static int openssl_x509v3_subjectAltName(BIO *bio, X509_EXTENSION *extension)
{
	GENERAL_NAMES *names;
	const X509V3_EXT_METHOD *method = NULL;
	ASN1_OCTET_STRING *extension_data;
	long i, length, num;
	const unsigned char *p;

	method = X509V3_EXT_get(extension);
	if (method == NULL) {
		return -1;
	}

	extension_data = X509_EXTENSION_get_data(extension);
	p = extension_data->data;
	length = extension_data->length;
	if (method->it) {
		names = (GENERAL_NAMES*) (ASN1_item_d2i(NULL, &p, length,
			ASN1_ITEM_ptr(method->it)));
	} else {
		names = (GENERAL_NAMES*) (method->d2i(NULL, &p, length));
	}
	if (names == NULL) {
		php_openssl_store_errors();
		return -1;
	}

	num = sk_GENERAL_NAME_num(names);
	for (i = 0; i < num; i++) {
		GENERAL_NAME *name;
		ASN1_STRING *as;
		name = sk_GENERAL_NAME_value(names, i);
		switch (name->type) {
			case GEN_EMAIL:
				BIO_puts(bio, "email:");
				as = name->d.rfc822Name;
				BIO_write(bio, ASN1_STRING_get0_data(as),
					ASN1_STRING_length(as));
				break;
			case GEN_DNS:
				BIO_puts(bio, "DNS:");
				as = name->d.dNSName;
				BIO_write(bio, ASN1_STRING_get0_data(as),
					ASN1_STRING_length(as));
				break;
			case GEN_URI:
				BIO_puts(bio, "URI:");
				as = name->d.uniformResourceIdentifier;
				BIO_write(bio, ASN1_STRING_get0_data(as),
					ASN1_STRING_length(as));
				break;
			default:
				/* use builtin print for GEN_OTHERNAME, GEN_X400,
				 * GEN_EDIPARTY, GEN_DIRNAME, GEN_IPADD and GEN_RID
				 */
				GENERAL_NAME_print(bio, name);
			}
			/* trailing ', ' except for last element */
			if (i < (num - 1)) {
				BIO_puts(bio, ", ");
			}
	}
	sk_GENERAL_NAME_pop_free(names, GENERAL_NAME_free);

	return 0;
}

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.