zend_bool php_openssl_pkey_init_dsa(DSA *dsa, zval *data)
{
	BIGNUM *p, *q, *g, *priv_key, *pub_key;
	const BIGNUM *priv_key_const, *pub_key_const;

	OPENSSL_PKEY_SET_BN(data, p);
	OPENSSL_PKEY_SET_BN(data, q);
	OPENSSL_PKEY_SET_BN(data, g);
	if (!p || !q || !g || !DSA_set0_pqg(dsa, p, q, g)) {
		return 0;
	}

	OPENSSL_PKEY_SET_BN(data, pub_key);
	OPENSSL_PKEY_SET_BN(data, priv_key);
	if (pub_key) {
		return DSA_set0_key(dsa, pub_key, priv_key);
	}

	/* generate key */
	PHP_OPENSSL_RAND_ADD_TIME();
	if (!DSA_generate_key(dsa)) {
		return 0;
	}

	/* if BN_mod_exp return -1, then DSA_generate_key succeed for failed key
	 * so we need to double check that public key is created */
	DSA_get0_key(dsa, &pub_key_const, &priv_key_const);
	if (!pub_key_const || BN_is_zero(pub_key_const)) {
		return 0;
	}
	/* all good */
	return 1;
}

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.