Messages in this thread |  | | Date | Sat, 23 Apr 2022 12:00:33 +0200 | From | "Jason A. Donenfeld" <> | Subject | Re: [PATCH v5 11/11] random: insist on random_get_entropy() existing in order to simplify |
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Hi Sandy,
On Sat, Apr 23, 2022 at 10:24:07AM +0800, Sandy Harris wrote: > On Sat, Apr 23, 2022 at 6:37 AM Jason A. Donenfeld <Jason@zx2c4.com> wrote: > > > > All platforms are now guaranteed to provide some value for > > random_get_entropy(). In case some bug leads to this not being so, we > > print a warning, ... > > Would it make sense to test at compile time? If there is no hardware > RNG nor a cycle counter, then the kernel should be compiled with > the gcc latent entropy plugin. Generate a warning suggesting that, > or even an error insisting on it.
Unfortunately, as a last ditch warning safeguard against bugs, I don't think that's something we can determine at build time. A lot of this machinery is dynamic. Fortunately a single check at init time brings with it zero appreciable overhead.
Jason
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