From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CB77606A88F for ; Thu, 12 Nov 2026 12:53:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=XSa7wrsR Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xRUIX-0004Ob-De; Thu, 12 Nov 2026 07:53:01 -0500 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 1xRUIU-0004O7-TI for qemu-devel@nongnu.org; Thu, 12 Nov 2026 07:52:59 -0500 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 1xRUIT-0000uM-Bt for qemu-devel@nongnu.org; Thu, 12 Nov 2026 07:52:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1794487976; 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=U63rO2VyuXrLmUGjVFO3QADGaD6C20+QctHvzcSRH30=; b=XSa7wrsRiyoVFSy2dW6tbc/sfciKUmxJHZzFEClP1fCVxhlcE74rvi9CEzTW2EN+2oj4vv /K8KebFjVMQMGgqxUU7fq2Ib5t/oBg9w5BT5S1DgCT5gST2PhgjLx4TWzC7/kGU8eEwNLU AUv8uFpj20wwe7vDBtwrTNHWA8x6Sx8= 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-447-H4ym9genNBiJ9EpS_a0DHA-1; Thu, 12 Nov 2026 07:52:55 -0500 X-MC-Unique: H4ym9genNBiJ9EpS_a0DHA-1 X-Mimecast-MFC-AGG-ID: H4ym9genNBiJ9EpS_a0DHA_1794487974 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (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 D09171891FA0; Thu, 12 Nov 2026 12:52:47 +0000 (UTC) Received: from redhat.com (unknown [10.44.32.60]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2487618004FF; Thu, 12 Nov 2026 12:52:45 +0000 (UTC) Date: Thu, 12 Nov 2026 13:52:43 +0100 From: Kevin Wolf To: Thomas Huth Cc: qemu-devel@nongnu.org, Hanna Reitz , qemu-block@nongnu.org Subject: Re: [PATCH] block/vhdx-log: Improve sanity checks to avoid OOB accesses with bad images Message-ID: References: <20261111150659.253918-1-thuth@redhat.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261111150659.253918-1-thuth@redhat.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 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: qemu development List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Am 11.11.2026 um 16:06 hat Thomas Huth geschrieben: > The multiplication "hdr->descriptor_count * sizeof(VHDXLogDescriptor)" in > vhdx_log_hdr_is_valid() can overflow on 32-bit systems, so this function > could mark bad images as valid when the truncated result is smaller than > hdr->entry_length. Switch to a division on the right hand side instead to > avoid the overflow problems. > > The second problem is in vhdx_log_read_desc(): desc_sectors is a 32-bit > value, thus the multiplication "desc_sectors * VHDX_LOG_SECTOR_SIZE" is > also done with 32 bit arithmetics, and the result is used as "size_t" > parameter for qemu_try_blockalign(), i.e. the parameter here is also > only 32 bits on 32-bit systems. Let's add a sanity check here to avoid > the overflow problem that could lead to trouble later. > > Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3860 > Signed-off-by: Thomas Huth Thanks, applied to the block branch. Kevin