Driver Problems? Questions? Issues?
Put OSR's experience to work for you! Contact us for assistance with:
  • Creating the right design for your requirements
  • Reviewing your existing driver code
  • Analyzing driver reliability/performance issues
  • Custom training mixed with consulting and focused directly on your specific areas of interest/concern.
Check us out. OSR, the Windows driver experts.

On-Access, Transparent, Per-File Data Encryption:

OSR's File Encryption Solution Framework (FESF) provides all the infrastructure you need to build a transparent file encryption product REALLY FAST.

Super flexible policy determination and customization, all done in user-mode. Extensive starter/sample code provided.

Proven, robust, flexible. In use in multiple commercial products.

Currently available on Windows. FESF for Linux will ship in 2018.

For more info: https://www.osr.com/fesf

Go Back   OSR Online Lists > ntfsd
Welcome, Guest
You must login to post to this list
  Message 1 of 1  
17 Mar 17 07:13
Mauro Leggieri
xxxxxx@mauroleggieri.com
Join Date: 02 Jun 2016
Posts To This List: 29
FilterGetMessage and insufficient buffers

Hi, Because couldn't find documentation nor samples, I did some reverse engineering on FilterGetMessage/FltSendMessage/etc. calls and would like to confirm the behavior if the buffer that receives a message or reply from/to driver is not large enough. Based on what I see, assuming we are sending a message from driver to usermode 1) If buffer size of FilterGetMessage is small, the API will return ERROR_INSUFFICIENT_BUFFER or ERROR_MORE_DATA and we can retry the call using a larger buffer. FltSendMessage will wait for a new request from usermode. 2) When we call FilterReplyMessage with a larger buffer FltSendMessage expects to receive, FltSendMessage will return STATUS_BUFFER_OVERFLOW or STATUS_BUFFER_TOO_SMALL. Usermode will get the win32 error. Sounds right? Regards, Mauro.
Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You must login to OSR Online AND be a member of the ntfsd list to be able to post.

All times are GMT -5. The time now is 07:20.


Copyright ©2015, OSR Open Systems Resources, Inc.
Based on vBulletin Copyright ©2000 - 2005, Jelsoft Enterprises Ltd.
Modified under license