[PATCH net] virtio_net: check virtqueue_add_sgs() return value

[PATCH net] virtio_net: check virtqueue_add_sgs() return value

[wangyunjian]

From: Yunjian Wang <wangyunjian@huawei.com>

As virtqueue_add_sgs() can fail, we should check the return value.

Addresses-Coverity-ID: 1464439 ("Unchecked return value")
Fixes: a7c58146cf9a ("virtio_net: don't crash if virtqueue is broken.")
Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
---
 drivers/net/virtio_net.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index b0b81458ca94..2b852578551e 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1743,6 +1743,7 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 {
 	struct scatterlist *sgs[4], hdr, stat;
 	unsigned out_num = 0, tmp;
+	int ret;
 
 	/* Caller should know better */
 	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
@@ -1762,7 +1763,9 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
 	sgs[out_num] = &stat;
 
 	BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
-	virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
+	ret = virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
+	if (ret < 0)
+		return false;
 
 	if (unlikely(!virtqueue_kick(vi->cvq)))
 		return vi->ctrl->status == VIRTIO_NET_OK;
-- 
2.23.0

Re: [PATCH net] virtio_net: check virtqueue_add_sgs() return value

[Michael S. Tsirkin]

On Mon, Jul 05, 2021 at 09:53:39PM +0800, wangyunjian wrote:
> From: Yunjian Wang <wangyunjian@huawei.com>
> 
> As virtqueue_add_sgs() can fail, we should check the return value.
> 
> Addresses-Coverity-ID: 1464439 ("Unchecked return value")
> Fixes: a7c58146cf9a ("virtio_net: don't crash if virtqueue is broken.")

What does this have to do with it?

> Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> ---
>  drivers/net/virtio_net.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index b0b81458ca94..2b852578551e 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1743,6 +1743,7 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
>  {
>  	struct scatterlist *sgs[4], hdr, stat;
>  	unsigned out_num = 0, tmp;
> +	int ret;
>  
>  	/* Caller should know better */
>  	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
> @@ -1762,7 +1763,9 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
>  	sgs[out_num] = &stat;
>  
>  	BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
> -	virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
> +	ret = virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
> +	if (ret < 0)
> +		return false;

and maybe dev_warn here. these things should not happen.


>  
>  	if (unlikely(!virtqueue_kick(vi->cvq)))
>  		return vi->ctrl->status == VIRTIO_NET_OK;
> -- 
> 2.23.0

RE: [PATCH net] virtio_net: check virtqueue_add_sgs() return value

[wangyunjian]

> -----Original Message-----
> From: Michael S. Tsirkin [mailto:mst@redhat.com]
> Sent: Tuesday, July 6, 2021 2:08 AM
> To: wangyunjian <wangyunjian@huawei.com>
> Cc: kuba@kernel.org; davem@davemloft.net; netdev@vger.kernel.org;
> jasowang@redhat.com; dingxiaoxiong <dingxiaoxiong@huawei.com>
> Subject: Re: [PATCH net] virtio_net: check virtqueue_add_sgs() return value
> 
> On Mon, Jul 05, 2021 at 09:53:39PM +0800, wangyunjian wrote:
> > From: Yunjian Wang <wangyunjian@huawei.com>
> >
> > As virtqueue_add_sgs() can fail, we should check the return value.
> >
> > Addresses-Coverity-ID: 1464439 ("Unchecked return value")
> > Fixes: a7c58146cf9a ("virtio_net: don't crash if virtqueue is
> > broken.")
> 
> What does this have to do with it?

It's this commit that removes the check.
So delete this fix tag?

> 
> > Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> > ---
> >  drivers/net/virtio_net.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index
> > b0b81458ca94..2b852578551e 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -1743,6 +1743,7 @@ static bool virtnet_send_command(struct
> > virtnet_info *vi, u8 class, u8 cmd,  {
> >  	struct scatterlist *sgs[4], hdr, stat;
> >  	unsigned out_num = 0, tmp;
> > +	int ret;
> >
> >  	/* Caller should know better */
> >  	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)); @@
> > -1762,7 +1763,9 @@ static bool virtnet_send_command(struct virtnet_info
> *vi, u8 class, u8 cmd,
> >  	sgs[out_num] = &stat;
> >
> >  	BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
> > -	virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
> > +	ret = virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
> > +	if (ret < 0)
> > +		return false;
> 
> and maybe dev_warn here. these things should not happen.

OK, I will add it in next version.

Thanks
Yunjian

> 
> 
> >
> >  	if (unlikely(!virtqueue_kick(vi->cvq)))
> >  		return vi->ctrl->status == VIRTIO_NET_OK;
> > --
> > 2.23.0