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=-18.8 required=3.0 tests=BAYES_00,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, 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 3BB02C433DB for ; Fri, 15 Jan 2021 12:33:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4DDC2388B for ; Fri, 15 Jan 2021 12:33:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733196AbhAOMdc (ORCPT ); Fri, 15 Jan 2021 07:33:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:39656 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733147AbhAOMd0 (ORCPT ); Fri, 15 Jan 2021 07:33:26 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id B88DC23359; Fri, 15 Jan 2021 12:33:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610713991; bh=NV5wkySH4VnUgK2tzF+GQZE4gy+uyLRbMXb4TMmlVpg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i7bA25RyK5/UZHBONB7ijhbIJWv+LthNoNb6bwYAQuaZVeE4ZHWNRT2gi7VNhkk6P pAKGczvBSqF2wfko1KrpdJDswDfIdiXunFLd2cvmhtNYB3FQEXm6LZ0yOSiP97errK WA/FpMs1cCs23+Jz2AtShSfi1CV1ZEM/DmsFFMQ0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+825f0f9657d4e528046e@syzkaller.appspotmail.com, Ming Lei , Christoph Hellwig , Jens Axboe Subject: [PATCH 4.19 41/43] block: fix use-after-free in disk_part_iter_next Date: Fri, 15 Jan 2021 13:28:11 +0100 Message-Id: <20210115121959.034428248@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210115121957.037407908@linuxfoundation.org> References: <20210115121957.037407908@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ming Lei commit aebf5db917055b38f4945ed6d621d9f07a44ff30 upstream. 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 Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/genhd.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/block/genhd.c +++ b/block/genhd.c @@ -208,14 +208,17 @@ struct hd_struct *disk_part_iter_next(st part = rcu_dereference(ptbl->part[piter->idx]); if (!part) continue; + get_device(part_to_dev(part)); + piter->part = part; if (!part_nr_sects_read(part) && !(piter->flags & DISK_PITER_INCL_EMPTY) && !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 && - piter->idx == 0)) + piter->idx == 0)) { + put_device(part_to_dev(part)); + piter->part = NULL; continue; + } - get_device(part_to_dev(part)); - piter->part = part; piter->idx += inc; break; }