bit more progress

internal/oidc/idp.go

@@ -0,0 +1,115 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   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 oidc
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/coreos/go-oidc/v3/oidc"
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"golang.org/x/oauth2"
+)
+
+const (
+	// CallbackPath is the API path for receiving callback tokens from external OIDC providers
+	CallbackPath = "/auth/callback"
+	profileScope = "profile"
+	emailScope   = "email"
+	groupsScope  = "groups"
+)
+
+type IDP interface {
+	HandleCallback(ctx context.Context, state string, code string) (*Claims, error)
+}
+
+type idp struct {
+	oauth2Config oauth2.Config
+	provider     *oidc.Provider
+	oidcConf     *oidc.Config
+	log          *logrus.Logger
+}
+
+func NewIDP(config *config.Config, log *logrus.Logger) (IDP, error) {
+
+	// oidc isn't enabled so we don't need to do anything
+	if !config.OIDCConfig.Enabled {
+		return nil, nil
+	}
+
+	// validate config fields
+	if config.OIDCConfig.IDPID == "" {
+		return nil, fmt.Errorf("not set: IDPID")
+	}
+	if config.OIDCConfig.IDPName == "" {
+		return nil, fmt.Errorf("not set: IDPName")
+	}
+	if config.OIDCConfig.Issuer == "" {
+		return nil, fmt.Errorf("not set: Issuer")
+	}
+	if config.OIDCConfig.ClientID == "" {
+		return nil, fmt.Errorf("not set: ClientID")
+	}
+	if config.OIDCConfig.ClientSecret == "" {
+		return nil, fmt.Errorf("not set: ClientSecret")
+	}
+	if len(config.OIDCConfig.Scopes) == 0 {
+		return nil, fmt.Errorf("not set: Scopes")
+	}
+
+	provider, err := oidc.NewProvider(context.Background(), config.OIDCConfig.Issuer)
+	if err != nil {
+		return nil, err
+	}
+
+	oauth2Config := oauth2.Config{
+		// client_id and client_secret of the client.
+		ClientID:     config.OIDCConfig.ClientID,
+		ClientSecret: config.OIDCConfig.ClientSecret,
+
+		// The redirectURL.
+		RedirectURL: fmt.Sprintf("%s://%s%s", config.Protocol, config.Host, CallbackPath),
+
+		// Discovery returns the OAuth2 endpoints.
+		Endpoint: provider.Endpoint(),
+
+		// "openid" is a required scope for OpenID Connect flows.
+		//
+		// Other scopes, such as "groups" can be requested.
+		Scopes: config.OIDCConfig.Scopes,
+	}
+
+	// create a config for verifier creation
+	oidcConf := &oidc.Config{
+		ClientID: config.OIDCConfig.ClientID,
+	}
+	if config.OIDCConfig.SkipVerification {
+		oidcConf.SkipClientIDCheck = true
+		oidcConf.SkipExpiryCheck = true
+		oidcConf.SkipIssuerCheck = true
+	}
+
+	return &idp{
+		oauth2Config: oauth2Config,
+		oidcConf:     oidcConf,
+		provider:     provider,
+		log:          log,
+	}, nil
+}