3 ms·

And DragonFlyBSD provides HAMMER https://www.dragonflybsd.org/hammer/ https://www.dragonflybsd.org/hammer/ Worth mentioning, BSD were the only systems that dis

by akerro 10y ago

And DragonFlyBSD provides HAMMER https://www.dragonflybsd.org/hammer/ https://www.dragonflybsd.org/hammer/ Worth mentioning, BSD were the only systems that disabled Intels RNG after leaks that it might be compromised and Intel cooperate with NSA. https://www.freebsdfoundation.org/donate/ https://www.freebsdfoundation.org/donate/ https://www.openbsd.org/donations.html https://www.openbsd.org/donations.html https://www.dragonflybsd.org/donations/ https://www.dragonflybsd.org/donations/

CJefferson 10y ago
With regards the RNG, to be it showed a lack of understanding of how seeding RNG generators work. Perhaps Intel's RNG can, in some cases, be persuaded to produce a low-quality, or otherwise broken stream. This seems plausable (there could be a deniable 'bug' which causes this to happen), but there are many low quality data streams fed into the random number generator, it never hurts to add another. However, for things like VMs, soon after startup the CPU RNG is about the only possible source of random data, so I suspect there are more users who are being hurt by not having a well enough seeded RNG than those being helped by it being disabled (which is none). If these two points seem contradictory, they are not. It would always be better to have multiple sources of quality input to the RNG, because as long as one of them isn't corrupted / low quality, you will get decent quality random numbers out. Safety in numbers!
- beagle3 10y ago
  > because as long as one of them isn't corrupted / low quality There's a hidden assumption here that they are independent. Without malice, that will be true. However, a malicious CPU might, for example, sniff other sources in order to produce a bad mixture. It's unlikely, but not impossible, and certainly something that intelligence agencies would do if they had the chance.
  - CJefferson 10y ago
    That would also require breaking the mixing function (which no-one knows how to do, and is typically a high-quality hashing function), and measuring the other sources (many of which are related to details of how the kernel does various things, like measure hard drive latency). You could, in principle, hard-wire understanding of some kernel's version of the mixer, and crack the used hashing function, and then inject nasty bits into the random number generator. However, there is no way you could ever plausibly deny what you did at a future date when the chip is eventually photographed and you could easily break it by just tweaking the random number generator (which happens almost every kernel version anyway, as new methods of gathering randomness are added). If the CPU really was willing to go to that extent, it would be much, much easier to just monkey-patch the code to edit the register containing the returned random number, whenever rand() (or whatever) is called.

by akerro 10y ago

CJefferson 10y ago

With regards the RNG, to be it showed a lack of understanding of how seeding RNG generators work. Perhaps Intel's RNG can, in some cases, be persuaded to produce a low-quality, or otherwise broken stream. This seems plausable (there could be a deniable 'bug' which causes this to happen), but there are many low quality data streams fed into the random number generator, it never hurts to add another. However, for things like VMs, soon after startup the CPU RNG is about the only possible source of random data, so I suspect there are more users who are being hurt by not having a well enough seeded RNG than those being helped by it being disabled (which is none). If these two points seem contradictory, they are not. It would always be better to have multiple sources of quality input to the RNG, because as long as one of them isn't corrupted / low quality, you will get decent quality random numbers out. Safety in numbers!

beagle3 10y ago
> because as long as one of them isn't corrupted / low quality There's a hidden assumption here that they are independent. Without malice, that will be true. However, a malicious CPU might, for example, sniff other sources in order to produce a bad mixture. It's unlikely, but not impossible, and certainly something that intelligence agencies would do if they had the chance.
- CJefferson 10y ago
  That would also require breaking the mixing function (which no-one knows how to do, and is typically a high-quality hashing function), and measuring the other sources (many of which are related to details of how the kernel does various things, like measure hard drive latency). You could, in principle, hard-wire understanding of some kernel's version of the mixer, and crack the used hashing function, and then inject nasty bits into the random number generator. However, there is no way you could ever plausibly deny what you did at a future date when the chip is eventually photographed and you could easily break it by just tweaking the random number generator (which happens almost every kernel version anyway, as new methods of gathering randomness are added). If the CPU really was willing to go to that extent, it would be much, much easier to just monkey-patch the code to edit the register containing the returned random number, whenever rand() (or whatever) is called.