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=unavailable 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 2179BC52D54 for ; Thu, 27 Feb 2020 14:09:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA32D24691 for ; Thu, 27 Feb 2020 14:09:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812543; bh=EbQDuUGt0WEfjAtVVoBBJSO/K69KsAREfIwf2SmiYVY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=PCh/uvHQpNtkDLaxuSCIcVlf/3kY7XRyI10ONsHCFgogWOVunvGiuqMsKUV1twVW1 fnudpoZtVolYyBXQK+zungm/Gqxst4CKAijLOZ7CjgIai3hB1HFb2DxCnFVxaX1CYu 9tPaYRf3kDGGxQ/XPVzXyxIifBpLuGG0MdquxiS8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388326AbgB0OJC (ORCPT ); Thu, 27 Feb 2020 09:09:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:46760 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388306AbgB0OIy (ORCPT ); Thu, 27 Feb 2020 09:08:54 -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 35F4624656; Thu, 27 Feb 2020 14:08:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582812533; bh=EbQDuUGt0WEfjAtVVoBBJSO/K69KsAREfIwf2SmiYVY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ioNomucrVndTs29P44OC1kaRWxy/tDwdlGiqTgJjbGYd9Wi+VvaWX8nlh9S8L+qd8 yThcCe6TSm5QDqWVVpxcf+kfOhUrGOR2oIN0BkN0Hm7Jy6MRQAUWH4bbFwO/ccr8E8 zKZ0UNn4DSSKuZDsfuVnhbnvV3gA5zsLjqPcBQ5Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Borislav Petkov Subject: [PATCH 5.4 053/135] x86/mce/amd: Fix kobject lifetime Date: Thu, 27 Feb 2020 14:36:33 +0100 Message-Id: <20200227132237.110616024@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132228.710492098@linuxfoundation.org> References: <20200227132228.710492098@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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/mce/amd.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) --- a/arch/x86/kernel/cpu/mce/amd.c +++ b/arch/x86/kernel/cpu/mce/amd.c @@ -1161,9 +1161,12 @@ 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) @@ -1365,8 +1368,12 @@ static int threshold_create_bank(unsigne 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; @@ -1376,13 +1383,11 @@ 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)