feat: Add support to poll users on external SSO (#12592)

Additional support for vendor-specific admin API
integrations for OpenID, to ensure validity of
credentials on MinIO.

Every 5minutes check for validity of credentials
on MinIO with vendor specific IDP.

internal/config/identity/openid/help.go

@@ -62,6 +62,24 @@ var (
 			Optional:    true,
 			Type:        "csv",
 		},
+		config.HelpKV{
+			Key:         Vendor,
+			Description: `Specify vendor type for vendor specific behavior to checking validity of temporary credentials and service accounts on MinIO`,
+			Optional:    true,
+			Type:        "string",
+		},
+		config.HelpKV{
+			Key:         KeyCloakRealm,
+			Description: `Specify Keycloak 'realm' name, only honored if vendor was set to 'keycloak' as value, if no realm is specified 'master' is default`,
+			Optional:    true,
+			Type:        "string",
+		},
+		config.HelpKV{
+			Key:         KeyCloakAdminURL,
+			Description: `Specify Keycloak 'admin' REST API endpoint e.g. http://localhost:8080/auth/admin/`,
+			Optional:    true,
+			Type:        "string",
+		},
 		config.HelpKV{
 			Key:         config.Comment,
 			Description: config.DefaultComment,

internal/config/identity/openid/jwt.go

@@ -32,6 +32,7 @@ import (
 	jwtgo "github.com/golang-jwt/jwt"
 	"github.com/minio/minio/internal/auth"
 	"github.com/minio/minio/internal/config"
+	"github.com/minio/minio/internal/config/identity/openid/provider"
 	"github.com/minio/pkg/env"
 	iampolicy "github.com/minio/pkg/iam/policy"
 	xnet "github.com/minio/pkg/net"
@@ -50,12 +51,77 @@ type Config struct {
 	DiscoveryDoc DiscoveryDoc
 	ClientID     string
 	ClientSecret string
+	provider     provider.Provider
 	publicKeys   map[string]crypto.PublicKey
 	transport    *http.Transport
 	closeRespFn  func(io.ReadCloser)
 	mutex        *sync.Mutex
 }
 
+// LookupUser lookup userid for the provider
+func (r *Config) LookupUser(userid string) (provider.User, error) {
+	if r.provider != nil {
+		user, err := r.provider.LookupUser(userid)
+		if err != nil && err != provider.ErrAccessTokenExpired {
+			return user, err
+		}
+		if err == provider.ErrAccessTokenExpired {
+			if err = r.provider.LoginWithClientID(r.ClientID, r.ClientSecret); err != nil {
+				return user, err
+			}
+			user, err = r.provider.LookupUser(userid)
+		}
+		return user, err
+	}
+	// Without any specific logic for a provider, all accounts
+	// are always enabled.
+	return provider.User{ID: userid, Enabled: true}, nil
+}
+
+const (
+	keyCloakVendor = "keycloak"
+)
+
+// InitializeProvider initializes if any additional vendor specific
+// information was provided, initialization will return an error
+// initial login fails.
+func (r *Config) InitializeProvider(kvs config.KVS) error {
+	vendor := env.Get(EnvIdentityOpenIDVendor, kvs.Get(Vendor))
+	if vendor == "" {
+		return nil
+	}
+	switch vendor {
+	case keyCloakVendor:
+		adminURL := env.Get(EnvIdentityOpenIDKeyCloakAdminURL, kvs.Get(KeyCloakAdminURL))
+		realm := env.Get(EnvIdentityOpenIDKeyCloakRealm, kvs.Get(KeyCloakRealm))
+		return r.InitializeKeycloakProvider(adminURL, realm)
+	default:
+		return fmt.Errorf("Unsupport vendor %s", keyCloakVendor)
+	}
+}
+
+// ProviderEnabled returns true if any vendor specific provider is enabled.
+func (r *Config) ProviderEnabled() bool {
+	r.mutex.Lock()
+	defer r.mutex.Unlock()
+	return r.provider != nil
+}
+
+// InitializeKeycloakProvider - initializes keycloak provider
+func (r *Config) InitializeKeycloakProvider(adminURL, realm string) error {
+	r.mutex.Lock()
+	defer r.mutex.Unlock()
+
+	var err error
+	r.provider, err = provider.KeyCloak(
+		provider.WithAdminURL(adminURL),
+		provider.WithOpenIDConfig(provider.DiscoveryDoc(r.DiscoveryDoc)),
+		provider.WithTransport(r.transport),
+		provider.WithRealm(realm),
+	)
+	return err
+}
+
 // PopulatePublicKey - populates a new publickey from the JWKS URL.
 func (r *Config) PopulatePublicKey() error {
 	r.mutex.Lock()
@@ -228,9 +294,15 @@ const (
 	ClaimPrefix  = "claim_prefix"
 	ClientID     = "client_id"
 	ClientSecret = "client_secret"
+	Vendor       = "vendor"
 	Scopes       = "scopes"
 	RedirectURI  = "redirect_uri"
 
+	// Vendor specific ENV only enabled if the Vendor matches == "vendor"
+	KeyCloakRealm    = "keycloak_realm"
+	KeyCloakAdminURL = "keycloak_admin_url"
+
+	EnvIdentityOpenIDVendor       = "MINIO_IDENTITY_OPENID_VENDOR"
 	EnvIdentityOpenIDClientID     = "MINIO_IDENTITY_OPENID_CLIENT_ID"
 	EnvIdentityOpenIDClientSecret = "MINIO_IDENTITY_OPENID_CLIENT_SECRET"
 	EnvIdentityOpenIDJWKSURL      = "MINIO_IDENTITY_OPENID_JWKS_URL"
@@ -239,6 +311,10 @@ const (
 	EnvIdentityOpenIDClaimPrefix  = "MINIO_IDENTITY_OPENID_CLAIM_PREFIX"
 	EnvIdentityOpenIDRedirectURI  = "MINIO_IDENTITY_OPENID_REDIRECT_URI"
 	EnvIdentityOpenIDScopes       = "MINIO_IDENTITY_OPENID_SCOPES"
+
+	// Vendor specific ENVs only enabled if the Vendor matches == "vendor"
+	EnvIdentityOpenIDKeyCloakRealm    = "MINIO_IDENTITY_OPENID_KEYCLOAK_REALM"
+	EnvIdentityOpenIDKeyCloakAdminURL = "MINIO_IDENTITY_OPENID_KEYCLOAK_ADMIN_URL"
 )
 
 // DiscoveryDoc - parses the output from openid-configuration
@@ -397,6 +473,10 @@ func LookupConfig(kvs config.KVS, transport *http.Transport, closeRespFn func(io
 		return c, err
 	}
 
+	if err = c.InitializeProvider(kvs); err != nil {
+		return c, err
+	}
+
 	return c, nil
 }
 

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

@@ -0,0 +1,184 @@
+// 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"
+	"strings"
+	"sync"
+)
+
+// Token - parses the output from IDP access 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) {
+	lookupUserID := k.adminURL + "/realms" + k.realm + "/users/" + userid
+	req, err := http.NewRequest(http.MethodGet, lookupUserID, nil)
+	if err != nil {
+		return User{}, err
+	}
+	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 %s - keycloak user lookup returned %v", userid, resp.Status)
+}
+
+// Option is a function type that accepts a pointer Target
+type Option func(*KeycloakProvider)
+
+// WithTransport provide custom transport
+func WithTransport(transport *http.Transport) 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
+}

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

@@ -0,0 +1,59 @@
+// 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 "errors"
+
+// DiscoveryDoc - parses the output from openid-configuration
+// for example https://accounts.google.com/.well-known/openid-configuration
+type DiscoveryDoc struct {
+	Issuer                           string   `json:"issuer,omitempty"`
+	AuthEndpoint                     string   `json:"authorization_endpoint,omitempty"`
+	TokenEndpoint                    string   `json:"token_endpoint,omitempty"`
+	UserInfoEndpoint                 string   `json:"userinfo_endpoint,omitempty"`
+	RevocationEndpoint               string   `json:"revocation_endpoint,omitempty"`
+	JwksURI                          string   `json:"jwks_uri,omitempty"`
+	ResponseTypesSupported           []string `json:"response_types_supported,omitempty"`
+	SubjectTypesSupported            []string `json:"subject_types_supported,omitempty"`
+	IDTokenSigningAlgValuesSupported []string `json:"id_token_signing_alg_values_supported,omitempty"`
+	ScopesSupported                  []string `json:"scopes_supported,omitempty"`
+	TokenEndpointAuthMethods         []string `json:"token_endpoint_auth_methods_supported,omitempty"`
+	ClaimsSupported                  []string `json:"claims_supported,omitempty"`
+	CodeChallengeMethodsSupported    []string `json:"code_challenge_methods_supported,omitempty"`
+}
+
+// User represents information about user.
+type User struct {
+	Name    string `json:"username"`
+	ID      string `json:"id"`
+	Enabled bool   `json:"enabled"`
+}
+
+// Standard errors.
+var (
+	ErrNotImplemented     = errors.New("function not implemented")
+	ErrAccessTokenExpired = errors.New("access_token expired or unauthorized")
+)
+
+// Provider implements indentity provider specific admin operations, such as
+// looking up users, fetching additional attributes etc.
+type Provider interface {
+	LoginWithUser(username, password string) error
+	LoginWithClientID(clientID, clientSecret string) error
+	LookupUser(userid string) (User, error)
+}