Try working from providers/implementations/rands/seed_src.c You'll need
to reimplement seed_src_generate() to use your RNG.
To use your custom seed source, you can either use the OpenSSL
configuration file to set a "random" section that includes a "seed"
setting or you can call RAND_set_seed_source_type() early in your
startup sequence.
Pauli
On 14/9/21 8:19 am, Kory Hamzeh wrote:
Hi,
We are upgrading from OpenSSL 1.0.1g+OpenSSL-FIPS-2.0.5 to 3.0.0. Yes, I know,
big jump. We have our own entropy source we use to seed the OpenSSL DRBG. This
is a basic code snippet of how we set it up:
DRBG_CTX *dctx = FIPS_get_default_drbg();
FIPS_drbg_init(dctx, NID_aes_256_ctr, DRBG_FLAG_CTR_USE_DF);
FIPS_drbg_set_callbacks(dctx,
rand_get_entropy,
rand_free_entropy,
0,
rand_get_entropy,
rand_free_entropy);
Error checking has been removed in the example for the sake of brevity.
I am trying to figure out how to implement this with OpenSSL 3. From what I
have read in the docs, I need to create a rand provider. But I still feel like
I don’t understand how it all fit together. I did look at fuzz_rand.c and
fake_rand.c, and if I understood everything correctly, neither of them use an
external entropy/seed source.
Are there better examples of what I am looking for?
Thanks,
Kory
