Modifying read data buffers

NTFSD
1

Hi,

I am trying to decrypt data by trapping the IRP_MJ_READ. I allocate a MDl in my read routine and pass it as the context to the readcompletion routine. There is modify the UserBuffer in place – still I am not able to see the decrypted data – I can just see the previously encrypted data. I am just trying get encryption and decryption working for notepad files at present. Plz advice.

Thanx,
Prithvi

Do you Yahoo!?
Win a $20,000 Career Makeover at Yahoo! HotJobs

2

Prithvi,

Notepad can actually be the most difficult application to get working
properly, since it uses memory mapped files.

Are you encrypting/decrypting the data in-place? If so, you are placing
encrypted text into the version that Notepad “sees”.

Are you encrypting just paging I/O? User I/O? Non-cached I/O?

Telling us that your filter “doesn’t work” is a bit like saying (to any
experienced developer) “my program does not do what I intended it to do,
can you tell me what I’m doing wrong?” Without considerable detail as
to what you are doing it is unlikely anyone on this list can suggest the
solution to your problem.

Regards,

Tony

Tony Mason
Consulting Partner
OSR Open Systems Resources, Inc.
http://www.osr.com

From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Prithvi
Sent: Saturday, May 08, 2004 9:54 PM
To: ntfsd redirect
Subject: [ntfsd] Modifying read data buffers

Hi,

I am trying to decrypt data by trapping the IRP_MJ_READ. I allocate a
MDl in my read routine and pass it as the context to the readcompletion
routine. There is modify the UserBuffer in place – still I am not able
to see the decrypted data – I can just see the previously encrypted
data. I am just trying get encryption and decryption working for notepad
files at present. Plz advice.

Thanx,
Prithvi

Do you Yahoo!?
Win a $20,000 Career Makeover at Yahoo! HotJobs
http:ure_footer_textlink/evt=23983/*http://hotjobs.sweepstakes.yahoo.com/care
ermakeover> — Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17 You are currently subscribed
to ntfsd as: xxxxx@osr.com To unsubscribe send a blank email to
xxxxx@lists.osr.com</http:>