Re: [RFC PATCH v2 0/9] Add LSM access controls and auditing to io_uring

On 2021-08-11 16:48, Paul Moore wrote: > Draft #2 of the patchset which brings auditing and proper LSM access > controls to the io_uring subsystem. The original patchset was posted > in late May and can be found via lore using the link below: > > https://lore.kernel.org/linux-security-module/162163367115.8379.845901263... > > This draft should incorporate all of the feedback from the original > posting as well as a few smaller things I noticed while playing > further with the code. The big change is of course the selective > auditing in the io_uring op servicing, but that has already been > discussed quite a bit in the original thread so I won't go into > detail here; the important part is that we found a way to move > forward and this draft captures that. For those of you looking to > play with these patches, they are based on Linus' v5.14-rc5 tag and > on my test system they boot and appear to function without problem; > they pass the selinux-testsuite and audit-testsuite and I have not > noticed any regressions in the normal use of the system. If you want > to get a copy of these patches straight from git you can use the > "working-io_uring" branch in the repo below: > > git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux.git > https://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux.git > > Beyond the existing test suite tests mentioned above, I've cobbled > together some very basic, very crude tests to exercise some of the > things I care about from a LSM/audit perspective. These tests are > pretty awful (I'm not kidding), but they might be helpful for the > other LSM/audit developers who want to test things: > > https://drop.paul-moore.com/90.kUgq > > There are currently two tests: 'iouring.2' and 'iouring.3'; > 'iouring.1' was lost in a misguided and overzealous 'rm' command. > The first test is standalone and basically tests the SQPOLL > functionality while the second tests sharing io_urings across process > boundaries and the credential/personality sharing mechanism. The > console output of both tests isn't particularly useful, the more > interesting bits are in the audit and LSM specific logs. The > 'iouring.2' command requires no special arguments to run but the > 'iouring.3' test is split into a "server" and "client"; the server > should be run without argument: > > % ./iouring.3s > >>> server started, pid = 11678 > >>> memfd created, fd = 3 > >>> io_uring created; fd = 5, creds = 1 > > ... while the client should be run with two arguments: the first is > the PID of the server process, the second is the "memfd" fd number: > > % ./iouring.3c 11678 3 > >>> client started, server_pid = 11678 server_memfd = 3 > >>> io_urings = 5 (server) / 5 (client) > >>> io_uring ops using creds = 1 > >>> async op result: 36 > >>> async op result: 36 > >>> async op result: 36 > >>> async op result: 36 > >>> START file contents > What is this life if, full of care, > we have no time to stand and stare. > >>> END file contents > > The tests were hacked together from various sources online, > attribution and links to additional info can be found in the test > sources, but I expect these tests to die a fiery death in the not > to distant future as I work to add some proper tests to the SELinux > and audit test suites. > > As I believe these patches should spend a full -rcX cycle in > linux-next, my current plan is to continue to solicit feedback on > these patches while they undergo additional testing (next up is > verification of the audit filter code for io_uring). Assuming no > critical issues are found on the mailing lists or during testing, I > will post a proper patchset later with the idea of merging it into > selinux/next after the upcoming merge window closes. > > Any comments, feedback, etc. are welcome. Thanks for the tests. I have a bunch of userspace patches to add to the last set I posted and these tests will help exercise them. I also have one more kernel patch to post... I'll dive back into that now. I had wanted to post them before now but got distracted with AUDIT_TRIM breakage.

> --- > > Casey Schaufler (1): > Smack: Brutalist io_uring support with debug > > Paul Moore (8): > audit: prepare audit_context for use in calling contexts beyond > syscalls > audit,io_uring,io-wq: add some basic audit support to io_uring > audit: dev/test patch to force io_uring auditing > audit: add filtering for io_uring records > fs: add anon_inode_getfile_secure() similar to > anon_inode_getfd_secure() > io_uring: convert io_uring to the secure anon inode interface > lsm,io_uring: add LSM hooks to io_uring > selinux: add support for the io_uring access controls > > > fs/anon_inodes.c | 29 ++ > fs/io-wq.c | 4 + > fs/io_uring.c | 69 +++- > include/linux/anon_inodes.h | 4 + > include/linux/audit.h | 26 ++ > include/linux/lsm_hook_defs.h | 5 + > include/linux/lsm_hooks.h | 13 + > include/linux/security.h | 16 + > include/uapi/linux/audit.h | 4 +- > kernel/audit.h | 7 +- > kernel/audit_tree.c | 3 +- > kernel/audit_watch.c | 3 +- > kernel/auditfilter.c | 15 +- > kernel/auditsc.c | 483 +++++++++++++++++++----- > security/security.c | 12 + > security/selinux/hooks.c | 34 ++ > security/selinux/include/classmap.h | 2 + > security/smack/smack_lsm.c | 64 ++++ > 18 files changed, 678 insertions(+), 115 deletions(-) > - RGB -- Richard Guy Briggs <rgb(a)redhat.com&gt; Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635