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freifunk-gluon / l3roamd

BSD 2-Clause "Simplified" License
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[intercom] initialize the rng #24

Closed t-8ch closed 6 years ago

t-8ch commented 6 years ago

Currently src/intercom.c uses rand() to produce nonces. This RNG is deterministic and seeded to the value 1 on startup. This makes nonce collisions quite likely.

The RNG should be seeded with a nonconstant value.

christf commented 6 years ago

this is addressed by #21 => I took this into a different PR.

t-8ch commented 6 years ago

Thinking about further, I think we should not use srand(time(0)). If we have many systems rebooting at the same time, for example after a powercut in a big installation, we can experience duplicate nonces. We should probably use getrandom(2) or /dev/urandom. Personally I would prefer getrandom(2), but it requires Linux >= 3.17 and has no wrapper support in musl.

christf commented 6 years ago

we are on linux >4.4 so requiring kernel >=3.17 is no issue imho.

christf commented 6 years ago

this will be handled by #25 - no need to keep issue AND pr.