On Thu, Nov 29, 2018 at 11:07 AM Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote: > On Wed, Nov 28, 2018 at 10:52 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote: > > On Tue, Nov 27, 2018 at 6:50 AM Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote: > > > Hi Ondrej, > > > > > > On Tue, 27 Nov 2018 09:53:32 +0100 Ondrej Mosnacek <omosnace@xxxxxxxxxx> wrote: > > > > > > > > Hm... seems that there was some massive overhaul in the VFS code right > > > > at the wrong moment... There are new hooks for mounting now and the > > > > > > The mount changes have been in linux-next since before the last > > > release ... > > > > > > > code that our commit changes is now here: > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git/tree/security/selinux/hooks.c?h=for-next#n3131 > > > > > > > > It seems that the logic is still the same, just now our patch (or the > > > > VFS one) needs to be updated to change the above line as such > > > > (untested pseudo-patch): > > > > > > > > - if (fc->purpose == FS_CONTEXT_FOR_KERNEL_MOUNT) > > > > + if (fc->purpose == (FS_CONTEXT_FOR_KERNEL_MOUNT|FS_CONTEXT_FOR_SUBMOUNT)) > > > > > > OK, so from tomorrow I will use that merge resolution. Someone needs > > > to remember to tell Linus about this when the latter of the vfs and > > > selinux trees reach him. > > > > I will, or at least I'll do my best to remember; since we only have a > > few more week until the merge window I like my odds. FWIW, I > > typically do a test merge on top of Linus' tree before sending the > > SELinux PR just to verify that everything is relatively clean and > > there are no surprises. > > > > Ondrej, please work with David Howells to ensure that submounts are > > handled correctly in his mount rework. > > OK, I will verify that the SELinux submount fix rebased on top of > vfs/work.mount in the way I suggested above passes the same testing > (seliinux-testsuite + NFS crossmnt reproducer). I am now building two > kernels (vfs/work.mount with and without the fix) to test. Let me know > if there is anything more to do. I tested the proposed patch ([1]; fixed as per correction from David Howells) applied on top of patches v4.19-rc3..vfs/work.mount applied on top of the 4.19.5-300 Fedora 29 kernel. However, the submount test was still failing, so I looked again at the list of the possible 'purpose' values and it turns out the value used by NFS et al. is actually FS_CONTEXT_FOR_ROOT_MOUNT (it is actually documented nicely in Documentation/filesystems/mount_api.txt). So I'll need to build a new test kernel with updated patch ([2]) and retest... BTW, the vfs/work.mount changes alone seem to cause some overlay test failures (I didn't test a clean 4.19.5 so it may be due to some stable patch as well): Test Summary Report ------------------- overlay/test (Wstat: 3072 Tests: 119 Failed: 12) Failed tests: 66, 74, 76-77, 79, 87, 95, 103, 108, 110-111 117 Non-zero exit status: 12 The failing tests are all in the context mount section, but I don't think this is (directly) related to [3] because there are much more tests failing and the kernel I was testing didn't include the problematic OverlayFS patch. Perhaps the VFS patches somehow broke the parsing of the context= mount option? [1] https://gitlab.com/omos/linux-public/commit/fe5478717ddde92e3ea599e14051ad57522fdf47 [2] https://gitlab.com/omos/linux-public/commit/f5c58adc7babd62e4bfe8cda799459d263dc5186 [3] https://github.com/SELinuxProject/selinux-kernel/issues/43 -- Ondrej Mosnacek <omosnace at redhat dot com> Associate Software Engineer, Security Technologies Red Hat, Inc.
