On 02/11/2015 03:01 PM, Eric W. Biederman wrote:

"Michael Kerrisk (man-pages)" [off-list ref] writes:

quoted

Hi Eric,

Ping!

Cheers,

Michael


On 2 February 2015 at 16:37, Michael Kerrisk (man-pages)
[off-list ref] wrote:

quoted

Hi Eric,

Thanks for writing this up!

On 12/12/2014 10:54 PM, Eric W. Biederman wrote:

quoted

Files with access permissions such as ---rwx---rwx give fewer
permissions to their group then they do to everyone else.  Which means
dropping groups with setgroups(0, NULL) actually grants a process
privileges.

The uprivileged setting of gid_map turned out not to be safe after

        ^^^^^^^^^^^
unprivileged  -- typo fix

Thanks for confirming.

quoted

quoted

quoted

this change.  Privilege setting of gid_map can be interpreted as
meaning yes it is ok to drop groups.

I had trouble to parse that sentence (and I'd like to make sure that
the right sentence ends up in the commit message). Did you mean:

    "*Unprivileged* setting of gid_map can be interpreted as meaning
     yes it is ok to drop groups"
?

Or something else?

I meant:  Setting of gid_map with privilege has been clarified to mean
that dropping groups is ok.  This allows existing programs that set
gid_map with privilege to work without changes.  That is newgidmap
continues to work unchanged.

Thanks. I added that text to the changelog message.

Cheers,

Michael



-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/