Hello,
How to make call to “User mode application functions” from IFS filter driver. I have a COM dll / exe ,wanna access its functionality
( Say : encryption & decryption via streaming ) from the IFS filter driver code.Is it good idea to put CRYPTO API functionality into
the filter driver code ? If not , please suggest some workaround to achieve the encryption / decryption functionality from IFS filter
driver code or how to access the User mode application functions.
Many Thanx in Adv
Regards
deepak
Hello,
How to make call to “User mode application functions” from IFS filter driver. I have a COM dll / exe ,wanna access its functionality
( Say : encryption & decryption via streaming ) from the IFS filter driver code.Is it good idea to put CRYPTO API functionality into
the filter driver code ? If not , please suggest some workaround to achieve the encryption / decryption functionality from IFS filter
driver code or how to access the User mode application functions.
Many Thanx in Adv
Regards
deepak
You cannot call CryptoAPI or any COM DLLs from the kernel-mode module. Forget this forever. This is against the OS design principles.
So, either use the undocumented fips.sys (which is kernel mode CryptoAPI) or reimplement the algorithms yourself in a kmode code. AES code is rather simple, nothing fancy. So is MD5.
The last solution is inverted call path, but it is a) slow b) the implementation cost is maybe larger then porting the reference implementation of AES to the kernel.
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com
----- Original Message -----
From: Deepak.Singh
To: Windows File Systems Devs Interest List
Sent: Tuesday, October 12, 2004 10:26 AM
Subject: [ntfsd] Callback to User mode application from IFS filter Driver
Hello,
How to make call to “User mode application functions” from IFS filter driver. I have a COM dll / exe ,wanna access its functionality
( Say : encryption & decryption via streaming ) from the IFS filter driver code.Is it good idea to put CRYPTO API functionality into
the filter driver code ? If not , please suggest some workaround to achieve the encryption / decryption functionality from IFS filter
driver code or how to access the User mode application functions.
Many Thanx in Adv
Regards
deepak
Questions? First check the IFS FAQ at https://www.osronline.com/article.cfm?id=17
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Deepak,
If you were to develop your filter as a minifilter the filter manager comes with kernel/user communication APIs.
One way to handle this with an existing filter is by having your user mode application send down private FSCTRL irps to your control device object. Your filter then pends these IRP and holds on to them until it has a message to send to user mode. It fills in the data and completes the irp. The user mode side does the processing and can send an irp down with reply information. You would then need to send down another request irp that would be pended.
If you need to do a lot of communication (as in encrypt/decrypt services) I would recommend having multiple user mode threads sending down multiple asynchronous irps each to cut down on the latency of processing operations.
A side benefit of this model is that from the filter you can tell when the user mode application goes away (even unexpectedly) because you will see the cleanup and close on your control device object.
There are other models as well such as setting up a piece of shared memory between user/kernel model and then synchronizing the access to the buffer.
Neal Christiansen
Microsoft File System Filter Group Lead
This posting is provided "AS IS" with no warranties, and confers no rights
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of Deepak.Singh
Sent: Monday, October 11, 2004 11:27 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] Callback to User mode application from IFS filter Driver
Hello,
?
How to make call to "User mode application functions"??from IFS filter driver. I have a COM dll / exe ,wanna access?its functionality
( Say? : encryption & decryption via streaming ) from the IFS filter driver code.Is it good idea to put CRYPTO API functionality into
the filter driver code ? If not , please suggest some workaround to achieve the encryption / decryption functionality from IFS filter
driver code or how to access the User mode application functions.
?
?
Many Thanx in Adv
Regards
deepak
?
Questions? First check the IFS FAQ at The NT Insider:Windows NT Virtual Memory (Part I)
You are currently subscribed to ntfsd as: unknown lmsubst tag argument: ''
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