From patchwork Thu Nov 9 13:58:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 1862062 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4SR3bQ5Wh3z1yRQ for ; Fri, 10 Nov 2023 01:04:02 +1100 (AEDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r15bg-0001Zk-32; Thu, 09 Nov 2023 09:02:04 -0500 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 1r15aH-0005rk-5o; Thu, 09 Nov 2023 09:00:38 -0500 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1r15a5-0005qU-V1; Thu, 09 Nov 2023 09:00:36 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 156B631BC3; Thu, 9 Nov 2023 16:59:42 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id 20289344FC; Thu, 9 Nov 2023 16:59:34 +0300 (MSK) Received: (nullmailer pid 1462794 invoked by uid 1000); Thu, 09 Nov 2023 13:59:33 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Thomas Huth , Paolo Bonzini , Michael Tokarev Subject: [Stable-7.2.7 13/62] hw/scsi/scsi-disk: Disallow block sizes smaller than 512 [CVE-2023-42467] Date: Thu, 9 Nov 2023 16:58:41 +0300 Message-Id: <20231109135933.1462615-13-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Thomas Huth We are doing things like nb_sectors /= (s->qdev.blocksize / BDRV_SECTOR_SIZE); in the code here (e.g. in scsi_disk_emulate_mode_sense()), so if the blocksize is smaller than BDRV_SECTOR_SIZE (=512), this crashes with a division by 0 exception. Thus disallow block sizes of 256 bytes to avoid this situation. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1813 CVE: 2023-42467 Signed-off-by: Thomas Huth Message-ID: <20230925091854.49198-1-thuth@redhat.com> Signed-off-by: Paolo Bonzini (cherry picked from commit 7cfcc79b0ab800959716738aff9419f53fc68c9c) Signed-off-by: Michael Tokarev diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c index e493c28814..915e0369cb 100644 --- a/hw/scsi/scsi-disk.c +++ b/hw/scsi/scsi-disk.c @@ -1624,9 +1624,10 @@ static void scsi_disk_emulate_mode_select(SCSIDiskReq *r, uint8_t *inbuf) * Since the existing code only checks/updates bits 8-15 of the block * size, restrict ourselves to the same requirement for now to ensure * that a block size set by a block descriptor and then read back by - * a subsequent SCSI command will be the same + * a subsequent SCSI command will be the same. Also disallow a block + * size of 256 since we cannot handle anything below BDRV_SECTOR_SIZE. */ - if (bs && !(bs & ~0xff00) && bs != s->qdev.blocksize) { + if (bs && !(bs & ~0xfe00) && bs != s->qdev.blocksize) { s->qdev.blocksize = bs; trace_scsi_disk_mode_select_set_blocksize(s->qdev.blocksize); }