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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 1F20FC5DF63 for ; Wed, 6 Nov 2019 22:04:46 +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 E41E92173E for ; Wed, 6 Nov 2019 22:04:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E41E92173E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35504 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSTPw-0007qd-TZ for qemu-devel@archiver.kernel.org; Wed, 06 Nov 2019 17:04:44 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:58689) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iSTNC-0006CO-0h for qemu-devel@nongnu.org; Wed, 06 Nov 2019 17:01:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iSTN9-0000ym-NW for qemu-devel@nongnu.org; Wed, 06 Nov 2019 17:01:53 -0500 Received: from mail-lj1-f196.google.com ([209.85.208.196]:46934) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1iSTN5-0000r0-Jp; Wed, 06 Nov 2019 17:01:49 -0500 Received: by mail-lj1-f196.google.com with SMTP id e9so14632386ljp.13; Wed, 06 Nov 2019 14:01:46 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:reply-to:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=10Ig8AwXMLBYpUHj1k4mvqSlSkrplfJnIascRvTVn0Y=; b=fz+6VHPxgeNIo4wGhXASbyPhjSM0vWvTLP1u5ntPBgBE/rPnGh8uYx6ef5aicuPbu4 c1QXCm6V0Kmnsx2HnqpJHqT4ivFwfSDf8GM7uDvOz8Fau4E8ZSnCzuY1CBL4pf1qab4V jTGOnqXxEkaqP28v2Zw2f7wk5VC5QsEfKEyt0qpHLA6IrFQz+W3PIpgtui3GRQDdTr98 MjqHpxXW4GGwYEYHYjwTCZuZW1a9NlMjaQdRifXkyCPjmfyRfaUYfjfLFLzGO2PRHU4R QYWhPufNFE+w5JSrTQMXqN6C9t4gpWocp9B+zy0S3ihraxLsNL6Ph/qUJ/J/SOIRg4wj 55Ug== X-Gm-Message-State: APjAAAXndSlVzePhvgiuDjRPbbLhVqQEkqSl8ebI0zM+QBWFuMmTa9KE Mh2OfePx5hts5KaU13vI9l8= X-Google-Smtp-Source: APXvYqwELuqykBMNTwHn+q968z02vn3Rt3FQKLaKJqRCnd/kv7mmPSmFQSmqKhS2Bn7UcEF+oq96dQ== X-Received: by 2002:a2e:3016:: with SMTP id w22mr3600747ljw.117.1573077705065; Wed, 06 Nov 2019 14:01:45 -0800 (PST) Received: from [10.9.0.22] ([46.166.128.205]) by smtp.gmail.com with ESMTPSA id q26sm23660lfo.65.2019.11.06.14.01.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 06 Nov 2019 14:01:43 -0800 (PST) Subject: Re: [QEMU-SECURITY] ide: fix assertion in ide_dma_cb() to prevent qemu DoS from quest To: "Michael S. Tsirkin" References: <1562335669-10127-1-git-send-email-alex.popov@linux.com> <20191106070530-mutt-send-email-mst@kernel.org> From: Alexander Popov Autocrypt: addr=alex.popov@linux.com; prefer-encrypt=mutual; keydata= mQINBFX15q4BEADZartsIW3sQ9R+9TOuCFRIW+RDCoBWNHhqDLu+Tzf2mZevVSF0D5AMJW4f UB1QigxOuGIeSngfmgLspdYe2Kl8+P8qyfrnBcS4hLFyLGjaP7UVGtpUl7CUxz2Hct3yhsPz ID/rnCSd0Q+3thrJTq44b2kIKqM1swt/F2Er5Bl0B4o5WKx4J9k6Dz7bAMjKD8pHZJnScoP4 dzKPhrytN/iWM01eRZRc1TcIdVsRZC3hcVE6OtFoamaYmePDwWTRhmDtWYngbRDVGe3Tl8bT 7BYN7gv7Ikt7Nq2T2TOfXEQqr9CtidxBNsqFEaajbFvpLDpUPw692+4lUbQ7FL0B1WYLvWkG cVysClEyX3VBSMzIG5eTF0Dng9RqItUxpbD317ihKqYL95jk6eK6XyI8wVOCEa1V3MhtvzUo WGZVkwm9eMVZ05GbhzmT7KHBEBbCkihS+TpVxOgzvuV+heCEaaxIDWY/k8u4tgbrVVk+tIVG 99v1//kNLqd5KuwY1Y2/h2MhRrfxqGz+l/f/qghKh+1iptm6McN//1nNaIbzXQ2Ej34jeWDa xAN1C1OANOyV7mYuYPNDl5c9QrbcNGg3D6gOeGeGiMn11NjbjHae3ipH8MkX7/k8pH5q4Lhh Ra0vtJspeg77CS4b7+WC5jlK3UAKoUja3kGgkCrnfNkvKjrkEwARAQABtCZBbGV4YW5kZXIg UG9wb3YgPGFsZXgucG9wb3ZAbGludXguY29tPokCVwQTAQgAQQIbIwIeAQIXgAULCQgHAwUV CgkICwUWAgMBAAIZARYhBLl2JLAkAVM0bVvWTo4Oneu8fo+qBQJdehKcBQkLRpLuAAoJEI4O neu8fo+qrkgP/jS0EhDnWhIFBnWaUKYWeiwR69DPwCs/lNezOu63vg30O9BViEkWsWwXQA+c SVVTz5f9eB9K2me7G06A3U5AblOJKdoZeNX5GWMdrrGNLVISsa0geXNT95TRnFqE1HOZJiHT NFyw2nv+qQBUHBAKPlk3eL4/Yev/P8w990Aiiv6/RN3IoxqTfSu2tBKdQqdxTjEJ7KLBlQBm 5oMpm/P2Y/gtBiXRvBd7xgv7Y3nShPUDymjBnc+efHFqARw84VQPIG4nqVhIei8gSWps49DX kp6v4wUzUAqFo+eh/ErWmyBNETuufpxZnAljtnKpwmpFCcq9yfcMlyOO9/viKn14grabE7qE 4j3/E60wraHu8uiXJlfXmt0vG16vXb8g5a25Ck09UKkXRGkNTylXsAmRbrBrA3Moqf8QzIk9 p+aVu/vFUs4ywQrFNvn7Qwt2hWctastQJcH3jrrLk7oGLvue5KOThip0SNicnOxVhCqstjYx KEnzZxtna5+rYRg22Zbfg0sCAAEGOWFXjqg3hw400oRxTW7IhiE34Kz1wHQqNif0i5Eor+TS 22r9iF4jUSnk1jaVeRKOXY89KxzxWhnA06m8IvW1VySHoY1ZG6xEZLmbp3OuuFCbleaW07OU 9L8L1Gh1rkAz0Fc9eOR8a2HLVFnemmgAYTJqBks/sB/DD0SuuQINBFX15q4BEACtxRV/pF1P XiGSbTNPlM9z/cElzo/ICCFX+IKg+byRvOMoEgrzQ28ah0N5RXQydBtfjSOMV1IjSb3oc23z oW2J9DefC5b8G1Lx2Tz6VqRFXC5OAxuElaZeoowV1VEJuN3Ittlal0+KnRYY0PqnmLzTXGA9 GYjw/p7l7iME7gLHVOggXIk7MP+O+1tSEf23n+dopQZrkEP2BKSC6ihdU4W8928pApxrX1Lt tv2HOPJKHrcfiqVuFSsb/skaFf4uveAPC4AausUhXQVpXIg8ZnxTZ+MsqlwELv+Vkm/SNEWl n0KMd58gvG3s0bE8H2GTaIO3a0TqNKUY16WgNglRUi0WYb7+CLNrYqteYMQUqX7+bB+NEj/4 8dHw+xxaIHtLXOGxW6zcPGFszaYArjGaYfiTTA1+AKWHRKvD3MJTYIonphy5EuL9EACLKjEF v3CdK5BLkqTGhPfYtE3B/Ix3CUS1Aala0L+8EjXdclVpvHQ5qXHs229EJxfUVf2ucpWNIUdf lgnjyF4B3R3BFWbM4Yv8QbLBvVv1Dc4hZ70QUXy2ZZX8keza2EzPj3apMcDmmbklSwdC5kYG EFT4ap06R2QW+6Nw27jDtbK4QhMEUCHmoOIaS9j0VTU4fR9ZCpVT/ksc2LPMhg3YqNTrnb1v RVNUZvh78zQeCXC2VamSl9DMcwARAQABiQI8BBgBCAAmAhsMFiEEuXYksCQBUzRtW9ZOjg6d 67x+j6oFAl16ErcFCQtGkwkACgkQjg6d67x+j6q7zA/+IsjSKSJypgOImN9LYjeb++7wDjXp qvEpq56oAn21CvtbGus3OcC0hrRtyZ/rC5Qc+S5SPaMRFUaK8S3j1vYC0wZJ99rrmQbcbYMh C2o0k4pSejaINmgyCajVOhUhln4IuwvZke1CLfXe1i3ZtlaIUrxfXqfYpeijfM/JSmliPxwW BRnQRcgS85xpC1pBUMrraxajaVPwu7hCTke03v6bu8zSZlgA1rd9E6KHu2VNS46VzUPjbR77 kO7u6H5PgQPKcuJwQQ+d3qa+5ZeKmoVkc2SuHVrCd1yKtAMmKBoJtSku1evXPwyBzqHFOInk mLMtrWuUhj+wtcnOWxaP+n4ODgUwc/uvyuamo0L2Gp3V5ItdIUDO/7ZpZ/3JxvERF3Yc1md8 5kfflpLzpxyl2fKaRdvxr48ZLv9XLUQ4qNuADDmJArq/+foORAX4BBFWvqZQKe8a9ZMAvGSh uoGUVg4Ks0uC4IeG7iNtd+csmBj5dNf91C7zV4bsKt0JjiJ9a4D85dtCOPmOeNuusK7xaDZc gzBW8J8RW+nUJcTpudX4TC2SGeAOyxnM5O4XJ8yZyDUY334seDRJWtS4wRHxpfYcHKTewR96 IsP1USE+9ndu6lrMXQ3aFsd1n1m1pfa/y8hiqsSYHy7JQ9Iuo9DxysOj22UNOmOE+OYPK48D j3lCqPk= Message-ID: <0de2309d-a913-b962-f6aa-1b03ee16dc03@linux.com> Date: Thu, 7 Nov 2019 01:01:40 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191106070530-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.85.208.196 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: , Reply-To: alex.popov@linux.com Cc: Andrea Arcangeli , sstabellini@kernel.org, pmatouse@redhat.com, mdroth@linux.vnet.ibm.com, qemu-block@nongnu.org, qemu-devel@nongnu.org, qemu-stable@nongnu.org, Kashyap Chamarthy , Paolo Bonzini , John Snow , pjp@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 06.11.2019 15:08, Michael S. Tsirkin wrote: > On Wed, Nov 06, 2019 at 01:17:51PM +0300, Alexander Popov wrote: >> On 27.07.2019 00:09, Alexander Popov wrote: >>> On 26.07.2019 2:25:03 GMT+02:00, John Snow wrote: >>>> Oh, this is fun. >>> ... >>>> I can worry about a proper fix for 4.2+. >>> >>> Hello John, >>> >>> Thanks for your letter. >>> >>> I double-checked the git history and mailing list, I'm still sure >>> that my fix for this assertion is correct. >> >> Hello! >> >> I'm pointing politely to this issue again. >> >> It crashes qemu during syzkaller fuzzing. >> >> It's really annoying to manually apply the fix against it to qemu. > > I understand. Maybe the fuzzer can be taught to skip the > specific issue for now? Michael, thanks for your reply. Yes, of course. You just forbid the fuzzer to use /dev/sg in the guest. But I would rather fix the issue. -- Best regards, Alexander