4 ms·
Speculative execution seems like something that would be very intuitively insecure even to a layperson(relative to the field of course). I'm wondering, was thi
by debt 9y ago
Speculative execution seems like something that would be very intuitively insecure even to a layperson(relative to the field of course).
I'm wondering, was this vulnerability theorized first and later found out to be an actual vulnerability? Or was this something that nobody had any clue about?
I'm only saying this, because from a security perspective, I imagine somewhere at some point very early on someone had to have pointed out the potential for something like speculative execution to eventually cause security problems.
I just don't understand how chip designers assumed speculative execution wouldn't eventually cause security problems. Is it because chip designers were prioritizing performance above security?
- baybal2 9y agoLong time ago, in a far away office park there was an intense discussion over so called "flag early" and "flag after" designs. Flag early camp argument was - protected pages should not be allowed to be fetched to begin with by any insecure execution flow, and we need to pagefault before speculative execution The "flag after" camp was all for post-factum pagefaulting when the branch has finished execution, so you do not need to pagefault for every branch, and only do it for the branch that has "won" Chip design magazines from nineties has all that well covered.
- mark-r 9y agoSpeculative execution isn't supposed to leak information; if the speculative instructions aren't supposed to execute, all traces of them should be rolled back. I'd be curious to see what the details of this bug really are. I'm not sure how much will be disclosed in the interests of keeping exploits from popping up.
- dboreham 9y ago"all traces" includes timing differences in execution of non-privileged code, which it turns out are not rolled back.
- blattimwind 9y agoOr side-effects by loading data into the cache hierarchy.
- im3w1l 9y agohttps://news.ycombinator.com/item?id=14988652 https://news.ycombinator.com/item?id=14988652
- debt 9y agoIncredible that in this day and age that chip designers do not prioritize performance over security.
- userbinator 9y agoI think the chip designers never thought of security much: https://news.ycombinator.com/item?id=16062223 https://news.ycombinator.com/item?id=16062223 It's a similar situation to other timing attacks, which have been around practically as long as caches.
- djsumdog 9y agoAccording to this comment, it has been theorized for quite some time: https://news.ycombinator.com/item?id=16066165 https://news.ycombinator.com/item?id=16066165 With this particular computer scientist, who talked about this problem before, referenced in Google's paper: http://www.cs.binghamton.edu/~dima/ http://www.cs.binghamton.edu/~dima/