Latest idea to force usage of custom engine

[Frederick Gotham]

I have abandoned my old idea of trying to get libOpenSSL to always read my 
engine info from the config file (/etc/ssl/openssl.cnf).

Instead I'm going to try to manually load my own engine in the source code 
for libOpenSSL.


I have created a new function in "rand_lib.c" as follows:


static void Do_Whatever_Needs_Done_For_TPM2(void)
{
        CRYPTO_THREAD_write_lock(rand_meth_lock);
        {
                /* Initialize the dynamic engine loader */
                ENGINE_load_dynamic();

                ENGINE *tpm2_engine;
         
                /* If the first fails, try the second one */
                (tpm2_engine = ENGINE_by_id("tpm2tss")) || (tpm2_engine = 
ENGINE_by_id("libtpm2tss"));
                
                if ( NULL == tpm2_engine )
                {
                        assert( 0 == "Do_Whatever_Needs_Done_For_TPM2: tpm2
_engine == NULL" );
                        abort();
                }

                int init_res = ENGINE_init(tpm2_engine);
                
                if ( !init_res )
                {
                        assert( 0 == "Do_Whatever_Needs_Done_For_TPM2: init_res 
== 0" );
                        abort();
                }
                        
                RAND_METHOD const *const p_rm = ENGINE_get_RAND(tpm2_engine);

                if ( NULL == p_rm )
                {
                        assert( 0 == "Do_Whatever_Needs_Done_For_TPM2: p_rm == 
NULL" );
                        abort();
                }
                        
                funct_ref = tpm2_engine;

                default_RAND_meth = p_rm;
                
                rand_meth = *default_RAND_meth;  /* Even set the Drbg func 
pointers */
        }
        CRYPTO_THREAD_unlock(rand_meth_lock);
}



And then the next thing I've done is added the following code to the start 
of "RAND_get_rand_method":



const RAND_METHOD *RAND_get_rand_method(void)
{
        static int first_time_for_entire_process = 1;
        
        if ( first_time_for_entire_process )
        {
                first_time_for_entire_process = 0;
                Do_Whatever_Needs_Done_For_TPM2();
        }

        /* The rest of the function goes here */
}


I'm testing it now but it still seems that something isn't right.

I'm going to keep at this until every process (including ssh-keygen) is 
using my custom engine for random numbers.