The 5.3 kernel is out [LWN.net]

The 5.3 kernel is out

Posted Sep 17, 2019 9:07 UTC (Tue) by patrakov (subscriber, #97174)
In reply to: The 5.3 kernel is out by Cyberax
Parent article: The 5.3 kernel is out

We already have jitterentropy_rng - unfortunately and by mistake, as a cryptoalg rng, not as hwrng. It extracts random bits from variations of timing of some CPU and memory operations, i.e. essentially from unsycnhronized clocks in different parts of the system. I will look at its conversion to something (e.g. hwrng) that can actually provide the entropy that Linux accounts for.

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The 5.3 kernel is out

Posted Sep 17, 2019 9:41 UTC (Tue) by njs (subscriber, #40338) [Link] (1 responses)

IIRC Ted T'so has a longstanding veto on using jitterentropy to increment the random pool entropy counter in the past, on the grounds that we don't actually know where the apparent randomness comes from and whether it's actually unpredictable or not, esp. against an active attacker who can manipulate microarchitectural state.

The 5.3 kernel is out

Posted Sep 17, 2019 9:44 UTC (Tue) by patrakov (subscriber, #97174) [Link]

Thanks, that's useful to know. But he surely knows that Debian installs haveged by default on systems lacking rdrand, thus circumventing his veto.