Messages in this thread | | | Date | Wed, 04 Mar 2015 15:00:01 +0100 | From | "Michael Kerrisk (man-pages)" <> | Subject | Re: [PATCH 2/2] user_namespaces.7: Update the documention to reflect the fixes for negative groups |
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On 02/02/2015 10:31 PM, Alban Crequy wrote: > Hello, > > Thanks for updating the man page. > > On 12 December 2014 at 22:54, Eric W. Biederman <ebiederm@xmission.com> wrote: > (...) >> Furthermore to preserve in some form the useful applications that have >> been setting gid_map without privilege the file /proc/[pid]/setgroups >> was added to allow disabling setgroups. With the setgroups system >> call permanently disabled in a user namespace it again becomes safe to >> allow writes to gid_map without privilege. >> >> Here is my meager attempt to update user_namespaces.7 to reflect these >> issues. > > The program userns_child_exec.c in user_namespaces.7 should be updated > to write in /proc/.../setgroups, near the line: > /* Update the UID and GID maps in the child */ > > Otherwise, the example given in the manpage does not work: > $ ./userns_child_exec -p -m -U -M '0 1000 1' -G '0 1000 1' bash
Thanks, Alban. I've added code to the example to handle /proc/PID/setgroups (and tested).
Cheers,
Michael
-- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/
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