OpenSSL::X509::Extension#value=

static VALUE
ossl_x509ext_set_value(VALUE self, VALUE data)
{
    X509_EXTENSION *ext;
    ASN1_OCTET_STRING *asn1s;

    GetX509Ext(self, ext);
    data = ossl_to_der_if_possible(data);
    StringValue(data);

    asn1s = ASN1_OCTET_STRING_new();
    if (!asn1s)
        ossl_raise(eX509ExtError, "ASN1_OCTET_STRING_new");
    if (!ASN1_OCTET_STRING_set(asn1s, (unsigned char *)RSTRING_PTR(data),
                               RSTRING_LENINT(data))) {
        ASN1_OCTET_STRING_free(asn1s);
        ossl_raise(eX509ExtError, "ASN1_OCTET_STRING_set");
    }
    if (!X509_EXTENSION_set_data(ext, asn1s)) {
        ASN1_OCTET_STRING_free(asn1s);
        ossl_raise(eX509ExtError, "X509_EXTENSION_set_data");
    }
    ASN1_OCTET_STRING_free(asn1s);

    return data;
}