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[2620:137:e000::1:20]) by mx.google.com with ESMTP id q14-20020a65684e000000b0039dae8c6305si10943818pgt.471.2022.04.23.01.51.34; Sat, 23 Apr 2022 01:51:49 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232294AbiDWC4X (ORCPT + 99 others); Fri, 22 Apr 2022 22:56:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231970AbiDWC4V (ORCPT ); Fri, 22 Apr 2022 22:56:21 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D63E464714; Fri, 22 Apr 2022 19:53:25 -0700 (PDT) Received: from kwepemi500016.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4KlbS71Q0czhYFk; Sat, 23 Apr 2022 10:53:11 +0800 (CST) Received: from [10.174.176.103] (10.174.176.103) by kwepemi500016.china.huawei.com (7.221.188.220) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sat, 23 Apr 2022 10:53:22 +0800 Message-ID: Date: Sat, 23 Apr 2022 10:53:22 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH -next v2] nbd: fix possible overflow on 'first_minor' in nbd_dev_add() From: "zhangwensheng (E)" To: , CC: , , References: <20220407032505.3797948-1-zhangwensheng5@huawei.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.176.103] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemi500016.china.huawei.com (7.221.188.220) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-5.4 required=5.0 tests=BAYES_00,NICE_REPLY_A, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org friendly ping... 在 2022/4/16 14:09, zhangwensheng (E) 写道: > friendly ping... > > 在 2022/4/7 11:25, Zhang Wensheng 写道: >> 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 >> --- >> v1->v2: >> - add the line "disk->first_minor = index << part_shift;" which has >> been deleted by mistake in v1. >> >>   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 5a1f98494ddd..9448aacbcf0f 100644 >> --- a/drivers/block/nbd.c >> +++ b/drivers/block/nbd.c >> @@ -1800,17 +1800,7 @@ 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; >> @@ -1915,8 +1905,19 @@ 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; > .