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 lists1p.gnu.org (lists1p.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 17299C43458 for ; Tue, 14 Jul 2026 10:31:45 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wjaQE-0000AX-1S; Tue, 14 Jul 2026 06:31:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wjaQC-0000A1-3Q for qemu-devel@nongnu.org; Tue, 14 Jul 2026 06:31:28 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wjaQA-0000Nn-Cr for qemu-devel@nongnu.org; Tue, 14 Jul 2026 06:31:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784025084; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=V56KDeHPvSnP+RbpyDQRLpcZSniVoMZLvEDFxm2UFHU=; b=bPO2Dwwf/exGsfN0rxZMF+6V0JqGgjZwvqAkxt0mN1BpbgWHfBrGMmdLM4UkyF6YLD6CZQ 5zmvbk3b1miYqFzYnfYoKtaopZFHmGkXTvcCXm0xrnrTuDEQ9Voe14b9GLSIv8r2pYAkMa RikqraR8Mxpgp5kBD+gOhLMm1IBaraA= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-471-qp3sk66iO-iAscefXPuUcQ-1; Tue, 14 Jul 2026 06:31:20 -0400 X-MC-Unique: qp3sk66iO-iAscefXPuUcQ-1 X-Mimecast-MFC-AGG-ID: qp3sk66iO-iAscefXPuUcQ_1784025079 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EA3071800370; Tue, 14 Jul 2026 10:31:18 +0000 (UTC) Received: from redhat.com (unknown [10.44.33.162]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CDF9CD6E; Tue, 14 Jul 2026 10:31:16 +0000 (UTC) Date: Tue, 14 Jul 2026 12:31:14 +0200 From: Kevin Wolf To: malike Cc: qemu-devel@nongnu.org, stefanha@redhat.com, hreitz@redhat.com, qemu-block@nongnu.org Subject: Re: [PATCH] block/cloop: fix integer overflow in total_sectors calculation Message-ID: References: <20260713031750.58448-1-malike@kylinos.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260713031750.58448-1-malike@kylinos.cn> X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 Received-SPF: permerror client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.01, SPF_HELO_PASS=-0.001, T_SPF_PERMERROR=0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development 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 Am 13.07.2026 um 05:17 hat malike geschrieben: > The total_sectors is computed as n_blocks * sectors_per_block where > both operands are uint32_t. The multiplication is performed in 32-bit > arithmetic and can overflow when the product exceeds UINT32_MAX, > producing a value much smaller than the true image size. The result > is assigned to int64_t total_sectors but the 32-bit multiplication > has already wrapped around, and the zero-extension to 64-bit does > not recover the correct value. > > This causes the block layer to reject valid I/O requests (DoS) when > the reported total_sectors is smaller than the actual image. > > Use 64-bit arithmetic by casting one operand to uint64_t so the > multiplication is performed in 64-bit precision. > > Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3972 > Signed-off-by: Ma Like Thanks, applied to the block branch. Kevin