Re: Palladium and buffer over runs

2002-08-30 Thread Ben Laurie

bear wrote:
 
 On Thu, 29 Aug 2002, Frank Andrew Stevenson wrote:
 
 
What is there to prevent that one single undisclosed buffer overrun bug in
a component such as Internet Explorer won't shoot down the whole DRM
scheme of Palladium ? Presumably IE will be able to run while the machine
is in a trusted state, but if the IE can be subverted by injecting
compromising code through a buffer overrun, the security of DRM material
that is viewed in one window could be compromised through malicious code
that has been introduced through another browser window.
 
 
 It's my understanding of Palladium that it can enforce a separate
 data space for applications by creating a memory space which is
 encrypted with a key known to only that application.
 
 Given that, I think a cracker could subvert IE normally, but that
 wouldn't result in any access to the protected space of any other
 applications.  And as long as IE is actually separate from your
 OS (if you're running it on your Mac, or under WINE from Linux,
 for example), it shouldn't give him/her access to anything
 inside the OS.

Apart from the content being accessed by IE, of course, which is quite 
likely to be the stuff that is supposed to be DRMed. Oh, but Palladium 
isn't for that. I forgot.

Cheers,

Ben.

-- 
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Re: Palladium and buffer over runs

2002-08-29 Thread bear



On Thu, 29 Aug 2002, Frank Andrew Stevenson wrote:


What is there to prevent that one single undisclosed buffer overrun bug in
a component such as Internet Explorer won't shoot down the whole DRM
scheme of Palladium ? Presumably IE will be able to run while the machine
is in a trusted state, but if the IE can be subverted by injecting
compromising code through a buffer overrun, the security of DRM material
that is viewed in one window could be compromised through malicious code
that has been introduced through another browser window.

It's my understanding of Palladium that it can enforce a separate
data space for applications by creating a memory space which is
encrypted with a key known to only that application.

Given that, I think a cracker could subvert IE normally, but that
wouldn't result in any access to the protected space of any other
applications.  And as long as IE is actually separate from your
OS (if you're running it on your Mac, or under WINE from Linux,
for example), it shouldn't give him/her access to anything
inside the OS.

Bear


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