From patchwork Sat May 21 07:37:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 12857717 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6F37DC433FE for ; Sat, 21 May 2022 07:24:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354752AbiEUHYT (ORCPT ); Sat, 21 May 2022 03:24:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54912 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232990AbiEUHYQ (ORCPT ); Sat, 21 May 2022 03:24:16 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 988306CA91; Sat, 21 May 2022 00:24:15 -0700 (PDT) Received: from kwepemi100011.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4L4w6J2r3ZzgY89; Sat, 21 May 2022 15:22:48 +0800 (CST) Received: from kwepemm600009.china.huawei.com (7.193.23.164) by kwepemi100011.china.huawei.com (7.221.188.134) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 21 May 2022 15:24:13 +0800 Received: from huawei.com (10.175.127.227) by kwepemm600009.china.huawei.com (7.193.23.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 21 May 2022 15:24:13 +0800 From: Yu Kuai To: , , , CC: , , , Subject: [PATCH -next v3 5/6] nbd: fix possible overflow on 'first_minor' in nbd_dev_add() Date: Sat, 21 May 2022 15:37:48 +0800 Message-ID: <20220521073749.3146892-6-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220521073749.3146892-1-yukuai3@huawei.com> References: <20220521073749.3146892-1-yukuai3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemm600009.china.huawei.com (7.193.23.164) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Zhang Wensheng When 'index' is a big numbers, it may become negative which forced to 'int'. then 'index << part_shift' might overflow to a positive value that is not greater than '0xfffff', then sysfs might complains about duplicate creation. Because of this, move the 'index' judgment to the front will fix it and be better. Fixes: b0d9111a2d53 ("nbd: use an idr to keep track of nbd devices") Fixes: 940c264984fd ("nbd: fix possible overflow for 'first_minor' in nbd_dev_add()") Signed-off-by: Zhang Wensheng Signed-off-by: Yu Kuai Reviewed-by: Josef Bacik --- drivers/block/nbd.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index ec736cc52134..349bc3da878d 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1814,17 +1814,7 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs) refcount_set(&nbd->refs, 0); INIT_LIST_HEAD(&nbd->list); disk->major = NBD_MAJOR; - - /* Too big first_minor can cause duplicate creation of - * sysfs files/links, since index << part_shift might overflow, or - * MKDEV() expect that the max bits of first_minor is 20. - */ disk->first_minor = index << part_shift; - if (disk->first_minor < index || disk->first_minor > MINORMASK) { - err = -EINVAL; - goto out_free_work; - } - disk->minors = 1 << part_shift; disk->fops = &nbd_fops; disk->private_data = nbd; @@ -1929,8 +1919,19 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) if (!netlink_capable(skb, CAP_SYS_ADMIN)) return -EPERM; - if (info->attrs[NBD_ATTR_INDEX]) + if (info->attrs[NBD_ATTR_INDEX]) { index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); + + /* + * Too big first_minor can cause duplicate creation of + * sysfs files/links, since index << part_shift might overflow, or + * MKDEV() expect that the max bits of first_minor is 20. + */ + if (index < 0 || index > MINORMASK >> part_shift) { + printk(KERN_ERR "nbd: illegal input index %d\n", index); + return -EINVAL; + } + } if (!info->attrs[NBD_ATTR_SOCKETS]) { printk(KERN_ERR "nbd: must specify at least one socket\n"); return -EINVAL;