On Wed, May 18, 2016 at 4:29 AM, Ingo Molnar <mi...@kernel.org> wrote: > > * Kees Cook <keesc...@chromium.org> wrote: > >> > I think there is something way more subtle going on here, and it bothers me >> > exactly because it is subtle. It may be that it is OK right now, but there >> > are alarm bells going on all over my brain on this. I'm going to stare at >> > this for a bit and see if I can make sense of it; but if it turns out that >> > what we have is something really problematic it might be better to apply a >> > big >> > hammer and avoid future breakage once and for all. >> >> Sounds good. I would just like to decouple this from the KASLR improvements. >> This fragility hasn't changed as a result of that work, but I'd really like >> to >> have that series put to bed -- I've spent a lot of time already cleaning up >> it >> and other areas of the compressed kernel code. :) > > So I disagree on that: while technically kASLR is independent of relocations, > your > series already introduced such a relocation bug and I don't want to further > increase complexity via kASLR without first increasing robustness.
Well, in my defense, the bug was never actually reachable. > So could we try something to either detect or avoid such subtle and hard to > debug > relocation bugs in very early boot code? I've sent this (the readelf patch which detects the bug from the KASLR series), but hpa wants to do a more comprehensive version. Could we temporarily use my version of this, since it appears to accomplish at least a subset of the new goal? And on a related topic, how would you like me to send Thomas Garnier's memory base randomization series? Pull request, or as a series like I've done with the other KASLR improvements? -Kees -- Kees Cook Chrome OS & Brillo Security
