Re: [PATCH] staging: ft1000: Copy from user into correct data

[Belisko Marek]

Hi Steven,

On Thu, Nov 11, 2010 at 5:29 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> While doing a ktest.pl I used a MIN_CONFIG that had STAGING enabled, and
> a randconfig with CONFIG_DEBUG_STRICT_USER_COPY_CHECKS enabled caught
> the following bug:
>
> In file included from /home/rostedt/work/autotest/nobackup/linux-test.git/arch/x86/include/asm/uaccess.h:571:0,
> Â Â Â Â Â Â Â Â from /home/rostedt/work/autotest/nobackup/linux-test.git/include/linux/poll.h:14,
> Â Â Â Â Â Â Â Â from /home/rostedt/work/autotest/nobackup/linux-test.git/drivers/staging/ft1000/ft1000-usb/ft1000_chdev.c:32:
> In function 'copy_from_user',
> Â Âinlined from 'ft1000_ChIoctl' at /home/rostedt/work/autotest/nobackup/linux-test.git/drivers/staging/ft1000/ft1000-usb/ft1000_chdev.c:702:36:
> /home/rostedt/work/autotest/nobackup/linux-test.git/arch/x86/include/asm/uaccess_32.h:212:26: error: call to 'copy_from_user_overflow' declared with attribute error: copy_from_user() buffer size is not provably correct
>
>
> Looking at the code it was obvious what the problem was. The pointer
> dpram_data was being allocated but the address was being written to.
> Looking at the comment above the code shows that it use to write into an
> element of that pointer where the '&' is appropriate. But now that it
> writes to the pointer itself, we need to remove the '&' otherwise we
> write over the pointer and not into the data it points to.
Good catch but anyway this interface is removed. Already send patches to Greg-KH
but there was some patch problem so they're not applied to next yet.
Thanks for effort.
>
> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
>
> diff --git a/drivers/staging/ft1000/ft1000-usb/ft1000_chdev.c b/drivers/staging/ft1000/ft1000-usb/ft1000_chdev.c
> index 87a6487..8e8197d 100644
> --- a/drivers/staging/ft1000/ft1000-usb/ft1000_chdev.c
> +++ b/drivers/staging/ft1000/ft1000-usb/ft1000_chdev.c
> @@ -699,7 +699,7 @@ static long ft1000_ChIoctl (struct file *File, unsigned int Command,
> Â Â Â Â Â Â Â Â Â Â Â Âbreak;
>
> Â Â Â Â Â Â Â Â //if ( copy_from_user(&(dpram_command.dpram_blk), (PIOCTL_DPRAM_BLK)Argument, msgsz+2) ) {
> - Â Â Â Â Â Â Â Âif ( copy_from_user(&dpram_data, argp, msgsz+2) ) {
> + Â Â Â Â Â Â Â Âif ( copy_from_user(dpram_data, argp, msgsz+2) ) {
> Â Â Â Â Â Â Â Â Â Â DEBUG("FT1000:ft1000_ChIoctl: copy fault occurred\n");
> Â Â Â Â Â Â Â Â Â Â result = -EFAULT;
> Â Â Â Â Â Â Â Â }
>
>
>

thanks,

marek

-- 
as simple and primitive as possible
-------------------------------------------------
Marek Belisko - OPEN-NANDRA
Freelance Developer

Ruska Nova Ves 219 | Presov, 08005 Slovak Republic
Tel: +421 915 052 184
skype: marekwhite
icq: 290551086
web: http://open-nandra.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/