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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id D0DE3C83F17 for ; Fri, 18 Jul 2025 08:29:34 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ucgSm-0003Q5-E2; Fri, 18 Jul 2025 04:29:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ucgSc-0003Lk-8y for qemu-devel@nongnu.org; Fri, 18 Jul 2025 04:28:54 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ucgSV-00053z-PY for qemu-devel@nongnu.org; Fri, 18 Jul 2025 04:28:52 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1752827324; 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=7kY0hUzHy+1xksL8EsYzei/AzxcaJy0QGDXDCxTluJ4=; b=cxitjrzGIA9bY+OStS9RUoZx/+l4drcfFm5rzfMo/USyrXLkDiG8Th2bHgZ4mSdM9s3u8Z ePh3giu0nMRiYZ8EJIJ9TAtbxxm4ILgMlLoEK6xeYgQBJD6l4blELfgGETHbggkYbpqXrg cmDxEuUpE6a0o+hSIR7Xbj4x4xPiyOE= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-54-hOfxkIPkOeahuO3rtSvjSQ-1; Fri, 18 Jul 2025 04:28:42 -0400 X-MC-Unique: hOfxkIPkOeahuO3rtSvjSQ-1 X-Mimecast-MFC-AGG-ID: hOfxkIPkOeahuO3rtSvjSQ_1752827321 Received: by mail-ej1-f71.google.com with SMTP id a640c23a62f3a-ae3c8477f1fso128950066b.3 for ; Fri, 18 Jul 2025 01:28:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752827321; x=1753432121; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=7kY0hUzHy+1xksL8EsYzei/AzxcaJy0QGDXDCxTluJ4=; b=GDz9vYPuXqJB16bjBaNoci4rb7paIwjlTihFBuFLcOQgoPJExbhylV5NkmEF11XXzR EmkHyCF9zgv7u4ufH48KtxdbSide/9vYT8j2b6ERjijCOuzodIyW9O4io135SNeV4Mfp +7P7FFmmiTaTrcbb4W3JkAwBgXvLTNvRwCPuMjulUpmRicLSBpn8BaqlNqu5mpJQkGQT S2KRHGjeaaIeHDY2av411Bq5/RvSOMrPtLltA1SP8rJoOJED7LlX7kBs8lgYi/REOdvJ fdvaVWJ2gUPUVocul3Vm+NCQHIudcClnO3mIFpFWPCEzpdVxP7SzUDG9F5mNferfS7MH nL0A== X-Gm-Message-State: AOJu0YzGP1RDO52YjPCCwJ/7dE+9j8e0Gq3uOy6Wq/RRQIVa+6JdDwS7 Qt1uRmk4xQYkYLTHOF8mXsJBd9LNMK72QruOFeSjZE5uuU6pUgnwS2ZQ2ADMWhY3lP/QocALloi Bd6IE0jJEbFl8/3m/4EWApnemgjbksG4QjlrEIXLOYGCwaLbetSwnRzytnRPzY158NRQ8xKOIW0 rpQrdf7Fe/QgSTSMz7esG2jcEIHahcrKk= X-Gm-Gg: ASbGnct6W5vjNI//oEqsSlQNhmIik3ih7LdAkP7EJEjmmsWgJUeGmhJnyO66s5DXVi4 y8zy7WgWKBC9rBz1g+6l5dVhTr3LzpkzrwOamryh2Cj6oP6tbvc1PbinFQXhq/uJU4VvNnyB4Xf USerWKnLtVp5Y1j7Vd12/u/Q== X-Received: by 2002:a17:907:3c83:b0:ae3:bd92:e69b with SMTP id a640c23a62f3a-ae9c99814c7mr1034236766b.7.1752827321023; Fri, 18 Jul 2025 01:28:41 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFyEZj5EJqYckVvBSu8ghamCtIGS5k89o0krQiAjPuY0CyQfCfi/XKO91VzAFrzj9hUk58en8tNwTEwkvkY+aY= X-Received: by 2002:a17:907:3c83:b0:ae3:bd92:e69b with SMTP id a640c23a62f3a-ae9c99814c7mr1034234666b.7.1752827320644; Fri, 18 Jul 2025 01:28:40 -0700 (PDT) MIME-Version: 1.0 References: <20250716072854.13403-1-vsementsov@yandex-team.ru> In-Reply-To: <20250716072854.13403-1-vsementsov@yandex-team.ru> From: Lei Yang Date: Fri, 18 Jul 2025 16:28:02 +0800 X-Gm-Features: Ac12FXyykOgvccBzN1fMtJt5A6vlz1KnOV4MqK5gM6xaArn92MJHiOAJpNTrBE4 Message-ID: Subject: Re: [PATCH v2] net/tap: drop too small packets To: Vladimir Sementsov-Ogievskiy Cc: qemu-devel@nongnu.org, jasowang@redhat.com, d-tatianin@yandex-team.ru Content-Type: multipart/alternative; boundary="000000000000cd11e3063a2fe9f2" Received-SPF: pass client-ip=170.10.133.124; envelope-from=leiyang@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --000000000000cd11e3063a2fe9f2 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Tested this patch v2 again,everything works fine. Tested-by: Lei Yang On Wed, Jul 16, 2025 at 3:29=E2=80=AFPM Vladimir Sementsov-Ogievskiy < vsementsov@yandex-team.ru> wrote: > Theoretically tap_read_packet() may return size less than > s->host_vnet_hdr_len, and next, we'll work with negative size > (in case of !s->using_vnet_hdr). Let's avoid it. > > Don't proceed with size =3D=3D s->host_vnet_hdr_len as well in case > of !s->using_vnet_hdr, it doesn't make sense. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > > v2: change "<" -> "<=3D" > > net/tap.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/net/tap.c b/net/tap.c > index 23536c09b46..2a859360193 100644 > --- a/net/tap.c > +++ b/net/tap.c > @@ -190,6 +190,11 @@ static void tap_send(void *opaque) > break; > } > > + if (s->host_vnet_hdr_len && size <=3D s->host_vnet_hdr_len) { > + /* Invalid packet */ > + break; > + } > + > if (s->host_vnet_hdr_len && !s->using_vnet_hdr) { > buf +=3D s->host_vnet_hdr_len; > size -=3D s->host_vnet_hdr_len; > -- > 2.48.1 > > --000000000000cd11e3063a2fe9f2 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Tested this patch v2 again,everything works fine.

=
Tested-by: Lei Yang <le= iyang@redhat.com>

On Wed, Jul 16, 2025 at= 3:29=E2=80=AFPM Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> wrote:
Theoretically tap_read_packet(= ) may return size less than
s->host_vnet_hdr_len, and next, we'll work with negative size
(in case of !s->using_vnet_hdr). Let's avoid it.

Don't proceed with size =3D=3D s->host_vnet_hdr_len as well in case<= br> of !s->using_vnet_hdr, it doesn't make sense.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
---

v2: change "<" -> "<=3D"

=C2=A0net/tap.c | 5 +++++
=C2=A01 file changed, 5 insertions(+)

diff --git a/net/tap.c b/net/tap.c
index 23536c09b46..2a859360193 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -190,6 +190,11 @@ static void tap_send(void *opaque)
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0break;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}

+=C2=A0 =C2=A0 =C2=A0 =C2=A0 if (s->host_vnet_hdr_len && size &l= t;=3D s->host_vnet_hdr_len) {
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 /* Invalid packet */
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 break;
+=C2=A0 =C2=A0 =C2=A0 =C2=A0 }
+
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (s->host_vnet_hdr_len && !s= ->using_vnet_hdr) {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0buf=C2=A0 +=3D s->host_v= net_hdr_len;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0size -=3D s->host_vnet_h= dr_len;
--
2.48.1

--000000000000cd11e3063a2fe9f2--