport.DialTLS = nil
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transport.Dial = nil
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transport.DialContext = (&net.Dialer{
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Timeout: 15 * time.Second, KeepAlive: 30 * time.Second,
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Control: repeaterBlockSensitiveDial,
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}).DialContext
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}
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if insecure {
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cfg := &tls.Config{InsecureSkipVerify: true} //nolint:gosec // explicit user option for pentest targets
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if transport.TLSClientConfig != nil {
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cfg = transport.TLSClientConfig.Clone()
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cfg.InsecureSkipVerify = true
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}
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transport.TLSClientConfig = cfg
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}
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return transport
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}
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func repeaterAllowLocal() bool {
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v := strings.TrimSpace(os.Getenv(repeaterAllowLocalEnv))
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return v == "1" || strings.EqualFold(v, "true")
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}
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func repeaterCheckURL(u *url.URL) error {
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if repeaterAllowLocal() {
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return nil
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}
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host := strings.TrimSuffix(strings.TrimSpace(u.Hostname()), ".")
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// URL.Hostname may retain an IPv6 zone (for example fe80::1%eth0); the
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// zone is not part of the address classification.
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if zone := strings.IndexByte(host, '%'); zone >= 0 {
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host = host[:zone]
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}
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ip := net.ParseIP(host)
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if ip == nil && repeaterLooksNumericHost(host) {
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var ok bool
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ip, ok = repeaterParseLegacyIPv4(host)
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if !ok {
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return fmt.Errorf("拒绝无法解析的数字主机地址 %q", host)
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}
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}
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if strings.EqualFold(host, "localhost") || (ip != nil && repeaterIsBlockedDialIP(ip)) {
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return fmt.Errorf("拒绝访问本机/链路本地地址（如确需访问本机服务，设置 %s=1）", repeaterAllowLocalEnv)
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}
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return nil
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}
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// repeaterLooksNumericHost identifies the legacy numeric spellings accepted by
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// common proxy/resolver implementations (decimal, octal, hexadecimal and
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// dotted inet_aton forms). A numeric-looking value that fails to parse is
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// rejected instead of being handed to a proxy for its own interpretation.
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func repeaterLooksNumericHost(host string) bool {
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if host == "" || host[0] < '0' || host[0] > '9' {
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return false
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}
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for i := 0; i < len(host); i++ {
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c := host[i]
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switch {
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case c == '.':
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case c >= '0' && c <= '9':
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case c >= 'a' && c <= 'f', c >= 'A' && c <= 'F':
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case c == 'x' || c == 'X':
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default:
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return false
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}
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}
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return true
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}
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// repeaterParseLegacyIPv4 follows inet_aton's 1-, 2-, 3- and 4-part IPv4
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// notation. Parts with a leading zero are octal and parts with 0x are hex.
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func repeaterParseLegacyIPv4(host string) (net.IP, bool) {
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parts := strings.Split(host, ".")
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if len(parts) < 1 || len(parts) > 4 {
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return nil, false
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}
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values := make([]uint64, len(parts))
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for i, part := range parts {
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if part == "" {
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return nil, false
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}
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base := 10
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digits := part
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if len(digits) > 2 && digits[0] == '0' && (digits[1] == 'x' || digits[1] == 'X') {
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base, digits = 16, digits[2:]
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} else if len(digits) > 1 && digits[0] == '0' {
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base = 8
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}
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if digits == "" {
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return nil, false
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}
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value, err := strconv.ParseUint(digits, base, 32)
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if err != nil {
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return nil, false
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}
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values[i] = value
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}
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var value uint64
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switch len(values) {
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case 1:
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value = values[0]
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case 2:
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if values[0] > 0xff || values[1] > 0xffffff {
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return nil, false
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}
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value = values[0]<<24 | values[1]
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case 3:
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if values[0] > 0xff || values[1] > 0xff || values[2] > 0xffff {
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return nil, false
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}
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value = values[0]<<24 | values[1]<<16 | values[2]
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case 4:
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for _, part := range values {
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if part > 0xff {
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return nil, false
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}
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}
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value = values[0]<<24 | values[1]<<16 | values[2]<<8 | values[3]
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}
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if value > 0xffffffff {
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return nil, false
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}
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return net.IPv4(byte(value>>24), byte(value>>16), byte(value>>8), byte(value)), true
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}
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func repeaterIsBlockedDialIP(ip net.IP) bool {
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if ip == nil {
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return true
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}
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if v4 := ip.To4(); v4 != nil {
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ip = v4
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}
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return ip.IsLoopback() || ip.IsLinkLocalUnicast() || ip.IsLinkLocalMulticast() ||
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ip.IsInterfaceLocalMulticast() || ip.IsUnspecified() || ip.IsMulticast()
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}
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func repeaterBlockSensitiveDial(_, address string, _ syscall.RawConn) error {
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if repeaterAllowLocal() {
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return nil
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}
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host, _, err := net.SplitHostPort(address)
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if err != nil {
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return err
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}
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ip := net.ParseIP(host)
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if ip == nil {
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return fmt.Errorf("无法解析目标地址 %q", host)
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}
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if repeaterIsBlockedDialIP(ip) {
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return fmt.Errorf("拒绝访问本机/链路本地地址 %s（如确需访问本机服务，设置 %s=1）", ip, repeaterAllowLocalEnv)
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}
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return nil
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}
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func repeaterRedactError(err error) string {
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var urlErr *url.Error
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if errors.As(err, &urlErr) {
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host := ""
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if parsed, parseErr := url.Parse(urlErr.URL); parseErr == nil {
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host = parsed.Host
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}
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if urlErr.Err != nil {
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return fmt.Sprintf("%s %s: %s", urlErr.Op, host, urlErr.Err)
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}
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return fmt.Sprintf("%s %s: 未知错误", urlErr.Op, host)
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}
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return err.Error()
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}
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