Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Haiyang Zhang <haiyangz@microsoft.com>
To:     Vitaly Kuznetsov <vkuznets@redhat.com>,
        Haiyang Zhang <haiyangz@linuxonhyperv.com>
CC:     "davem@davemloft.net" <davem@davemloft.net>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        KY Srinivasan <kys@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "olaf@aepfle.de" <olaf@aepfle.de>,
        "devel@linuxdriverproject.org" <devel@linuxdriverproject.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH net-next,2/2] hv_netvsc: Add range checking for rx packet
 offset and length
Thread-Topic: [PATCH net-next,2/2] hv_netvsc: Add range checking for rx packet
 offset and length
Thread-Index: AQHTwhBc67ZwczHR5Eq1DbAW+9tjDaPd7/kWgAAAUnA=
Date:   Fri, 23 Mar 2018 15:25:48 +0000
Message-ID: <BL0PR2101MB11087DD996F43224D09E35B2CAA80@BL0PR2101MB1108.namprd21.prod.outlook.com>
References: <20180322190114.25596-1-haiyangz@linuxonhyperv.com>
        <20180322190114.25596-3-haiyangz@linuxonhyperv.com>
 <87sh8q4y9s.fsf@vitty.brq.redhat.com>
In-Reply-To: <87sh8q4y9s.fsf@vitty.brq.redhat.com>
Accept-Language: en-US
Content-Language: en-US
msip_labels: MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Enabled=True;
 MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SiteId=72f988bf-86f1-41af-91ab-2d7cd011db47;
 MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Owner=haiyangz@microsoft.com;
 MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_SetDate=2018-03-23T15:25:47.0054790Z;
 MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Name=General;
 MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Application=Microsoft Azure
 Information Protection;
 MSIP_Label_f42aa342-8706-4288-bd11-ebb85995028c_Extended_MSFT_Method=Automatic;
 Sensitivity=General
x-originating-ip: [69.130.166.81]
x-ms-publictraffictype: Email
x-microsoft-exchange-diagnostics: 1;BL0PR2101MB1121;7:IullSY0Awy4Outn3LHYmNMBuiUHOA2P1bYW4HGzlC/rXOwejqeNHUqhrnTs1o1NqSYBJrSHk4+jBJepD7jQhY7chePRf1FbyawdD6VJ4otdMBN3XtOk903VVr2BvCgNyN2mbzaeyFVF4032RmHhMXn8GPI+pq3cPOatPzwkNUmRLcqQeFSi72yJwm6jEf2fodkmbdNg1qKHDIxv6cfNdpNgMs6+Zzmsm5ydeF7YKZlK6qi4f7rgqcIZ7Ome2/Aic;20:Gm97slc+Qbc96+7D2sn2KxLaMmiRgjtyGKLrYhh2psGr39U62HsuACCtEESfMCDtKkAPnMsYnOGypgpxk0isEQqSUpBPfd0gNCup/xxaf7MiRm5zwZaqT7F5o0GN5XshN2/0p1PJR+zREXLV+gcavzFFKcY9ZROwxmF+e34U5f8=
x-ms-exchange-antispam-srfa-diagnostics: SOS;
x-ms-office365-filtering-ht: Tenant
x-ms-office365-filtering-correlation-id: e785d2c2-ca52-4966-4b02-08d590d25ab9
x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(4652020)(48565401081)(5600026)(4604075)(3008032)(4534165)(4627221)(201703031133081)(201702281549075)(2017052603328)(7193020);SRVR:BL0PR2101MB1121;
x-ms-traffictypediagnostic: BL0PR2101MB1121:
x-microsoft-antispam-prvs: <BL0PR2101MB1121CE53BA11E05A566A3E73CAA80@BL0PR2101MB1121.namprd21.prod.outlook.com>
x-exchange-antispam-report-test: UriScan:(28532068793085)(89211679590171)(9452136761055);
x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(8211001083)(61425038)(6040522)(2401047)(5005006)(8121501046)(3231221)(944501327)(52105095)(3002001)(93006095)(93001095)(10201501046)(6055026)(61426038)(61427038)(6041310)(20161123560045)(20161123558120)(20161123564045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123562045)(6072148)(201708071742011);SRVR:BL0PR2101MB1121;BCL:0;PCL:0;RULEID:;SRVR:BL0PR2101MB1121;
x-forefront-prvs: 0620CADDF3
x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(39860400002)(396003)(366004)(39380400002)(376002)(346002)(13464003)(189003)(199004)(53546011)(6506007)(33656002)(5250100002)(6346003)(102836004)(229853002)(110136005)(26005)(54906003)(186003)(10290500003)(3660700001)(68736007)(25786009)(4326008)(22452003)(316002)(97736004)(2900100001)(3846002)(6116002)(5660300001)(74316002)(8936002)(8990500004)(7696005)(86362001)(6246003)(10090500001)(478600001)(86612001)(105586002)(99286004)(76176011)(53936002)(3280700002)(55016002)(11346002)(14454004)(446003)(9686003)(6436002)(81166006)(81156014)(305945005)(8676002)(66066001)(7736002)(2906002)(106356001);DIR:OUT;SFP:1102;SCL:1;SRVR:BL0PR2101MB1121;H:BL0PR2101MB1108.namprd21.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1;
received-spf: None (protection.outlook.com: microsoft.com does not designate
 permitted sender hosts)
authentication-results: spf=none (sender IP is )
 smtp.mailfrom=haiyangz@microsoft.com; 
x-microsoft-antispam-message-info: RQNj9b7ASoKMZHiq5y+74uFoqMr1XMt+3e8EKVIa/QXpLvAfHojxOuJj04Jnc5Zwpa2eJ9l06txkelgkwnUQpP5i/scc4vD/JAu2G6wlBfXWltYgxFwiCOP/RHxqhAhJ58zuMZNM3+26rELGJP6cF420fDexO9Zf+skuR6YGKCLsVwXbmo+ahsVxjqpa1l+d/0w5PtElrs8ZP2zOakHjfrANpQvHZrXBG5Oqxy0TEVTO8QIR+oDOPYbY+C6IQW5p7JJYjP4KRNh4SrJRtFjz2HjJj5nWIg2gBKQ4UVtEFTKfZJdBNpy6QIIasBegPIHko2m+rOYcIU3EaxShUDboAQ==
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: microsoft.com
X-MS-Exchange-CrossTenant-Network-Message-Id: e785d2c2-ca52-4966-4b02-08d590d25ab9
X-MS-Exchange-CrossTenant-originalarrivaltime: 23 Mar 2018 15:25:48.1016
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL0PR2101MB1121
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


> -----Original Message-----
> From: Vitaly Kuznetsov <vkuznets@redhat.com>
> Sent: Friday, March 23, 2018 11:17 AM
> To: Haiyang Zhang <haiyangz@linuxonhyperv.com>
> Cc: davem@davemloft.net; netdev@vger.kernel.org; Haiyang Zhang
> <haiyangz@microsoft.com>; KY Srinivasan <kys@microsoft.com>; Stephen
> Hemminger <sthemmin@microsoft.com>; olaf@aepfle.de;
> devel@linuxdriverproject.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH net-next,2/2] hv_netvsc: Add range checking for rx pa=
cket
> offset and length
>=20
> Haiyang Zhang <haiyangz@linuxonhyperv.com> writes:
>=20
> > From: Haiyang Zhang <haiyangz@microsoft.com>
> >
> > This patch adds range checking for rx packet offset and length.
> > It may only happen if there is a host side bug.
> >
> > Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> > ---
> >  drivers/net/hyperv/hyperv_net.h |  1 +
> >  drivers/net/hyperv/netvsc.c     | 17 +++++++++++++++--
> >  2 files changed, 16 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/hyperv/hyperv_net.h
> > b/drivers/net/hyperv/hyperv_net.h index 0db3bd1ea06f..49c05ac894e5
> > 100644
> > --- a/drivers/net/hyperv/hyperv_net.h
> > +++ b/drivers/net/hyperv/hyperv_net.h
> > @@ -793,6 +793,7 @@ struct netvsc_device {
> >
> >  	/* Receive buffer allocated by us but manages by NetVSP */
> >  	void *recv_buf;
> > +	u32 recv_buf_size; /* allocated bytes */
> >  	u32 recv_buf_gpadl_handle;
> >  	u32 recv_section_cnt;
> >  	u32 recv_section_size;
> > diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
> > index 1ddb2c39b6e4..a6700d65f206 100644
> > --- a/drivers/net/hyperv/netvsc.c
> > +++ b/drivers/net/hyperv/netvsc.c
> > @@ -289,6 +289,8 @@ static int netvsc_init_buf(struct hv_device *device=
,
> >  		goto cleanup;
> >  	}
> >
> > +	net_device->recv_buf_size =3D buf_size;
> > +
> >  	/*
> >  	 * Establish the gpadl handle for this buffer on this
> >  	 * channel.  Note: This call uses the vmbus connection rather @@
> > -1095,11 +1097,22 @@ static int netvsc_receive(struct net_device
> > *ndev,
> >
> >  	/* Each range represents 1 RNDIS pkt that contains 1 ethernet frame *=
/
> >  	for (i =3D 0; i < count; i++) {
> > -		void *data =3D recv_buf
> > -			+ vmxferpage_packet->ranges[i].byte_offset;
> > +		u32 offset =3D vmxferpage_packet->ranges[i].byte_offset;
> >  		u32 buflen =3D vmxferpage_packet->ranges[i].byte_count;
> > +		void *data;
> >  		int ret;
> >
> > +		if (unlikely(offset + buflen > net_device->recv_buf_size)) {
> > +			status =3D NVSP_STAT_FAIL;
> > +			netif_err(net_device_ctx, rx_err, ndev,
> > +				  "Packet offset:%u + len:%u too big\n",
> > +				  offset, buflen);
>=20
> This shouldn't happen, of course, but I'd rather ratelimit this error or =
even used
> something like netdev_WARN_ONCE().

Actually I thought about ratelimit, but this range check is only to catch h=
ost side bug.=20
It should not happen.=20
But if it happens, the VM should not be used anymore. And we need to debug
the host. Similarly, some other this kind of checks in the same function ar=
e not using
ratelimit:

        if (unlikely(nvsp->hdr.msg_type !=3D NVSP_MSG1_TYPE_SEND_RNDIS_PKT)=
) {
                netif_err(net_device_ctx, rx_err, ndev,
                          "Unknown nvsp packet type received %u\n",
                          nvsp->hdr.msg_type);

Thanks,
- Haiyang