Writes to port 0x64, 0xcf9 etc.

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Kamala
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Joined: Sun Nov 28, 2010 11:03 am

Writes to port 0x64, 0xcf9 etc.

Post by Kamala »

Hi,

When I try to write to port 0x64 (keyboard controller command port), 0xcf9 etc. to reset the system, it works under Fedora, Debian but not under Windows or Ubuntu. It looks like I am missing something obvious that Windows/Ubuntu does while others don't or vise versa. Would you happen to know what it might be? Thanks.

Kamala
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Brendan
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Re: Writes to port 0x64, 0xcf9 etc.

Post by Brendan »

Hi,
Kamala wrote:When I try to write to port 0x64 (keyboard controller command port), 0xcf9 etc. to reset the system, it works under Fedora, Debian but not under Windows or Ubuntu. It looks like I am missing something obvious that Windows/Ubuntu does while others don't or vise versa. Would you happen to know what it might be?
I'm not too sure what might be causing the security vulnerability in Fedora or Debian. I'd assume that you're running a normal process as "root" on these systems, and they're still using some sort of antiquated "let root be malicious in case it's a video driver in user space" design flaw.


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Brendan
For all things; perfection is, and will always remain, impossible to achieve in practice. However; by striving for perfection we create things that are as perfect as practically possible. Let the pursuit of perfection be our guide.
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Gigasoft
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Re: Writes to port 0x64, 0xcf9 etc.

Post by Gigasoft »

I'm not too sure what might be causing the security vulnerability in Fedora or Debian. I'd assume that you're running a normal process as "root" on these systems, and they're still using some sort of antiquated "let root be malicious in case it's a video driver in user space" design flaw.
I guess it would be this: http://linux.die.net/man/2/iopl
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Kamala
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Re: Writes to port 0x64, 0xcf9 etc.

Post by Kamala »

Yes, I was running as root on all three distros to test this and it is the same code. I suspect Windows and Ubuntu disables something in an attempt to render the operations I am attempting on those ports ineffective (system reset) while Debian and Fedora does not. I understand it is likely Windows/Ubuntu are rendering those ops ineffective for the sake of security. But, I am trying to find out what it is Windows/Ubuntu does that Debian/Fedora does not. Thanks.

Kamala
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