1 files changed, 172 insertions, 0 deletions
diff --git a/routers/web/auth/saml.go b/routers/web/auth/saml.go
new file mode 100644
index 0000000000..29d689d2e9
--- /dev/null
+++ b/routers/web/auth/saml.go
@@ -0,0 +1,172 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package auth
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"strings"
+
+	"code.gitea.io/gitea/models/auth"
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
+	"code.gitea.io/gitea/modules/web/middleware"
+	"code.gitea.io/gitea/services/auth/source/saml"
+	"code.gitea.io/gitea/services/externalaccount"
+
+	"github.com/markbates/goth"
+)
+
+func SignInSAML(ctx *context.Context) {
+	provider := ctx.Params(":provider")
+
+	loginSource, err := auth.GetActiveAuthSourceByName(ctx, provider, auth.SAML)
+	if err != nil || loginSource == nil {
+		ctx.NotFound("SAMLMetadata", err)
+		return
+	}
+
+	if err = loginSource.Cfg.(*saml.Source).Callout(ctx.Req, ctx.Resp); err != nil {
+		if strings.Contains(err.Error(), "no provider for ") {
+			ctx.Error(http.StatusNotFound)
+			return
+		}
+		ctx.ServerError("SignIn", err)
+	}
+}
+
+func SignInSAMLCallback(ctx *context.Context) {
+	provider := ctx.Params(":provider")
+	loginSource, err := auth.GetActiveAuthSourceByName(ctx, provider, auth.SAML)
+	if err != nil || loginSource == nil {
+		ctx.NotFound("SignInSAMLCallback", err)
+		return
+	}
+
+	if loginSource == nil {
+		ctx.ServerError("SignIn", fmt.Errorf("no valid provider found, check configured callback url in provider"))
+		return
+	}
+
+	u, gothUser, err := samlUserLoginCallback(*ctx, loginSource, ctx.Req, ctx.Resp)
+	if err != nil {
+		ctx.ServerError("SignInSAMLCallback", err)
+		return
+	}
+
+	if u == nil {
+		if ctx.Doer != nil {
+			// attach user to already logged in user
+			err = externalaccount.LinkAccountToUser(ctx, ctx.Doer, gothUser, auth.SAML)
+			if err != nil {
+				ctx.ServerError("LinkAccountToUser", err)
+				return
+			}
+
+			ctx.Redirect(setting.AppSubURL + "/user/settings/security")
+			return
+		} else if !setting.Service.AllowOnlyInternalRegistration && false {
+			// TODO: allow auto registration from saml users (OAuth2 uses the following setting.OAuth2Client.EnableAutoRegistration)
+		} else {
+			// no existing user is found, request attach or new account
+			showLinkingLogin(ctx, gothUser, auth.SAML)
+			return
+		}
+	}
+
+	handleSamlSignIn(ctx, loginSource, u, gothUser)
+}
+
+func handleSamlSignIn(ctx *context.Context, source *auth.Source, u *user_model.User, gothUser goth.User) {
+	if err := updateSession(ctx, nil, map[string]any{
+		"uid":   u.ID,
+		"uname": u.Name,
+	}); err != nil {
+		ctx.ServerError("updateSession", err)
+		return
+	}
+
+	// Clear whatever CSRF cookie has right now, force to generate a new one
+	ctx.Csrf.DeleteCookie(ctx)
+
+	// Register last login
+	u.SetLastLogin()
+
+	// update external user information
+	if err := externalaccount.UpdateExternalUser(ctx, u, gothUser, auth.SAML); err != nil {
+		if !errors.Is(err, util.ErrNotExist) {
+			log.Error("UpdateExternalUser failed: %v", err)
+		}
+	}
+
+	if err := resetLocale(ctx, u); err != nil {
+		ctx.ServerError("resetLocale", err)
+		return
+	}
+
+	if redirectTo := ctx.GetSiteCookie("redirect_to"); len(redirectTo) > 0 {
+		middleware.DeleteRedirectToCookie(ctx.Resp)
+		ctx.RedirectToFirst(redirectTo)
+		return
+	}
+
+	ctx.Redirect(setting.AppSubURL + "/")
+}
+
+func samlUserLoginCallback(ctx context.Context, authSource *auth.Source, request *http.Request, response http.ResponseWriter) (*user_model.User, goth.User, error) {
+	samlSource := authSource.Cfg.(*saml.Source)
+
+	gothUser, err := samlSource.Callback(request, response)
+	if err != nil {
+		return nil, gothUser, err
+	}
+
+	user := &user_model.User{
+		LoginName:   gothUser.UserID,
+		LoginType:   auth.SAML,
+		LoginSource: authSource.ID,
+	}
+
+	hasUser, err := user_model.GetUser(ctx, user)
+	if err != nil {
+		return nil, goth.User{}, err
+	}
+
+	if hasUser {
+		return user, gothUser, nil
+	}
+
+	// search in external linked users
+	externalLoginUser := &user_model.ExternalLoginUser{
+		ExternalID:    gothUser.UserID,
+		LoginSourceID: authSource.ID,
+	}
+	hasUser, err = user_model.GetExternalLogin(ctx, externalLoginUser)
+	if err != nil {
+		return nil, goth.User{}, err
+	}
+	if hasUser {
+		user, err = user_model.GetUserByID(request.Context(), externalLoginUser.UserID)
+		return user, gothUser, err
+	}
+
+	// no user found to login
+	return nil, gothUser, nil
+}
+
+func SAMLMetadata(ctx *context.Context) {
+	provider := ctx.Params(":provider")
+	loginSource, err := auth.GetActiveAuthSourceByName(ctx, provider, auth.SAML)
+	if err != nil || loginSource == nil {
+		ctx.NotFound("SAMLMetadata", err)
+		return
+	}
+	if err = loginSource.Cfg.(*saml.Source).Metadata(ctx.Req, ctx.Resp); err != nil {
+		ctx.ServerError("SAMLMetadata", err)
+	}
+}