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Software components for data protection, secure storage and transfer

extented attributes (encrypted, compressed)

Also by EldoS: Solid File System
A virtual file system that offers a feature-rich storage for application documents and data with built-in compression and encryption.
#18444
Posted: 12/12/2011 04:48:46
by Kalle Seybold (Standard support level)
Joined: 11/24/2011
Posts: 16

Hello,

I evaluating you CBFS and I want to use the extented attributes like compressed and encryted.

Is this possible? Do you have any sample code how to use it?

Furthermore; Is there a sample code for

OnGetFileSecurity
OnSetFileSecurity

?

Best regards
Kalle
#18451
Posted: 12/12/2011 09:39:43
by Volodymyr Zinin (EldoS Corp.)

Quote
Kalle Seybold wrote:
I evaluating you CBFS and I want to use the extented attributes like compressed and encryted.

Is this possible? Do you have any sample code how to use it?

Just return such attributes from the OnGetFileInfo and OnEnumerateDirectory callbacks. CallbackFS does nothing extra with it.


Quote
Kalle Seybold wrote:
Furthermore; Is there a sample code for

OnGetFileSecurity OnSetFileSecurity

?

See the Mapper sample source code. BTW these callbacks are optional and if they are not implemented it means the file system doesn't support security (like FATFS). But of course you can still have some security by checking in the OnCreate and OnOpen callbacks what a process requests to open a file and return some error (usually ERROR_ACCESS_DENIED). In this case the originator of the create/open file request won't obtain a handle to a file and won't be able to work with it.
#18455
Posted: 12/12/2011 12:12:28
by Kalle Seybold (Standard support level)
Joined: 11/24/2011
Posts: 16

Just returning the attributes does not work.
On NTFS rigt click file -> properties -> a button is shown for the extented attributes, on CBSF I get only the standard attributes, but no button for the extented attributes (see attached pdf , rename to pdf). Any idea?


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#18456
Posted: 12/12/2011 12:25:48
by Eugene Mayevski (EldoS Corp.)

1) Have you implemented security-related callbacks?
2) Have you set the filesystem name to NTFS?


Sincerely yours
Eugene Mayevski
#18459
Posted: 12/12/2011 13:29:02
by Volodymyr Zinin (EldoS Corp.)

It seems the problem is because CallbackFS doesn't returns appropriate flags when the system asks about it. Actually it's the FILE_SUPPORTS_ENCRYPTION and FILE_FILE_COMPRESSION flags of the FILE_FS_ATTRIBUTE_INFORMATION structure which are returned during the IRP_MJ_QUERY_VOLUME_INFORMATION (for details see MSDN).
I think it's possible in future releases to allow these flags to set. But why is it necessary for you?
#18462
Posted: 12/13/2011 03:44:34
by Kalle Seybold (Standard support level)
Joined: 11/24/2011
Posts: 16

We are devoloping a custom-solution where we merge data from diffent sources into a virtual file system. But some of the data are encrypted and some sould be marked comming from a specific source(that would be compressed).

Windows explorer shows encrypted and copmpressed files in a diffent colour.
So these attributes are a way to give the user more informationen.

What do you think, when are you supporting these flages (days, weeks, mounth, years)?
Also by EldoS: CallbackDisk
Create virtual disks backed by memory or custom location, expose disk images as disks and more.

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