bit more progress

internal/api/client/auth/auth.go

@@ -38,7 +38,10 @@ const (
 	// OauthAuthorizePath is the API path for authorization requests (eg., authorize this app to act on my behalf as a user)
 	OauthAuthorizePath = "/oauth/authorize"
 	// CallbackPath is the API path for receiving callback tokens from external OIDC providers
-	CallbackPath = "/auth/callback"
+	CallbackPath = oidc.CallbackPath
+
+	callbackStateParam = "state"
+	callbackCodeParam  = "code"
 
 	sessionUserID       = "userid"
 	sessionClientID     = "client_id"
@@ -89,6 +92,8 @@ func (m *Module) Route(s router.Router) error {
 	s.AttachHandler(http.MethodGet, OauthAuthorizePath, m.AuthorizeGETHandler)
 	s.AttachHandler(http.MethodPost, OauthAuthorizePath, m.AuthorizePOSTHandler)
 
+	s.AttachHandler(http.MethodGet, CallbackPath, m.CallbackGETHandler)
+
 	s.AttachMiddleware(m.OauthTokenMiddleware)
 	return nil
 }

internal/api/client/auth/callback.go

@@ -18,4 +18,22 @@
 
 package auth
 
+import (
+	"net/http"
 
+	"github.com/gin-gonic/gin"
+)
+
+// CallbackGETHandler parses a token from an external auth provider.
+func (m *Module) CallbackGETHandler(c *gin.Context) {
+	state := c.Query(callbackStateParam)
+	code := c.Query(callbackCodeParam)
+
+	claims, err := m.idp.HandleCallback(c.Request.Context(), state, code)
+	if err != nil {
+		c.String(http.StatusForbidden, err.Error())
+		return
+	}
+
+	c.JSON(http.StatusOK, claims)
+}

internal/api/client/auth/signin.go

@@ -39,7 +39,13 @@ type login struct {
 // The idea is to present a sign in page to the user, where they can enter their username and password.
 // The form will then POST to the sign in page, which will be handled by SignInPOSTHandler
 func (m *Module) SignInGETHandler(c *gin.Context) {
-	m.log.WithField("func", "SignInGETHandler").Trace("serving sign in html")
+	l := m.log.WithField("func", "SignInGETHandler")
+	l.Trace("entering sign in handler")
+	if m.idp != nil && m.config.OIDCConfig.Issuer != "" {
+		l.Debug("redirecting to external idp at %s", m.config.OIDCConfig.Issuer)
+		c.Redirect(http.StatusFound, m.config.OIDCConfig.Issuer)
+		return
+	}
 	c.HTML(http.StatusOK, "sign-in.tmpl", gin.H{})
 }
 

internal/cliactions/server/server.go

@@ -122,7 +122,7 @@ var Start cliactions.GTSAction = func(ctx context.Context, c *config.Config, log
 		return fmt.Errorf("error starting processor: %s", err)
 	}
 
-	idp, err := oidc.NewIDP(c)
+	idp, err := oidc.NewIDP(c, log)
 	if err != nil {
 		return fmt.Errorf("error creating oidc idp: %s", err)
 	}

internal/cliactions/testrig/testrig.go

@@ -67,7 +67,7 @@ var Start cliactions.GTSAction = func(ctx context.Context, _ *config.Config, log
 		return fmt.Errorf("error starting processor: %s", err)
 	}
 
-	idp, err := oidc.NewIDP(c)
+	idp, err := oidc.NewIDP(c, log)
 	if err != nil {
 		return fmt.Errorf("error creating oidc idp: %s", err)
 	}

internal/oidc/claims.go

@@ -0,0 +1,25 @@
+/*
+   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
+
+// Claims represents claims as found in an id_token returned from an OIDC flow.
+type Claims struct {
+	Email  string   `json:"email"`
+	Groups []string `json:"groups"`
+}

internal/oidc/handlecallback.go

@@ -0,0 +1,68 @@
+/*
+   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"
+	"errors"
+	"fmt"
+)
+
+func (i *idp) HandleCallback(ctx context.Context, state string, code string) (*Claims, error) {
+	l := i.log.WithField("func", "HandleCallback")
+
+	if state == "" {
+		return nil, errors.New("state was empty string")
+	}
+
+	if code == "" {
+		return nil, errors.New("code was empty string")
+	}
+
+	// TODO: verify state
+
+	l.Debug("exchanging code for oauth2token")
+	oauth2Token, err := i.oauth2Config.Exchange(ctx, code)
+	if err != nil {
+		return nil, fmt.Errorf("error exchanging code for oauth2token: %s", err)
+	}
+
+	l.Debug("extracting id_token")
+	rawIDToken, ok := oauth2Token.Extra("id_token").(string)
+	if !ok {
+		return nil, errors.New("no id_token in oauth2token")
+	}
+	l.Debug("raw id token: %s", rawIDToken)
+
+	// Parse and verify ID Token payload.
+	l.Debug("verifying id_token")
+	idTokenVerifier := i.provider.Verifier(i.oidcConf)
+	idToken, err := idTokenVerifier.Verify(ctx, rawIDToken)
+	if err != nil {
+		return nil, fmt.Errorf("could not verify id token: %s", err)
+	}
+
+	l.Debug("extracting claims from id_token")
+	claims := &Claims{}
+	if err := idToken.Claims(claims); err != nil {
+		return nil, fmt.Errorf("could not parse claims from idToken: %s", err)
+	}
+
+	return claims, nil
+}

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
+}

internal/oidc/oidc.go

@@ -1,76 +0,0 @@
-package oidc
-
-import (
-	"context"
-	"fmt"
-
-	"github.com/coreos/go-oidc/v3/oidc"
-	"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 {
-}
-
-type idp struct {
-	oauth2Config    oauth2.Config
-	provider        *oidc.Provider
-	idTokenVerifier *oidc.IDTokenVerifier
-}
-
-func NewIDP(config *config.Config) (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")
-	}
-
-	aaaaaaaaaaaaaaaaaaaaaaaaaaaa
-
-
-	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,
-	}
-
-	idTokenVerifier := provider.Verifier(&oidc.Config{ClientID: config.OIDCConfig.ClientID})
-
-	return &idp{
-		oauth2Config:    oauth2Config,
-		idTokenVerifier: idTokenVerifier,
-	}, nil
-}