On Wed, Jul 12, 2017 at 08:20:21AM -0400, Mimi Zohar wrote: > Right, currently the only way of knowing is by looking at the IMA > measurement list to see if modified files are re-measured or, as you > said, by looking at the code. Who's actually using this, and do they do any kind of checks, or document the filesystem-specific limitations? --b. > > I started working on adding logging/audit messages, but have not yet > posted them. A very preliminary set of patches is available from > https://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity. > git/next-log-iversion-experimental. > > 2745b7be961a ima: indicate possibly missing file measurements or verification > 0c81a8c56153 security: define new LSM sb_post_new_mount hook > > Mimi > > > > > ext4 only provides a working i_version counter when you mount with "-o > > i_version", so it's trivial to tell there. xfs and btrfs also have > > functional i_version counter implementations, but there is no such > > mount option for them (it's always on there). NFSv4 and AFS can provide > > one too (as they're supplied by the server). > > > > Suppose I want to use IMA on something else (say, ubifs). How do I know > > whether I'm only going to get "initial file integrity verification and > > measurement" or whether it'll be updated after being written? > > > > Now, I happen to know that ubifs does _not_ support the i_version > > counter because I can poke through the kernel sources and tell, but how > > is Joe Random Linux User to know this? > > > > Does that not matter for some reason? Is there a whitelist of > > filesystems being maintained in some userland package? > > > > Sorry if it seems like I'm being dense here, but I really just don't > > understand how we can allow this code to be so cavalier about using the > > i_version counter without taking steps to ensure that it actually does > > a damned thing at all. > >
