From: Jason Wang <jasowang@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
Dan Carpenter <dan.carpenter@oracle.com>
Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, kernel-janitors@vger.kernel.org,
kuba@kernel.org
Subject: Re: [PATCH net] vhost_vdpa: Return -EFUALT if copy_from_user() fails
Date: Mon, 26 Oct 2020 10:59:37 +0800 [thread overview]
Message-ID: <4485cc8d-ac69-c725-8493-eda120e29c41@redhat.com> (raw)
In-Reply-To: <20201023113326-mutt-send-email-mst@kernel.org>
On 2020/10/23 下午11:34, Michael S. Tsirkin wrote:
> On Fri, Oct 23, 2020 at 03:08:53PM +0300, Dan Carpenter wrote:
>> The copy_to/from_user() functions return the number of bytes which we
>> weren't able to copy but the ioctl should return -EFAULT if they fail.
>>
>> Fixes: a127c5bbb6a8 ("vhost-vdpa: fix backend feature ioctls")
>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> Needed for stable I guess.
Agree.
Acked-by: Jason Wang <jasowang@redhat.com>
>> ---
>> drivers/vhost/vdpa.c | 10 +++++-----
>> 1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>> index 62a9bb0efc55..c94a97b6bd6d 100644
>> --- a/drivers/vhost/vdpa.c
>> +++ b/drivers/vhost/vdpa.c
>> @@ -428,12 +428,11 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
>> void __user *argp = (void __user *)arg;
>> u64 __user *featurep = argp;
>> u64 features;
>> - long r;
>> + long r = 0;
>>
>> if (cmd == VHOST_SET_BACKEND_FEATURES) {
>> - r = copy_from_user(&features, featurep, sizeof(features));
>> - if (r)
>> - return r;
>> + if (copy_from_user(&features, featurep, sizeof(features)))
>> + return -EFAULT;
>> if (features & ~VHOST_VDPA_BACKEND_FEATURES)
>> return -EOPNOTSUPP;
>> vhost_set_backend_features(&v->vdev, features);
>> @@ -476,7 +475,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *filep,
>> break;
>> case VHOST_GET_BACKEND_FEATURES:
>> features = VHOST_VDPA_BACKEND_FEATURES;
>> - r = copy_to_user(featurep, &features, sizeof(features));
>> + if (copy_to_user(featurep, &features, sizeof(features)))
>> + r = -EFAULT;
>> break;
>> default:
>> r = vhost_dev_ioctl(&v->vdev, cmd, argp);
next prev parent reply other threads:[~2020-10-26 2:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-23 12:08 [PATCH net] vhost_vdpa: Return -EFUALT if copy_from_user() fails Dan Carpenter
2020-10-23 15:34 ` Michael S. Tsirkin
2020-10-26 2:59 ` Jason Wang [this message]
2020-11-18 6:08 ` Jason Wang
2020-11-18 8:59 ` Michael S. Tsirkin
2020-11-18 9:39 ` Jason Wang
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