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From: Jens Axboe <axboe@suse.de>
To: Jesper Juhl <juhl-lkml@dif.dk>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] remember to check return value from __copy_to_user() in cdrom_read_cdda_old()
Date: Tue, 7 Sep 2004 10:02:23 +0200	[thread overview]
Message-ID: <20040907080223.GF6323@suse.de> (raw)
In-Reply-To: <Pine.LNX.4.61.0409062335250.2705@dragon.hygekrogen.localhost>

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@dif.dk>
> 
> 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


  reply	other threads:[~2004-09-07  8:09 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-06 21:46 [PATCH] remember to check return value from __copy_to_user() in cdrom_read_cdda_old() Jesper Juhl
2004-09-07  8:02 ` Jens Axboe [this message]
2004-09-07  9:32   ` Paul Mackerras
2004-09-07  9:34     ` Jens Axboe
2004-09-07  9:59       ` Andrew Morton
2004-09-07 10:09         ` Jens Axboe
2004-09-07 10:12           ` Andrew Morton
2004-09-07 10:15             ` Jens Axboe
2004-09-07 10:23       ` viro
2004-09-07 10:30         ` Jens Axboe
2004-09-07 10:45           ` viro
2004-09-07 11:42             ` Jens Axboe
2004-09-07  9:58     ` Jens Axboe

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