On Wed, Apr 15, 2009 at 04:16:09PM -0500, Serge E. Hallyn wrote: > Quoting Oren Laadan (orenl@xxxxxxxxxxxxxxx): > > > > > > Serge E. Hallyn wrote: > > > Quoting Dave Hansen (dave@xxxxxxxxxxxxxxxxxx): > > >> On Wed, 2009-04-15 at 23:21 +0400, Alexey Dobriyan wrote: > > >>> Is sysctl to control CAP_SYS_ADMIN on restart(2) OK? > > >> If the point is not to let users even *try* restarting things if it > > >> *might* not work, then I guess this might be reasonable. > > >> > > >> If the goal is to increase security by always requiring CAP_SYS_ADMIN > > >> for "dangerous" operations, I fear it will be harmful. We may have > > >> people adding features that are not considering the security impact of > > >> what they're doing just because the cases they care about all require > > >> privilege. > > > > > > Nah, I disagree. (Or put another way, that wouldn't be the goal) > > > There are two administrators we want to satisfy: > > > > > > 1. the one who wants his users to do partial checkpoints, but doesn't > > > want to risk giving away any privilege at all in the process. He'll > > > be satisified by setting restart(2) to not require cap_sys_admin, > > > and his users just won't be able to do a whole container. A lot of > > > users will be happy with that (though no SYSVIPC support, then). > > > > There is also a middle way: use setuid program to allow creation > > of a new namespace (under your favorite policy), then drop the > > privileges and continue as unprivileged inside that container. > > > > IOW, don't make the initial container-creation a barrier for the > > entire operation. > > That is still possible here. But I don't think it's relevant. > > What Alexey wants, I believe, is for users to be able to not have > to worry about there being exploitable bugs in restart(2) which > unprivileged users can play with. And for the usual distro-kernel > reasons, saying use 'CONFIG_CHECKPOINT=n' is not an option. This is correct, yes. If I would be a sysadmin who knows a bit about kernel internals, I'd never trust restart(2) to get it right. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
