Well, is it ever useful to be able to drop unneeded capabilities while retaining the same uid/gid? It certainly sounds like a reasonable thing to want to do. I'm reluctant to apply this without at least considering that possibility.
On Fri, Feb 02, 2018 at 12:30:50AM -0200, Marcos Felipe Schwarz wrote: > Is there any reason why they couldn't be the same? > > One reason in favor is that the option for running ovs as a non-root user > can't be deactivated correctly by the means in the documentation . It > states that setting OVS_USER_ID to 'root:root', or commenting the variable > out in /etc/sysconfig/openvswitch should revert the behavior back to normal. > The patch above enforces the expected behaviour without requiring > tinkering both > ovs-vswitchd and ovsdb-server systemd scripts to remove the "--user > OVS_USER_ID" parameter that is hardcoded. > >  Non-root User Support: > https://github.com/openvswitch/ovs/blob/master/rhl/README.RHEL.rst > > On Thu, Feb 1, 2018 at 10:23 PM, Ben Pfaff <b...@ovn.org> wrote: > > > OK, I understand now that the goal is that passing "--user $UID" should > > not call setuid() or setgid(). In that case, though, why pass the > > --user option at all? I believe that, with this patch, "--user $UID" > > and "" yield equivalent behavior. > > > > Thanks, > > > > Ben. > > > > On Thu, Feb 01, 2018 at 09:34:12PM -0200, Marcos Felipe Schwarz wrote: > > > Hi Ben, > > > > > > I agree that the purpose of the canges was not cleared in the patch. The > > > full discussion is at > > > https://mail.openvswitch.org/pipermail/ovs-discuss/2018- > > January/046061.html. > > > But in a nutshell, this change is a fancy way to avoid the actual > > problem, > > > that's why it's not intuitive. The actual problem is the current method > > to > > > change the ovs user at (daemon_become_new_user_linux), drops the > > > CAP_SYS_ADMIN capability, even when you are "changing" from root to > > itself, > > > which occurs in rhel based distros when you use OVS_USER="root:toot". My > > > PoC solution  was to force the CAP_SYS_ADMIN during the user change, > > but > > > this would give more permission to openvswitch process than necessary on > > > most of the situations, for instance when DPDK and UIO are not required. > > > The fix in the current patch was proposed by Aaron , which involves to > > > avoid changing the user when it is already the desired user (and group), > > > this fixes the problem without the downsides of the initial solution and > > > avoids unnecessary calls. > > > > > >  > > > https://mail.openvswitch.org/pipermail/ovs-discuss/2018- > > January/045959.html > > >  > > > https://mail.openvswitch.org/pipermail/ovs-discuss/2018- > > January/045973.html > > > Regards, > > > > > > Marcos Schwarz > > > > > > On Thu, Feb 1, 2018 at 7:27 PM, Ben Pfaff <b...@ovn.org> wrote: > > > > > > > On Thu, Feb 01, 2018 at 03:42:03PM -0200, Marcos Felipe Schwarz wrote: > > > > > Since 2.8.0 OVS runs as non-root user on rhel distros, but the > > current > > > > > implementation breaks the ability to run as root with DPDK and as a > > > > > consequence there is no way possible to use UIO drivers on kernel > > 4.0 and > > > > > newer [1, 2]. > > > > >  http://dpdk.org/browse/dpdk/commit/?id=cdc242f260e766 > > > > > bd95a658b5e0686a62ec04f5b0 > > > > >  https://www.kernel.org/doc/Documentation/vm/pagemap.txt > > > > > > > > > > Fixes: e3e738a3d058 ("redhat: allow dpdk to also run as non-root > > user") > > > > > Signed-off-by: Marcos Schwarz <marcos.f....@gmail.com> > > > > > Acked-by: Aaron Conole <acon...@redhat.com> > > > > > > > > Thanks for the patch. > > > > > > > > I understand from the commit message the ultimate goal of this patch. > > I > > > > don't yet understand what change it is actually making. In particular, > > > > what is the purpose of the following change; what does it do? > > > > > > > > > --- a/lib/daemon-unix.c > > > > > +++ b/lib/daemon-unix.c > > > > > @@ -1047,5 +1047,6 @@ daemon_set_new_user(const char *user_spec) > > > > > } > > > > > } > > > > > > > > > > - switch_user = true; > > > > > + if (!uid_verify(uid) || !gid_verify(gid)) > > > > > + switch_user = true; > > > > > } > > > > > > > > Thanks, > > > > > > > > Ben. > > > > > > _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev