[U-Boot] U-Boot TFTP protection

[Stefan Johansson]

Hello,
We have been looking at protecting U-Boot from (malicious) TFTP overwrites.
We want to do this after our ARMv7 U-Boot has relocated.

The memory map looks like this (I hope):

---------------------------  Top of DRAM
| U-Boot (Protected)
| -------------------------- U_Boot_start
| Heap (Protected)
| -------------------------- Start_Heap = U_Boot_start - Heap_Size
| Stack (Protected)
| -------------------------- Start_Stack = Start_Heap - Stack_Size
| Buffers (Protected)
| -------------------------- ???
| Free DRAM (Not Protected)
---------------------------  Start of DRAM

I seem to get lost in the code trying to find possible buffers, can you please give a hint how I can find the address "???"

Best Regards,
Stefan