NetX Secure AEAD Cipher checking

[ReKawashima]

If AEAD Cipher is enabled, AEAD Cipher checking is necessary to detect cipher algorithms other than AES-CCM or AES-GCM. NX_SECURE_AEAD_CIPHER_CHECK macro defines whether the AEAD chcking is used or not.

But actually, the AEAD checking is not working even if NX_SECURE_AEAD_CIPHER_CHECK macro is defined (See https://github.com/azure-rtos/netxduo/blob/master/nx_secure/src/nx_secure_tls_record_payload_decrypt.c#L158 ). Also, if using cipher algorithms other than AES-CCM or AES-GCM, the communicating counterparty will raise a Bad Record MAC alert.

I think it's a bug in the code. I suggest the following change.

Note: When apply this change, the warning "NX_SECURE_AEAD_CIPHER_CHECK macro redefined" will happened. Please clear the warning.

https://github.com/azure-rtos/netxduo/blob/master/nx_secure/inc/nx_secure_tls.h#L123

Incorrect	#ifndef NX_SECURE_AEAD_CIPHER_CHECK #define NX_SECURE_AEAD_CIPHER_CHECK(a)                  NX_FALSE #endif /* NX_SECURE_AEAD_CIPHER_CHECK */
Correct	#ifdef NX_SECURE_AEAD_CIPHER_CHECK         <-- #define NX_SECURE_AEAD_CIPHER_CHECK(a)                  NX_FALSE #endif /* NX_SECURE_AEAD_CIPHER_CHECK */

[yanwucai]

If you are implementing AEAD ciphers other than AES-CCM or AES-GCM, you can define NX_SECURE_AEAD_CIPHER_CHECK to detect your new algorithms. This macro allows you to extend the conditions to check other algorithms. For example, you can define the macro like:
#define NX_SECURE_AEAD_CIPHER_CHECK(a) ((a) == YOUR_ALGORITHM_ID)

[ReKawashima]

Hi @yanwucai -san,
Thank you for your prompt response.

Sorry. I was misunderstanding.
NX_SECURE_AEAD_CIPHER_CHECK macro defines a additional chcking method, not the use / non-use of the chcking. Right?
If correct, please update sample code (https://github.com/azure-rtos/netxduo/blob/master/nx_secure/inc/nx_secure_user_sample.h#L100) for easy understanding.

Thanks.

[TiejunMS]

Fixed here: https://github.com/azure-rtos/netxduo/blob/d9d7fb05bd6a7a6b50a54c762e1730d8a8054cbb/nx_secure/inc/nx_secure_user_sample.h#L103