linux-kernel - Re: [PATCH] vfio: simplify kmalloc+copy_from_user to memdup

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Date:	Fri, 09 Nov 2012 14:06:29 +0100
From:	Alex Williamson <alex.williamson@...hat.com>
To:	Fengguang Wu <fengguang.wu@...el.com>
Cc:	linux-kernel@...r.kernel.org, Julia Lawall <julia.lawall@...6.fr>
Subject: Re: [PATCH] vfio: simplify kmalloc+copy_from_user to memdup_user

On Fri, 2012-11-02 at 10:43 +0800, Fengguang Wu wrote:
> Generated by: coccinelle/api/memdup_user.cocci
> 
> Acked-by: Julia Lawall <julia.lawall@...6.fr>
> Reported-by: Fengguang Wu <fengguang.wu@...el.com>
> ---
> 
>  drivers/vfio/pci/vfio_pci.c |   13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> --- linux.orig/drivers/vfio/pci/vfio_pci.c	2012-10-23 18:21:57.118168335 +0800
> +++ linux/drivers/vfio/pci/vfio_pci.c	2012-11-02 10:39:36.101317628 +0800
> @@ -327,15 +327,10 @@ static long vfio_pci_ioctl(void *device_
>  			    hdr.count > vfio_pci_get_irq_count(vdev, hdr.index))
>  				return -EINVAL;
>  
> -			data = kmalloc(hdr.count * size, GFP_KERNEL);
> -			if (!data)
> -				return -ENOMEM;
> -
> -			if (copy_from_user(data, (void __user *)(arg + minsz),
> -					   hdr.count * size)) {
> -				kfree(data);
> -				return -EFAULT;
> -			}
> +			data = memdup_user((void __user *)(arg + minsz),
> +					   hdr.count * size);
> +			if (IS_ERR(data))
> +				return PTR_ERR(data);
>  		}
>  
>  		mutex_lock(&vdev->igate);


Thanks for the patch.  Looks reasonable to me.  I'll add it to my next
tree for 3.8.  Thanks,

Alex

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