On Sat, Oct 05, 2024 at 08:57:32AM +1000, Dave Chinner wrote: > On Fri, Oct 04, 2024 at 09:21:19AM +0200, Christian Brauner wrote: > > On Fri, Oct 04, 2024 at 10:46:27AM GMT, Dave Chinner wrote: > > > On Thu, Oct 03, 2024 at 06:17:31PM +0200, Jan Kara wrote: > > > > On Thu 03-10-24 23:59:51, Dave Chinner wrote: > > > > > As for the landlock code, I think it needs to have it's own internal > > > > > tracking mechanism and not search the sb inode list for inodes that > > > > > it holds references to. LSM cleanup should be run before before we > > > > > get to tearing down the inode cache, not after.... > > > > > > > > Well, I think LSM cleanup could in principle be handled together with the > > > > fsnotify cleanup but I didn't check the details. > > > > > > I'm not sure how we tell if an inode potentially has a LSM related > > > reference hanging off it. The landlock code looks to make an > > > assumption in that the only referenced inodes it sees will have a > > > valid inode->i_security pointer if landlock is enabled. i.e. it > > > calls landlock_inode(inode) and dereferences the returned value > > > without ever checking if inode->i_security is NULL or not. Correct, i_security should always be valid when this hook is called because it means that at least Landlock is enabled and then i_security refers to a valid LSM blob. > > > > > > I mean, we could do a check for inode->i_security when the refcount > > > is elevated and replace the security_sb_delete hook with an > > > security_evict_inode hook similar to the proposed fsnotify eviction > > > from evict_inodes(). That would be nice. > > > > > > But screwing with LSM instructure looks .... obnoxiously complex > > > from the outside... > > > > Imho, please just focus on the immediate feedback and ignore all the > > extra bells and whistles that we could or should do. I prefer all of > > that to be done after this series lands. > > Actually, it's not as bad as I thought it was going to be. I've > already moved both fsnotify and LSM inode eviction to > evict_inodes() as preparatory patches... Good, please Cc me and Günther on related patch series. FYI, we have the two release_inodes tests to check this hook in tools/testing/selftests/landlock/fs_test.c > > Dave Chinner (2): > vfs: move fsnotify inode eviction to evict_inodes() > vfs, lsm: rework lsm inode eviction at unmount > > fs/inode.c | 52 +++++++++++++--- > fs/notify/fsnotify.c | 60 ------------------- > fs/super.c | 8 +-- > include/linux/lsm_hook_defs.h | 2 +- > include/linux/security.h | 2 +- > security/landlock/fs.c | 134 ++++++++++-------------------------------- > security/security.c | 31 ++++++---- > 7 files changed, 99 insertions(+), 190 deletions(-) > > -Dave. > -- > Dave Chinner > david@xxxxxxxxxxxxx >
