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  Message 1 of 6  
01 Aug 18 02:21
vidhya
xxxxxx@yahoo.co.in
Join Date: 05 Jan 2018
Posts To This List: 16
query in File system Mini filter driver

I need to send a internal IRP from mini filter driver to my volume filter driver sitting above volsnap. I need to get the FltObjects->FileObject->Vpb->Realdevice device object from my file system mini filter driver. when I tried accessing this pointer my system crashed. Later on I discovered that my FltObjects->FileObject is always NULL. In which cases this file object will be NULL.I am trying to access FileObject in my Precallback routine which I have registered for IRP_MJ_MOUNT_VOLUME. Is there a way to get the volume filter driver's device object from mini filter driver. I used FltGetDeviceObject and IoGetAttachedDevice in sequence thinking that it is the other way to get Vpb->Realdevice. But when I used FltGetDeviceObject and IoGetAttachedDevice function the device object that I get doesn't match any object in deviceTree. I am not sure what objects I getting when I use these functions FltGetDeviceObject and IoGetAttachedDevice. Any inputs on this would be helpful
  Message 2 of 6  
01 Aug 18 03:47
rod widdowson
xxxxxx@steadingsoftware.com
Join Date: 11 Sep 2006
Posts To This List: 869
query in File system Mini filter driver

> I used FltGetDeviceObject and IoGetAttachedDevice in sequence I think you need IoGetDeviceAttachmentBaseRef; from the Fine Manual: > IoGetAttachedDevice returns the highest-level device attached to the > specified device. > The IoGetDeviceAttachmentBaseRef routine returns a pointer to the > lowest-level device object in a file system or device driver stack. You'll need to check, but I'm pretty sure that this is the File System device. /Rod
  Message 3 of 6  
01 Aug 18 05:20
vidhya
xxxxxx@yahoo.co.in
Join Date: 05 Jan 2018
Posts To This List: 16
query in File system Mini filter driver

I have tried using IoGetDeviceAttachmentBaseRef also..but I am not getting the device object of my volume filter driver. Infact the device object pointer which I get as output is not seen anywhere in deviceTree utility. I thought that deviceTree shows all the device objects in the machine. But looks like its not the case or am I missing something so obvious.
  Message 4 of 6  
03 Aug 18 05:16
NtDev Geek
xxxxxx@gmail.com
Join Date: 09 Aug 2013
Posts To This List: 43
query in File system Mini filter driver

yes it is very common to see FltObjects->FileObject is always NULL. ./nT
  Message 5 of 6  
03 Aug 18 06:24
vidhya
xxxxxx@yahoo.co.in
Join Date: 05 Jan 2018
Posts To This List: 16
query in File system Mini filter driver

Is there a way to get the volume filter driver's device object from mini filter driver. I need to get the FltObjects->FileObject->Vpb->Realdevice device object for which the Mount Request is targeted from my file system mini filter driver.
  Message 6 of 6  
03 Aug 18 13:24
Jamey Kirby
xxxxxx@gmail.com
Join Date: 31 Dec 2014
Posts To This List: 58
query in File system Mini filter driver

I think maybe you are over architecting your filter. You don't need any of that stuff for what you are trying to achieve. I went down that road once, and backed out quickly. Keep it simple. On Fri, Aug 3, 2018 at 6:23 AM xxxxx@yahoo.co.in < xxxxx@lists.osr.com> wrote: > Is there a way to get the volume filter driver's device object from mini > filter driver. > > I need to get the FltObjects->FileObject->Vpb->Realdevice device object > for which the Mount Request is targeted from my file system mini filter > driver. > > > > <...excess quoted lines suppressed...> -- Jamey Kirby Disrupting the establishment since 1964 *This is a personal email account and as such, emails are not subject to archiving. Nothing else really matters.* --
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