From: Xavier <none@...>
Date: 2005-01-26T07:30:54+09:00
Subject: Potential DoS in cgi.rb with apache & mod_fastcgi

Hi Group,

I am getting many errors like the following in my apache logs:

/usr/lib/ruby/1.8/cgi.rb:725: [BUG] rb_sys_fail() - errno == 0
ruby 1.8.2 (2004-12-25) [i686-linux]

This error occurs whenever the client breaks the connection.
The fastcgi process logs the error and exits with an untrapped signal 6
error message.

This can lead to a DoS because mod_fastcgi will stop spawning fcgi's
whenever processes have failed to keep running for at least 30 seconds.

How could I either prevent cgi.rb from breaking or trap and recover from
the signal 6?
A simple Signal.trap(6) does not work, e.g.

 FCGI.each_cgi do |cgi|
   Signal.trap(6){exit(2)}
   do_CGI(cgi)
 end

does not catch the signal.


Any help greatly appreciated,
Xavier