Re: [PATCH] vfio powerpc: implemented IOMMU driver for VFIO

From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Paul Mackerras <paulus@samba.org>,
	linuxppc-dev@lists.ozlabs.org,
	David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH] vfio powerpc: implemented IOMMU driver for VFIO
Date: Wed, 12 Dec 2012 17:59:08 +1100	[thread overview]
Message-ID: <50C82B3C.1060006@ozlabs.ru> (raw)
In-Reply-To: <1354899707.3224.86.camel@bling.home>

On 08/12/12 04:01, Alex Williamson wrote:
>> +	case VFIO_IOMMU_MAP_DMA: {
>> +		vfio_iommu_spapr_tce_dma_map param;
>> +		struct iommu_table *tbl = container->tbl;
>> +		enum dma_data_direction direction;
>> +		unsigned long locked, lock_limit;
>> +
>> +		if (WARN_ON(!tbl))
>> +			return -ENXIO;
>> +
>> +		minsz = offsetofend(vfio_iommu_spapr_tce_dma_map, size);
>> +
>> +		if (copy_from_user(&param, (void __user *)arg, minsz))
>> +			return -EFAULT;
>> +
>> +		if (param.argsz < minsz)
>> +			return -EINVAL;
>> +
>> +		if ((param.flags & VFIO_DMA_MAP_FLAG_READ) &&
>> +				(param.flags & VFIO_DMA_MAP_FLAG_WRITE))
>> +			direction = DMA_BIDIRECTIONAL;
>> +		else if (param.flags & VFIO_DMA_MAP_FLAG_READ)
>> +			direction = DMA_TO_DEVICE;
>> +		else if (param.flags & VFIO_DMA_MAP_FLAG_WRITE)
>> +			direction = DMA_FROM_DEVICE;
>> +		else
>> +			return -EINVAL;
>
> flags needs to be sanitized too.  Return EINVAL if any unknown bit is
> set or else sloppy users may make it very difficult to make use of those
> flag bits later.

It already returns -EINVAL on any bit set except READ/WRITE, no?

-- 
Alexey