4 ms·
A fence of some kind that stops the speculation on access to protected address space would be better. Trying to stub out values would mean you have to throw th
by simcop2387 9y ago
A fence of some kind that stops the speculation on access to protected address space would be better. Trying to stub out values would mean you have to throw the speculation out anyway, and a fence could be setup to prevent access. This might still allow an attack on kaslr since you could use the timing of the speculation to determine if a fence got hit or not.
- AstralStorm 9y agoIt it's just one of timing attacks possible on x86. Cache miss timing has been used in the past to create covert channels and exfiltrate keys. Memory controller issues have been explored too. Modern general purpose CPUs sacrificed some security for performance. There are few security or performance guarantees. It is not an architecture geared to realtime and fully deterministic operation.
- akira2501 9y ago> Modern general purpose CPUs sacrificed some security for performance. I don't think that's a fair way of stating it. I think it's a case of independent performance improvements in branch prediction, cache architecture and out-of-order instruction retirement that on their own have negligible security impact but when combined in a single system reveal emergent behavior.