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 X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,URIBL_SBL,URIBL_SBL_A autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A1A0C433FF for ; Tue, 13 Aug 2019 10:06:13 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D274020665 for ; Tue, 13 Aug 2019 10:06:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D274020665 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:50744 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hxTgx-00062v-Tl for qemu-devel@archiver.kernel.org; Tue, 13 Aug 2019 06:06:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58964) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hxTgX-0005dI-T0 for qemu-devel@nongnu.org; Tue, 13 Aug 2019 06:05:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hxTgW-0007Hk-Rg for qemu-devel@nongnu.org; Tue, 13 Aug 2019 06:05:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50832) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hxTgW-0007H6-Mc for qemu-devel@nongnu.org; Tue, 13 Aug 2019 06:05:44 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9E5547E437; Tue, 13 Aug 2019 10:05:42 +0000 (UTC) Received: from kaapi (unknown [10.33.36.9]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CE26D6E701; Tue, 13 Aug 2019 10:05:29 +0000 (UTC) Date: Tue, 13 Aug 2019 15:35:26 +0530 (IST) From: P J P X-X-Sender: pjp@kaapi To: =?ISO-8859-15?Q?Philippe_Mathieu-Daud=E9?= In-Reply-To: <20190809063835.6717-2-ppandit@redhat.com> Message-ID: References: <20190809063835.6717-1-ppandit@redhat.com> <20190809063835.6717-2-ppandit@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Tue, 13 Aug 2019 10:05:42 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v3 1/2] scsi: lsi: exit infinite loop while executing script (CVE-2019-12068) X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Fam Zheng , Marcelo Tosatti , Mark Cave-Ayland , QEMU Developers , Bugs SysSec , Paolo Bonzini , Stefano Garzarella Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" +-- On Fri, 9 Aug 2019, P J P wrote --+ | From: Prasad J Pandit | | When executing script in lsi_execute_script(), the LSI scsi | adapter emulator advances 's->dsp' index to read next opcode. | This can lead to an infinite loop if the next opcode is empty. | Exit such loop after reading 10k empty opcodes. | | Reported-by: Bugs SysSec | Signed-off-by: Prasad J Pandit | --- | hw/scsi/lsi53c895a.c | 11 ++++++++++- | 1 file changed, 10 insertions(+), 1 deletion(-) | | Update v3: raise an illegal instruction interrupt and exit | -> https://lists.gnu.org/archive/html/qemu-devel/2019-08/msg01427.html | | diff --git a/hw/scsi/lsi53c895a.c b/hw/scsi/lsi53c895a.c | index 10468c1ec1..e703ef4c9d 100644 | --- a/hw/scsi/lsi53c895a.c | +++ b/hw/scsi/lsi53c895a.c | @@ -185,6 +185,9 @@ static const char *names[] = { | /* Flag set if this is a tagged command. */ | #define LSI_TAG_VALID (1 << 16) | | +/* Maximum instructions to process. */ | +#define LSI_MAX_INSN 10000 | + | typedef struct lsi_request { | SCSIRequest *req; | uint32_t tag; | @@ -1132,7 +1135,13 @@ static void lsi_execute_script(LSIState *s) | | s->istat1 |= LSI_ISTAT1_SRUN; | again: | - insn_processed++; | + if (++insn_processed > LSI_MAX_INSN) { | + trace_lsi_execute_script_tc_illegal(); | + lsi_script_dma_interrupt(s, LSI_DSTAT_IID); | + lsi_disconnect(s); | + trace_lsi_execute_script_stop(); | + return; | + } | insn = read_dword(s, s->dsp); | if (!insn) { | /* If we receive an empty opcode increment the DSP by 4 bytes | Ping...?! -- Prasad J Pandit / Red Hat Product Security Team 47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F