Re: [PATCH] remember to check return value from __copy_to_user() in cdrom_read_cdda_old()

[Jens Axboe]

On Mon, Sep 06 2004, Jesper Juhl wrote:
> 
> Hi,
> 
> Here's a patch to ensure that the return value from __copy_to_user() gets 
> checked in cdrom_read_cdda_old().
> I assume that returning -EFAULT if the copy fails to copy all bytes is an 
> appropriate action, but please correct me if I'm wrong.
> 
> Signed-off-by: Jesper Juhl <juhl-lkml@xxxxxx>
> 
> diff -up linux-2.6.9-rc1-bk13-orig/drivers/cdrom/cdrom.c linux-2.6.9-rc1-bk13/drivers/cdrom/cdrom.c
> --- linux-2.6.9-rc1-bk13-orig/drivers/cdrom/cdrom.c	2004-08-24 20:44:01.000000000 +0200
> +++ linux-2.6.9-rc1-bk13/drivers/cdrom/cdrom.c	2004-09-06 23:41:20.000000000 +0200
> @@ -1959,7 +1959,10 @@ static int cdrom_read_cdda_old(struct cd
>  		ret = cdrom_read_block(cdi, &cgc, lba, nr, 1, CD_FRAMESIZE_RAW);
>  		if (ret)
>  			break;
> -		__copy_to_user(ubuf, cgc.buffer, CD_FRAMESIZE_RAW * nr);
> +		if (__copy_to_user(ubuf, cgc.buffer, CD_FRAMESIZE_RAW * nr)) {
> +			kfree(cgc.buffer);
> +			return -EFAULT;
> +		}
>  		ubuf += CD_FRAMESIZE_RAW * nr;
>  		nframes -= nr;
>  		lba += nr;

__copy_to_user is the unchecking version of copy_to_user.

-- 
Jens Axboe

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