diff --git a/authorization/api.go b/authorization/api.go new file mode 100644 index 0000000..0d931a0 --- /dev/null +++ b/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"` +} diff --git a/authorization/authz.go b/authorization/authz.go new file mode 100644 index 0000000..daebbcb --- /dev/null +++ b/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 +} diff --git a/authorization/authz_test.go b/authorization/authz_test.go new file mode 100644 index 0000000..47cf401 --- /dev/null +++ b/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) +} diff --git a/authorization/plugin.go b/authorization/plugin.go new file mode 100644 index 0000000..cab571e --- /dev/null +++ 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 +} diff --git a/authorization/response.go b/authorization/response.go new file mode 100644 index 0000000..ee4cb2d --- /dev/null +++ b/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 +}