[PATCH 2/2] Staging: bcm: Fix an integer overflow in IOCTL_BCM_NVM_READ/WRITE

[Dan Carpenter]

On Sat, Dec 17, 2011 at 11:53:38AM -0500, Kevin McKinney wrote:
> Variables stNVMReadWrite.uioffset and stNVMReadWrite.uiNumBytes
> are chosen from userspace and can be very high. The sum of
> these two digits would result in a small number. Therefore,
> this patch reorganizes the equation to remove the integer
> overflow.
> 
> Signed-off-by: Kevin McKinney <klmckinney1 at gmail.com>
> ---
>  drivers/staging/bcm/Bcmchar.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/staging/bcm/Bcmchar.c b/drivers/staging/bcm/Bcmchar.c
> index 179707b..f365a5a 100644
> --- a/drivers/staging/bcm/Bcmchar.c
> +++ b/drivers/staging/bcm/Bcmchar.c
> @@ -1303,7 +1303,7 @@ cntrlEnd:
>  		 * Deny the access if the offset crosses the cal area limit.
>  		 */
>  
> -		if ((stNVMReadWrite.uiOffset + stNVMReadWrite.uiNumBytes) > Adapter->uiNVMDSDSize) {
> +		if (stNVMReadWrite.uiOffset > (Adapter->uiNVMDSDSize - stNVMReadWrite.uiNumBytes)) {
                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Now you have a problem on this side.  ;)

First verify that stNVMReadWrite.uiNumBytes is less than
Adapter->uiNVMDSDSize before you do the subtraction.

regards,
dan carpenter


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: Digital signature
URL: <http://driverdev.linuxdriverproject.org/pipermail/driverdev-devel/attachments/20111217/f605a900/attachment.asc>