On Thu, 2023-04-06 at 15:11 -0400, Stefan Berger wrote: > > On 4/6/23 14:46, Jeff Layton wrote: > > On Thu, 2023-04-06 at 17:01 +0200, Christian Brauner wrote: > > > On Thu, Apr 06, 2023 at 10:36:41AM -0400, Paul Moore wrote: > > > > > Correct. As long as IMA is also measuring the upper inode then it seems > > like you shouldn't need to do anything special here. > > Unfortunately IMA does not notice the changes. With the patch provided in the other email IMA works as expected. > It looks like remeasurement is usually done in ima_check_last_writer. That gets called from __fput which is called when we're releasing the last reference to the struct file. You've hooked into the ->release op, which gets called whenever filp_close is called, which happens when we're disassociating the file from the file descriptor table. So...I don't get it. Is ima_file_free not getting called on your file for some reason when you go to close it? It seems like that should be handling this. In any case, I think this could use a bit more root-cause analysis. > > > > What sort of fs are you using for the upper layer? > > jffs2: > > /dev/mtdblock4 on /run/initramfs/ro type squashfs (ro,relatime,errors=continue) > /dev/mtdblock5 on /run/initramfs/rw type jffs2 (rw,relatime) > cow on / type overlay (rw,relatime,lowerdir=run/initramfs/ro,upperdir=run/initramfs/rw/cow,workdir=run/initramfs/rw/work) > jffs2 does not have a proper i_version counter, I'm afraid. But, IMA should handle that OK (by assuming that it always needs to remeasure when there is no i_version counter). -- Jeff Layton <jlayton@xxxxxxxxxx>
