Messages in this thread | | | Subject | Re: Some highmem pages still in use after shrink_all_memory()? | From | Nigel Cunningham <> | Date | Mon, 08 Mar 2004 18:41:40 +1300 |
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Hi.
On Mon, 2004-03-08 at 19:36, Andy Isaacson wrote: > Note that there are some applications for which it is a *bug* if an > mlocked page gets written out to magnetic media. (gpg, for example.) > I imagine that they'd rather lose the mapping and get a page fault on > the next reference (which they can then fix up with a new mmap and > mlock) than have precious key material written to disk.
For such an application, we'd have to provide a mechanism to allow an application to set/clear a page's Nosave flag. We'd probably also want to be able to notify user space that a suspend cycle has just occurred and the page contents are invalid.
> However, I don't see how to implement a cryptographically secure swsusp.
It would be possible with Suspend2 - one could implement a backend (page transformer or writer) that implemented encryption and required the user to enter a passphrase at resume time.
> (The importance of this behavior is obviously dependent on your threat > model. Perhaps the Sufficiently Paranoid gpg users will simply need to > avoid using swsusp.)
Yes. Or close all gpg apps before suspending?
Nigel
-- Nigel Cunningham C/- Westminster Presbyterian Church Belconnen 61 Templeton Street, Cook, ACT 2614. +61 (2) 6251 7727(wk); +61 (2) 6253 0250 (home)
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