Re: [PATCH] kmsg: Honor dmesg_restrict sysctl on /dev/kmsg

From: Kees Cook
Date: Wed Feb 27 2013 - 13:05:59 EST


On Fri, Feb 22, 2013 at 01:18:57PM -0500, Josh Boyer wrote:
> Originally, the addition of dmesg_restrict covered both the syslog
> method of accessing dmesg, as well as /dev/kmsg itself. This was done
> indirectly by security_syslog calling cap_syslog before doing any LSM
> checks.

Actually, are the security_syslog() checks in /dev/kmsg correct? There is
only one used in devkmsg_open which uses SYSLOG_ACTION_READ_ALL. Shouldn't
it be using SYSLOG_ACTION_OPEN? And have SYSLOG_ACTION_READ_ALL added to
devkmsg_read? (And should we add one for write?)


Kees Cook
Chrome OS Security
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