Messages in this thread | | | Date | Mon, 20 Jun 2011 15:07:48 +1000 (EST) | From | James Morris <> | Subject | Re: [RFC 2/5 v4] procfs: add hidepid= and gid= mount options |
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[please cc: the lsm list with this kind of thing]
> This patch adds support of mount options to restrict access to > /proc/PID/ directories. The default backward-compatible 'relaxed' > behaviour is left untouched.
Can you provide evidence that this is a useful feature? e.g. examples of exploits / techniques which would be _usefully_ hampered or blocked.
> The first mount option is called "hidepid" and its value defines how much > info about processes we want to be available for non-owners: > > hidepid=0 (default) means the current behaviour - anybody may read all > world-readable /proc/PID/* files.
Why not utilize unix perms on the proc files? Perhaps via stricter overall defaults which are selected at kernel build or runtime.
> hidepid=1 means users may not access any /proc/<pid>/ directories, but their > own. Sensitive files like cmdline, io, sched*, status, wchan are now > protected against other users. As permission checking done in > proc_pid_permission() and files' permissions are left untouched, > programs expecting specific files' permissions are not confused.
IMHO such programs are beyond broken and have voided their kernel warranty.
-- James Morris <jmorris@namei.org>
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