On 09/10/2013 08:42 AM, Dave Chinner wrote: > On Fri, Sep 06, 2013 at 11:30:33AM +1000, Dave Chinner wrote: >> On Wed, Sep 04, 2013 at 02:38:33PM +0800, Gao feng wrote: >>> This patchset add two helper functions to convert user space project id >>> to kernel space project id without any struct changed. >>> >>> Since the projid_map of user namespace has limit the range of valid project >>> ids for user namespace, we can safely allow user to change file's project >>> id in un-init user namespace. >> >> This doesn't address any of the concerns about whether access to >> project IDs are valid in a user namaspacee environment. >> >> Project IDs are not the same as UIDs and GIDs. They got included in >> all the mapping stuff because of the fact that they are used for >> quotas, but the fact is that they are not a property owned by a user >> or a group or control access. >> >> IOWs, project IDs are an *accounting* construct rather than an >> *access control mechanism* If project IDs are being used by the >> system administrators for accounting the space used by a *mount >> namespace* container, then they must not be modifiable by a user >> in a user namespace. >> >> This is a fundamentally different use case from UID/GID mapping, >> because there is no possible competing access for on-disk uid/gid >> fields possible from the initns like there is for project quotas. >> IOWs, project quota IDs are not owned by a namespace, and so mapping >> them like we do for UID/GID is not clearly the right solution for >> everyone. >> >> So, there's a bigger policy issue here that needs to be decided >> first. i.e. whether project quotas and therefore project IDs should >> be accessible to users inside a user namespace. >> >> If we decide to make it optional so that a system administrator can >> chose whether project IDs are to be mapped via the userns mapping >> infrastructure, then we need some kind of infrastructure to support >> and enforce that first. > > BTW, if we are making project IDs mapped to userns, stuff like > XFS_PROJID_DEFAULT and project ID inheritence need work as well... > Yes, let's make it simple, if we find some cases that we have to make project IDs mapped to userns, let's restart this work :) Thanks _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
