From patchwork Mon Jul 12 06:09:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 476327 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-24.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD6F3C07E99 for ; Mon, 12 Jul 2021 06:22:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B87C661107 for ; Mon, 12 Jul 2021 06:22:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235430AbhGLGZO (ORCPT ); Mon, 12 Jul 2021 02:25:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:45380 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235148AbhGLGYd (ORCPT ); Mon, 12 Jul 2021 02:24:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A0B4561151; Mon, 12 Jul 2021 06:21:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626070878; bh=rNG5DcWA9KDHMgAglAzkWJWc5snz95lOb8j/k4helOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ns4VpueGZt/0Gru+if0uxQ2pKaRM1K0I2HrcgHYgLco9zaglyXYqKWQnaM+I6OMzz IGXOza5GzWO9qfyOgdP5pIlaZzKSdOe8Bw2eY0RuDxNrmjapvoiQkcwwfjy0sCELn/ n7Pq4X1GGNNlryGO+HjKlaS0GVq215W2STmovG0M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nathan Chancellor , Kees Cook , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 5.4 180/348] ACPI: bgrt: Fix CFI violation Date: Mon, 12 Jul 2021 08:09:24 +0200 Message-Id: <20210712060724.774999925@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060659.886176320@linuxfoundation.org> References: <20210712060659.886176320@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Nathan Chancellor [ Upstream commit f37ccf8fce155d08ae2a4fb3db677911ced0c21a ] clang's Control Flow Integrity requires that every indirect call has a valid target, which is based on the type of the function pointer. The *_show() functions in this file are written as if they will be called from dev_attr_show(); however, they will be called from sysfs_kf_seq_show() because the files were created by sysfs_create_group() and the sysfs ops are based on kobj_sysfs_ops because of kobject_add_and_create(). Because the *_show() functions do not match the type of the show() member in struct kobj_attribute, there is a CFI violation. $ cat /sys/firmware/acpi/bgrt/{status,type,version,{x,y}offset}} 1 0 1 522 307 $ dmesg | grep "CFI failure" [ 267.761825] CFI failure (target: type_show.d5e1ad21498a5fd14edbc5c320906598.cfi_jt+0x0/0x8): [ 267.762246] CFI failure (target: xoffset_show.d5e1ad21498a5fd14edbc5c320906598.cfi_jt+0x0/0x8): [ 267.762584] CFI failure (target: status_show.d5e1ad21498a5fd14edbc5c320906598.cfi_jt+0x0/0x8): [ 267.762973] CFI failure (target: yoffset_show.d5e1ad21498a5fd14edbc5c320906598.cfi_jt+0x0/0x8): [ 267.763330] CFI failure (target: version_show.d5e1ad21498a5fd14edbc5c320906598.cfi_jt+0x0/0x8): Convert these functions to the type of the show() member in struct kobj_attribute so that there is no more CFI violation. Because these functions are all so similar, combine them into a macro. Fixes: d1ff4b1cdbab ("ACPI: Add support for exposing BGRT data") Link: https://github.com/ClangBuiltLinux/linux/issues/1406 Signed-off-by: Nathan Chancellor Reviewed-by: Kees Cook Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/acpi/bgrt.c | 57 ++++++++++++++------------------------------- 1 file changed, 18 insertions(+), 39 deletions(-) diff --git a/drivers/acpi/bgrt.c b/drivers/acpi/bgrt.c index 19bb7f870204..e0d14017706e 100644 --- a/drivers/acpi/bgrt.c +++ b/drivers/acpi/bgrt.c @@ -15,40 +15,19 @@ static void *bgrt_image; static struct kobject *bgrt_kobj; -static ssize_t version_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.version); -} -static DEVICE_ATTR_RO(version); - -static ssize_t status_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.status); -} -static DEVICE_ATTR_RO(status); - -static ssize_t type_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_type); -} -static DEVICE_ATTR_RO(type); - -static ssize_t xoffset_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_x); -} -static DEVICE_ATTR_RO(xoffset); - -static ssize_t yoffset_show(struct device *dev, - struct device_attribute *attr, char *buf) -{ - return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_y); -} -static DEVICE_ATTR_RO(yoffset); +#define BGRT_SHOW(_name, _member) \ + static ssize_t _name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ + { \ + return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab._member); \ + } \ + struct kobj_attribute bgrt_attr_##_name = __ATTR_RO(_name) + +BGRT_SHOW(version, version); +BGRT_SHOW(status, status); +BGRT_SHOW(type, image_type); +BGRT_SHOW(xoffset, image_offset_x); +BGRT_SHOW(yoffset, image_offset_y); static ssize_t image_read(struct file *file, struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t off, size_t count) @@ -60,11 +39,11 @@ static ssize_t image_read(struct file *file, struct kobject *kobj, static BIN_ATTR_RO(image, 0); /* size gets filled in later */ static struct attribute *bgrt_attributes[] = { - &dev_attr_version.attr, - &dev_attr_status.attr, - &dev_attr_type.attr, - &dev_attr_xoffset.attr, - &dev_attr_yoffset.attr, + &bgrt_attr_version.attr, + &bgrt_attr_status.attr, + &bgrt_attr_type.attr, + &bgrt_attr_xoffset.attr, + &bgrt_attr_yoffset.attr, NULL, };