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=-19.1 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_NONE, 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 55A0CC433ED for ; Thu, 20 May 2021 11:25:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3AFA9613E5 for ; Thu, 20 May 2021 11:25:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241335AbhETL1D (ORCPT ); Thu, 20 May 2021 07:27:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:47834 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239999AbhETLG4 (ORCPT ); Thu, 20 May 2021 07:06:56 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3975661D30; Thu, 20 May 2021 10:05:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621505143; bh=Sz6EOdc7yV52bDWQgKlyk4LCblp+4sumZFTP9xmgSn8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CLDSbpXgBX+d99fx3U4ygjrB03lftueVMXA7dhwSeOxcAhDwbHCsmcfkNS7CQ3iJk MnS+9Y75Q4me2Covx1HuByLwGJJv7Wfq2OFcvfxPRcZN4FJoi72bAbdezS4WDcF/Go nSishVS5kqqvfGsnosBc0S67CfYxnF/aAeM6+VZc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mikulas Patocka , Dan Carpenter , Mike Snitzer , Nobuhiro Iwamatsu Subject: [PATCH 4.9 220/240] dm ioctl: fix out of bounds array access when no devices Date: Thu, 20 May 2021 11:23:32 +0200 Message-Id: <20210520092116.089755523@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092108.587553970@linuxfoundation.org> References: <20210520092108.587553970@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: Mikulas Patocka commit 4edbe1d7bcffcd6269f3b5eb63f710393ff2ec7a upstream. If there are not any dm devices, we need to zero the "dev" argument in the first structure dm_name_list. However, this can cause out of bounds write, because the "needed" variable is zero and len may be less than eight. Fix this bug by reporting DM_BUFFER_FULL_FLAG if the result buffer is too small to hold the "nl->dev" value. Signed-off-by: Mikulas Patocka Reported-by: Dan Carpenter Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer [iwamatsu: Adjust context] Signed-off-by: Nobuhiro Iwamatsu Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-ioctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -524,7 +524,7 @@ static int list_devices(struct dm_ioctl * Grab our output buffer. */ nl = get_result_buffer(param, param_size, &len); - if (len < needed) { + if (len < needed || len < sizeof(nl->dev)) { param->flags |= DM_BUFFER_FULL_FLAG; goto out; }