Re: [RFC][PATCH] procfs: Add /proc/<pid>/mapped_files

From: Cyrill Gorcunov
Date: Wed Jan 14 2015 - 10:33:31 EST


On Wed, Jan 14, 2015 at 05:25:01PM +0200, Kirill A. Shutemov wrote:
...
> >
> > This gives lsof and suchlike a way to determine the pathnames of files
> > mapped into a process without incurring the O(N^2) behavior of the
> > maps file.
>
> We already have /proc/PID/map_files/ directory which lists all mapped
> files. Should we consider relaxing permission checking there and move it
> outside CONFIG_CHECKPOINT_RESTORE instead?
>
> Restriction to CAP_SYSADMIN for follow_link is undertansble, but why do we
> restrict readdir and readlink?

We didn't think this functionality might be needed someone but us (criu camp),
so that the rule of thumb was CONFIG_CHECKPOINT_RESTORE + CAP_SYSADMIN, until
otherwise strictly needed. So I think now we can relax security rules a bit
and allow to readdir and such for owners.

Cyrill
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