First published: Wed Jun 22 2011(Updated: )
Currently a single process may register exit handlers unlimited times. It may lead to a bloated listeners chain and very slow process terminations. E.g. after 10KK sent TASKSTATS_CMD_ATTR_REGISTER_CPUMASKs ~300 Mb of kernel memory is stolen for the handlers chain and "time id" shows 2-7 seconds instead of normal 0.003. It makes it possible to exhaust all kernel memory and to eat much of CPU time by triggerring numerous exits on a single CPU ie it makes it possible for unprivileged user eat kernel memory and CPU without triggering OOM killer. Introduced in f9fd8914c1acca0d98b69d831b128d5b52f03c51. References: <a href="http://seclists.org/oss-sec/2011/q2/664">http://seclists.org/oss-sec/2011/q2/664</a> <a href="http://lists.openwall.net/linux-kernel/2011/06/16/605">http://lists.openwall.net/linux-kernel/2011/06/16/605</a> Acknowledgements: Red Hat would like to thank Vasiliy Kulikov of Openwall for reporting this issue.
Credit: secalert@redhat.com secalert@redhat.com
Affected Software | Affected Version | How to fix |
---|---|---|
Linux Linux kernel | <=2.6.39.1 | |
debian/linux-2.6 |
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