Fix link/origin referrer and login redirect (#36279)

Fix #35998

1. Fix `<a rel>` :
    * "_blank" already means "noopener"
* "noreferrer" is already provided by page's `<meta name="referrer">`
2. Fix "redirect_to" mechisam
* Use "referer" header to determine the redirect link for a successful
login
3. Simplify code and merge duplicate logic

routers/common/blockexpensive.go

@@ -24,7 +24,7 @@ func BlockExpensive() func(next http.Handler) http.Handler {
 			ret := determineRequestPriority(reqctx.FromContext(req.Context()))
 			if !ret.SignedIn {
 				if ret.Expensive || ret.LongPolling {
-					http.Redirect(w, req, setting.AppSubURL+"/user/login", http.StatusSeeOther)
+					http.Redirect(w, req, middleware.RedirectLinkUserLogin(req), http.StatusSeeOther)
 					return
 				}
 			}

routers/web/auth/2fa.go

@@ -26,7 +26,7 @@ var (
 func TwoFactor(ctx *context.Context) {
 	ctx.Data["Title"] = ctx.Tr("twofa")
 
-	if CheckAutoLogin(ctx) {
+	if performAutoLogin(ctx) {
 		return
 	}
 
@@ -99,7 +99,7 @@ func TwoFactorPost(ctx *context.Context) {
 func TwoFactorScratch(ctx *context.Context) {
 	ctx.Data["Title"] = ctx.Tr("twofa_scratch")
 
-	if CheckAutoLogin(ctx) {
+	if performAutoLogin(ctx) {
 		return
 	}
 
@@ -151,7 +151,7 @@ func TwoFactorScratchPost(ctx *context.Context) {
 			return
 		}
 
-		handleSignInFull(ctx, u, remember, false)
+		handleSignInFull(ctx, u, remember)
 		if ctx.Written() {
 			return
 		}

routers/web/auth/auth.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"html/template"
 	"net/http"
+	"net/url"
 	"strings"
 
 	"code.gitea.io/gitea/models/auth"
@@ -126,20 +127,47 @@ func resetLocale(ctx *context.Context, u *user_model.User) error {
 	return nil
 }
 
-func RedirectAfterLogin(ctx *context.Context) {
+func rememberAuthRedirectLink(ctx *context.Context) {
 	redirectTo := ctx.FormString("redirect_to")
 	if redirectTo == "" {
-		redirectTo = ctx.GetSiteCookie("redirect_to")
+		if ref, err := url.Parse(ctx.Req.Referer()); err == nil && httplib.IsCurrentGiteaSiteURL(ctx, ctx.Req.Referer()) {
+			// the request paths starting with "/user/" are either:
+			// * auth related pages: don't redirect back to them
+			// * user settings pages: they have "require sign-in" protection already, no "referer redirect" would happen
+			skipRefererRedirect := strings.HasPrefix(ref.Path, setting.AppSubURL+"/user/")
+			if !skipRefererRedirect {
+				redirectTo = ref.RequestURI()
+			}
+		}
 	}
-	middleware.DeleteRedirectToCookie(ctx.Resp)
-	nextRedirectTo := setting.AppSubURL + string(setting.LandingPageURL)
-	if setting.LandingPageURL == setting.LandingPageLogin {
-		nextRedirectTo = setting.AppSubURL + "/" // do not cycle-redirect to the login page
+	if redirectTo != "" {
+		middleware.SetRedirectToCookie(ctx.Resp, redirectTo)
 	}
-	ctx.RedirectToCurrentSite(redirectTo, nextRedirectTo)
 }
 
-func CheckAutoLogin(ctx *context.Context) bool {
+func consumeAuthRedirectLink(ctx *context.Context) string {
+	redirects := []string{ctx.FormString("redirect_to"), middleware.GetRedirectToCookie(ctx.Req)}
+	middleware.DeleteRedirectToCookie(ctx.Resp)
+	if setting.LandingPageURL == setting.LandingPageLogin {
+		redirects = append(redirects, setting.AppSubURL+"/") // do not cycle-redirect to the login page
+	} else {
+		redirects = append(redirects, setting.AppSubURL+string(setting.LandingPageURL))
+	}
+	for _, link := range redirects {
+		if link != "" && httplib.IsCurrentGiteaSiteURL(ctx, link) {
+			return link
+		}
+	}
+	return setting.AppSubURL + "/"
+}
+
+func redirectAfterAuth(ctx *context.Context) {
+	ctx.RedirectToCurrentSite(consumeAuthRedirectLink(ctx))
+}
+
+func performAutoLogin(ctx *context.Context) bool {
+	rememberAuthRedirectLink(ctx)
+
 	isSucceed, err := autoSignIn(ctx) // try to auto-login
 	if err != nil {
 		if errors.Is(err, auth_service.ErrAuthTokenInvalidHash) {
@@ -150,13 +178,8 @@ func CheckAutoLogin(ctx *context.Context) bool {
 		return true
 	}
 
-	redirectTo := ctx.FormString("redirect_to")
-	if len(redirectTo) > 0 {
-		middleware.SetRedirectToCookie(ctx.Resp, redirectTo)
-	}
-
 	if isSucceed {
-		RedirectAfterLogin(ctx)
+		redirectAfterAuth(ctx)
 		return true
 	}
 
@@ -181,11 +204,11 @@ func prepareSignInPageData(ctx *context.Context) {
 
 // SignIn render sign in page
 func SignIn(ctx *context.Context) {
-	if CheckAutoLogin(ctx) {
+	if performAutoLogin(ctx) {
 		return
 	}
 	if ctx.IsSigned {
-		RedirectAfterLogin(ctx)
+		redirectAfterAuth(ctx)
 		return
 	}
 	prepareSignInPageData(ctx)
@@ -295,19 +318,19 @@ func SignInPost(ctx *context.Context) {
 
 // This handles the final part of the sign-in process of the user.
 func handleSignIn(ctx *context.Context, u *user_model.User, remember bool) {
-	redirect := handleSignInFull(ctx, u, remember, true)
+	handleSignInFull(ctx, u, remember)
 	if ctx.Written() {
 		return
 	}
-	ctx.Redirect(redirect)
+	redirectAfterAuth(ctx)
 }
 
-func handleSignInFull(ctx *context.Context, u *user_model.User, remember, obeyRedirect bool) string {
+func handleSignInFull(ctx *context.Context, u *user_model.User, remember bool) {
 	if remember {
 		nt, token, err := auth_service.CreateAuthTokenForUserID(ctx, u.ID)
 		if err != nil {
 			ctx.ServerError("CreateAuthTokenForUserID", err)
-			return setting.AppSubURL + "/"
+			return
 		}
 
 		ctx.SetSiteCookie(setting.CookieRememberName, nt.ID+":"+token, setting.LogInRememberDays*timeutil.Day)
@@ -316,7 +339,7 @@ func handleSignInFull(ctx *context.Context, u *user_model.User, remember, obeyRe
 	userHasTwoFactorAuth, err := auth.HasTwoFactorOrWebAuthn(ctx, u.ID)
 	if err != nil {
 		ctx.ServerError("HasTwoFactorOrWebAuthn", err)
-		return setting.AppSubURL + "/"
+		return
 	}
 
 	if err := updateSession(ctx, []string{
@@ -335,7 +358,7 @@ func handleSignInFull(ctx *context.Context, u *user_model.User, remember, obeyRe
 		session.KeyUserHasTwoFactorAuth: userHasTwoFactorAuth,
 	}); err != nil {
 		ctx.ServerError("RegenerateSession", err)
-		return setting.AppSubURL + "/"
+		return
 	}
 
 	// Language setting of the user overwrites the one previously set
@@ -346,7 +369,7 @@ func handleSignInFull(ctx *context.Context, u *user_model.User, remember, obeyRe
 		}
 		if err := user_service.UpdateUser(ctx, u, opts); err != nil {
 			ctx.ServerError("UpdateUser Language", fmt.Errorf("Error updating user language [user: %d, locale: %s]", u.ID, ctx.Locale.Language()))
-			return setting.AppSubURL + "/"
+			return
 		}
 	}
 
@@ -359,21 +382,8 @@ func handleSignInFull(ctx *context.Context, u *user_model.User, remember, obeyRe
 	// Register last login
 	if err := user_service.UpdateUser(ctx, u, &user_service.UpdateOptions{SetLastLogin: true}); err != nil {
 		ctx.ServerError("UpdateUser", err)
-		return setting.AppSubURL + "/"
+		return
 	}
-
-	if redirectTo := ctx.GetSiteCookie("redirect_to"); redirectTo != "" && httplib.IsCurrentGiteaSiteURL(ctx, redirectTo) {
-		middleware.DeleteRedirectToCookie(ctx.Resp)
-		if obeyRedirect {
-			ctx.RedirectToCurrentSite(redirectTo)
-		}
-		return redirectTo
-	}
-
-	if obeyRedirect {
-		ctx.Redirect(setting.AppSubURL + "/")
-	}
-	return setting.AppSubURL + "/"
 }
 
 // extractUserNameFromOAuth2 tries to extract a normalized username from the given OAuth2 user.
@@ -436,10 +446,7 @@ func SignUp(ctx *context.Context) {
 	// Show Disabled Registration message if DisableRegistration or AllowOnlyExternalRegistration options are true
 	ctx.Data["DisableRegistration"] = setting.Service.DisableRegistration || setting.Service.AllowOnlyExternalRegistration
 
-	redirectTo := ctx.FormString("redirect_to")
-	if len(redirectTo) > 0 {
-		middleware.SetRedirectToCookie(ctx.Resp, redirectTo)
-	}
+	rememberAuthRedirectLink(ctx)
 
 	ctx.HTML(http.StatusOK, tplSignUp)
 }
@@ -817,13 +824,7 @@ func handleAccountActivation(ctx *context.Context, user *user_model.User) {
 	}
 
 	ctx.Flash.Success(ctx.Tr("auth.account_activated"))
-	if redirectTo := ctx.GetSiteCookie("redirect_to"); len(redirectTo) > 0 {
-		middleware.DeleteRedirectToCookie(ctx.Resp)
-		ctx.RedirectToCurrentSite(redirectTo)
-		return
-	}
-
-	ctx.Redirect(setting.AppSubURL + "/")
+	redirectAfterAuth(ctx)
 }
 
 // ActivateEmail render the activate email page

routers/web/auth/oauth.go

@@ -21,7 +21,6 @@ import (
 	"code.gitea.io/gitea/modules/optional"
 	"code.gitea.io/gitea/modules/session"
 	"code.gitea.io/gitea/modules/setting"
-	"code.gitea.io/gitea/modules/web/middleware"
 	source_service "code.gitea.io/gitea/services/auth/source"
 	"code.gitea.io/gitea/services/auth/source/oauth2"
 	"code.gitea.io/gitea/services/context"
@@ -42,10 +41,7 @@ func SignInOAuth(ctx *context.Context) {
 		return
 	}
 
-	redirectTo := ctx.FormString("redirect_to")
-	if len(redirectTo) > 0 {
-		middleware.SetRedirectToCookie(ctx.Resp, redirectTo)
-	}
+	rememberAuthRedirectLink(ctx)
 
 	// try to do a direct callback flow, so we don't authenticate the user again but use the valid accesstoken to get the user
 	user, gothUser, err := oAuth2UserLoginCallback(ctx, authSource, ctx.Req, ctx.Resp)
@@ -398,13 +394,7 @@ func handleOAuth2SignIn(ctx *context.Context, authSource *auth.Source, u *user_m
 			return
 		}
 
-		if redirectTo := ctx.GetSiteCookie("redirect_to"); len(redirectTo) > 0 {
-			middleware.DeleteRedirectToCookie(ctx.Resp)
-			ctx.RedirectToCurrentSite(redirectTo)
-			return
-		}
-
-		ctx.Redirect(setting.AppSubURL + "/")
+		redirectAfterAuth(ctx)
 		return
 	}
 

routers/web/auth/openid.go

@@ -35,7 +35,7 @@ func SignInOpenID(ctx *context.Context) {
 		return
 	}
 
-	if CheckAutoLogin(ctx) {
+	if performAutoLogin(ctx) {
 		return
 	}
 

routers/web/auth/password.go

@@ -16,7 +16,6 @@ import (
 	"code.gitea.io/gitea/modules/templates"
 	"code.gitea.io/gitea/modules/timeutil"
 	"code.gitea.io/gitea/modules/web"
-	"code.gitea.io/gitea/modules/web/middleware"
 	"code.gitea.io/gitea/services/context"
 	"code.gitea.io/gitea/services/forms"
 	"code.gitea.io/gitea/services/mailer"
@@ -236,7 +235,7 @@ func ResetPasswdPost(ctx *context.Context) {
 			return
 		}
 
-		handleSignInFull(ctx, u, remember, false)
+		handleSignInFull(ctx, u, remember)
 		if ctx.Written() {
 			return
 		}
@@ -308,11 +307,5 @@ func MustChangePasswordPost(ctx *context.Context) {
 
 	log.Trace("User updated password: %s", ctx.Doer.Name)
 
-	if redirectTo := ctx.GetSiteCookie("redirect_to"); redirectTo != "" {
-		middleware.DeleteRedirectToCookie(ctx.Resp)
-		ctx.RedirectToCurrentSite(redirectTo)
-		return
-	}
-
-	ctx.Redirect(setting.AppSubURL + "/")
+	redirectAfterAuth(ctx)
 }

routers/web/auth/webauthn.go

@@ -26,7 +26,7 @@ var tplWebAuthn templates.TplName = "user/auth/webauthn"
 func WebAuthn(ctx *context.Context) {
 	ctx.Data["Title"] = ctx.Tr("twofa")
 
-	if CheckAutoLogin(ctx) {
+	if performAutoLogin(ctx) {
 		return
 	}
 
@@ -156,12 +156,8 @@ func WebAuthnPasskeyLogin(ctx *context.Context) {
 	}
 
 	remember := false // TODO: implement remember me
-	redirect := handleSignInFull(ctx, user, remember, false)
-	if redirect == "" {
-		redirect = setting.AppSubURL + "/"
-	}
-
-	ctx.JSONRedirect(redirect)
+	handleSignInFull(ctx, user, remember)
+	ctx.JSONRedirect(consumeAuthRedirectLink(ctx))
 }
 
 // WebAuthnLoginAssertion submits a WebAuthn challenge to the browser
@@ -274,11 +270,7 @@ func WebAuthnLoginAssertionPost(ctx *context.Context) {
 	}
 
 	remember := ctx.Session.Get("twofaRemember").(bool)
-	redirect := handleSignInFull(ctx, user, remember, false)
-	if redirect == "" {
-		redirect = setting.AppSubURL + "/"
-	}
+	handleSignInFull(ctx, user, remember)
 	_ = ctx.Session.Delete("twofaUid")
-
-	ctx.JSONRedirect(redirect)
+	ctx.JSONRedirect(consumeAuthRedirectLink(ctx))
 }

routers/web/repo/issue_view.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"math/big"
 	"net/http"
-	"net/url"
 	"sort"
 	"strconv"
 
@@ -33,6 +32,7 @@ import (
 	"code.gitea.io/gitea/modules/templates"
 	"code.gitea.io/gitea/modules/templates/vars"
 	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/modules/web/middleware"
 	asymkey_service "code.gitea.io/gitea/services/asymkey"
 	"code.gitea.io/gitea/services/context"
 	"code.gitea.io/gitea/services/context/upload"
@@ -408,7 +408,7 @@ func ViewIssue(ctx *context.Context) {
 	}
 
 	ctx.Data["Reference"] = issue.Ref
-	ctx.Data["SignInLink"] = setting.AppSubURL + "/user/login?redirect_to=" + url.QueryEscape(ctx.Data["Link"].(string))
+	ctx.Data["SignInLink"] = middleware.RedirectLinkUserLogin(ctx.Req)
 	ctx.Data["IsIssuePoster"] = ctx.IsSigned && issue.IsPoster(ctx.Doer.ID)
 	ctx.Data["HasIssuesOrPullsWritePermission"] = ctx.Repo.CanWriteIssuesOrPulls(issue.IsPull)
 	ctx.Data["HasProjectsWritePermission"] = ctx.Repo.CanWrite(unit.TypeProjects)

routers/web/web.go

@@ -159,9 +159,7 @@ func verifyAuthWithOptions(options *common.VerifyOptions) func(ctx *context.Cont
 					}
 					ctx.Data["Title"] = ctx.Tr("auth.must_change_password")
 					ctx.Data["ChangePasscodeLink"] = setting.AppSubURL + "/user/change_password"
-					if ctx.Req.URL.Path != "/user/events" {
-						middleware.SetRedirectToCookie(ctx.Resp, setting.AppSubURL+ctx.Req.URL.RequestURI())
-					}
+					middleware.SetRedirectToCookie(ctx.Resp, setting.AppSubURL+ctx.Req.URL.RequestURI())
 					ctx.Redirect(setting.AppSubURL + "/user/settings/change_password")
 					return
 				}
@@ -172,7 +170,7 @@ func verifyAuthWithOptions(options *common.VerifyOptions) func(ctx *context.Cont
 			}
 		}
 
-		// Redirect to dashboard (or alternate location) if user tries to visit any non-login page.
+		// When a signed-in user visits a page that requires sign-out (e.g.: "/user/login"), redirect to home (or alternate location)
 		if options.SignOutRequired && ctx.IsSigned && ctx.Req.URL.RequestURI() != "/" {
 			ctx.RedirectToCurrentSite(ctx.FormString("redirect_to"))
 			return
@@ -187,10 +185,7 @@ func verifyAuthWithOptions(options *common.VerifyOptions) func(ctx *context.Cont
 
 		if options.SignInRequired {
 			if !ctx.IsSigned {
-				if ctx.Req.URL.Path != "/user/events" {
-					middleware.SetRedirectToCookie(ctx.Resp, setting.AppSubURL+ctx.Req.URL.RequestURI())
-				}
-				ctx.Redirect(setting.AppSubURL + "/user/login")
+				ctx.Redirect(middleware.RedirectLinkUserLogin(ctx.Req))
 				return
 			} else if !ctx.Doer.IsActive && setting.Service.RegisterEmailConfirm {
 				ctx.Data["Title"] = ctx.Tr("auth.active_your_account")
@@ -200,12 +195,8 @@ func verifyAuthWithOptions(options *common.VerifyOptions) func(ctx *context.Cont
 		}
 
 		// Redirect to log in page if auto-signin info is provided and has not signed in.
-		if !options.SignOutRequired && !ctx.IsSigned &&
-			ctx.GetSiteCookie(setting.CookieRememberName) != "" {
-			if ctx.Req.URL.Path != "/user/events" {
-				middleware.SetRedirectToCookie(ctx.Resp, setting.AppSubURL+ctx.Req.URL.RequestURI())
-			}
-			ctx.Redirect(setting.AppSubURL + "/user/login")
+		if !options.SignOutRequired && !ctx.IsSigned && ctx.GetSiteCookie(setting.CookieRememberName) != "" {
+			ctx.Redirect(middleware.RedirectLinkUserLogin(ctx.Req))
 			return
 		}