@@ -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)

 			}

 		}

@@ -1,16 +1,19 @@

 package authorization

 import (

+	"bufio"

 	"bytes"

 	"fmt"

 	"io"

-	"io/ioutil"

 	"net/http"

 	"strings"

 	"github.com/Sirupsen/logrus"

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

 )

+const maxBodySize = 1048576 // 1MB

+

 // NewCtx creates new authZ context, it is used to store authorization information related to a specific docker

 // REST http session

 // A context provides two method:

@@ -52,18 +55,12 @@ type Ctx struct {

 func (ctx *Ctx) AuthZRequest(w http.ResponseWriter, r *http.Request) error {

 	var body []byte

 	if sendBody(ctx.requestURI, r.Header) {

-		var (

-			err         error

-			drainedBody io.ReadCloser

-		)

-		drainedBody, r.Body, err = drainBody(r.Body)

-		if err != nil {

-			return err

-		}

-		defer drainedBody.Close()

-		body, err = ioutil.ReadAll(drainedBody)

-		if err != nil {

-			return err

+		if r.ContentLength < maxBodySize {

+			var err error

+			body, r.Body, err = drainBody(r.Body)

+			if err != nil {

+				return err

+			}

 		}

 	}

@@ -126,15 +123,21 @@ func (ctx *Ctx) AuthZResponse(rm ResponseModifier, r *http.Request) error {

 // drainBody dump the body, it reads the body data into memory and

 // see go sources /go/src/net/http/httputil/dump.go

-func drainBody(b io.ReadCloser) (io.ReadCloser, io.ReadCloser, error) {

-	var buf bytes.Buffer

-	if _, err := buf.ReadFrom(b); err != nil {

-		return nil, nil, err

-	}

-	if err := b.Close(); err != nil {

+func drainBody(body io.ReadCloser) ([]byte, io.ReadCloser, error) {

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

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

+

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

+	if err != io.EOF {

+		// This means the request is larger than our max

+		if err == bufio.ErrBufferFull {

+			return nil, newBody, nil

+		}

+		// This means we had an error reading

 		return nil, nil, err

 	}

-	return ioutil.NopCloser(&buf), ioutil.NopCloser(bytes.NewReader(buf.Bytes())), nil

+

+	return data, newBody, nil

 }

 // sendBody returns true when request/response body should be sent to AuthZPlugin