From patchwork Fri Jan 15 12:27:45 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: 364523 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=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 8D066C4332B for ; Fri, 15 Jan 2021 13:09:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B9DD2256F for ; Fri, 15 Jan 2021 13:09:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732145AbhAOMan (ORCPT ); Fri, 15 Jan 2021 07:30:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:36296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732134AbhAOMal (ORCPT ); Fri, 15 Jan 2021 07:30:41 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 06F0723339; Fri, 15 Jan 2021 12:29:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610713775; bh=LMQDJL6IMoGr4gmCyC0xciArqURJfZSJriojVS7m+jU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AApCyUqLLrzvylDMP0zP0240m5vatLD013emKmmr9jVz3Komm9kDbtAQSr7VDW+6Z 7o/X8sv1c6yq1k8S0AnNBrQ17Es9QVG9Vz0Oq9PaiONymEC3DVUiH7HpJnte07CGSb QNIv0O6OsqnYDcbRFCc1vR1QWxTn8A9RUslwKEWw= 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 4.4 17/18] block: fix use-after-free in disk_part_iter_next Date: Fri, 15 Jan 2021 13:27:45 +0100 Message-Id: <20210115121955.957022131@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210115121955.112329537@linuxfoundation.org> References: <20210115121955.112329537@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 @@ -158,14 +158,17 @@ 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; }