Hi! > On Fri, Oct 28, 2016 at 01:21:36PM +0200, Pavel Machek wrote: > > > Has this been tested on a system vulnerable to rowhammer, and if so, was > > > it reliable in mitigating the issue? > > > > > > Which particular attack codebase was it tested against? > > > > I have rowhammer-test here, > > > > commit 9824453fff76e0a3f5d1ac8200bc6c447c4fff57 > > Author: Mark Seaborn <mseab...@chromium.org> > > ... from which repo? > > > I do not have vulnerable machine near me, so no "real" tests, but > > I'm pretty sure it will make the error no longer reproducible with the > > newer version. [Help welcome ;-)] > > Even if we hope this works, I think we have to be very careful with that > kind of assertion. Until we have data is to its efficacy, I don't think > we should claim that this is an effective mitigation.
Ok, so it turns out I was right. On my vulnerable machine, normally bug is reproducible in less than 500 iterations: Iteration 432 (after 1013.31s) error at 0xda7cf280: got 0xffffffffffffffef Iteration 446 (after 1102.56s) error at 0xec21ea00: got 0xffffffefffffffff Iteration 206 (after 497.50s) error at 0xd07d1438: got 0xffffffffffffffdf Iteration 409 (after 1350.96s) error at 0xbd3b9108: got 0xefffffffffffffff Iteration 120 (after 326.08s) error at 0xe398c438: got 0xffffffffffffffdf With nohammer, I'm at 2300 iterations, and still no faults. Daniel Gruss <dan...@gruss.cc> claims he has an attack that can do 30 flips a second on modern hardware. I'm not going to buy broken hardware just for a test. Code is at https://github.com/IAIK/rowhammerjs/tree/master/native . Would someone be willing to get it running on vulnerable machine and test kernel patches? Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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