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=-9.8 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 D6BA1C433E0 for ; Fri, 17 Jul 2020 04:48:08 +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 9E05120759 for ; Fri, 17 Jul 2020 04:48:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QHdTXXHV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9E05120759 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34504 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jwII3-00041q-Sf for qemu-devel@archiver.kernel.org; Fri, 17 Jul 2020 00:48:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45860) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jwIHP-0003Ja-6L for qemu-devel@nongnu.org; Fri, 17 Jul 2020 00:47:27 -0400 Received: from mail-oi1-x241.google.com ([2607:f8b0:4864:20::241]:44175) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jwIHN-00084U-A6 for qemu-devel@nongnu.org; Fri, 17 Jul 2020 00:47:26 -0400 Received: by mail-oi1-x241.google.com with SMTP id k6so6992059oij.11 for ; Thu, 16 Jul 2020 21:47:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=0/foZzYkMGzDzriQ1t2QMrr1pQ8f72oFP6E6FFnsXVQ=; b=QHdTXXHVa8Y3OBK0stLe/yDb5cLaZGplwblMpo0uxQXb/B2LJgrKPe6ehbGZkviBlz GgNMOj6cPdUz3nq8oPe4TT3D0a7Ef2YSmIFvNxpAWGc4XK0gpbQDdq6hN1Jvt9kOMt/+ 1ItAvW2yOz9Uoq5M9wVwDs6bRQTsN3CdwYKGj3LLpufzsap3Ck2Cx6roY2ujqVkW9Rmb cZvKXM9/bBiXXMY8mqcotiO+bt8FGJ3uRzER01zgPk4ZpEOs+hhp1GfoDBm6/fskghsl BhgktKdbSBjvRt+gNKZlUtz0b0UiomVkrhSeZ/BtPhywMg1ch54/2EIqDbpm5C7Q4OG6 wdww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=0/foZzYkMGzDzriQ1t2QMrr1pQ8f72oFP6E6FFnsXVQ=; b=oGk8jfaKCLKpi3hqF2uRQa1jmU2tfYhSHz+RZJ0zpqwzyiwSxYbEf/JuW4FFqNaAHX aorrPzxuHewvjuGQ51rje1BUnF0HQLBX1vx+sUj6FJ2ofR5kPGipQd2aefkWQEKy6BHs qjyU1eCYNUApj2PB34nMvuN1E/jQIdoTVmeILx7Ju+gc+D0/uZS39qIt0GyLrouEm4Dq C7HqYNXdI4Gj+lLVo6hEDvZ/Uub6MR5ou3n4eNLLR7k7JKcStsr44uE3/5NFlsBAtNLz F8g4WmSCpiK49Djx7WBxot5rbkR62YqI8kJnQD6XK7VkekNmYVtOe98VUz39uUAjiC0N EVCg== X-Gm-Message-State: AOAM532QjpvwgNKPs2ozEpZVh2gmVcA5hMiqrXNLG2G9ySaUf1dlsQUR eo8X/AmUw8+i+FTV2fn2l8DUwNYVtJ8YE6MazhE= X-Google-Smtp-Source: ABdhPJyMqAyaoo0jzePpb7zaYSYgXMWMuKbj9R4D+VlPyiuL/Mt3pEJoxGfhxxtJFP3AKiH5NOs+Cd6qJioicbLoIkU= X-Received: by 2002:a05:6808:486:: with SMTP id z6mr6580640oid.56.1594961244006; Thu, 16 Jul 2020 21:47:24 -0700 (PDT) MIME-Version: 1.0 References: <20200716161453.61295-1-liq3ea@163.com> <281e3c85-b8eb-0c3e-afc3-41011861b8ea@redhat.com> In-Reply-To: <281e3c85-b8eb-0c3e-afc3-41011861b8ea@redhat.com> From: Li Qiang Date: Fri, 17 Jul 2020 12:46:48 +0800 Message-ID: Subject: Re: [PATCH] e1000e: using bottom half to send packets To: Jason Wang Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2607:f8b0:4864:20::241; envelope-from=liq3ea@gmail.com; helo=mail-oi1-x241.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , Dmitry Fleytman , Li Qiang , Qemu Developers , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Jason Wang =E4=BA=8E2020=E5=B9=B47=E6=9C=8817=E6=97= =A5=E5=91=A8=E4=BA=94 =E4=B8=8A=E5=8D=8811:10=E5=86=99=E9=81=93=EF=BC=9A > > > On 2020/7/17 =E4=B8=8A=E5=8D=8812:14, Li Qiang wrote: > > Alexander Bulekov reported a UAF bug related e1000e packets send. > > > > -->https://bugs.launchpad.net/qemu/+bug/1886362 > > > > This is because the guest trigger a e1000e packet send and set the > > data's address to e1000e's MMIO address. So when the e1000e do DMA > > it will write the MMIO again and trigger re-entrancy and finally > > causes this UAF. > > > > Paolo suggested to use a bottom half whenever MMIO is doing complicate > > things in here: > > -->https://lists.nongnu.org/archive/html/qemu-devel/2020-07/msg03342.ht= ml > > > > Reference here: > > 'The easiest solution is to delay processing of descriptors to a bottom > > half whenever MMIO is doing something complicated. This is also better > > for latency because it will free the vCPU thread more quickly and leave > > the work to the I/O thread.' > > > I think several things were missed in this patch (take virtio-net as a > reference), do we need the following things: > Thanks Jason, In fact I know this, I'm scared for touching this but I want to try. Thanks for your advice. > - Cancel the bh when VM is stopped. Ok. I think add a vm state change notifier for e1000e can address this. > - A throttle to prevent bh from executing too much timer? Ok, I think add a config timeout and add a timer in e1000e can address this= . > - A flag to record whether or not this a pending tx (and migrate it?) Is just a flag enough? Could you explain more about the idea behind processing the virtio-net/e1000e using bh like this? For example, if the guest trigger a lot of packets send and if the bh is scheduled in IO thread. So will we lost packets? How we avoid this in virtio-net. Thanks, Li Qiang > > Thanks > > > > > > This patch fixes this UAF. > > > > Signed-off-by: Li Qiang > > --- > > hw/net/e1000e_core.c | 25 +++++++++++++++++-------- > > hw/net/e1000e_core.h | 2 ++ > > 2 files changed, 19 insertions(+), 8 deletions(-) > > > > diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c > > index bcd186cac5..6165b04b68 100644 > > --- a/hw/net/e1000e_core.c > > +++ b/hw/net/e1000e_core.c > > @@ -2423,32 +2423,27 @@ e1000e_set_dbal(E1000ECore *core, int index, ui= nt32_t val) > > static void > > e1000e_set_tctl(E1000ECore *core, int index, uint32_t val) > > { > > - E1000E_TxRing txr; > > core->mac[index] =3D val; > > > > if (core->mac[TARC0] & E1000_TARC_ENABLE) { > > - e1000e_tx_ring_init(core, &txr, 0); > > - e1000e_start_xmit(core, &txr); > > + qemu_bh_schedule(core->tx[0].tx_bh); > > } > > > > if (core->mac[TARC1] & E1000_TARC_ENABLE) { > > - e1000e_tx_ring_init(core, &txr, 1); > > - e1000e_start_xmit(core, &txr); > > + qemu_bh_schedule(core->tx[1].tx_bh); > > } > > } > > > > static void > > e1000e_set_tdt(E1000ECore *core, int index, uint32_t val) > > { > > - E1000E_TxRing txr; > > int qidx =3D e1000e_mq_queue_idx(TDT, index); > > uint32_t tarc_reg =3D (qidx =3D=3D 0) ? TARC0 : TARC1; > > > > core->mac[index] =3D val & 0xffff; > > > > if (core->mac[tarc_reg] & E1000_TARC_ENABLE) { > > - e1000e_tx_ring_init(core, &txr, qidx); > > - e1000e_start_xmit(core, &txr); > > + qemu_bh_schedule(core->tx[qidx].tx_bh); > > } > > } > > > > @@ -3322,6 +3317,16 @@ e1000e_vm_state_change(void *opaque, int running= , RunState state) > > } > > } > > > > +static void e1000e_core_tx_bh(void *opaque) > > +{ > > + struct e1000e_tx *tx =3D opaque; > > + E1000ECore *core =3D tx->core; > > + E1000E_TxRing txr; > > + > > + e1000e_tx_ring_init(core, &txr, tx - &core->tx[0]); > > + e1000e_start_xmit(core, &txr); > > +} > > + > > void > > e1000e_core_pci_realize(E1000ECore *core, > > const uint16_t *eeprom_templ, > > @@ -3340,6 +3345,8 @@ e1000e_core_pci_realize(E1000ECore *core, > > for (i =3D 0; i < E1000E_NUM_QUEUES; i++) { > > net_tx_pkt_init(&core->tx[i].tx_pkt, core->owner, > > E1000E_MAX_TX_FRAGS, core->has_vnet); > > + core->tx[i].core =3D core; > > + core->tx[i].tx_bh =3D qemu_bh_new(e1000e_core_tx_bh, &core->tx= [i]); > > } > > > > net_rx_pkt_init(&core->rx_pkt, core->has_vnet); > > @@ -3367,6 +3374,8 @@ e1000e_core_pci_uninit(E1000ECore *core) > > for (i =3D 0; i < E1000E_NUM_QUEUES; i++) { > > net_tx_pkt_reset(core->tx[i].tx_pkt); > > net_tx_pkt_uninit(core->tx[i].tx_pkt); > > + qemu_bh_delete(core->tx[i].tx_bh); > > + core->tx[i].tx_bh =3D NULL; > > } > > > > net_rx_pkt_uninit(core->rx_pkt); > > diff --git a/hw/net/e1000e_core.h b/hw/net/e1000e_core.h > > index aee32f7e48..94ddc6afc2 100644 > > --- a/hw/net/e1000e_core.h > > +++ b/hw/net/e1000e_core.h > > @@ -77,6 +77,8 @@ struct E1000Core { > > unsigned char sum_needed; > > bool cptse; > > struct NetTxPkt *tx_pkt; > > + QEMUBH *tx_bh; > > + E1000ECore *core; > > } tx[E1000E_NUM_QUEUES]; > > > > struct NetRxPkt *rx_pkt; >