 | | limits.conf devastatingly broken? (was: Preventing fork bombs?
ulimit complet | limits.conf devastatingly broken? (was: Preventing fork bombs?
ulimit complet 2003-12-30 - By Jason Tackaberry
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On Mon, 2003-12-29 at 20:33, Jason Tackaberry wrote:
> Since this is a system where users are given shell access, I 'm applying
> appropriate ulimits on login. However, having tested with a trivial
> fork bomb (while (1) fork()), ulimits are proving to be broken -- the
> system still drags, and root gets out of memory errors (unacceptable!).
Further to my email yesterday, I have discovered
/etc/security/limits.conf, and have added the following lines:
@(protected) hard nproc 10
@(protected) hard cpu 1
@(protected) hard as 10240
When I log in as a student and execute the trivial fork bomb, now
instead of root getting out-of-memory errors, everything seems to block
until eventually the kernel starts killing _all_ userspace processes
(even root ones -- services start dying left and right). I can 't log in
at the console, and am forced to reboot the server.
This is a desperate call for help. I refuse to believe that one lowly
user can bring down a properly configured RHEL with a stupid
while(1)fork(). I 've _got_ to be doing something wrong, but I just
don 't know what.
Best,
Jason.
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