Re: [Linux-ima-user] Reading binary_runtime_measurements in a structure

[Lavina J. <lav...@gm...>]

Hi,

The binary format described in /Documentation/ima/INSTALL is as follows:

PCR#   Digest     Flags    Filename       Separator
32 bit || 20*8 bit || 32 bit || char[x<=40] || '\0'

I tried reading the binary file and figured out the format is actually
slightly different. There is a 32 bit field (all zeros) after PCR#,
filenames include full path rather than just the name and are greater than
40 characters as well. The separator is '\n'.

So the format is as follows:
PCR#   Zeros    Digest     Flags  Filename  Separator
32 bit || 32 bit || 20*8 bit || 32 bit || char[x] || '\n'

This works for me but I wonder why is it different from what is documented.
Is it dependent on kernel or platform?

Kind Regards,
Lavina


On Wed, Jul 30, 2008 at 6:23 AM, Reiner Sailer <sa...@us...> wrote:

> The format of the binary measurements is in the Documentation/ima/INSTALL
> file after patching the kernel. I believe the binary format is described is
> section 5.
>
> The binary format for each measurement has one variable length field (the
> name and path of the file being measured) which is the last parameter.
>
> There should also be some open-source code in the TrouSerS TSS stack
> implementation that reads those measurements, but I have not looked at this
> so this is a guess.
> [TrouSerS: http://trousers.sourceforge.net/]
>
> Reiner
>
>
>
>
>  From:       "Lavina Jain" <lav...@gm...>
>
>  To:         lin...@li...
>
>  Cc:         lav...@gm...
>
>  Date:       07/30/2008 03:25 AM
>
>  Subject:    [Linux-ima-user] Reading binary_runtime_measurements in a
> structure
>
>
>
>
>
>
> Hi,
>
> I was wondering whether it is possible to read an entry in
> binary_runtime_measurements in a C structure using a C program. Can
> somebody please explain the format of the binary file.
>
> Is there any application or code already available that verifies a PCR
> aggregate against measurement list.
>
> Kind Regards,
> Lavina
>
> --
> "Unravelling life's mysteries and discovering life's secrets may take the
> courage and determination found only in a self-motivated pursuit."
> - Peter McWilliams
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-- 
"Unravelling life's mysteries and discovering life's secrets may take the
courage and determination found only in a self-motivated pursuit."
- Peter McWilliams