On Mon, Nov 29, 2021 at 09:10:29AM -0500, James Bottomley wrote: > On Mon, 2021-11-29 at 08:53 -0500, Stefan Berger wrote: > > On 11/29/21 07:50, James Bottomley wrote: > > > On Sun, 2021-11-28 at 22:58 -0600, Serge E. Hallyn wrote: > > > > On Sat, Nov 27, 2021 at 04:45:49PM +0000, James Bottomley wrote: > > > > > Currently we get one entry in the IMA log per unique file > > > > > event. So, if you have a measurement policy and it measures a > > > > > particular binary it will not get measured again if it is > > > > > subsequently executed. For Namespaced IMA, the correct > > > > > behaviour > > > > > seems to be to log once per inode per namespace (so every > > > > > unique > > > > > execution in a namespace gets a separate log entry). Since > > > > > logging > > > > > once per inode per namespace is > > > > I suspect I'll need to do a more in depth reading of the existing > > > > code, but I'll ask the lazy question anyway (since you say "the > > > > correct behavior seems to be") - is it actually important that > > > > files which were appraised under a parent namespace's policy > > > > already > > > > should be logged again? > > > I think so. For a couple of reasons, assuming the namespace > > > eventually > > > gets its own log entries, which the next incremental patch proposed > > > to > > > do by virtualizing the securityfs entries. If you don't do this: > > > > To avoid duplicate efforts, an implementation of a virtualized > > securityfs is in this series here: > > > > https://github.com/stefanberger/linux-ima-namespaces/commits/v5.15%2Bimans.20211119.v3 > > > > It starts with 'securityfs: Prefix global variables with secruityfs_' > > That's quite a big patch series. I already actually implemented this > as part of the RFC for getting the per namespace measurement log. The > attached is basically what I did. > > Most of the time we don't require namespacing the actual virtualfs > file, because it's world readable. IMA has a special requirement in > this regard because the IMA files should be readable (and writeable > when we get around to policy updates) by the admin of the namespace but > their protection is 0640 or 0440. I thought the simplest solution > would be to make an additional flag that coped with the permissions and > a per-inode flag way of making the file as "accessible by userns > admin". Doing something simple like this gives a much smaller > diffstat: That's a NAK from me. Stefan's series might be bigger but it does things correctly. I appreciate the keep it simple attitude but no. I won't speciale-case securityfs or similar stuff in core vfs helpers. Christian
