From nobody Sat Apr 11 11:05:20 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77580C19F2A for ; Thu, 11 Aug 2022 14:49:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234973AbiHKOtR (ORCPT ); Thu, 11 Aug 2022 10:49:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229594AbiHKOtP (ORCPT ); Thu, 11 Aug 2022 10:49:15 -0400 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B1FC90802 for ; Thu, 11 Aug 2022 07:49:13 -0700 (PDT) Received: from localhost.localdomain (unknown [83.149.199.65]) by mail.ispras.ru (Postfix) with ESMTPS id BD73640D403E; Thu, 11 Aug 2022 14:49:10 +0000 (UTC) From: Andrey Strachuk To: Maarten Lankhorst Cc: Andrey Strachuk , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Geert Uytterhoeven , Helge Deller , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org Subject: [PATCH v2] drm/fb-helper: add virtual screen size check to drm_fb_helper_check_var() Date: Thu, 11 Aug 2022 17:48:50 +0300 Message-Id: <20220811144850.215377-1-strochuk@ispras.ru> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add virtual screen size check to drm_fb_helper_check_var() in order to validate userspace input. Found by Linux Verification Center (linuxtesting.org) with syzkaller. Signed-off-by: Andrey Strachuk Fixes: 785b93ef8c30 ("drm/kms: move driver specific fb common code to helpe= r functions (v2)") Reviewed-by: Geert Uytterhoeven --- drivers/gpu/drm/drm_fb_helper.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helpe= r.c index 2d4cee6a10ff..5c8b211769eb 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -1355,6 +1355,12 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo= *var, (drm_format_info_block_height(fb->format, 0) > 1)) return -EINVAL; =20 + /* verify that virtual resolution >=3D physical resolution */ + if (var->xres_virtual < var->xres) + var->xres_virtual =3D var->xres; + if (var->yres_virtual < var->yres) + var->yres_virtual =3D var->yres; + /* * Changes struct fb_var_screeninfo are currently not pushed back * to KMS, hence fail if different settings are requested. --=20 2.25.1