If we take a look at any ENGINE_load_XXX function, we find that they all has
similar structure:
ENGINE *toadd = engine_XXX();
if(!toadd) return;
ENGINE_add(toadd);
ENGINE_free(toadd);
ERR_clear_error();
My question is: why we need call ENGINE_free(toadd) ??
Somewhere inside it calls EVP_PKEY_asn1_free(), which besides everything
else desroy all AMETH structures, created during engine initialization via
EVP_PKEY_asn1_set_* .
So, let's consider following example:
CRYPTO_malloc_init();
ERR_load_crypto_strings();
ENGINE_load_builtin_engines();
e = ENGINE_by_id("XXX");
ENGINE_set_default(e, ENGINE_METHOD_ALL);
OpenSSL_add_all_algorithms();
OpenSSL_add_ssl_algorithms();
EVP_PKEY *signing_key = ENGINE_load_private_key(e, NULL, NULL, NULL);
// bla-bla-bla...
And, if in engine load priv func we write something like
EVP_PKEY *pkey = EVP_PKEY_new();
pkey->ameth = ENGINE_get_pkey_asn1_meth(eng, NID_id_SOME_NID);
it's not gonna work, because all ASN1 structures, carefully created by
engine via calls to EVP_PKEY_asn1_set_* are invalid and possibly corrupted
at this moment.
Is it a design issue, or provided example is invalid (but it taken from
openssl sources, hm...)?
