On Wed, 31 Jul 2013 10:21:19 +1000 Dave Chinner <david@xxxxxxxxxxxxx> wrote: [...] > The only thing I think we still need to address is whether > xfs_ioc_setattr() should allow users within a namespace to change > the project ID of a file they otherwise own. That function is > currently changed to use a inode_owner_or_capable() check and so if > the uids match inside the namespace the modification is allowed. Right, so before this change the caller has to own the file or be CAP_FOWNER in init_user_ns. Changing to using inode_owner_or_capable() means the caller has to own the file (and the inode's uid must be valid in current_user_ns) or be CAP_FOWNER in current_user_ns. I don't see how this lets the user the user do something inside the userns that they can't do outside. Basically I think we want to treat projids as a non namespace aware identifier, but it sounds like maybe we don't want them manipulated from userns context at all. > However, right now for project IDs I think we have decided to limit > manipulations to the init user namespace and not expose project IDs > inside user namespaces at all. Hence I think that xfs_ioc_setattr() > needs a further check for this... If we don't want to allow setting the projid from a userns, the check I would propose inside the if (mask & FSX_EXTSIZE) block is: if (current_user_ns() != &init_user_ns) Is the appropriate error return for this EINVAL? (thats what a similar check in kernel/taskstats.c returns) > Cheers, > > Dave. _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
