On Tue 2018-07-24 14:47:54, Oliver Neukum wrote: > On Di, 2018-07-24 at 14:01 +0200, Pavel Machek wrote: > > Hi! > > > > > > > > "There have some functions be locked-down because > > > > > > there have no appropriate mechanisms to check the > > > > > > integrity of writing data." > > > > > > https://patchwork.kernel.org/patch/10476751/ > > > > > > > > > > So your goal is to make hibernation compatible with kernel > > > > > lockdown? Do your patches provide sufficient security that hibernation > > > > > can be enabled with kernel lockdown? > > > > > > > > OK, maybe I am dense, but if the key comes from user space, will that > > > > be enough? > > > > > > > > > > Good point, we once tried to generate key in kernel, but people > > > suggest to generate key in userspace and provide it to the > > > kernel, which is what ecryptfs do currently, so it seems this > > > should also be safe for encryption in kernel. > > > > Safe against what kind of attack? Please describe what kind of > > security you are trying to provide. > > Unsigned code must not take over the priviledge level of signed code. > Hence: > > 1. Unsigned code must not allowed to read sensitive parts of signed > code's memory space > > 2. Unsigned code must not be able to alter the memory space of > signed code -> snapshots that are changed must not be able to be > resumed Ok. > > I don't think generating key in userspace is good enough for providing > > guarantees for secure-boot. > > Why? Because then, userpace has both key (now) and encrypted image (after reboot), so it can decrypt, modify, re-encrypt...? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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