Windows System Software -- Consulting, Training, Development -- Unique Expertise, Guaranteed Results

Home NTDEV

More Info on Driver Writing and Debugging


The free OSR Learning Library has more than 50 articles on a wide variety of topics about writing and debugging device drivers and Minifilters. From introductory level to advanced. All the articles have been recently reviewed and updated, and are written using the clear and definitive style you've come to expect from OSR over the years.


Check out The OSR Learning Library at: https://www.osr.com/osr-learning-library/


Before Posting...

Please check out the Community Guidelines in the Announcements and Administration Category.

Effect of opening/getting a handle to a file vs obreferenceobjectbyhandle on deleting the file?

brad_Hbrad_H Member Posts: 29
edited April 26 in NTDEV

Hi all

If i understand correctly, if you have a open handle on a file, whether you got this handle in kernel or user-mode, you can't delete the file simply via explorer, and you have to close the handle (but correct me if Im wrong)

But what about the case that you only incremented the reference count by something like obreferenceobjectbyhandle?
lets say i get the handle, then use obreferenceobjectbyhandle, later on i only need to use ObDereferenceObject to close the handle right? or do i need to use both obreferenceobjectbyhandle and also close the handle as well, so the file could get deleted later on without problem?

can i just close the handle right after i do obreferenceobjectbyhandle if i only want to work the file file_object and not the handle?

Comments

  • brad_Hbrad_H Member Posts: 29

    I also forgot to mention that i call FltCreateFile before calling obreferenceobjectbyhandle, so i assume the reference count is incremented by two now right? basically my question is how can i properly close this file after I am done using the file object? (and i only need the file object not the handle, also note that i know there are better ways to do this, for example by using FltCreateFileEx, but thats for another day..)

Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Upcoming OSR Seminars
OSR has suspended in-person seminars due to the Covid-19 outbreak. But, don't miss your training! Attend via the internet instead!
Developing Minifilters 24 May 2021 Live, Online
Writing WDF Drivers 14 June 2021 Live, Online
Internals & Software Drivers 27 September 2021 Live, Online
Kernel Debugging 15 November 2021 Live, Online