fix crash in case of specially-crafted HTTP requests (#2166) (#2169)

internal/httpserv/handler_logger.go

@@ -0,0 +1,63 @@
+package httpserv
+
+import (
+	"bytes"
+	"fmt"
+	"net/http"
+	"net/http/httputil"
+
+	"github.com/bluenviron/mediamtx/internal/logger"
+)
+
+type loggerWriter struct {
+	w      http.ResponseWriter
+	status int
+	buf    bytes.Buffer
+}
+
+func (w *loggerWriter) Header() http.Header {
+	return w.w.Header()
+}
+
+func (w *loggerWriter) Write(b []byte) (int, error) {
+	if w.status == 0 {
+		w.status = http.StatusOK
+	}
+	w.buf.Write(b)
+	return w.w.Write(b)
+}
+
+func (w *loggerWriter) WriteHeader(statusCode int) {
+	w.status = statusCode
+	w.w.WriteHeader(statusCode)
+}
+
+func (w *loggerWriter) dump() string {
+	var buf bytes.Buffer
+	fmt.Fprintf(&buf, "%s %d %s\n", "HTTP/1.1", w.status, http.StatusText(w.status))
+	w.w.Header().Write(&buf)
+	buf.Write([]byte("\n"))
+	if w.buf.Len() > 0 {
+		fmt.Fprintf(&buf, "(body of %d bytes)", w.buf.Len())
+	}
+	return buf.String()
+}
+
+// log requests and responses.
+type handlerLogger struct {
+	http.Handler
+	log logger.Writer
+}
+
+func (h *handlerLogger) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	h.log.Log(logger.Debug, "[conn %v] %s %s", r.RemoteAddr, r.Method, r.URL.Path)
+
+	byts, _ := httputil.DumpRequest(r, true)
+	h.log.Log(logger.Debug, "[conn %v] [c->s] %s", r.RemoteAddr, string(byts))
+
+	logw := &loggerWriter{w: w}
+
+	h.Handler.ServeHTTP(logw, r)
+
+	h.log.Log(logger.Debug, "[conn %v] [s->c] %s", r.RemoteAddr, logw.dump())
+}