From patchwork Wed May 8 22:02:08 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Colin King X-Patchwork-Id: 10936541 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C7F67912 for ; Wed, 8 May 2019 22:02:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B1B3428A11 for ; Wed, 8 May 2019 22:02:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B023628A26; Wed, 8 May 2019 22:02:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 32ACD28A1D for ; Wed, 8 May 2019 22:02:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728648AbfEHWCL (ORCPT ); Wed, 8 May 2019 18:02:11 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:53933 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726837AbfEHWCL (ORCPT ); Wed, 8 May 2019 18:02:11 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1hOUdc-0007yV-Eg; Wed, 08 May 2019 22:02:08 +0000 From: Colin King To: Josef Bacik , Jens Axboe , linux-block@vger.kernel.org, nbd@other.debian.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] nbd: add null check on dev_list to avoid potential null pointer dereference Date: Wed, 8 May 2019 23:02:08 +0100 Message-Id: <20190508220208.26146-1-colin.king@canonical.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Colin Ian King The call to nla_nest_start_noflag can return a null pointer and currently this is not being checked and this can lead to a null pointer dereference when the null pointer dev_list is passed to function nla_nest_end. Fix this by adding in a null pointer check. Addresses-Coverity: ("Dereference null return value") Fixes: 47d902b90a32 ("nbd: add a status netlink command") Signed-off-by: Colin Ian King --- drivers/block/nbd.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 053958a8a2ba..ed263963e778 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -2117,6 +2117,10 @@ static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info) } dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST); + if (!dev_list) { + nlmsg_free(reply); + goto out; + } if (index == -1) { ret = idr_for_each(&nbd_index_idr, &status_cb, reply); if (ret) {