dedicated server uses cl_download_mapsrc without initializing it

[Xylemon]

https://sourceforge.net/p/fteqw/tickets/150/

ferneu1 wrote on 2022-06-10:

When you run FTE as a dedicated server and tell the server to load a map it does not have, it will try to use the value of cl_download_mapsrcto download the map. The problem is that cl_download_mapsrc only gets initialized after the code exits the dedicated server loop.

Things get really confusing because a cvar named cl_download_mapsrc gets registered because it is included in QUAKEOVERRIDES (see common/fs.c) and, because of that, the server will reply with a valid string if you request the value of that cvar. The problem is that the code will try to use the C variable named cl_download_mapsrc, and that one never gets initialized.

So, basically, anyone can crash a dedicated FTE server by simply telling it to load a map it doesn't have. Which was something I discovered when I mistakenly misspelled E1M1 as EE1M1