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Any chance that Meltdown or Spectre were not backdoors (statistically)?

by yorby 9y ago

PhantomGremlin 9y ago
How, exactly, does that happen? Do dozens of Intel people all get together in a conference room? So an Intel Project Manager comes into the room and says to a bunch of Intel's CPU designers: "the ghost of Andy Grove says we have to put a backdoor in for the NSA. They want it to be obscure. What they want us to do is to speculatively execute instructions across the user/kernel protection boundary. But wait ... don't allow the effects of those instructions to be easily visible. After all, it is nominally a protection boundary. Instead, just make sure to disturb the CPU cache. NSA can then easily observe cache timing changes and use that to read kernel memory. That should be good enough for NSA's needs. But, boy, won't people have a meltdown if this ever becomes widely known?" "Oh, and by the way, top Intel engineers, you must keep this secret 'forever'. You can't tell anyone outside the company. You need to keep this on a 'need to know' with all your fellow design, verification, and test engineers, whom you must swear to secrecy. You can't anonymously leak this, or the NSA will find out and send you off to Gitmo for rendition. Mum's the word." "Also, guys, there's no point in putting in this backdoor for a single chip. We must carry this backdoor forward to every new CPU design team that we bring on for every new CPU chip Intel makes. Sure, some chips are designed in Oregon and some in Israel, and some may even be designed in cyberspace. But we'll be sure to keep this backdoor in all future implementations. We need to let future CPU architects know that they must forever honor this promise we made to the NSA." Yeah, that could have happened. Or, more likely, out of the 1,000,000 design decisions, big and small, that go into creating a modern CPU which has literally billions of transistors, nobody involved thought this was a serious enough concern. If they thought of it at all. Because, ultimately, they get paid for shipping functional silicon rather than for worrying about information leakage in every possible corner case. If this were so simple, why didn't someone figure it out before? Meltdown is mostly Intel, but the similar Spectre exploit affects Intel, ARM, and AMD. And has for many years. Are all the engineers at all of those companies in on this backdoor? Or was the backdoor so diabolically clever that only the "CPU architect cabal" at these companies the only ones who needed to know?
- speedplane 9y ago
  An intentional backdoor: no. But an intentional ignorance of a major security vulnerability: extremely likely. Computer architects have been aware of covert channels for literally decades, from heat signatures, to CPU usage... heck it's even taught in most CS or ECE Master degrees with respect to caching. I wouldn't go as far as saying these two vulnerabilities were "obvious" to most programmers or computer engineers, but they must have been known to many people at the major chip-makers. Someone must have raised it some meeting, probably multiple meetings, and were probably shot down. So not a conspiracy theory, just lack of proper incentives to keep products secure.
microcolonel 9y ago
If you make any effort to understand how these bugs work, it's hard to imagine they were designed intentionally. Though you could make the argument that it's likely some people knew about them and didn't say, but that's a different argument I think.

Any chance that Meltdown or Spectre were not backdoors (statistically)?

by yorby 9y ago

Any chance that Meltdown or Spectre were not backdoors (statistically)?

How, exactly, does that happen? Do dozens of Intel people all get together in a conference room? So an Intel Project Manager comes into the room and says to a bunch of Intel's CPU designers: "the ghost of Andy Grove says we have to put a backdoor in for the NSA. They want it to be obscure. What they want us to do is to speculatively execute instructions across the user/kernel protection boundary. But wait ... don't allow the effects of those instructions to be easily visible. After all, it is nominally a protection boundary. Instead, just make sure to disturb the CPU cache. NSA can then easily observe cache timing changes and use that to read kernel memory. That should be good enough for NSA's needs. But, boy, won't people have a meltdown if this ever becomes widely known?" "Oh, and by the way, top Intel engineers, you must keep this secret 'forever'. You can't tell anyone outside the company. You need to keep this on a 'need to know' with all your fellow design, verification, and test engineers, whom you must swear to secrecy. You can't anonymously leak this, or the NSA will find out and send you off to Gitmo for rendition. Mum's the word." "Also, guys, there's no point in putting in this backdoor for a single chip. We must carry this backdoor forward to every new CPU design team that we bring on for every new CPU chip Intel makes. Sure, some chips are designed in Oregon and some in Israel, and some may even be designed in cyberspace. But we'll be sure to keep this backdoor in all future implementations. We need to let future CPU architects know that they must forever honor this promise we made to the NSA." Yeah, that could have happened. Or, more likely, out of the 1,000,000 design decisions, big and small, that go into creating a modern CPU which has literally billions of transistors, nobody involved thought this was a serious enough concern. If they thought of it at all. Because, ultimately, they get paid for shipping functional silicon rather than for worrying about information leakage in every possible corner case. If this were so simple, why didn't someone figure it out before? Meltdown is mostly Intel, but the similar Spectre exploit affects Intel, ARM, and AMD. And has for many years. Are all the engineers at all of those companies in on this backdoor? Or was the backdoor so diabolically clever that only the "CPU architect cabal" at these companies the only ones who needed to know?

speedplane 9y ago
An intentional backdoor: no. But an intentional ignorance of a major security vulnerability: extremely likely. Computer architects have been aware of covert channels for literally decades, from heat signatures, to CPU usage... heck it's even taught in most CS or ECE Master degrees with respect to caching. I wouldn't go as far as saying these two vulnerabilities were "obvious" to most programmers or computer engineers, but they must have been known to many people at the major chip-makers. Someone must have raised it some meeting, probably multiple meetings, and were probably shot down. So not a conspiracy theory, just lack of proper incentives to keep products secure.

microcolonel 9y ago

If you make any effort to understand how these bugs work, it's hard to imagine they were designed intentionally. Though you could make the argument that it's likely some people knew about them and didn't say, but that's a different argument I think.