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Date: Fri, 13 Mar 2015 09:56:58 +0000
From: halfdog <me@...fdog.net>
To: oss-security@...ts.openwall.com
Subject: Disabling reading of kernel log buffer reading for user

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Hello List,

After years working on Linux, I just found out, that any user not only root can read the kernel log buffer - I never even considered that this could be the case.

As this behavior is documented and expected, this is not a security vulnerability. But to avoid things like in [1], I would like to disable that on my machines.

Questions:

* What would be the side effects of making /dev/kmesg only root accessible? Maybe syslog not able to write kmessages to log?

* Would it be safe to disable the syslog syscall for action SYSLOG_ACTION_READ_* and all users except root and syslog? Does someone have tested selinux config for that?

hd


[1] http://www.halfdog.net/Security/2015/HavingFunWithDmesg/

- -- 
http://www.halfdog.net/
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