| Date | Wed, 22 Nov 2017 17:19:07 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH 00/23] KAISER: unmap most of the kernel from userspace page tables |
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Hi!
> KAISER makes it harder to defeat KASLR, but makes syscalls and > interrupts slower. These patches are based on work from a team at > Graz University of Technology posted here[1]. The major addition is > support for Intel PCIDs which builds on top of Andy Lutomorski's PCID > work merged for 4.14. PCIDs make KAISER's overhead very reasonable > for a wide variety of use cases.
Is it useful?
> Full Description: > > KAISER is a countermeasure against attacks on kernel address > information. There are at least three existing, published, > approaches using the shared user/kernel mapping and hardware features > to defeat KASLR. One approach referenced in the paper locates the > kernel by observing differences in page fault timing between > present-but-inaccessable kernel pages and non-present pages.
I mean... evil userspace will still be able to determine kernel's location using cache aliasing effects, right? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html [unhandled content-type:application/pgp-signature] |