===================
MIB3 Key derivation
===================
This section is dedicated to the key derivation process on the MIB3 High (VAG) head unit.

As per this:

.. code-block:: c

   void fscryptUnlock(char *path)

    {
        int iVar1;
        1.
        local_8 = ___stack_chk_guard;
        fprintf(_stdout,"Call to fscryptUnlock with Path %s\n",path,&stdout,0);
        iVar1 = waitfor_timeout("/dev/mobicore-userif",0xffffffffffffffff,0xffffffffffffffff,1);
        if (iVar1 == 0) {
            iVar1 = get_key_desc?(path,&local_60);
            if (iVar1 == 0) {
            iVar2 = KeyStoreOpen();
            if (iVar2 == 0) {
                iVar2 = KeyStoreGet(&local_60,0x10,&local_48,0x40);
                if (iVar2 == 0) {
                KeyStoreClose();
                iVar2 = fscryptKeyAdd(&local_48,&local_60);
                if (iVar2 < 0) {
                    iVar1 = -5;
                    fscryptKeyWipe(&local_48,0x40);
                }
                else {
                    fscryptKeyWipe(&local_48,0x40);
                }
                }
                else {
                KeyStoreClose();
                iVar1 = -3;
                }
            }
            else {
                iVar1 = -3;
                perror("Failed to connect to TEE");
            }
            }
        }
        else {
            iVar1 = -3;
            fwrite("Failed to wait for kinibi interface\n",1,0x24,_stderr);
        }
        if (local_8 == ___stack_chk_guard) {
            return;
        }
                            /* WARNING: Subroutine does not return */
        __stack_chk_fail(iVar1);
    }

Or in a diagram:

.. figure:: images/fscrypt.drawio.svg




.. code-block:: c

   void KeyStoreGet(void *key_id,uint id_len,void *key_buffer,uint key_len)


TODO:

  * What is located at ``/dev/mobicore-userif`` in domu1?