[wdmaudiodev] Re: Capturing protected audio using MS Detours
- From: ambrish dantrey <a4ambrish@xxxxxxxxx>
- To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>, Matthew.van.Eerde@xxxxxxxxxxxxx
- Date: Thu, 5 Sep 2013 01:36:58 +0530
Thanks Matthew for your answer.
What does control of player mean here?
Let me give you an example. If I had a bluray disk with protected audio
data, I can't directly read it since data is encrypted. Only some trusted
playback applications (e.g. Cyberlink PowerDVD) have keys to decrypt it.
These playback applications use DRM calls to make sure there is a trusted
audio driver to handle protected data. Once DRM calls succeed they start
sending data over to driver through GetBuffer() and ReleaseBuffer() calls.
The assumption is that once DRM calls succeed, it is safe to hand over
decrypted data to OS (and driver).
However, I can easily inject detoured functions into PowerDVD process and
capture the decrypted data. I don't need source code of player or any other
authentication.
Doesn't this represent a hole in DRM pipeline?
Thanks and regards,
Ambrish
On Wed, Sep 4, 2013 at 10:10 PM, Matthew van Eerde <
Matthew.van.Eerde@xxxxxxxxxxxxx> wrote:
> Sure, you can do that, but at that point you’re already on the other
> side of the airtight hatchway. If you have control of the player, you don’t
> need detours at all; you can just read the data directly from the source.*
> ***
>
> ** **
>
> *From:* wdmaudiodev-bounce@xxxxxxxxxxxxx [mailto:
> wdmaudiodev-bounce@xxxxxxxxxxxxx] *On Behalf Of *ambrish dantrey
> *Sent:* Wednesday, September 4, 2013 9:35 AM
> *To:* wdmaudiodev@xxxxxxxxxxxxx
> *Subject:* [wdmaudiodev] Capturing protected audio using MS Detours****
>
> ** **
>
> I just did a POC which captures audio data using MS detours. All I did was
> to detour GetBuffer() and ReleaseBuffer() calls and dump audio data in a
> file. I have tested it out and it seem to be working fine.****
>
> I was wondering how this POC will behave with protected content (HBR audio
> data usually available with BDs). Will it be able to capture protected data?
> ****
>
> ** **
>
> I have no intention of capturing protected content. It's just that I don't
> see anything preventing someone from ripping protected audio content using
> MS detours and was wondering if Microsoft puts in some sort of checks to
> prevent it. (e.g. restriction on protected audio playback if detour.dll is
> loaded in process).****
>
> Thanks and regards,
> Ambrish****
>
> ** **
>
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