Merge pull request #15365 from twistlock/14674-docker-authz

Docker authorization plug-in infrastructure

authorization/api.go

@@ -0,0 +1,52 @@
+package authorization
+
+const (
+	// AuthZApiRequest is the url for daemon request authorization
+	AuthZApiRequest = "AuthZPlugin.AuthZReq"
+
+	// AuthZApiResponse is the url for daemon response authorization
+	AuthZApiResponse = "AuthZPlugin.AuthZRes"
+
+	// AuthZApiImplements is the name of the interface all AuthZ plugins implement
+	AuthZApiImplements = "authz"
+)
+
+// Request holds data required for authZ plugins
+type Request struct {
+	// User holds the user extracted by AuthN mechanism
+	User string `json:"User,omitempty"`
+
+	// UserAuthNMethod holds the mechanism used to extract user details (e.g., krb)
+	UserAuthNMethod string `json:"UserAuthNMethod,omitempty"`
+
+	// RequestMethod holds the HTTP method (GET/POST/PUT)
+	RequestMethod string `json:"RequestMethod,omitempty"`
+
+	// RequestUri holds the full HTTP uri (e.g., /v1.21/version)
+	RequestURI string `json:"RequestUri,omitempty"`
+
+	// RequestBody stores the raw request body sent to the docker daemon
+	RequestBody []byte `json:"RequestBody,omitempty"`
+
+	// RequestHeaders stores the raw request headers sent to the docker daemon
+	RequestHeaders map[string]string `json:"RequestHeaders,omitempty"`
+
+	// ResponseStatusCode stores the status code returned from docker daemon
+	ResponseStatusCode int `json:"ResponseStatusCode,omitempty"`
+
+	// ResponseBody stores the raw response body sent from docker daemon
+	ResponseBody []byte `json:"ResponseBody,omitempty"`
+
+	// ResponseHeaders stores the response headers sent to the docker daemon
+	ResponseHeaders map[string]string `json:"ResponseHeaders,omitempty"`
+}
+
+// Response represents authZ plugin response
+type Response struct {
+
+	// Allow indicating whether the user is allowed or not
+	Allow bool `json:"Allow"`
+
+	// Msg stores the authorization message
+	Msg string `json:"Msg,omitempty"`
+}

authorization/authz.go

@@ -0,0 +1,159 @@
+package authorization
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"strings"
+)
+
+// 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:
+// Authenticate Request:
+// Call authZ plugins with current REST request and AuthN response
+// Request contains full HTTP packet sent to the docker daemon
+// https://docs.docker.com/reference/api/docker_remote_api/
+//
+// Authenticate Response:
+// Call authZ plugins with full info about current REST request, REST response and AuthN response
+// The response from this method may contains content that overrides the daemon response
+// This allows authZ plugins to filter privileged content
+//
+// If multiple authZ plugins are specified, the block/allow decision is based on ANDing all plugin results
+// For response manipulation, the response from each plugin is piped between plugins. Plugin execution order
+// is determined according to daemon parameters
+func NewCtx(authZPlugins []Plugin, user, userAuthNMethod, requestMethod, requestURI string) *Ctx {
+	return &Ctx{plugins: authZPlugins, user: user, userAuthNMethod: userAuthNMethod, requestMethod: requestMethod, requestURI: requestURI}
+}
+
+// Ctx stores a a single request-response interaction context
+type Ctx struct {
+	user            string
+	userAuthNMethod string
+	requestMethod   string
+	requestURI      string
+	plugins         []Plugin
+	// authReq stores the cached request object for the current transaction
+	authReq *Request
+}
+
+// AuthZRequest authorized the request to the docker daemon using authZ plugins
+func (a *Ctx) AuthZRequest(w http.ResponseWriter, r *http.Request) (err error) {
+
+	var body []byte
+	if sendBody(a.requestURI, r.Header) {
+		var drainedBody io.ReadCloser
+		drainedBody, r.Body, err = drainBody(r.Body)
+		if err != nil {
+			return err
+		}
+		body, err = ioutil.ReadAll(drainedBody)
+		defer drainedBody.Close()
+
+		if err != nil {
+			return err
+		}
+	}
+
+	var h bytes.Buffer
+	err = r.Header.Write(&h)
+
+	if err != nil {
+		return err
+	}
+
+	a.authReq = &Request{
+		User:            a.user,
+		UserAuthNMethod: a.userAuthNMethod,
+		RequestMethod:   a.requestMethod,
+		RequestURI:      a.requestURI,
+		RequestBody:     body,
+		RequestHeaders:  headers(r.Header)}
+
+	for _, plugin := range a.plugins {
+
+		authRes, err := plugin.AuthZRequest(a.authReq)
+
+		if err != nil {
+			return err
+		}
+
+		if !authRes.Allow {
+			return fmt.Errorf(authRes.Msg)
+		}
+	}
+
+	return nil
+}
+
+// AuthZResponse authorized and manipulates the response from docker daemon using authZ plugins
+func (a *Ctx) AuthZResponse(rm ResponseModifier, r *http.Request) error {
+
+	a.authReq.ResponseStatusCode = rm.StatusCode()
+	a.authReq.ResponseHeaders = headers(rm.Header())
+
+	if sendBody(a.requestURI, rm.Header()) {
+		a.authReq.ResponseBody = rm.RawBody()
+	}
+
+	for _, plugin := range a.plugins {
+
+		authRes, err := plugin.AuthZResponse(a.authReq)
+
+		if err != nil {
+			return err
+		}
+
+		if !authRes.Allow {
+			return fmt.Errorf(authRes.Msg)
+		}
+	}
+
+	rm.Flush()
+
+	return nil
+}
+
+// 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) (r1, r2 io.ReadCloser, err error) {
+	var buf bytes.Buffer
+	if _, err = buf.ReadFrom(b); err != nil {
+		return nil, nil, err
+	}
+	if err = b.Close(); err != nil {
+		return nil, nil, err
+	}
+	return ioutil.NopCloser(&buf), ioutil.NopCloser(bytes.NewReader(buf.Bytes())), nil
+}
+
+// sendBody returns true when request/response body should be sent to AuthZPlugin
+func sendBody(url string, header http.Header) bool {
+
+	// Skip body for auth endpoint
+	if strings.HasSuffix(url, "/auth") {
+		return false
+	}
+
+	// body is sent only for text or json messages
+	v := header.Get("Content-Type")
+	return strings.HasPrefix(v, "text/") || v == "application/json"
+}
+
+// headers returns flatten version of the http headers excluding authorization
+func headers(header http.Header) map[string]string {
+	v := make(map[string]string, 0)
+	for k, values := range header {
+		// Skip authorization headers
+		if strings.EqualFold(k, "Authorization") || strings.EqualFold(k, "X-Registry-Config") || strings.EqualFold(k, "X-Registry-Auth") {
+			continue
+		}
+		for _, val := range values {
+			v[k] = val
+		}
+	}
+	return v
+}

authorization/authz_test.go

@@ -0,0 +1,220 @@
+package authorization
+
+import (
+	"encoding/json"
+	"fmt"
+	"github.com/docker/docker/pkg/plugins"
+	"github.com/docker/docker/pkg/tlsconfig"
+	"github.com/gorilla/mux"
+	"io/ioutil"
+	"log"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path"
+	"reflect"
+	"testing"
+)
+
+const pluginAddress = "authzplugin.sock"
+
+func TestAuthZRequestPlugin(t *testing.T) {
+
+	server := authZPluginTestServer{t: t}
+	go server.start()
+	defer server.stop()
+
+	authZPlugin := createTestPlugin(t)
+
+	request := Request{
+		User:           "user",
+		RequestBody:    []byte("sample body"),
+		RequestURI:     "www.authz.com",
+		RequestMethod:  "GET",
+		RequestHeaders: map[string]string{"header": "value"},
+	}
+	server.replayResponse = Response{
+		Allow: true,
+		Msg:   "Sample message",
+	}
+
+	actualResponse, err := authZPlugin.AuthZRequest(&request)
+
+	if err != nil {
+		t.Fatalf("Failed to authorize request %v", err)
+	}
+
+	if !reflect.DeepEqual(server.replayResponse, *actualResponse) {
+		t.Fatalf("Response must be equal")
+	}
+	if !reflect.DeepEqual(request, server.recordedRequest) {
+		t.Fatalf("Requests must be equal")
+	}
+}
+
+func TestAuthZResponsePlugin(t *testing.T) {
+
+	server := authZPluginTestServer{t: t}
+	go server.start()
+	defer server.stop()
+
+	authZPlugin := createTestPlugin(t)
+
+	request := Request{
+		User:        "user",
+		RequestBody: []byte("sample body"),
+	}
+	server.replayResponse = Response{
+		Allow: true,
+		Msg:   "Sample message",
+	}
+
+	actualResponse, err := authZPlugin.AuthZResponse(&request)
+
+	if err != nil {
+		t.Fatalf("Failed to authorize request %v", err)
+	}
+
+	if !reflect.DeepEqual(server.replayResponse, *actualResponse) {
+		t.Fatalf("Response must be equal")
+	}
+	if !reflect.DeepEqual(request, server.recordedRequest) {
+		t.Fatalf("Requests must be equal")
+	}
+}
+
+func TestResponseModifier(t *testing.T) {
+
+	r := httptest.NewRecorder()
+	m := NewResponseModifier(r)
+	m.Header().Set("h1", "v1")
+	m.Write([]byte("body"))
+	m.WriteHeader(500)
+
+	m.Flush()
+	if r.Header().Get("h1") != "v1" {
+		t.Fatalf("Header value must exists %s", r.Header().Get("h1"))
+	}
+	if !reflect.DeepEqual(r.Body.Bytes(), []byte("body")) {
+		t.Fatalf("Body value must exists %s", r.Body.Bytes())
+	}
+	if r.Code != 500 {
+		t.Fatalf("Status code must be correct %d", r.Code)
+	}
+}
+
+func TestResponseModifierOverride(t *testing.T) {
+
+	r := httptest.NewRecorder()
+	m := NewResponseModifier(r)
+	m.Header().Set("h1", "v1")
+	m.Write([]byte("body"))
+	m.WriteHeader(500)
+
+	overrideHeader := make(http.Header)
+	overrideHeader.Add("h1", "v2")
+	overrideHeaderBytes, err := json.Marshal(overrideHeader)
+	if err != nil {
+		t.Fatalf("override header failed %v", err)
+	}
+
+	m.OverrideHeader(overrideHeaderBytes)
+	m.OverrideBody([]byte("override body"))
+	m.OverrideStatusCode(404)
+	m.Flush()
+	if r.Header().Get("h1") != "v2" {
+		t.Fatalf("Header value must exists %s", r.Header().Get("h1"))
+	}
+	if !reflect.DeepEqual(r.Body.Bytes(), []byte("override body")) {
+		t.Fatalf("Body value must exists %s", r.Body.Bytes())
+	}
+	if r.Code != 404 {
+		t.Fatalf("Status code must be correct %d", r.Code)
+	}
+}
+
+// createTestPlugin creates a new sample authorization plugin
+func createTestPlugin(t *testing.T) *authorizationPlugin {
+	plugin := &plugins.Plugin{Name: "authz"}
+	var err error
+	pwd, err := os.Getwd()
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	plugin.Client, err = plugins.NewClient("unix:///"+path.Join(pwd, pluginAddress), tlsconfig.Options{InsecureSkipVerify: true})
+
+	if err != nil {
+		t.Fatalf("Failed to create client %v", err)
+	}
+
+	return &authorizationPlugin{name: "plugin", plugin: plugin}
+}
+
+// AuthZPluginTestServer is a simple server that implements the authZ plugin interface
+type authZPluginTestServer struct {
+	listener net.Listener
+	t        *testing.T
+	// request stores the request sent from the daemon to the plugin
+	recordedRequest Request
+	// response stores the response sent from the plugin to the daemon
+	replayResponse Response
+}
+
+// start starts the test server that implements the plugin
+func (t *authZPluginTestServer) start() {
+	r := mux.NewRouter()
+	os.Remove(pluginAddress)
+	l, err := net.ListenUnix("unix", &net.UnixAddr{Name: pluginAddress, Net: "unix"})
+	if err != nil {
+		t.t.Fatalf("Failed to listen %v", err)
+	}
+	t.listener = l
+
+	r.HandleFunc("/Plugin.Activate", t.activate)
+	r.HandleFunc("/"+AuthZApiRequest, t.auth)
+	r.HandleFunc("/"+AuthZApiResponse, t.auth)
+	t.listener, err = net.Listen("tcp", pluginAddress)
+	server := http.Server{Handler: r, Addr: pluginAddress}
+	server.Serve(l)
+}
+
+// stop stops the test server that implements the plugin
+func (t *authZPluginTestServer) stop() {
+
+	os.Remove(pluginAddress)
+
+	if t.listener != nil {
+		t.listener.Close()
+	}
+}
+
+// auth is a used to record/replay the authentication api messages
+func (t *authZPluginTestServer) auth(w http.ResponseWriter, r *http.Request) {
+
+	t.recordedRequest = Request{}
+
+	defer r.Body.Close()
+	body, err := ioutil.ReadAll(r.Body)
+	json.Unmarshal(body, &t.recordedRequest)
+	b, err := json.Marshal(t.replayResponse)
+	if err != nil {
+		log.Fatal(err)
+	}
+	w.Write(b)
+
+}
+
+func (t *authZPluginTestServer) activate(w http.ResponseWriter, r *http.Request) {
+
+	b, err := json.Marshal(plugins.Manifest{Implements: []string{AuthZApiImplements}})
+	if err != nil {
+		log.Fatal(err)
+	}
+	w.Write(b)
+}

authorization/plugin.go

@@ -0,0 +1,87 @@
+package authorization
+
+import (
+	"github.com/Sirupsen/logrus"
+	"github.com/docker/docker/pkg/plugins"
+)
+
+// Plugin allows third party plugins to authorize requests and responses
+// in the context of docker API
+type Plugin interface {
+
+	// AuthZRequest authorize the request from the client to the daemon
+	AuthZRequest(authReq *Request) (authRes *Response, err error)
+
+	// AuthZResponse authorize the response from the daemon to the client
+	AuthZResponse(authReq *Request) (authRes *Response, err error)
+}
+
+// NewPlugins constructs and initialize the authorization plugins based on plugin names
+func NewPlugins(names []string) []Plugin {
+	plugins := make([]Plugin, len(names))
+	for i, name := range names {
+		plugins[i] = newAuthorizationPlugin(name)
+	}
+	return plugins
+}
+
+// authorizationPlugin is an internal adapter to docker plugin system
+type authorizationPlugin struct {
+	plugin *plugins.Plugin
+	name   string
+}
+
+func newAuthorizationPlugin(name string) Plugin {
+	return &authorizationPlugin{name: name}
+}
+
+func (a *authorizationPlugin) AuthZRequest(authReq *Request) (authRes *Response, err error) {
+
+	logrus.Debugf("AuthZ requset using plugins %s", a.name)
+
+	err = a.initPlugin()
+	if err != nil {
+		return nil, err
+	}
+
+	authRes = &Response{}
+	err = a.plugin.Client.Call(AuthZApiRequest, authReq, authRes)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return authRes, nil
+}
+
+func (a *authorizationPlugin) AuthZResponse(authReq *Request) (authRes *Response, err error) {
+
+	logrus.Debugf("AuthZ response using plugins %s", a.name)
+
+	err = a.initPlugin()
+	if err != nil {
+		return nil, err
+	}
+
+	authRes = &Response{}
+	err = a.plugin.Client.Call(AuthZApiResponse, authReq, authRes)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return authRes, nil
+}
+
+// initPlugin initialize the authorization plugin if needed
+func (a *authorizationPlugin) initPlugin() (err error) {
+
+	// Lazy loading of plugins
+	if a.plugin == nil {
+		a.plugin, err = plugins.Get(a.name, AuthZApiImplements)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

authorization/response.go

@@ -0,0 +1,140 @@
+package authorization
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"net"
+	"net/http"
+)
+
+// ResponseModifier allows authorization plugins to read and modify the content of the http.response
+type ResponseModifier interface {
+	http.ResponseWriter
+
+	// RawBody returns the current http content
+	RawBody() []byte
+
+	// RawHeaders returns the current content of the http headers
+	RawHeaders() ([]byte, error)
+
+	// StatusCode returns the current status code
+	StatusCode() int
+
+	// OverrideBody replace the body of the HTTP reply
+	OverrideBody(b []byte)
+
+	// OverrideHeader replace the headers of the HTTP reply
+	OverrideHeader(b []byte) error
+
+	// OverrideStatusCode replaces the status code of the HTTP reply
+	OverrideStatusCode(statusCode int)
+
+	// Flush flushes all data to the HTTP response
+	Flush() error
+}
+
+// NewResponseModifier creates a wrapper to an http.ResponseWriter to allow inspecting and modifying the content
+func NewResponseModifier(rw http.ResponseWriter) ResponseModifier {
+	return &responseModifier{rw: rw, header: make(http.Header)}
+}
+
+// responseModifier is used as an adapter to http.ResponseWriter in order to manipulate and explore
+// the http request/response from docker daemon
+type responseModifier struct {
+	// The original response writer
+	rw     http.ResponseWriter
+	status int
+	// body holds the response body
+	body []byte
+	// header holds the response header
+	header http.Header
+	// statusCode holds the response status code
+	statusCode int
+}
+
+// WriterHeader stores the http status code
+func (rm *responseModifier) WriteHeader(s int) {
+	rm.statusCode = s
+}
+
+// Header returns the internal http header
+func (rm *responseModifier) Header() http.Header {
+	return rm.header
+}
+
+// Header returns the internal http header
+func (rm *responseModifier) StatusCode() int {
+	return rm.statusCode
+}
+
+// Override replace the body of the HTTP reply
+func (rm *responseModifier) OverrideBody(b []byte) {
+	rm.body = b
+}
+
+func (rm *responseModifier) OverrideStatusCode(statusCode int) {
+	rm.statusCode = statusCode
+}
+
+// Override replace the headers of the HTTP reply
+func (rm *responseModifier) OverrideHeader(b []byte) error {
+	header := http.Header{}
+	err := json.Unmarshal(b, &header)
+
+	if err != nil {
+		return err
+	}
+	rm.header = header
+	return nil
+}
+
+// Write stores the byte array inside content
+func (rm *responseModifier) Write(b []byte) (int, error) {
+	rm.body = append(rm.body, b...)
+	return len(b), nil
+}
+
+// Body returns the response body
+func (rm *responseModifier) RawBody() []byte {
+	return rm.body
+}
+
+func (rm *responseModifier) RawHeaders() ([]byte, error) {
+	var b bytes.Buffer
+	err := rm.header.Write(&b)
+	if err != nil {
+		return nil, err
+	}
+	return b.Bytes(), nil
+}
+
+// Hijack returns the internal connection of the wrapped http.ResponseWriter
+func (rm *responseModifier) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	hijacker, ok := rm.rw.(http.Hijacker)
+	if !ok {
+		return nil, nil, fmt.Errorf("Internal reponse writer doesn't support the Hijacker interface")
+	}
+	return hijacker.Hijack()
+}
+
+// Flush flushes all data to the HTTP response
+func (rm *responseModifier) Flush() error {
+
+	// Copy the status code
+	if rm.statusCode > 0 {
+		rm.rw.WriteHeader(rm.statusCode)
+	}
+
+	// Copy the header
+	for k, vv := range rm.header {
+		for _, v := range vv {
+			rm.rw.Header().Add(k, v)
+		}
+	}
+
+	// Write body
+	_, err := rm.rw.Write(rm.body)
+	return err
+}