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Sauerbraten engine development

by Aardappel on 03/03/2004 05:18, 1571 messages, last message: 03/14/2008 18:53, 1351223 views, last view: 12/09/2021 02:33

This thread is for discussion of Sauerbraten coding issues / implementation ideas etc.

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#1505: Server crash

by virtualblackfox on 06/20/2006 01:31

Today i had a crash to my server do to a cheater, here is what appened :

---------------------------
client connected (168-103-233-110.ptld.qwest.net)
[NewPlayer] Name: Paul
status: 6 remote clients, 13.2 send, 2.7 rec (K/sec)
[MapChange] New map:
[Chat] . : gg
[Chat] . : lol
status: 6 remote clients, 14.2 send, 2.8 rec (K/sec)
[MapChange] New map:
status: 6 remote clients, 17.1 send, 3.4 rec (K/sec)
status: 6 remote clients, 17.8 send, 3.5 rec (K/sec)
disconnected client
[MapChange] New map:
status: 5 remote clients, 11.0 send, 2.7 rec (K/sec)
[MapChange] New map:
status: 5 remote clients, 9.9 send, 2.4 rec (K/sec)
status: 5 remote clients, 9.8 send, 2.4 rec (K/sec)
[MapChange] New map:
status: 5 remote clients, 9.3 send, 2.3 rec (K/sec)
[MapChange] New map:
status: 5 remote clients, 9.0 send, 2.2 rec (K/sec)
status: 5 remote clients, 8.6 send, 2.1 rec (K/sec)
status: 5 remote clients, 8.3 send, 2.0 rec (K/sec)
status: 5 remote clients, 9.0 send, 2.2 rec (K/sec)
client connected
[NewPlayer] Name: Homo
disconnected client
disconnected client
client connected
[NewPlayer] Name: .
status: 5 remote clients, 10.0 send, 2.2 rec (K/sec)
[MapChange] New map:
disconnected client
status: 4 remote clients, 8.4 send, 2.3 rec (K/sec)
client connected
[NewPlayer] Name: Rareware
sending request to sauerbraten.org...
masterserver reply:

your server was registered
[NameChange] Rareware -> Homonculus
[MapChange] New map:
status: 5 remote clients, 9.5 send, 2.5 rec (K/sec)
[Chat] . : paul you are a cheater
[Chat] Homonculus : goddamn respawn limit
[Chat] Homonculus : >:I
[Chat] Homonculus : this is retarded :3
status: 5 remote clients, 11.2 send, 2.8 rec (K/sec)
[Chat] . : dnx, kick paul please
disconnected client
[MapChange] New map:
[Chat] . : paul go home
status: 4 remote clients, 8.8 send, 2.6 rec (K/sec)
[Chat] Paul : sorry
status: 4 remote clients, 7.1 send, 2.3 rec (K/sec)
[MapChange] New map:
disconnected client
client connected
[NewPlayer] Name: .
disconnected client
client connected
[NewPlayer] Name: .
disconnected client
status: 3 remote clients, 6.1 send, 2.0 rec (K/sec)
client connected
[NewPlayer] Name: .
client connected
[NewPlayer] Name: unnamed
status: 5 remote clients, 7.2 send, 2.1 rec (K/sec)
[Chat] . : /kick Paul
[Chat] . : doesn't work :(
[MapChange] New map:
status: 5 remote clients, 9.8 send, 2.4 rec (K/sec)
[Kick] dnx
client (168-103-233-110.ptld.qwest.net) disconnected because: kicked/banned

disconnected client (168-103-233-110.ptld.qwest.net)
---------------------------

My server does some printf on events so you could see what appened.

After the last line (dnx having kicked the cheater) the server crash with this stack trace :

---------------------------
sauerbraten_debug.exe!fpsserver::captureserv::movebases(const char * team=0x00000108, const vec & oldpos={...}, const vec & newpos={...}) Line 381 + 0x3 bytes C++
sauerbraten_debug.exe!fpsserver::captureserv::leavebases(const char * team=0x00000108, const vec & o={...}) Line 396 C++
sauerbraten_debug.exe!fpsserver::clientdisconnect(int n=0) Line 596 C++
sauerbraten_debug.exe!serverslice(int seconds=1150756441, unsigned int timeout=5) Line 439 + 0x1c bytes C++
sauerbraten_debug.exe!initserver(bool dedicated=true) Line 532 + 0x12 bytes C++
---------------------------

When i break i see some things :
"char * team=0x00000108" is an invalid adress (just a function offset on NULL pointer) due to the fact that getinfo returned NULL (because clients[i]->type==ST_EMPTY).

So we have a playing client (num=0) that had type==ST_EMPTY but i don't known how he managed to do that. Also note that if m_capture has been false no crash would have hapened.

I don't known if it was something wanted by the cheater by some reason or if it is just a random bug that hapenned to a cheater but could have hapenned to everyone.

Just adding a "if (ci == NULL) return;" could solve this particular problem but it think that maybe it is a chance to find the root cause.

I will let my debugger breaked on this error till tomorrow so if you have questions about the program state just ask (too late for me to do debugging :D)