Proper way to free all data in spdm_context

[LeeTroy]

I'm running libspdm in a embedded project, the spdm context will be created and released over and over again.
However, I found there's no proper way to release some of data within context.

https://github.com/DMTF/spdm-emu/blob/3630f472927a42a4f1b8847b0372258d715577a3/spdm_emu/spdm_requester_emu/spdm_requester_spdm.c#L454-L467

res = libspdm_read_responder_root_public_certificate(m_use_hash_algo,
                                                     m_use_asym_algo,
                                                     &data, &data_size,
                                                     &hash, &hash_size);
if (res) {
    libspdm_x509_get_cert_from_cert_chain(
        (uint8_t *)data + sizeof(spdm_cert_chain_t) + hash_size,
        data_size - sizeof(spdm_cert_chain_t) - hash_size, 0,
        &root_cert, &root_cert_size);
    libspdm_zero_mem(&parameter, sizeof(parameter));
    parameter.location = LIBSPDM_DATA_LOCATION_LOCAL;
    libspdm_set_data(spdm_context,
                     LIBSPDM_DATA_PEER_PUBLIC_ROOT_CERT,
                     &parameter, (void *)root_cert, root_cert_size);
}

• libspdm_read_responder_root_public_certificate allocates data
• data can't be release because root_cert sit inside data
• libspdm_get_data doesn't support LIBSPDM_DATA_PEER_PUBLIC_ROOT_CERT, even if it is supported, the pointer is root_cert but not data.

One solution I can think of storing data pointer with LIBSPDM_DATA_APP_CONTEXT_DATA, and release it when the spdm context is not needed.

Thanks!

[jyao1]

See DMTF/spdm-emu#287