Hi All,
I am working on a enryption application using minifilter driver.
I want to clear window’s cache for related file by using CC routines flushdata & purgecachesection. Is it fine if I will do this(purging of cache) in create post callback.(Any drawback apart from performance hit).
Reason to do so is that my application does not load at startup although my minifilter do(but simply skip calls untill application starts), so if somebody access files prior to filter load than it will result in encrypted data in cache.
So i just want to clear cache for related files before my application starts & after my application stops.
Any Suggestions.
It’ll work as long as the file is not memory mapped at that point.
xxxxx@gmail.com wrote:
Hi All,
I am working on a enryption application using minifilter driver.
I want to clear window’s cache for related file by using CC routines flushdata & purgecachesection. Is it fine if I will do this(purging of cache) in create post callback.(Any drawback apart from performance hit).
Reason to do so is that my application does not load at startup although my minifilter do(but simply skip calls untill application starts), so if somebody access files prior to filter load than it will result in encrypted data in cache.
So i just want to clear cache for related files before my application starts & after my application stops.
Any Suggestions.
Questions? First check the IFS FAQ at https://www.osronline.com/article.cfm?id=17
You are currently subscribed to ntfsd as: xxxxx@alfasp.com
To unsubscribe send a blank email to xxxxx@lists.osr.com
–
King regards, Dejan
http://www.alfasp.com
File system audit, security and encryption kits.
Just curious. Is there anyone here *not* working on an encryption driver?
----- Original Message -----
From:
To: “Windows File Systems Devs Interest List”
Sent: Thursday, November 09, 2006 2:58 AM
Subject: [ntfsd] Clearing cache in Post Create Callback of minifilter
> Hi All,
>
> I am working on a enryption application using minifilter driver.
>
> I want to clear window’s cache for related file by using CC routines
> flushdata & purgecachesection. Is it fine if I will do this(purging of
> cache) in create post callback.(Any drawback apart from performance hit).
>
> Reason to do so is that my application does not load at startup although
> my minifilter do(but simply skip calls untill application starts), so if
> somebody access files prior to filter load than it will result in
> encrypted data in cache.
>
> So i just want to clear cache for related files before my application
> starts & after my application stops.
>
> Any Suggestions.
>
> —
> Questions? First check the IFS FAQ at
> https://www.osronline.com/article.cfm?id=17
>
> You are currently subscribed to ntfsd as: xxxxx@netlib.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>
Me. 
–
Slava Imameyev, xxxxx@hotmail.com
“Neil Weicher” wrote in message news:xxxxx@ntfsd…
> Just curious. Is there anyone here not working on an encryption driver?
>
> ----- Original Message -----
> From:
> To: “Windows File Systems Devs Interest List”
> Sent: Thursday, November 09, 2006 2:58 AM
> Subject: [ntfsd] Clearing cache in Post Create Callback of minifilter
>
>
>> Hi All,
>>
>> I am working on a enryption application using minifilter driver.
>>
>> I want to clear window’s cache for related file by using CC routines
>> flushdata & purgecachesection. Is it fine if I will do this(purging of
>> cache) in create post callback.(Any drawback apart from performance hit).
>>
>> Reason to do so is that my application does not load at startup although
>> my minifilter do(but simply skip calls untill application starts), so if
>> somebody access files prior to filter load than it will result in
>> encrypted data in cache.
>>
>> So i just want to clear cache for related files before my application
>> starts & after my application stops.
>>
>> Any Suggestions.
>>
>> —
>> Questions? First check the IFS FAQ at
>> https://www.osronline.com/article.cfm?id=17
>>
>> You are currently subscribed to ntfsd as: xxxxx@netlib.com
>> To unsubscribe send a blank email to xxxxx@lists.osr.com
>>
>
>
> Just curious. Is there anyone here *not* working on an encryption driver?
Sure there is, but data encryption filter is apparently the most
wanted one and also mostly underestimated one.
Lots of people (and lots of project managers apparently) think
that they do it like “Okay we take FileSpy sources and we just add a few
lines of code into IRP_MJ_READ handler and it will work”.
L.
I just started: be prepared for stupid questions…I count on your kind
understanding
“Neil Weicher” wrote in message news:xxxxx@ntfsd…
> Just curious. Is there anyone here not working on an encryption driver?
>
> ----- Original Message -----
> From:
> To: “Windows File Systems Devs Interest List”
> Sent: Thursday, November 09, 2006 2:58 AM
> Subject: [ntfsd] Clearing cache in Post Create Callback of minifilter
>
>
>> Hi All,
>>
>> I am working on a enryption application using minifilter driver.
>>
>> I want to clear window’s cache for related file by using CC routines
>> flushdata & purgecachesection. Is it fine if I will do this(purging of
>> cache) in create post callback.(Any drawback apart from performance hit).
>>
>> Reason to do so is that my application does not load at startup although
>> my minifilter do(but simply skip calls untill application starts), so if
>> somebody access files prior to filter load than it will result in
>> encrypted data in cache.
>>
>> So i just want to clear cache for related files before my application
>> starts & after my application stops.
>>
>> Any Suggestions.
>>
>> —
>> Questions? First check the IFS FAQ at
>> https://www.osronline.com/article.cfm?id=17
>>
>> You are currently subscribed to ntfsd as: xxxxx@netlib.com
>> To unsubscribe send a blank email to xxxxx@lists.osr.com
>>
>
>
“Ladislav Zezula” wrote in message news:xxxxx@ntfsd…
> Lots of people (and lots of project managers apparently) think
> that they do it like “Okay we take FileSpy sources and we just add a few
> lines of code into IRP_MJ_READ handler and it will work”.
>
You’ve gotten that right, I have had at least two firms (one of which
should know better) that approached me with we need an encryption filter
next month… They just don’t get it.
–
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
http://www.windrvr.com
Remove StopSpam from the email to reply
ROFL! Not me, I’m working in user mode nowadays 
Neil Weicher wrote:
Just curious. Is there anyone here *not* working on an encryption driver?
----- Original Message -----
From:
> To: “Windows File Systems Devs Interest List”
> Sent: Thursday, November 09, 2006 2:58 AM
> Subject: [ntfsd] Clearing cache in Post Create Callback of minifilter
>
> > Hi All,
> >
> > I am working on a enryption application using minifilter driver.
> >
> > I want to clear window’s cache for related file by using CC routines
> > flushdata & purgecachesection. Is it fine if I will do this(purging of
> > cache) in create post callback.(Any drawback apart from performance hit).
> >
> > Reason to do so is that my application does not load at startup although
> > my minifilter do(but simply skip calls untill application starts), so if
> > somebody access files prior to filter load than it will result in
> > encrypted data in cache.
> >
> > So i just want to clear cache for related files before my application
> > starts & after my application stops.
> >
> > Any Suggestions.
> >
> > —
> > Questions? First check the IFS FAQ at
> > https://www.osronline.com/article.cfm?id=17
> >
> > You are currently subscribed to ntfsd as: xxxxx@netlib.com
> > To unsubscribe send a blank email to xxxxx@lists.osr.com
> >
>
> —
> Questions? First check the IFS FAQ at https://www.osronline.com/article.cfm?id=17
>
> You are currently subscribed to ntfsd as: xxxxx@alfasp.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
–
King regards, Dejan
http://www.alfasp.com
File system audit, security and encryption kits.
I guess my marketing is either so bad that noone approached me with such requests
(I have off the shelf products for encryption:-), or I really need to add headers
even though it will cause endless BSODs 
Don Burn wrote:
“Ladislav Zezula” wrote in message news:xxxxx@ntfsd…
> > Lots of people (and lots of project managers apparently) think
> > that they do it like “Okay we take FileSpy sources and we just add a few
> > lines of code into IRP_MJ_READ handler and it will work”.
> >
> You’ve gotten that right, I have had at least two firms (one of which
> should know better) that approached me with we need an encryption filter
> next month… They just don’t get it.
–
King regards, Dejan
http://www.alfasp.com
File system audit, security and encryption kits.
Me too
“Slava Imameyev” wrote in message news:xxxxx@ntfsd…
> Me.
>
> –
> Slava Imameyev, xxxxx@hotmail.com
>
>
> “Neil Weicher” wrote in message news:xxxxx@ntfsd…
>> Just curious. Is there anyone here not working on an encryption
>> driver?
>>
>> ----- Original Message -----
>> From:
>> To: “Windows File Systems Devs Interest List”
>> Sent: Thursday, November 09, 2006 2:58 AM
>> Subject: [ntfsd] Clearing cache in Post Create Callback of minifilter
>>
>>
>>> Hi All,
>>>
>>> I am working on a enryption application using minifilter driver.
>>>
>>> I want to clear window’s cache for related file by using CC routines
>>> flushdata & purgecachesection. Is it fine if I will do this(purging of
>>> cache) in create post callback.(Any drawback apart from performance
>>> hit).
>>>
>>> Reason to do so is that my application does not load at startup although
>>> my minifilter do(but simply skip calls untill application starts), so if
>>> somebody access files prior to filter load than it will result in
>>> encrypted data in cache.
>>>
>>> So i just want to clear cache for related files before my application
>>> starts & after my application stops.
>>>
>>> Any Suggestions.
>>>
>>> —
>>> Questions? First check the IFS FAQ at
>>> https://www.osronline.com/article.cfm?id=17
>>>
>>> You are currently subscribed to ntfsd as: xxxxx@netlib.com
>>> To unsubscribe send a blank email to xxxxx@lists.osr.com
>>>
>>
>>
>
>
>
>It’ll work as long as the file is not memory mapped at that point.
I know this as it is mentioned in documentation.
I am maintaining an Strem Context which I set at post create(if one not already exist).
And I am purging cache only if i am getting no Stream Context for the FileObject.
I just want to know that is there any flaw in this flow which can lead to data corruption issues.