Cannot run MBEDTLS Example

RE: Cannot run MBEDTLS Example

Chinguu — Thu, 30 Jul 2020 18:06:47 GMT

Hello, has this thread been solved i m getting the same error, it tells me:

#error "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in config.h"

However, i am using Windows.

RE: Cannot run MBEDTLS Example

Sigurd — Fri, 20 Sep 2019 15:17:23 GMT

[quote userid="83091" url="~/f/nordic-q-a/52352/cannot-run-mbedtls-example/210878"]so all my functions are like mbedtls_***() I wanna keep them that way[/quote]

I understand, but it might be useful to see how nrf_crypto uses mbedtls_* functions. E.g. we are seeding and adding the rng backend like this:

// Callback function used by mbed TLS to seed and reseed.
static int entropy_callback(void * p_entropy, unsigned char * p_buffer, size_t size)
{
    UNUSED_PARAMETER(p_entropy);

    nrf_drv_rng_block_rand(p_buffer, size);

    return 0;
}


ret_code_t nrf_crypto_rng_backend_init(void * const p_context, void * const p_temp_buffer)
{
    ret_code_t                  ret_val;
    int                         mbedtls_ret_val;
    mbedtls_ctr_drbg_context  * p_mbedtls_context =
        &((nrf_crypto_backend_rng_context_t *)p_context)->mbedtls_context;

    UNUSED_PARAMETER(p_temp_buffer);

    ret_val = nrf_drv_rng_init(NULL);

    if (ret_val != NRF_SUCCESS)
    {
        return ret_val;
    }

    mbedtls_ctr_drbg_init(p_mbedtls_context);

    // Initial seeding. The nrf_crypto_rng API does not support additional entropy in the initial
    // seeding. Additional entropy can be provided using nrf_crypto_rng_backend_reseed(),
    // which calls mbedtls_ctr_drbg_reseed().
    mbedtls_ret_val = mbedtls_ctr_drbg_seed(p_mbedtls_context,
                                            entropy_callback,
                                            NULL,
                                            NULL,
                                            0);

    ret_val = result_get(mbedtls_ret_val);

    return ret_val;
}

Anyways, if you upload the project, I could take a closer look at the issue. I could convert this to a private case, if you don't want to share the project publicly.

RE: Cannot run MBEDTLS Example

german_wings — Fri, 20 Sep 2019 09:07:11 GMT

Hey, There Thank you for responding

I am using the latest and the greatest SDK 15.3.0. all my previous code uses lmbedcrypto lib , so all my functions are like mbedtls_***() I wanna keep them that way 🙂 , However I could not understand my aes example from mbedtls website runs just fine on my NRF52 DK board. Just the entropy generator fails.

https://tls.mbed.org/kb/how-to/encrypt-with-aes-cbc this code runs fine as is no changes required , to generate IV(I am using static array right now as IV) I wanna use the mbedtls entropy generator (some thing from here tls.mbed.org/.../add-a-random-generator) , This is where I am stuck. The ECB mode would run ok. no problem in that , entropy is stuck.

RE: Cannot run MBEDTLS Example

Sigurd — Fri, 20 Sep 2019 08:54:57 GMT

Hi,

Could you upload the project ?

What SDK version are you using?

PS: Note that we have AES crypto examples using mbedtls backend here. Also see this and this page.