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Moving physical pages from user space

Moving physical pages from user space

Posted Sep 18, 2023 15:33 UTC (Mon) by NightMonkey (subscriber, #23051)
Parent article: Moving physical pages from user space

I am confident that there would be many eyes on all patches resulting from this conversation, and my ignorance is vast, but this would seem to open the "attack surface" of the kernel wider. Wouldn't you have to worry more about unauthorized attempts to access memory allocated to other processes? Or devices driver mapped memory?

And what about subtle interactions between the mechanisms used for virtual mappings and physical mapping by the kernel? If these subsystems are not "aware" of each other, could new bugs be introduced that would be hard to test for?

I'm not saying I believe one path or the other are better, but the security angle seems interesting here.

Cheers!

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Moving physical pages from user space

Posted Sep 18, 2023 18:14 UTC (Mon) by alonz (subscriber, #815) [Link]

Another potential security issue is that moving pages to a slower memory tier can help attackers using timing side channels.

Moving physical pages from user space

Posted Sep 19, 2023 2:45 UTC (Tue) by florianfainelli (subscriber, #61952) [Link] (1 responses)

Would a system call taking a PID work a bit better, security wise, while still meeting the initial intent?

Moving physical pages from user space

Posted Oct 2, 2023 8:40 UTC (Mon) by kaesaecracker (subscriber, #126447) [Link]

I think it might make it better, because you could add rules for which process can influence which process and because it would not tell you the physical addresses


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