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=-3.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 62B8AC433E1 for ; Tue, 26 May 2020 07:19:33 +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 22EBC2053B for ; Tue, 26 May 2020 07:19:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YULifFV2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 22EBC2053B 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]:36304 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jdTs4-00017R-AG for qemu-devel@archiver.kernel.org; Tue, 26 May 2020 03:19:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40904) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jdTrS-0000gy-GA for qemu-devel@nongnu.org; Tue, 26 May 2020 03:18:55 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:30863 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jdTrP-0003zD-25 for qemu-devel@nongnu.org; Tue, 26 May 2020 03:18:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590477528; 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=gmP9Y6PwbL3kpkvdhk7OEI6yLuh+MLADB97Xb2BGvQ0=; b=YULifFV2Vh0/I39YMjc0HuijSCT27cVhcDGdEKQM9Dy1GbC55rHwPj1ShVaadIC364BlKf PCbC4IBkJRkvUB7yS+7MSTAPzoxX4mBNJjMwL7Vq8Jwr4VvyFMjeX4XHU2M5fyNzn0XxY8 0HHkxu9mvg7Sdhvecy3a2uwSbmevucs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-148-TnF5FoCWOSOlAfO65OwGwg-1; Tue, 26 May 2020 03:18:44 -0400 X-MC-Unique: TnF5FoCWOSOlAfO65OwGwg-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5D9931005512; Tue, 26 May 2020 07:18:43 +0000 (UTC) Received: from kaapi (unknown [10.74.8.233]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 125E579C35; Tue, 26 May 2020 07:18:31 +0000 (UTC) Date: Tue, 26 May 2020 12:48:25 +0530 (IST) From: P J P X-X-Sender: pjp@kaapi To: Paolo Bonzini Subject: Re: [PATCH v2 2/3] megasas: avoid NULL pointer dereference In-Reply-To: Message-ID: References: <20200513192540.1583887-1-ppandit@redhat.com> <20200513192540.1583887-3-ppandit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Received-SPF: pass client-ip=205.139.110.61; envelope-from=ppandit@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/26 01:14:47 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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=-0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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 , QEMU Developers , Alexander Bulekov , Ding Ren , =?ISO-8859-15?Q?Marc-Andr=E9_Lureau?= , =?ISO-8859-15?Q?Philippe_Mathieu-Daud=E9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hello, +-- On Thu, 21 May 2020, Paolo Bonzini wrote --+ | I think the code here was expecting frame_size_p to be 0 if cmd->frame is | NULL. Can you check why this is not the case, or whether it ever was the | case? static MegasasCmd *megasas_enqueue_frame(MegasasState *s, hwaddr frame, ... int frame_size = MEGASAS_MAX_SGE * sizeof(union mfi_sgl); hwaddr frame_size_p = frame_size; <== = 128 * 16 = 2048 so 'frame_size_p' always starts with value '2048' ... cmd->frame = pci_dma_map(pcid, frame, &frame_size_p, 0); -> pci_dma_map -> dma_memory_map -> address_space_map mr = flatview_translate(fv, addr, &xlat, &l, is_write, attrs); ... if (atomic_xchg(&bounce.in_use, true)) { return NULL; <== NULL is returned from here } Later when address_space_map() returns 'NULL' above, '*plen' is not set to zero. diff --git a/exec.c b/exec.c index 5162f0d12f..4eea84bf66 100644 --- a/exec.c +++ b/exec.c @@ -3538,6 +3538,7 @@ void *address_space_map(AddressSpace *as, if (!memory_access_is_direct(mr, is_write)) { if (atomic_xchg(&bounce.in_use, true)) { + *plen = 0; return NULL; } I'll send a revised patch above. Thank you. -- Prasad J Pandit / Red Hat Product Security Team 8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D