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Subject: Re: [PATCH 1/2] vfio/fsl-mc: return -EFAULT if copy_to_user() fails
To:     Alex Williamson <alex.williamson@redhat.com>
Cc:     Dan Carpenter <dan.carpenter@oracle.com>,
        Cornelia Huck <cohuck@redhat.com>,
        Bharat Bhushan <Bharat.Bhushan@nxp.com>,
        Eric Auger <eric.auger@redhat.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
References: <20201023113450.GH282278@mwanda>
 <20201102144536.42a0e066@w520.home>
From:   Diana Craciun OSS <diana.craciun@oss.nxp.com>
Message-ID: <28a51535-5f4f-6a06-254e-29ef3dc999ba@oss.nxp.com>
Date:   Tue, 3 Nov 2020 19:19:44 +0200
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On 11/2/2020 11:45 PM, Alex Williamson wrote:
> 
> Thanks, Dan.
> 
> Diana, can I get an ack for this?  Thanks,


Yes, sure, I apologize for not doing it earlier.

Thanks,
Diana

> 
> Alex
> 
> On Fri, 23 Oct 2020 14:34:50 +0300
> Dan Carpenter <dan.carpenter@oracle.com> wrote:
> 
>> The copy_to_user() function returns the number of bytes remaining to be
>> copied, but this code should return -EFAULT.
>>
>> Fixes: df747bcd5b21 ("vfio/fsl-mc: Implement VFIO_DEVICE_GET_REGION_INFO ioctl call")
>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>> ---
>>   drivers/vfio/fsl-mc/vfio_fsl_mc.c | 8 ++++++--
>>   1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
>> index 0113a980f974..21f22e3da11f 100644
>> --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
>> +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
>> @@ -248,7 +248,9 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
>>   		info.size = vdev->regions[info.index].size;
>>   		info.flags = vdev->regions[info.index].flags;
>>   
>> -		return copy_to_user((void __user *)arg, &info, minsz);
>> +		if (copy_to_user((void __user *)arg, &info, minsz))
>> +			return -EFAULT;
>> +		return 0;
>>   	}
>>   	case VFIO_DEVICE_GET_IRQ_INFO:
>>   	{
>> @@ -267,7 +269,9 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
>>   		info.flags = VFIO_IRQ_INFO_EVENTFD;
>>   		info.count = 1;
>>   
>> -		return copy_to_user((void __user *)arg, &info, minsz);
>> +		if (copy_to_user((void __user *)arg, &info, minsz))
>> +			return -EFAULT;
>> +		return 0;
>>   	}
>>   	case VFIO_DEVICE_SET_IRQS:
>>   	{
>