How to communicate with user mode from kernel driver

NTDEV
1

Hello all,
I am a new bee in driver developement and currently developing a TDI - fiter
driver.
My driver should give access to applications that access internet based on
the decision done in user mode.

Let me explain clearly…

my driver captures the application when it tries to access internet but i
don’t know how to send this information to user mode. Also the driver should
wait until the user mode application responds back.If the user mode
application sends ‘OK’ then the application should be allowed to access the
internet. If it sends ‘No’ then the application should be denied.
I need to allow the user to select the application to allow or not by
displaying a dialog box.This can be done only in user mode…(My knowledge)…
So how can the driver wait until the user selects it.

Thanks
M V Ramana

Can’t have enough of SRK? http://server1.msn.co.in/sp05/iifa/ Help him bag
the award.

2

The recomended way to talk from the kernel to user space is an “inverted
call”. Basically, your helper service calls to the driver with one or more
IOCTL’s using overlapped I/O that pend in the driver till needed. When the
driver needs to call the service it fills in the output buffer of the IOCTL
with a request, then completes the request. When the helper gets the
completed IOCTL it processes the request and sends back in an IOCTL the
results. An article describing this is at
http://www.osronline.com/article.cfm?id=94

The advantages to this approach are, all the calls are documented and if the
helper app crashes this is handled easily.

As to the helper application, as long as performance does not become an
issue, you are correct that putting as much of the effort into a user space
application as possible is a good idea.

–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
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----- Original Message -----
From: “Mr. venkat”
To: “Windows System Software Devs Interest List”
Sent: Wednesday, June 08, 2005 4:59 AM
Subject: [ntdev] How to communicate with user mode from kernel driver

> Hello all,
> I am a new bee in driver developement and currently developing a TDI -
> fiter driver.
> My driver should give access to applications that access internet based on
> the decision done in user mode.
>
> Let me explain clearly…
>
> my driver captures the application when it tries to access internet but i
> don’t know how to send this information to user mode. Also the driver
> should wait until the user mode application responds back.If the user mode
> application sends ‘OK’ then the application should be allowed to access
> the internet. If it sends ‘No’ then the application should be denied.
> I need to allow the user to select the application to allow or not by
> displaying a dialog box.This can be done only in user mode…(My
> knowledge)…
> So how can the driver wait until the user selects it.
>
> Thanks
> M V Ramana
>
> _________________________________________________________________
> Can’t have enough of SRK? http://server1.msn.co.in/sp05/iifa/ Help him bag
> the award.
>
>
> —
> Questions? First check the Kernel Driver FAQ at
> http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@acm.org
> To unsubscribe send a blank email to xxxxx@lists.osr.com

3

One way is to create an event (CreateEvent) in user mode
(WaitForSingleObject) and wait for it to be signaled from the kernel
(KeSetEvent).

>> xxxxx@hotmail.com 6/8/2005 4:59:14 AM >>>
Hello all,
I am a new bee in driver developement and currently developing a TDI -
fiter
driver.
My driver should give access to applications that access internet based
on
the decision done in user mode.

Let me explain clearly…

my driver captures the application when it tries to access internet but
i
don’t know how to send this information to user mode. Also the driver
should
wait until the user mode application responds back.If the user mode
application sends ‘OK’ then the application should be allowed to access
the
internet. If it sends ‘No’ then the application should be denied.
I need to allow the user to select the application to allow or not by
displaying a dialog box.This can be done only in user mode…(My
knowledge)…
So how can the driver wait until the user selects it.

Thanks
M V Ramana

Can’t have enough of SRK? http://server1.msn.co.in/sp05/iifa/ Help
him bag
the award.

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@evitechnology.com
To unsubscribe send a blank email to xxxxx@lists.osr.com