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Worked fine for a couple of days before this. Anyone seen something like this, any ideas why this happened?
I guess you are using Fedora or OpenSuSE because nor Debian's , nor the default binary is compiled with smash stack protection ( -fstack-protector -D_FORTIFY_SOURCE=2 gcc flags ) ...
anyway :
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"Smashing the stack" colloquially refers to exploiting a buffer overflow (where do you think that buffer is? On the heap? No, it's on the stack, so the overflow is a stack overflow) deliberately in order to change the return address.
The OS can't distinguish malicious intent from an accident, however, so it assumes that anything that tries to overwrite the return address is an attempted stack smash.
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where "malicious intent" means smashing the stack to obtain unauthorized priviledged accesses ( eg a root shell execution or a remote shell execution or even a back-door )
The server was killed because the smash stack protection ( available since gcc-4.1 and since MS Visual Studio 2003 ) detected a smash stack event.
I usually compile also my own client with smash stack protection and I've suggested to compile official binaries with this and other protections :
http://openarena.ws/board/index.php?topic=1933.msg27771#msg27771