Messages in this thread |  | | From | Kees Cook <> | Date | Tue, 16 Apr 2019 17:58:56 -0500 | Subject | Re: BPF RNG |
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On Tue, Apr 16, 2019 at 10:13 AM Daniel Borkmann <daniel@iogearbox.net> wrote: > > On 04/16/2019 03:55 PM, Kees Cook wrote: > > [correcting Alexei's email address and resending...] > > > > On Tue, Apr 16, 2019 at 8:54 AM Kees Cook <keescook@google.com> wrote: > >> > >> Hi, > >> > >> In looking at prandom_u32() users, I noticed that BPF uses its own > >> state variable with bpf_user_rnd_u32(). It appears that this state is > > Correct, we split that off from the main one. > > >> never reseeded like regular prandom_u32(). (See __prandom_timer().) Is > >> this intentional, or should reseeding be happening? > > The prng is not to be used in any security-critical context. That said, > we optionally could perform reseeding from time to time, though that > should probably be done generically, so that all "external" > prandom_u32_state() users could register themselves upon init whether > they opt-in for periodic reseeding or not.
Yeah, it seemed like it should be built into the API. I'll add this to the TODO list. ;)
Thanks for double-checking.
-- Kees Cook
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