From patchwork Mon Dec 21 04:33:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 346599 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=-15.8 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, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 C8539C433DB for ; Mon, 21 Dec 2020 04:35:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E9B322CB2 for ; Mon, 21 Dec 2020 04:35:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726601AbgLUEfT (ORCPT ); Sun, 20 Dec 2020 23:35:19 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:39797 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725308AbgLUEfS (ORCPT ); Sun, 20 Dec 2020 23:35:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608525233; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=lZM3RNwmwWP54uqTbzBkqorYuZ8rgPl/4mZufV9L+F8=; b=EP7muUfrs0mBA3Kd7AwI6tNPKyhHhzoE7VhtENJk1P0GIYmtDpaSz8DuChC0UWAkcJWOmT vQ40dUiKJsJs9s69ImYfCYiYsLT683kZ+2K3UrAavaJYbgNh3sy1Tebv9JxbXrFPMrK9Av F0YRH9gqEfm4q4hUHb4oyFRDk94DOf4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-69-al7_xAzLP8yLWtMjbiG1vA-1; Sun, 20 Dec 2020 23:33:48 -0500 X-MC-Unique: al7_xAzLP8yLWtMjbiG1vA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 507C959; Mon, 21 Dec 2020 04:33:47 +0000 (UTC) Received: from localhost (ovpn-13-38.pek2.redhat.com [10.72.13.38]) by smtp.corp.redhat.com (Postfix) with ESMTP id CAF7160938; Mon, 21 Dec 2020 04:33:42 +0000 (UTC) From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , Ming Lei , stable@vger.kernel.org, syzbot+825f0f9657d4e528046e@syzkaller.appspotmail.com Subject: [PATCH] block: fix use-after-free in disk_part_iter_next Date: Mon, 21 Dec 2020 12:33:35 +0800 Message-Id: <20201221043335.2831589-1-ming.lei@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Make sure that bdgrab() is done on the 'block_device' instance before referring to it for avoiding use-after-free. Cc: Reported-by: syzbot+825f0f9657d4e528046e@syzkaller.appspotmail.com Signed-off-by: Ming Lei Reviewed-by: Christoph Hellwig --- block/genhd.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index b84b8671e627..2df3c5b1c9c8 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -244,15 +244,18 @@ struct block_device *disk_part_iter_next(struct disk_part_iter *piter) part = rcu_dereference(ptbl->part[piter->idx]); if (!part) continue; + piter->part = bdgrab(part); + if (!piter->part) + continue; if (!bdev_nr_sectors(part) && !(piter->flags & DISK_PITER_INCL_EMPTY) && !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 && - piter->idx == 0)) + piter->idx == 0)) { + bdput(piter->part); + piter->part = NULL; continue; + } - piter->part = bdgrab(part); - if (!piter->part) - continue; piter->idx += inc; break; }