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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: "Ивайло Димитров" <ivo.g.dimitrov.75@gmail.com>,
	"Pali Rohá" <pali.rohar@gmail.com>,
	"Greg KH" <gregkh@linuxfoundation.org>,
	"Ивайло Д" <freemangordon@abv.bg>,
	sre@ring0.de, omar.ramirez@copitl.com, tony@atomide.com,
	felipe.contreras@gmail.com, s-anna@ti.com, nm@ti.com,
	ohad@wizery.com, stable@vger.kernel.org,
	linux-kernel@vger.kernel.org, nico@ngolde.de
Subject: Re: [patch] Staging: tidspbridge: make mmap root-only so it is not a security problem
Date: Sun, 1 Dec 2013 15:27:56 +0300	[thread overview]
Message-ID: <20131201122756.GH5443@mwanda> (raw)
In-Reply-To: <20131201121006.GA26072@amd.pavel.ucw.cz>

On Sun, Dec 01, 2013 at 01:10:06PM +0100, Pavel Machek wrote:
> diff --git a/drivers/staging/tidspbridge/rmgr/drv_interface.c b/drivers/staging/tidspbridge/rmgr/drv_interface.c
> index 1aa4a3f..a8e86cf 100644
> --- a/drivers/staging/tidspbridge/rmgr/drv_interface.c
> +++ b/drivers/staging/tidspbridge/rmgr/drv_interface.c
> @@ -258,7 +258,17 @@ err:
>  /* This function maps kernel space memory to user space memory. */
>  static int bridge_mmap(struct file *filp, struct vm_area_struct *vma)
>  {
> -	u32 status;
> +	int status;
> +	struct omap_dsp_platform_data *pdata =
> +	    omap_dspbridge_dev->dev.platform_data;
> +	unsigned long start = vma->vm_pgoff << PAGE_SHIFT;
> +		
> +	if (start < pdata->phys_mempool_base)
> +		return -EINVAL;
> +
> +	if (vma->vm_end - vma->vm_start + (start - pdata->phys_mempool_base) 
> +	    > pdata->phys_mempool_size)

This test is vulnerable to integer overflows if you pick a very high
value for start.  Consider using the vm_iomap_memory() helper function
instead of calling remap_pfn_range() directly.  Commit 7314e613d5ff
('Fix a few incorrectly checked [io_]remap_pfn_range() calls') has an
example of how the conversion works.

regards,
dan carpenter


  reply	other threads:[~2013-12-01 12:27 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-30  9:58 Staging: tidspbridge: disable driver Ivajlo Dimitrov
2013-11-30 16:20 ` Greg KH
2013-11-30 17:27   ` Tony Lindgren
2013-11-30 19:19 ` Pavel Machek
2013-11-30 19:49   ` Dan Carpenter
2013-11-30 20:42     ` [patch] Staging: tidspbridge: make mmap root-only so it is not a security problem Pavel Machek
2013-11-30 22:05       ` Greg KH
2013-11-30 22:58         ` Pavel Machek
2013-12-01  3:45           ` Greg KH
2013-12-01  9:47             ` Pali Rohár
2013-12-01 11:26             ` Pavel Machek
2013-12-01 11:33               ` Pali Rohár
2013-12-01  9:41           ` Pali Rohár
2013-12-01  9:58             ` Ивайло Димитров
2013-12-01 12:10               ` Pavel Machek
2013-12-01 12:27                 ` Dan Carpenter [this message]
2013-12-01 18:14                   ` Ivajlo Dimitrov
2013-12-01 18:57                     ` Pavel Machek
2013-12-01 19:28                     ` Dan Carpenter

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