On Mon, Jan 11, 2021 at 10:51:20AM -0800, Darrick J. Wong wrote: > On Sun, Jan 10, 2021 at 07:41:02PM +0100, Pavel Machek wrote: > > Hi! > > > > On Fri 2020-10-09 10:37:32, Theodore Y. Ts'o wrote: > > > On Thu, Oct 08, 2020 at 03:22:59PM -0700, Josh Triplett wrote: > > > > > > > > I wasn't trying to make a *new* general principle or policy. I was under > > > > the impression that this *was* the policy, because it never occurred to > > > > me that it could be otherwise. It seemed like a natural aspect of the > > > > kernel/userspace boundary, to the point that the idea of it *not* being > > > > part of the kernel's stability guarantees didn't cross my mind. > > > > > > >From our perspective (and Darrick and I discussed this on this week's > > > ext4 video conference, so it represents the ext4 and xfs maintainer's > > > position) is that the file system format is different. First, the > > > on-disk format is not an ABI, and it is several orders more complex > > > than a system call interface. Second, we make no guarantees about > > > what the file system created by malicious tools will do. For example, > > > XFS developers reject bug reports from file system fuzzers, because > > My recollection of this is quite different -- sybot was sending multiple > zeroday exploits per week to the public xfs list, and nobody at Google > was helping us to /fix/ those bugs.Each report took hours of developer > time to extract the malicious image (because Dmitry couldn't figure out > how to add that ability to syzbot) and syscall sequence from the > reproducer program, plus whatever time it took to craft a patch, test > it, and push it through review. > > Dave and I complained to Dmitry about how the community had zero input > into the rate at which syzbot was allowed to look for xfs bugs. Nobody > at Google would commit to helping fix any of the XFS bugs, and Dmitry > would not give us better choices than (a) Google AI continuing to create > zerodays and leaving the community to clean up the mess, or (b) shutting > off syzbot entirely. At the time I said I would accept letting syzbot > run against xfs until it finds something, and turning it off until we > resolve the issue. That wasn't acceptable, because (I guess) nobody at > Google wants to put /any/ staff time into XFS at all. > > TLDR: XFS /does/ accept bug reports about fuzzed and broken images. > What we don't want is make-work Google AIs spraying zeroday code in > public places and the community developers having to clean up the mess. syzkaller is an open source project that implements a coverage-guided fuzzer for multiple operating system kernels; it's not "Google AI". Anyone can run syzkaller (either by itself, or as part of a syzbot instance) and find the same bugs. - Eric
