3 ms·

This is deeply interesting. I've sometimes contemplated the possibility of doing things like this to guard against memory errors causing mis-entry to particula

This is deeply interesting. I've sometimes contemplated the possibility of doing things like this to guard against memory errors causing mis-entry to particularly critical control flow paths - this is certainly an example of that. But never heard of anyone actually trying to do this until now. A "how to write rowhammer-resistant code" writeup would definitely be useful here - even if it is definitely something people cannot do for anything, I can certainly see cases where there is a case for it.

Palomides 3y ago
it's a long-known hazard in embedded and highly reliable systems, there are terms like "single-event upset" that might lead you in interesting directions
- addaon 3y ago
  Single event upsets are well-understood and easy (although not necessarily cheap) to mitigate in hardware -- ECC for RAM, CRCs for data in flight, and voting (or lockstep if detection is sufficeint) for computation. The challenge with Rowhammer is that it involves multiple, correlated bit flips; and depending on details of your system the correlations may be disguised by various remapping layers.
wongarsu 3y ago
I remember someone making a rust library for hardened bools, though with the idea of protecting against protecting against random bitflips, not targeted rowhammer attacks (though it should work about the same). The feedback from the rust subreddit was basically protecting the bool but not the if statement is of limited use. Potentially it can even make it worse, since there is now more code being executed that might become bitflipped. That inspired me to make a crate that periodically checksums your program code while it's running, to make sure it hasn't changed. Got it working on Windows and Linux, but then it ended up like most side projects. Maybe I should polish it up and publish it.

3 ms·

This is deeply interesting. I've sometimes contemplated the possibility of doing things like this to guard against memory errors causing mis-entry to particula

by hlandau 3y ago

Palomides 3y ago
it's a long-known hazard in embedded and highly reliable systems, there are terms like "single-event upset" that might lead you in interesting directions
- addaon 3y ago
  Single event upsets are well-understood and easy (although not necessarily cheap) to mitigate in hardware -- ECC for RAM, CRCs for data in flight, and voting (or lockstep if detection is sufficeint) for computation. The challenge with Rowhammer is that it involves multiple, correlated bit flips; and depending on details of your system the correlations may be disguised by various remapping layers.
wongarsu 3y ago
I remember someone making a rust library for hardened bools, though with the idea of protecting against protecting against random bitflips, not targeted rowhammer attacks (though it should work about the same). The feedback from the rust subreddit was basically protecting the bool but not the if statement is of limited use. Potentially it can even make it worse, since there is now more code being executed that might become bitflipped. That inspired me to make a crate that periodically checksums your program code while it's running, to make sure it hasn't changed. Got it working on Windows and Linux, but then it ended up like most side projects. Maybe I should polish it up and publish it.