Add assertion for the assumed tal_count(msg) >= sizeof(be16) in subdaemon_malformed_msg(...)

[practicalswift]

Add assertion for the assumed tal_count(msg) >= sizeof(be16) in subdaemon_malformed_msg(...).

An unsigned integer overflow will occur if tal_count(msg) >= sizeof(be16) does not hold true.

Explicit is better than implicit :-)

[cdecker]

ACK e1e3afe

[rustyrussell]

Good catch! But it'd be more robust to dump the message anyway when something goes wrong. We should print the whole thing (fromwire_peektype handles the case of a truncated message already).

So just change it to "tal_hex(msg, msg)".

[practicalswift]

@rustyrussell Updated and pushed. Did I understand your change request correctly? :-)