[PATCH 5/5] crypt_make_salt(): try to use actual random bytes for salt generation

[Steffen Nurpmeso]

Rasmus Villemoes wrote in
 <ab5109e4-2653-4da2-93b5-cf532f7b22d8 at prevas.dk>:
 |On 15/04/2024 21.05, Steffen Nurpmeso wrote:
 |> Rasmus Villemoes wrote in
 |>  <20240415125628.780178-6-rasmus.villemoes at prevas.dk>:
 |>|Instead of limiting the possible generated salts to 2^32 different
 |>|ones, try to get some actual random bits and mix those in. Keep the
 |>|old pseudo-random generation in place, so that even if
 |>|open_read_close() fails or only returns a partial result, we're not
 |>|doing any worse than previously.
 |>|
 |>|In fact, even with /dev/urandom being unavailable, this might still
 |>|improve things a bit since whatever sort-of random content might be in
 |>|the p buffer on entry is then mixed in.
 |> 
 |> By that time i thought (completely unrelated with your work) that
 |> the code from miscutils/seedrng.c which has a more broad view of
 |> where to get random data from should possibly be generalized.
 |> There are more than just one match for /dev/urandom, and they all
 |> want some random bits.
 |
 |Yeah, I know, I did go grepping for 'random' to see if bb already had
 |some "gimme some random bytes" helper, and I've also sort-of followed
 |the seedrng saga. But since there was no such helper, and just
 |best-effort here is good enough for a significant improvement in the
 |normal case, I just went with the oneliner open_read_close(), which is
 |also used in generate_uuid() without checking the return value. If some
 |common infrastructure for randomness should materialize, this can
 |trivially be switched over. But I really didn't want to tie this series
 |to creation of and bikeshedding over such infrastructure.

Understandable.

 |Rasmus
 |
 --End of <ab5109e4-2653-4da2-93b5-cf532f7b22d8 at prevas.dk>

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)