On 2022-06-24 11:26 am, johnea wrote:
I've run across a number of other references since that timeframe that
indicate that dropbear can run on no-MMU platforms using uClibc.
Searching hasn't really led to a conclusive answer. So, could you
please confirm:
Can dropbear run as a listening service on Cortex-M3 with no-MMU?
Previously I would say no - usually it would need to run from inetd that
executes a separate dropbear server process for each connection.
That is required because on a MMUless system the normal fork() doesn't
create separate memory spaces for each program, so they interfere with
each other.
But! In Dropbear 2022.82 it was changed to re-execute itself [1], so it
is possible that it would work OK on a MMUless system. You could see if
that works - there might be other assumptions that I have missed. Make
sure you try a few concurrent connections.
Cheers,
Matt
[1]
- Dropbear now re-executes itself rather than just forking for each
connection
(only on Linux). This allows ASLR to randomise address space for each
connection as a security mitigation. It should not have any visible
impact
- if there are any performance impacts in the wild please report it.
