@@ -1,9 +1,9 @@

 package server

 import (

-	"bytes"

+	"bufio"

 	"encoding/json"

-	"io/ioutil"

+	"io"

 	"net/http"

 	"runtime"

 	"strings"

@@ -14,6 +14,7 @@ import (

 	"github.com/docker/docker/dockerversion"

 	"github.com/docker/docker/errors"

 	"github.com/docker/docker/pkg/authorization"

+	"github.com/docker/docker/pkg/ioutils"

 	"github.com/docker/docker/pkg/version"

 	"golang.org/x/net/context"

 )

@@ -27,25 +28,37 @@ func debugRequestMiddleware(handler httputils.APIFunc) httputils.APIFunc {

 	return func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {

 		logrus.Debugf("%s %s", r.Method, r.RequestURI)

-		if r.Method == "POST" {

-			if err := httputils.CheckForJSON(r); err == nil {

-				var buf bytes.Buffer

-				if _, err := buf.ReadFrom(r.Body); err == nil {

-					r.Body.Close()

-					r.Body = ioutil.NopCloser(&buf)

-					var postForm map[string]interface{}

-					if err := json.Unmarshal(buf.Bytes(), &postForm); err == nil {

-						if _, exists := postForm["password"]; exists {

-							postForm["password"] = "*****"

-						}

-						formStr, errMarshal := json.Marshal(postForm)

-						if errMarshal == nil {

-							logrus.Debugf("form data: %s", string(formStr))

-						} else {

-							logrus.Debugf("form data: %q", postForm)

-						}

-					}

-				}

+		if r.Method != "POST" {

+			return handler(ctx, w, r, vars)

+		}

+		if err := httputils.CheckForJSON(r); err != nil {

+			return handler(ctx, w, r, vars)

+		}

+		maxBodySize := 4096 // 4KB

+		if r.ContentLength > int64(maxBodySize) {

+			return handler(ctx, w, r, vars)

+		}

+

+		body := r.Body

+		bufReader := bufio.NewReaderSize(body, maxBodySize)

+		r.Body = ioutils.NewReadCloserWrapper(bufReader, func() error { return body.Close() })

+

+		b, err := bufReader.Peek(maxBodySize)

+		if err != io.EOF {

+			// either there was an error reading, or the buffer is full (in which case the request is too large)

+			return handler(ctx, w, r, vars)

+		}

+

+		var postForm map[string]interface{}

+		if err := json.Unmarshal(b, &postForm); err == nil {

+			if _, exists := postForm["password"]; exists {

+				postForm["password"] = "*****"

+			}

+			formStr, errMarshal := json.Marshal(postForm)

+			if errMarshal == nil {

+				logrus.Debugf("form data: %s", string(formStr))

+			} else {

+				logrus.Debugf("form data: %q", postForm)

 			}

 		}