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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 35980C77B7E for ; Mon, 29 May 2023 08:21:17 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q3Y7D-0002Al-Pb; Mon, 29 May 2023 04:20:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q3Y74-00028B-W2; Mon, 29 May 2023 04:20:24 -0400 Received: from forwardcorp1b.mail.yandex.net ([178.154.239.136]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q3Y72-0005GK-73; Mon, 29 May 2023 04:20:22 -0400 Received: from mail-nwsmtp-smtp-corp-main-11.iva.yp-c.yandex.net (mail-nwsmtp-smtp-corp-main-11.iva.yp-c.yandex.net [IPv6:2a02:6b8:c0c:2c24:0:640:73f8:0]) by forwardcorp1b.mail.yandex.net (Yandex) with ESMTP id 6CBAF61C9E; Mon, 29 May 2023 11:20:05 +0300 (MSK) Received: from [IPV6:2a02:6b8:b081:b64e::1:1e] (unknown [2a02:6b8:b081:b64e::1:1e]) by mail-nwsmtp-smtp-corp-main-11.iva.yp-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id 4KGdqb3OiuQ0-93o4kUbD; Mon, 29 May 2023 11:20:04 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1685348404; bh=5Es5aQg6q6Y9kWAHLD6oIucR0bhhTYv8B4eWte4O4Wc=; h=From:In-Reply-To:Cc:Date:References:To:Subject:Message-ID; b=Ys1FvufMA88SvRyp/nRTW43vsl3ugagSzm+3KqraO3FDDvpE7g722A79nmZphgsYo oGk45skKowUFNKmo60Sy8kGd5fDEHsQlVv0RXMJZ3v5hWICdWyhlRdBo1PPdRtHTMw qi0XAYUc2WBQEGEOvWGlGRuvoTy12sLfVAFA2+Us= Authentication-Results: mail-nwsmtp-smtp-corp-main-11.iva.yp-c.yandex.net; dkim=pass header.i=@yandex-team.ru Message-ID: Date: Mon, 29 May 2023 11:20:09 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH v3 01/14] nbd/client: Use smarter assert To: Eric Blake , qemu-devel@nongnu.org Cc: libguestfs@redhat.com, "Dr . David Alan Gilbert" , "open list:Network Block Dev..." References: <20230515195343.1915857-1-eblake@redhat.com> <20230515195343.1915857-2-eblake@redhat.com> Content-Language: en-US From: Vladimir Sementsov-Ogievskiy In-Reply-To: <20230515195343.1915857-2-eblake@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=178.154.239.136; envelope-from=vsementsov@yandex-team.ru; helo=forwardcorp1b.mail.yandex.net X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.093, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 15.05.23 22:53, Eric Blake wrote: > Assigning strlen() to a uint32_t and then asserting that it isn't too > large doesn't catch the case of an input string 4G in length. > Thankfully, the incoming strings can never be that large: if the > export name or query is reflecting a string the client got from the > server, we already guarantee that we dropped the NBD connection if the > server sent more than 32M in a single reply to our NBD_OPT_* request; > if the export name is coming from qemu, nbd_receive_negotiate() > asserted that strlen(info->name) <= NBD_MAX_STRING_SIZE; and > similarly, a query string via x->dirty_bitmap coming from the user was > bounds-checked in either qemu-nbd or by the limitations of QMP. > Still, it doesn't hurt to be more explicit in how we write our > assertions to not have to analyze whether inadvertent wraparound is > possible. > > Fixes: 93676c88 ("nbd: Don't send oversize strings", v4.2.0) > Reported-by: Dr. David Alan Gilbert > Signed-off-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy -- Best regards, Vladimir