Validate language

Author: 6543

options/locale/locale_en-US.ini

@@ -440,6 +440,7 @@ website = Website
 location = Location
 update_theme = Update Theme
 update_profile = Update Profile
+update_language_not_found = Language '%s' is not available.
 update_profile_success = Your profile has been updated.
 change_username = Your username has been changed.
 change_username_prompt = Note: username changes also change your account URL.

routers/user/setting/profile.go

@@ -19,6 +19,7 @@ import (
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/util"
 
 	"github.com/unknwon/i18n"
 )
@@ -94,8 +95,12 @@ func ProfilePost(ctx *context.Context, form auth.UpdateProfileForm) {
 	ctx.User.KeepEmailPrivate = form.KeepEmailPrivate
 	ctx.User.Website = form.Website
 	ctx.User.Location = form.Location
-	if len(form.Language) == 5 {
-		// TODO: check if lang code is valide
+	if len(form.Language) != 0 {
+		if !util.IsStringInSlice(form.Language, setting.Langs) {
+			ctx.Flash.Error(ctx.Tr("settings.update_language_not_found", form.Language))
+			ctx.Redirect(setting.AppSubURL + "/user/settings")
+			return
+		}
 		ctx.User.Language = form.Language
 	}
 	ctx.User.Description = form.Description