OP#792 initial commit after fork

internal/config/identity/openid/provider/keycloak.go

@@ -0,0 +1,186 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package provider
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"path"
+	"strings"
+	"sync"
+)
+
+// Token - parses the output from IDP id_token.
+type Token struct {
+	AccessToken string `json:"access_token"`
+	Expiry      int    `json:"expires_in"`
+}
+
+// KeycloakProvider implements Provider interface for KeyCloak Identity Provider.
+type KeycloakProvider struct {
+	sync.Mutex
+
+	oeConfig DiscoveryDoc
+	client   http.Client
+	adminURL string
+	realm    string
+
+	// internal value refreshed
+	accessToken Token
+}
+
+// LoginWithUser authenticates username/password, not needed for Keycloak
+func (k *KeycloakProvider) LoginWithUser(username, password string) error {
+	return ErrNotImplemented
+}
+
+// LoginWithClientID is implemented by Keycloak service account support
+func (k *KeycloakProvider) LoginWithClientID(clientID, clientSecret string) error {
+	values := url.Values{}
+	values.Set("client_id", clientID)
+	values.Set("client_secret", clientSecret)
+	values.Set("grant_type", "client_credentials")
+
+	req, err := http.NewRequest(http.MethodPost, k.oeConfig.TokenEndpoint, strings.NewReader(values.Encode()))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := k.client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	var accessToken Token
+	if err = json.NewDecoder(resp.Body).Decode(&accessToken); err != nil {
+		return err
+	}
+
+	k.Lock()
+	k.accessToken = accessToken
+	k.Unlock()
+	return nil
+}
+
+// LookupUser lookup user by their userid.
+func (k *KeycloakProvider) LookupUser(userid string) (User, error) {
+	req, err := http.NewRequest(http.MethodGet, k.adminURL, nil)
+	if err != nil {
+		return User{}, err
+	}
+	req.URL.Path = path.Join(req.URL.Path, "realms", k.realm, "users", userid)
+
+	k.Lock()
+	accessToken := k.accessToken
+	k.Unlock()
+	if accessToken.AccessToken == "" {
+		return User{}, ErrAccessTokenExpired
+	}
+	req.Header.Set("Authorization", "Bearer "+accessToken.AccessToken)
+	resp, err := k.client.Do(req)
+	if err != nil {
+		return User{}, err
+	}
+	defer resp.Body.Close()
+	switch resp.StatusCode {
+	case http.StatusOK, http.StatusPartialContent:
+		var u User
+		if err = json.NewDecoder(resp.Body).Decode(&u); err != nil {
+			return User{}, err
+		}
+		return u, nil
+	case http.StatusNotFound:
+		return User{
+			ID:      userid,
+			Enabled: false,
+		}, nil
+	case http.StatusUnauthorized:
+		return User{}, ErrAccessTokenExpired
+	}
+	return User{}, fmt.Errorf("Unable to lookup - keycloak user lookup returned %v", resp.Status)
+}
+
+// Option is a function type that accepts a pointer Target
+type Option func(*KeycloakProvider)
+
+// WithTransport provide custom transport
+func WithTransport(transport http.RoundTripper) Option {
+	return func(p *KeycloakProvider) {
+		p.client = http.Client{
+			Transport: transport,
+		}
+	}
+}
+
+// WithOpenIDConfig provide OpenID Endpoint configuration discovery document
+func WithOpenIDConfig(oeConfig DiscoveryDoc) Option {
+	return func(p *KeycloakProvider) {
+		p.oeConfig = oeConfig
+	}
+}
+
+// WithAdminURL provide admin URL configuration for Keycloak
+func WithAdminURL(url string) Option {
+	return func(p *KeycloakProvider) {
+		p.adminURL = url
+	}
+}
+
+// WithRealm provide realm configuration for Keycloak
+func WithRealm(realm string) Option {
+	return func(p *KeycloakProvider) {
+		p.realm = realm
+	}
+}
+
+// KeyCloak initializes a new keycloak provider
+func KeyCloak(opts ...Option) (Provider, error) {
+	p := &KeycloakProvider{}
+
+	for _, opt := range opts {
+		opt(p)
+	}
+
+	if p.adminURL == "" {
+		return nil, errors.New("Admin URL cannot be empty")
+	}
+
+	_, err := url.Parse(p.adminURL)
+	if err != nil {
+		return nil, fmt.Errorf("Unable to parse the adminURL %s: %w", p.adminURL, err)
+	}
+
+	if p.client.Transport == nil {
+		p.client.Transport = http.DefaultTransport
+	}
+
+	if p.oeConfig.TokenEndpoint == "" {
+		return nil, errors.New("missing OpenID token endpoint")
+	}
+
+	if p.realm == "" {
+		p.realm = "master" // default realm
+	}
+
+	return p, nil
+}