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From: "Liu, Yong" <yong.liu@intel.com>
To: wangyunjian <wangyunjian@huawei.com>,
	Maxime Coquelin <maxime.coquelin@redhat.com>,
	"Xia, Chenbo" <chenbo.xia@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>, "stable@dpdk.org" <stable@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] vhost: fix accessing uninitialized variables
Date: Mon, 29 Mar 2021 01:44:57 +0000	[thread overview]
Message-ID: <16b519966ac94f8b922c89f624c7c4eb@intel.com> (raw)
In-Reply-To: <dc5f5132a35b4769b01f7217e1687e91@huawei.com>



> -----Original Message-----
> From: wangyunjian <wangyunjian@huawei.com>
> Sent: Saturday, March 27, 2021 6:06 PM
> To: Maxime Coquelin <maxime.coquelin@redhat.com>; Liu, Yong
> <yong.liu@intel.com>; Xia, Chenbo <chenbo.xia@intel.com>
> Cc: dev@dpdk.org; stable@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH] vhost: fix accessing uninitialized variables
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Maxime Coquelin
> > Sent: Wednesday, March 24, 2021 5:55 PM
> > To: Marvin Liu <yong.liu@intel.com>; chenbo.xia@intel.com
> > Cc: dev@dpdk.org; stable@dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH] vhost: fix accessing uninitialized variables
> >
> >
> >
> > On 3/3/21 8:27 AM, Marvin Liu wrote:
> > > This patch fixs coverity issue by adding initialization step before
> > > using temporary virtio header.
> > >
> > > Coverity issue: 366181, 366123
> > > Fixes: fb3815cc614d ("vhost: handle virtually non-contiguous buffers
> > > in Rx-mrg")
> > > Cc: stable@dpdk.org
> > >
> > > Signed-off-by: Marvin Liu <yong.liu@intel.com>
> > >
> > > diff --git a/lib/librte_vhost/virtio_net.c
> > > b/lib/librte_vhost/virtio_net.c index 583bf379c6..fe464b3088 100644
> > > --- a/lib/librte_vhost/virtio_net.c
> > > +++ b/lib/librte_vhost/virtio_net.c
> > > @@ -808,9 +808,10 @@ copy_mbuf_to_desc(struct virtio_net *dev,
> struct
> > > vhost_virtqueue *vq,
> > >
> > >  	hdr_mbuf = m;
> > >  	hdr_addr = buf_addr;
> > > -	if (unlikely(buf_len < dev->vhost_hlen))
> > > +	if (unlikely(buf_len < dev->vhost_hlen)) {
> > > +		memset(&tmp_hdr, 0, sizeof(struct
> virtio_net_hdr_mrg_rxbuf));
> > >  		hdr = &tmp_hdr;
> > > -	else
> > > +	} else
> > >  		hdr = (struct virtio_net_hdr_mrg_rxbuf *)(uintptr_t)hdr_addr;
> > >
> > >  	VHOST_LOG_DATA(DEBUG, "(%d) RX: num merge buffers %d\n",
> > >
> 
> I think it's better to revise it in this way:
> 

Thanks, yunjian. This patch for reported coverity issue.

The problem came from the read of net_hdr->csum_offset when using macro ASSIGN_UNLESS_EQUAL.
When net_hdr not completed in the first buffer, temporary net_hdr will be used which hasn't been initialized. 

Regards,
Marvin

> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index 583bf37..ccb73b9 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -420,6 +420,8 @@
>                         net_hdr->csum_offset = (offsetof(struct rte_sctp_hdr,
>                                                 cksum));
>                         break;
> +               default:
> +                       ASSIGN_UNLESS_EQUAL(net_hdr->csum_offset, 0);
>                 }
> 
> >
> > Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> >
> > Thanks,
> > Maxime


  reply	other threads:[~2021-03-29  1:45 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-03  7:27 Marvin Liu
2021-03-24  9:54 ` Maxime Coquelin
2021-03-27 10:06   ` wangyunjian
2021-03-29  1:44     ` Liu, Yong [this message]
2021-04-06  6:17 ` Xia, Chenbo
2021-04-07  2:48   ` Liu, Yong

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