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=-13.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 28A2DC47096 for ; Mon, 31 May 2021 08:24:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AEFD96128B for ; Mon, 31 May 2021 08:24:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230451AbhEaI0I (ORCPT ); Mon, 31 May 2021 04:26:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46456 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230422AbhEaIZu (ORCPT ); Mon, 31 May 2021 04:25:50 -0400 Received: from mail-ej1-x635.google.com (mail-ej1-x635.google.com [IPv6:2a00:1450:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 348AFC061761 for ; Mon, 31 May 2021 01:24:11 -0700 (PDT) Received: by mail-ej1-x635.google.com with SMTP id gb17so15426226ejc.8 for ; Mon, 31 May 2021 01:24:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=AMGF9A8NxX5xFp88g1oq61PA7j73RZ9YA7ACwFU1V+Y=; b=t/b9iXIrxu/JhKkcetsLcVbf2g4krNVZWx3+IVeEMFw0sT4uEsCq2s1mb1rXSouKd5 8vGX9l9EoyWU23XlOf6fbpTGEKT244+RAxx0pkIALHCSijxRIfLq+I/0vorhbC4LzH7c bsCW4UE+tho2K+PD0vu71vAeCOJOAIuPKtxqhH7g46apcPDd81Te5nAJVySLXax9PSzu B1GbsPIFOeR8m0t506LH1nMU04VAF4SQ4/9BJdTlq+rcNOjZlFo0imU8nBfv6LVe5W2i ZiIkppTZCx+QLvL+HmbmWN8taFPbZoND8j5ze+Zc+pAaxBSseBUdjkgiM4177f/51gNZ mZ0Q== 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=AMGF9A8NxX5xFp88g1oq61PA7j73RZ9YA7ACwFU1V+Y=; b=s40B3bH0D+2ZXNBKrdciSIWuHC8N1DL+70Gj+Yux4KZfjIpqr/ILsFNjBHIeEug1M8 WlfWLGZKIqdC8syaUMkT089Dpyd89Z9avFQ5UrGnTiHG0apLTQhr+UDUDuceDmSvX5Ya 0vNQ8RyiHv/uThzmmm3oNIYZqiRi62b8PkCWY7M7QK+mHMfBOQiby4rmPGYHVl9bpd5f 1u2liQ8ZB28F/DC9ArP+7vSmz1lcY27GcrS4TjAllUuIzhncwQdBvG6SqybtQ9VfSaXM gOKEUZsWbkGlvqIBE9HvLLtitOK+yp+FqUEXbeH+6LythU9f+I2X8jHF/jL8Hsw2H/J7 6Qeg== X-Gm-Message-State: AOAM530WUMQvLzY3Mgw7wxnkKQBe6WNHC6FDa7qKqXUlYSsQOuY0NrJZ h4bg8tOYHrBSw+HMcrojEzxs4eMC/sFI2TzMcEwj X-Google-Smtp-Source: ABdhPJyLXTMInE0lOUyC+YYVTDrsstRUXgMnU1e7dlRtQMym/NrAjnWfJ0HslXQMiem1oFI8/USmGvJadwSNN/fSxw4= X-Received: by 2002:a17:906:318b:: with SMTP id 11mr21157495ejy.395.1622449449822; Mon, 31 May 2021 01:24:09 -0700 (PDT) MIME-Version: 1.0 References: <20210528121157.105-1-xieyongji@bytedance.com> <49ab3d41-c5d8-a49d-3ff4-28ebfdba0181@redhat.com> <4ff90e78-0c7a-def6-ef84-367bcce4cea5@redhat.com> In-Reply-To: <4ff90e78-0c7a-def6-ef84-367bcce4cea5@redhat.com> From: Yongji Xie Date: Mon, 31 May 2021 16:23:59 +0800 Message-ID: Subject: Re: Re: [PATCH v3] virtio-net: Add validation for used length To: Jason Wang Cc: "Michael S. Tsirkin" , Jakub Kicinski , virtualization , netdev@vger.kernel.org, linux-kernel Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 31, 2021 at 3:51 PM Jason Wang wrote: > > > =E5=9C=A8 2021/5/31 =E4=B8=8B=E5=8D=883:19, Yongji Xie =E5=86=99=E9=81=93= : > > On Mon, May 31, 2021 at 2:49 PM Jason Wang wrote: > >> > >> =E5=9C=A8 2021/5/28 =E4=B8=8B=E5=8D=888:11, Xie Yongji =E5=86=99=E9=81= =93: > >>> This adds validation for used length (might come > >>> from an untrusted device) to avoid data corruption > >>> or loss. > >>> > >>> Signed-off-by: Xie Yongji > >>> --- > >>> drivers/net/virtio_net.c | 28 +++++++++++++++++++++------- > >>> 1 file changed, 21 insertions(+), 7 deletions(-) > >>> > >>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > >>> index 073fec4c0df1..01f15b65824c 100644 > >>> --- a/drivers/net/virtio_net.c > >>> +++ b/drivers/net/virtio_net.c > >>> @@ -732,6 +732,17 @@ static struct sk_buff *receive_small(struct net_= device *dev, > >>> > >>> rcu_read_lock(); > >>> xdp_prog =3D rcu_dereference(rq->xdp_prog); > >>> + if (unlikely(len > GOOD_PACKET_LEN)) { > >>> + pr_debug("%s: rx error: len %u exceeds max size %d\n", > >>> + dev->name, len, GOOD_PACKET_LEN); > >>> + dev->stats.rx_length_errors++; > >>> + if (xdp_prog) > >>> + goto err_xdp; > >>> + > >>> + rcu_read_unlock(); > >>> + put_page(page); > >>> + return NULL; > >>> + } > >>> if (xdp_prog) { > >>> struct virtio_net_hdr_mrg_rxbuf *hdr =3D buf + header_= offset; > >>> struct xdp_frame *xdpf; > >>> @@ -888,6 +899,16 @@ static struct sk_buff *receive_mergeable(struct = net_device *dev, > >>> > >>> rcu_read_lock(); > >>> xdp_prog =3D rcu_dereference(rq->xdp_prog); > >>> + if (unlikely(len > truesize)) { > >>> + pr_debug("%s: rx error: len %u exceeds truesize %lu\n", > >>> + dev->name, len, (unsigned long)ctx); > >>> + dev->stats.rx_length_errors++; > >>> + if (xdp_prog) > >>> + goto err_xdp; > >>> + > >>> + rcu_read_unlock(); > >>> + goto err_skb; > >>> + } > >> > >> Patch looks correct but I'd rather not bother XDP here. It would be > >> better if we just do the check before rcu_read_lock() and use err_skb > >> directly() to avoid RCU/XDP stuffs. > >> > > If so, we will miss the statistics of xdp_drops. Is it OK? > > > It should be ok, we still had drops and it was dropped before dealing > with XDP. > > The motivation is to have simple codes. > OK, will send v4 soon. Thanks, Yongji