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Date:   Fri, 11 Sep 2020 10:43:01 +0200
From:   Andrea Parri <parri.andrea@gmail.com>
To:     Haiyang Zhang <haiyangz@microsoft.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        KY Srinivasan <kys@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>,
        "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
        Andres Beltran <lkmlabelt@gmail.com>,
        Michael Kelley <mikelley@microsoft.com>,
        Saruhan Karademir <skarade@microsoft.com>,
        Juan Vazquez <juvazq@microsoft.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH v2] hv_netvsc: Add validation for untrusted Hyper-V values
Message-ID: <20200911084301.GA14414@andrea>
References: <20200910124748.19217-1-parri.andrea@gmail.com>
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> > @@ -740,12 +755,45 @@ static void netvsc_send_completion(struct
> > net_device *ndev,
> >  				   int budget)
> >  {
> >  	const struct nvsp_message *nvsp_packet = hv_pkt_data(desc);
> > +	u32 msglen = hv_pkt_datalen(desc);
> > +
> > +	/* Ensure packet is big enough to read header fields */
> > +	if (msglen < sizeof(struct nvsp_message_header)) {
> > +		netdev_err(ndev, "nvsp_message length too small: %u\n",
> > msglen);
> > +		return;
> > +	}
> > 
> >  	switch (nvsp_packet->hdr.msg_type) {
> >  	case NVSP_MSG_TYPE_INIT_COMPLETE:
> > +		if (msglen < sizeof(struct nvsp_message_init_complete)) {
> 
> This and other similar places should include header size:
> 		if (msglen < sizeof(struct nvsp_message_header) + sizeof(struct nvsp_message_init_complete)) {

Thanks for pointing this out; fixing for v3...

  Andrea