From mboxrd@z Thu Jan 1 00:00:00 1970 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 E25D0C54EBE for ; Tue, 20 Dec 2022 01:25:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233317AbiLTBZH (ORCPT ); Mon, 19 Dec 2022 20:25:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52484 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233199AbiLTBWj (ORCPT ); Mon, 19 Dec 2022 20:22:39 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7588165AD; Mon, 19 Dec 2022 17:21:51 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 5374DCE1147; Tue, 20 Dec 2022 01:21:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D4A0C433F1; Tue, 20 Dec 2022 01:21:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671499308; bh=NEUP6zN9OADZm5zNxMnUdUs2DJSQYC2jc+XVsX3Rf54=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JYbqeKVbha+Btq2UEggh2M++N0GDyzlSSy0TFB8j7Zx0NxaIm32b8fGsl0122GngK Pkv7SLj3h9IiJJbeqYfvWkgtHW+TzCCs33C5zSTIcGISES8Ehif2k8kS0jiRAQEz+G fvznbfXhBYVN6FKy6iyKj5nb/WY7d4lpoAa9QppeGw7KcIQJVx828nmgRQ7H/n7Z4Q DWd3EQNCy4HuZEhc5XqgQs4wjxM0XkSLAbQLiO3juZT3zCKv4HlQX+Cknt+atXJrlq cCMpaZ2aejWW5/cYrI3JJc1HjM7gDBe18W/alGKUfhWelQzqBYverwrJp9exwsK42n 0MzQkvIMWHB9g== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nathan Chancellor , Sami Tolvanen , Kees Cook , Sasha Levin , stefan@agner.ch, alison.wang@nxp.com, airlied@gmail.com, daniel@ffwll.ch, ndesaulniers@google.com, dri-devel@lists.freedesktop.org, llvm@lists.linux.dev Subject: [PATCH AUTOSEL 6.0 10/16] drm/fsl-dcu: Fix return type of fsl_dcu_drm_connector_mode_valid() Date: Mon, 19 Dec 2022 20:21:20 -0500 Message-Id: <20221220012127.1222311-10-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221220012127.1222311-1-sashal@kernel.org> References: <20221220012127.1222311-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nathan Chancellor [ Upstream commit 96d845a67b7e406cfed7880a724c8ca6121e022e ] With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG), indirect call targets are validated against the expected function pointer prototype to make sure the call target is valid to help mitigate ROP attacks. If they are not identical, there is a failure at run time, which manifests as either a kernel panic or thread getting killed. A proposed warning in clang aims to catch these at compile time, which reveals: drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c:74:16: error: incompatible function pointer types initializing 'enum drm_mode_status (*)(struct drm_connector *, struct drm_display_mode *)' with an expression of type 'int (struct drm_connector *, struct drm_display_mode *)' [-Werror,-Wincompatible-function-pointer-types-strict] .mode_valid = fsl_dcu_drm_connector_mode_valid, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 1 error generated. ->mode_valid() in 'struct drm_connector_helper_funcs' expects a return type of 'enum drm_mode_status', not 'int'. Adjust the return type of fsl_dcu_drm_connector_mode_valid() to match the prototype's to resolve the warning and CFI failure. Link: https://github.com/ClangBuiltLinux/linux/issues/1750 Reported-by: Sami Tolvanen Signed-off-by: Nathan Chancellor Reviewed-by: Kees Cook Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221102154215.78059-1-nathan@kernel.org Signed-off-by: Sasha Levin --- drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c index 4d4a715b429d..2c2b92324a2e 100644 --- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c +++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c @@ -60,8 +60,9 @@ static int fsl_dcu_drm_connector_get_modes(struct drm_connector *connector) return drm_panel_get_modes(fsl_connector->panel, connector); } -static int fsl_dcu_drm_connector_mode_valid(struct drm_connector *connector, - struct drm_display_mode *mode) +static enum drm_mode_status +fsl_dcu_drm_connector_mode_valid(struct drm_connector *connector, + struct drm_display_mode *mode) { if (mode->hdisplay & 0xf) return MODE_ERROR; -- 2.35.1