support CAS identity provider

Signed-off-by: hongming <talonwan@yunify.com>

pkg/apiserver/authentication/identityprovider/cas/cas.go

@@ -0,0 +1,96 @@
+/*
+Copyright 2020 The KubeSphere Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cas
+
+import (
+	"crypto/tls"
+	"fmt"
+	"github.com/mitchellh/mapstructure"
+	gocas "gopkg.in/cas.v2"
+	"kubesphere.io/kubesphere/pkg/apiserver/authentication/identityprovider"
+	"kubesphere.io/kubesphere/pkg/apiserver/authentication/oauth"
+	"net/http"
+	"net/url"
+)
+
+func init() {
+	identityprovider.RegisterOAuthProvider(&casProviderFactory{})
+}
+
+type cas struct {
+	RedirectURL        string `json:"redirectURL" yaml:"redirectURL"`
+	CASServerURL       string `json:"casServerURL" yaml:"casServerURL"`
+	InsecureSkipVerify bool   `json:"insecureSkipVerify" yaml:"insecureSkipVerify"`
+	client             *gocas.RestClient
+}
+
+type casProviderFactory struct {
+}
+
+type casIdentity struct {
+	User string `json:"user"`
+}
+
+func (c casIdentity) GetUserID() string {
+	return c.User
+}
+
+func (c casIdentity) GetUsername() string {
+	return c.User
+}
+
+func (c casIdentity) GetEmail() string {
+	return ""
+}
+
+func (f casProviderFactory) Type() string {
+	return "CASIdentityProvider"
+}
+
+func (f casProviderFactory) Create(options oauth.DynamicOptions) (identityprovider.OAuthProvider, error) {
+	var cas cas
+	if err := mapstructure.Decode(options, &cas); err != nil {
+		return nil, err
+	}
+	casURL, err := url.Parse(cas.CASServerURL)
+	if err != nil {
+		return nil, err
+	}
+	redirectURL, err := url.Parse(cas.RedirectURL)
+	if err != nil {
+		return nil, err
+	}
+	cas.client = gocas.NewRestClient(&gocas.RestOptions{
+		CasURL:     casURL,
+		ServiceURL: redirectURL,
+		Client: &http.Client{
+			Transport: &http.Transport{
+				TLSClientConfig: &tls.Config{InsecureSkipVerify: cas.InsecureSkipVerify},
+			},
+		},
+		URLScheme: nil,
+	})
+	return &cas, nil
+}
+
+func (c cas) IdentityExchange(ticket string) (identityprovider.Identity, error) {
+	resp, err := c.client.ValidateServiceTicket(gocas.ServiceTicket(ticket))
+	if err != nil {
+		return nil, fmt.Errorf("cas validate service ticket failed: %v", err)
+	}
+	return &casIdentity{User: resp.User}, nil
+}