On Sat, Jul 03, 2021 at 12:59:28PM +0200, John Wood wrote: > Hi, > > On Fri, Jul 02, 2021 at 05:08:09PM +0000, Alexander Lobakin wrote: > > > > On the other hand, it leaves a potentional window for attackers to > > perform brute force from xattr-incapable filesystems. So at the end > > of the day I think that the current implementation (a strong > > rejection of such filesystems) is way more secure than having > > a fallback I proposed. > > I've been thinking more about this: that the Brute LSM depends on xattr > support and I don't like this part. I want that brute force attacks can > be detected and mitigated on every system (with minimal dependencies). > So, now I am working in a solution without this drawback. I have some > ideas but I need to work on it. I have been coding and testing a bit my ideas but: Trying to track the applications faults info using kernel memory ends up in an easy to abuse system (denied of service due to large amount of memory in use) :( So, I continue with the v8 idea: xattr to track application crashes info. > > I'm planning to make a patch which will eliminate such weird rootfs > > type selection and just always use more feature-rich tmpfs if it's > > compiled in. So, as an alternative, you could add it to your series > > as a preparatory change and just add a Kconfig dependency on > > CONFIG_TMPFS && CONFIG_TMPFS_XATTR to CONFIG_SECURITY_FORK_BRUTE > > without messing with any fallbacks at all. > > What do you think? > > Great. But I hope this patch will not be necessary for Brute LSM :) My words are no longer valid ;) Thanks, John Wood
