Auth flow fixes (#82)

* preliminary fixes to broken auth flow

* fix some auth/cookie weirdness

* fmt

internal/api/client/auth/auth.go

@@ -36,8 +36,26 @@ const (
 	OauthTokenPath = "/oauth/token"
 	// OauthAuthorizePath is the API path for authorization requests (eg., authorize this app to act on my behalf as a user)
 	OauthAuthorizePath = "/oauth/authorize"
+
+	sessionUserID       = "userid"
+	sessionClientID     = "client_id"
+	sessionRedirectURI  = "redirect_uri"
+	sessionForceLogin   = "force_login"
+	sessionResponseType = "response_type"
+	sessionCode         = "code"
+	sessionScope        = "scope"
 )
 
+var sessionKeys []string = []string{
+	sessionUserID,
+	sessionClientID,
+	sessionRedirectURI,
+	sessionForceLogin,
+	sessionResponseType,
+	sessionCode,
+	sessionScope,
+}
+
 // Module implements the ClientAPIModule interface for
 type Module struct {
 	config *config.Config

internal/api/client/auth/authorize.go

@@ -26,7 +26,6 @@ import (
 
 	"github.com/gin-contrib/sessions"
 	"github.com/gin-gonic/gin"
-	"github.com/sirupsen/logrus"
 	"github.com/superseriousbusiness/gotosocial/internal/api/model"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -38,25 +37,30 @@ import (
 func (m *Module) AuthorizeGETHandler(c *gin.Context) {
 	l := m.log.WithField("func", "AuthorizeGETHandler")
 	s := sessions.Default(c)
-	s.Options(sessions.Options{
-		MaxAge: 120, // give the user 2 minutes to sign in before expiring their session
-	})
 
 	// UserID will be set in the session by AuthorizePOSTHandler if the caller has already gone through the authentication flow
 	// If it's not set, then we don't know yet who the user is, so we need to redirect them to the sign in page.
-	userID, ok := s.Get("userid").(string)
+	userID, ok := s.Get(sessionUserID).(string)
 	if !ok || userID == "" {
 		l.Trace("userid was empty, parsing form then redirecting to sign in page")
-		if err := parseAuthForm(c, l); err != nil {
-			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
-		} else {
-			c.Redirect(http.StatusFound, AuthSignInPath)
+		form := &model.OAuthAuthorize{}
+		if err := c.Bind(form); err != nil {
+			l.Debugf("invalid auth form: %s", err)
+			return
 		}
+		l.Tracef("parsed auth form: %+v", form)
+
+		if err := extractAuthForm(s, form); err != nil {
+			l.Debugf(fmt.Sprintf("error parsing form at /oauth/authorize: %s", err))
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+		c.Redirect(http.StatusFound, AuthSignInPath)
 		return
 	}
 
 	// We can use the client_id on the session to retrieve info about the app associated with the client_id
-	clientID, ok := s.Get("client_id").(string)
+	clientID, ok := s.Get(sessionClientID).(string)
 	if !ok || clientID == "" {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "no client_id found in session"})
 		return
@@ -64,7 +68,7 @@ func (m *Module) AuthorizeGETHandler(c *gin.Context) {
 	app := &gtsmodel.Application{
 		ClientID: clientID,
 	}
-	if err := m.db.GetWhere([]db.Where{{Key: "client_id", Value: app.ClientID}}, app); err != nil {
+	if err := m.db.GetWhere([]db.Where{{Key: sessionClientID, Value: app.ClientID}}, app); err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("no application found for client id %s", clientID)})
 		return
 	}
@@ -88,12 +92,12 @@ func (m *Module) AuthorizeGETHandler(c *gin.Context) {
 	}
 
 	// Finally we should also get the redirect and scope of this particular request, as stored in the session.
-	redirect, ok := s.Get("redirect_uri").(string)
+	redirect, ok := s.Get(sessionRedirectURI).(string)
 	if !ok || redirect == "" {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "no redirect_uri found in session"})
 		return
 	}
-	scope, ok := s.Get("scope").(string)
+	scope, ok := s.Get(sessionScope).(string)
 	if !ok || scope == "" {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "no scope found in session"})
 		return
@@ -107,7 +111,7 @@ func (m *Module) AuthorizeGETHandler(c *gin.Context) {
 		"appname":    app.Name,
 		"appwebsite": app.Website,
 		"redirect":   redirect,
-		"scope":      scope,
+		sessionScope: scope,
 		"user":       acct.Username,
 	})
 }
@@ -123,39 +127,47 @@ func (m *Module) AuthorizePOSTHandler(c *gin.Context) {
 	// We need to retrieve the original form submitted to the authorizeGEThandler, and
 	// recreate it on the request so that it can be used further by the oauth2 library.
 	// So first fetch all the values from the session.
-	forceLogin, ok := s.Get("force_login").(string)
+
+	forceLogin, ok := s.Get(sessionForceLogin).(string)
 	if !ok {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing force_login"})
 		return
 	}
-	responseType, ok := s.Get("response_type").(string)
+
+	responseType, ok := s.Get(sessionResponseType).(string)
 	if !ok || responseType == "" {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing response_type"})
 		return
 	}
-	clientID, ok := s.Get("client_id").(string)
+
+	clientID, ok := s.Get(sessionClientID).(string)
 	if !ok || clientID == "" {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing client_id"})
 		return
 	}
-	redirectURI, ok := s.Get("redirect_uri").(string)
+
+	redirectURI, ok := s.Get(sessionRedirectURI).(string)
 	if !ok || redirectURI == "" {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing redirect_uri"})
 		return
 	}
-	scope, ok := s.Get("scope").(string)
+
+	scope, ok := s.Get(sessionScope).(string)
 	if !ok {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing scope"})
 		return
 	}
-	userID, ok := s.Get("userid").(string)
+
+	userID, ok := s.Get(sessionUserID).(string)
 	if !ok {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing userid"})
 		return
 	}
 
 	// we're done with the session so we can clear it now
-	s.Clear()
+	for _, key := range sessionKeys {
+		s.Delete(key)
+	}
 	if err := s.Save(); err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
 		return
@@ -163,12 +175,12 @@ func (m *Module) AuthorizePOSTHandler(c *gin.Context) {
 
 	// now set the values on the request
 	values := url.Values{}
-	values.Set("force_login", forceLogin)
-	values.Set("response_type", responseType)
-	values.Set("client_id", clientID)
-	values.Set("redirect_uri", redirectURI)
-	values.Set("scope", scope)
-	values.Set("userid", userID)
+	values.Set(sessionForceLogin, forceLogin)
+	values.Set(sessionResponseType, responseType)
+	values.Set(sessionClientID, clientID)
+	values.Set(sessionRedirectURI, redirectURI)
+	values.Set(sessionScope, scope)
+	values.Set(sessionUserID, userID)
 	c.Request.Form = values
 	l.Tracef("values on request set to %+v", c.Request.Form)
 
@@ -178,18 +190,9 @@ func (m *Module) AuthorizePOSTHandler(c *gin.Context) {
 	}
 }
 
-// parseAuthForm parses the OAuthAuthorize form in the gin context, and stores
+// extractAuthForm checks the given OAuthAuthorize form, and stores
 // the values in the form into the session.
-func parseAuthForm(c *gin.Context, l *logrus.Entry) error {
-	s := sessions.Default(c)
-
-	// first make sure they've filled out the authorize form with the required values
-	form := &model.OAuthAuthorize{}
-	if err := c.ShouldBind(form); err != nil {
-		return err
-	}
-	l.Tracef("parsed form: %+v", form)
-
+func extractAuthForm(s sessions.Session, form *model.OAuthAuthorize) error {
 	// these fields are *required* so check 'em
 	if form.ResponseType == "" || form.ClientID == "" || form.RedirectURI == "" {
 		return errors.New("missing one of: response_type, client_id or redirect_uri")
@@ -201,10 +204,10 @@ func parseAuthForm(c *gin.Context, l *logrus.Entry) error {
 	}
 
 	// save these values from the form so we can use them elsewhere in the session
-	s.Set("force_login", form.ForceLogin)
-	s.Set("response_type", form.ResponseType)
-	s.Set("client_id", form.ClientID)
-	s.Set("redirect_uri", form.RedirectURI)
-	s.Set("scope", form.Scope)
+	s.Set(sessionForceLogin, form.ForceLogin)
+	s.Set(sessionResponseType, form.ResponseType)
+	s.Set(sessionClientID, form.ClientID)
+	s.Set(sessionRedirectURI, form.RedirectURI)
+	s.Set(sessionScope, form.Scope)
 	return s.Save()
 }

internal/api/client/auth/signin.go

@@ -62,7 +62,7 @@ func (m *Module) SignInPOSTHandler(c *gin.Context) {
 		return
 	}
 
-	s.Set("userid", userid)
+	s.Set(sessionUserID, userid)
 	if err := s.Save(); err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
 		return

internal/api/model/oauth.go

@@ -22,16 +22,16 @@ package model
 // See here: https://docs.joinmastodon.org/methods/apps/oauth/
 type OAuthAuthorize struct {
 	// Forces the user to re-login, which is necessary for authorizing with multiple accounts from the same instance.
-	ForceLogin string `form:"force_login,omitempty"`
+	ForceLogin string `form:"force_login" json:"force_login"`
 	// Should be set equal to `code`.
-	ResponseType string `form:"response_type"`
+	ResponseType string `form:"response_type" json:"response_type"`
 	// Client ID, obtained during app registration.
-	ClientID string `form:"client_id"`
+	ClientID string `form:"client_id" json:"client_id"`
 	// Set a URI to redirect the user to.
 	// If this parameter is set to urn:ietf:wg:oauth:2.0:oob then the authorization code will be shown instead.
 	// Must match one of the redirect URIs declared during app registration.
-	RedirectURI string `form:"redirect_uri"`
+	RedirectURI string `form:"redirect_uri" json:"redirect_uri"`
 	// List of requested OAuth scopes, separated by spaces (or by pluses, if using query parameters).
 	// Must be a subset of scopes declared during app registration. If not provided, defaults to read.
-	Scope string `form:"scope,omitempty"`
+	Scope string `form:"scope" json:"scope"`
 }

internal/router/session.go

@@ -22,6 +22,7 @@ import (
 	"crypto/rand"
 	"errors"
 	"fmt"
+	"net/http"
 
 	"github.com/gin-contrib/sessions"
 	"github.com/gin-contrib/sessions/memstore"
@@ -63,6 +64,14 @@ func useSession(cfg *config.Config, dbService db.DB, engine *gin.Engine) error {
 	}
 
 	store := memstore.NewStore(rs.Auth, rs.Crypt)
+	store.Options(sessions.Options{
+		Path:     "/",
+		Domain:   cfg.Host,
+		MaxAge:   120,                     // 2 minutes
+		Secure:   true,                    // only use cookie over https
+		HttpOnly: true,                    // exclude javascript from inspecting cookie
+		SameSite: http.SameSiteStrictMode, // https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-cookie-same-site-00#section-4.1.1
+	})
 	sessionName := fmt.Sprintf("gotosocial-%s", cfg.Host)
 	engine.Use(sessions.Sessions(sessionName, store))
 	return nil