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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 27D5BC3F35A for ; Thu, 27 Feb 2020 13:52:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F23522469F for ; Thu, 27 Feb 2020 13:52:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811534; bh=4PA2FXlDRYSxZN4Qkmz16p9cSWxza+zkjDl4XotCPrs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=M1C5dMzuFWVFifRt6CyAnY+jclp7G1OVvCEvpKPmhgAIShHREi5+1USLpceSIfiLC I0k3MaAjHX9r6saiIQUKwnUl7D7hoQpRIQM6CG6BOY8rZ9W4dEVo88S1Vu+ldYvN4P REFFyOVkKh372yM4yaY/zN/oEvxZPBblJHX9ulTU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730937AbgB0NwM (ORCPT ); Thu, 27 Feb 2020 08:52:12 -0500 Received: from mail.kernel.org ([198.145.29.99]:51634 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731491AbgB0NwL (ORCPT ); Thu, 27 Feb 2020 08:52:11 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 349952084E; Thu, 27 Feb 2020 13:52:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811530; bh=4PA2FXlDRYSxZN4Qkmz16p9cSWxza+zkjDl4XotCPrs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0gDO4EhZ5bHnXU1zDMmmfLSop9ZvIUqvDweHh4GOLGf1g4RSFm3AxTo/GPR7HBiFu JB1Ng4OIrH8u7VhkZcdWrw2BMrd9hkVOQ4fAqQIAAgoWg/LYwCyW9g3ZJ/4VdrVlh2 flzUZBQ6UDkZDtVIQW38yHDB+MjNGauglWyoVId4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Borislav Petkov Subject: [PATCH 4.9 130/165] x86/mce/amd: Fix kobject lifetime Date: Thu, 27 Feb 2020 14:36:44 +0100 Message-Id: <20200227132250.007861889@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132230.840899170@linuxfoundation.org> References: <20200227132230.840899170@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Thomas Gleixner commit 51dede9c05df2b78acd6dcf6a17d21f0877d2d7b upstream. Accessing the MCA thresholding controls in sysfs concurrently with CPU hotplug can lead to a couple of KASAN-reported issues: BUG: KASAN: use-after-free in sysfs_file_ops+0x155/0x180 Read of size 8 at addr ffff888367578940 by task grep/4019 and BUG: KASAN: use-after-free in show_error_count+0x15c/0x180 Read of size 2 at addr ffff888368a05514 by task grep/4454 for example. Both result from the fact that the threshold block creation/teardown code frees the descriptor memory itself instead of defining proper ->release function and leaving it to the driver core to take care of that, after all sysfs accesses have completed. Do that and get rid of the custom freeing code, fixing the above UAFs in the process. [ bp: write commit message. ] Fixes: 95268664390b ("[PATCH] x86_64: mce_amd support for family 0x10 processors") Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Cc: Link: https://lkml.kernel.org/r/20200214082801.13836-1-bp@alien8.de Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/mcheck/mce_amd.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c @@ -846,9 +846,12 @@ static const struct sysfs_ops threshold_ .store = store, }; +static void threshold_block_release(struct kobject *kobj); + static struct kobj_type threshold_ktype = { .sysfs_ops = &threshold_ops, .default_attrs = default_attrs, + .release = threshold_block_release, }; static const char *get_name(unsigned int bank, struct threshold_block *b) @@ -1073,8 +1076,12 @@ static int threshold_create_device(unsig return err; } -static void deallocate_threshold_block(unsigned int cpu, - unsigned int bank) +static void threshold_block_release(struct kobject *kobj) +{ + kfree(to_block(kobj)); +} + +static void deallocate_threshold_block(unsigned int cpu, unsigned int bank) { struct threshold_block *pos = NULL; struct threshold_block *tmp = NULL; @@ -1084,13 +1091,11 @@ static void deallocate_threshold_block(u return; list_for_each_entry_safe(pos, tmp, &head->blocks->miscj, miscj) { - kobject_put(&pos->kobj); list_del(&pos->miscj); - kfree(pos); + kobject_put(&pos->kobj); } - kfree(per_cpu(threshold_banks, cpu)[bank]->blocks); - per_cpu(threshold_banks, cpu)[bank]->blocks = NULL; + kobject_put(&head->blocks->kobj); } static void __threshold_remove_blocks(struct threshold_bank *b)