Commit Graph

68 Commits

Author SHA1 Message Date
Günther Noack
dc75f89046
selftests/landlock: Simplify ruleset creation and enforcement in fs_test
* Add enforce_fs() for defining and enforcing a ruleset in one step
* In some places, dropped "ASSERT_LE(0, fd)" checks after
  create_ruleset() call -- create_ruleset() already checks that.
* In some places, rename "file_fd" to "fd" if it is not needed to
  disambiguate any more.

Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20260327164838.38231-12-gnoack3000@gmail.com
[mic: Tweak subjet]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-04-07 18:51:10 +02:00
Günther Noack
f433fd3fa2
selftests/landlock: Check that coredump sockets stay unrestricted
Even when a process is restricted with the new
LANDLOCK_ACCESS_FS_RESOLVE_UNIX right, the kernel can continue writing
its coredump to the configured coredump socket.

In the test, we create a local server and rewire the system to write
coredumps into it.  We then create a child process within a Landlock
domain where LANDLOCK_ACCESS_FS_RESOLVE_UNIX is restricted and make
the process crash.  The test uses SO_PEERCRED to check that the
connecting client process is the expected one.

Includes a fix by Mickaël Salaün for setting the EUID to 0 (see [1]).

Link[1]: https://lore.kernel.org/all/20260218.ohth8theu8Yi@digikod.net/
Suggested-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20260327164838.38231-11-gnoack3000@gmail.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-04-07 18:51:10 +02:00
Günther Noack
0f42f5be0b
selftests/landlock: Audit test for LANDLOCK_ACCESS_FS_RESOLVE_UNIX
Add an audit test to check that Landlock denials from
LANDLOCK_ACCESS_FS_RESOLVE_UNIX result in audit logs in the expected
format.  (There is one audit test for each filesystem access right, so
we should add one for LANDLOCK_ACCESS_FS_RESOLVE_UNIX as well.)

Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20260327164838.38231-10-gnoack3000@gmail.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-04-07 18:51:09 +02:00
Günther Noack
9da41c65c9
selftests/landlock: Test LANDLOCK_ACCESS_FS_RESOLVE_UNIX
* Extract common helpers from an existing IOCTL test that
  also uses pathname unix(7) sockets.
* These tests use the common scoped domains fixture which is also used
  in other Landlock scoping tests and which was used in Tingmao Wang's
  earlier patch set in [1].

These tests exercise the cross product of the following scenarios:

* Stream connect(), Datagram connect(), Datagram sendmsg() and
  Seqpacket connect().
* Child-to-parent and parent-to-child communication
* The Landlock policy configuration as listed in the scoped_domains
  fixture.
  * In the default variant, Landlock domains are only placed where
    prescribed in the fixture.
  * In the "ALL_DOMAINS" variant, Landlock domains are also placed in
    the places where the fixture says to omit them, but with a
    LANDLOCK_RULE_PATH_BENEATH that allows connection.

Cc: Justin Suess <utilityemal77@gmail.com>
Cc: Tingmao Wang <m@maowtm.org>
Cc: Mickaël Salaün <mic@digikod.net>
Link[1]: https://lore.kernel.org/all/53b9883648225d5a08e82d2636ab0b4fda003bc9.1767115163.git.m@maowtm.org/
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20260327164838.38231-9-gnoack3000@gmail.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-04-07 18:51:09 +02:00
Günther Noack
db8201a3fa
selftests/landlock: Replace access_fs_16 with ACCESS_ALL in fs_test
The access_fs_16 variable was originally intended to stay frozen at 16
access rights so that audit tests would not need updating when new
access rights are added.  Now that we have 17 access rights, the name
is confusing.

Replace all uses of access_fs_16 with ACCESS_ALL and delete the
variable.

Suggested-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20260327164838.38231-8-gnoack3000@gmail.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-04-07 18:51:08 +02:00
Günther Noack
ae97330d1b
landlock: Control pathname UNIX domain socket resolution by path
* Add a new access right LANDLOCK_ACCESS_FS_RESOLVE_UNIX, which
  controls the lookup operations for named UNIX domain sockets.  The
  resolution happens during connect() and sendmsg() (depending on
  socket type).
* Change access_mask_t from u16 to u32 (see below)
* Hook into the path lookup in unix_find_bsd() in af_unix.c, using a
  LSM hook.  Make policy decisions based on the new access rights
* Increment the Landlock ABI version.
* Minor test adaptations to keep the tests working.
* Document the design rationale for scoped access rights,
  and cross-reference it from the header documentation.

With this access right, access is granted if either of the following
conditions is met:

* The target socket's filesystem path was allow-listed using a
  LANDLOCK_RULE_PATH_BENEATH rule, *or*:
* The target socket was created in the same Landlock domain in which
  LANDLOCK_ACCESS_FS_RESOLVE_UNIX was restricted.

In case of a denial, connect() and sendmsg() return EACCES, which is
the same error as it is returned if the user does not have the write
bit in the traditional UNIX file system permissions of that file.

The access_mask_t type grows from u16 to u32 to make space for the new
access right.  This also doubles the size of struct layer_access_masks
from 32 byte to 64 byte.  To avoid memory layout inconsistencies between
architectures (especially m68k), pack and align struct access_masks [2].

Document the (possible future) interaction between scoped flags and
other access rights in struct landlock_ruleset_attr, and summarize the
rationale, as discussed in code review leading up to [3].

This feature was created with substantial discussion and input from
Justin Suess, Tingmao Wang and Mickaël Salaün.

Cc: Tingmao Wang <m@maowtm.org>
Cc: Justin Suess <utilityemal77@gmail.com>
Cc: Kuniyuki Iwashima <kuniyu@google.com>
Suggested-by: Jann Horn <jannh@google.com>
Link[1]: https://github.com/landlock-lsm/linux/issues/36
Link[2]: https://lore.kernel.org/all/20260401.Re1Eesu1Yaij@digikod.net/
Link[3]: https://lore.kernel.org/all/20260205.8531e4005118@gnoack.org/
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20260327164838.38231-5-gnoack3000@gmail.com
[mic: Fix kernel-doc formatting, pack and align access_masks]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-04-07 18:51:06 +02:00
Günther Noack
15e8d739fd
selftests/landlock: Properly close a file descriptor
Add a missing close(srv_fd) call, and use EXPECT_EQ() to check the
result.

Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Fixes: f83d51a5bd ("selftests/landlock: Check IOCTL restrictions for named UNIX domain sockets")
Link: https://lore.kernel.org/r/20260101134102.25938-2-gnoack3000@gmail.com
[mic: Use EXPECT_EQ() and update commit message]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2026-01-09 11:52:47 +01:00
Tingmao Wang
14c00e30d3
selftests/landlock: Fix typo in fs_test
Signed-off-by: Tingmao Wang <m@maowtm.org>
Link: https://lore.kernel.org/r/62d18e06eeb26f62bc49d24c4467b3793c5ba32b.1766885035.git.m@maowtm.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-12-29 16:19:38 +01:00
Matthieu Buffet
e4aa4461d4
selftests/landlock: NULL-terminate unix pathname addresses
The size of Unix pathname addresses is computed in selftests using
offsetof(struct sockaddr_un, sun_path) + strlen(xxx). It should have
been that +1, which makes addresses passed to the libc and kernel
non-NULL-terminated. unix_mkname_bsd() fixes that in Linux so there is
no harm, but just using sizeof(the address struct) should improve
readability.

Signed-off-by: Matthieu Buffet <matthieu@buffet.re>
Reviewed-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20251202215141.689986-1-matthieu@buffet.re
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-12-26 20:38:58 +01:00
Matthieu Buffet
e1a57c3359
selftests/landlock: Remove invalid unix socket bind()
Remove bind() call on a client socket that doesn't make sense.
Since strlen(cli_un.sun_path) returns a random value depending on stack
garbage, that many uninitialized bytes are read from the stack as an
unix socket address. This creates random test failures due to the bind
address being invalid or already in use if the same stack value comes up
twice.

Fixes: f83d51a5bd ("selftests/landlock: Check IOCTL restrictions for named UNIX domain sockets")
Signed-off-by: Matthieu Buffet <matthieu@buffet.re>
Reviewed-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20251201003631.190817-1-matthieu@buffet.re
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-12-26 20:38:58 +01:00
Mickaël Salaün
54f9baf537
selftests/landlock: Add disconnected leafs and branch test suites
Test disconnected directories with two test suites
(layout4_disconnected_leafs and layout5_disconnected_branch) and 43
variants to cover the main corner cases.

These tests are complementary to the previous commit.

Add test_renameat() and test_exchangeat() helpers.

Test coverage for security/landlock is 92.1% of 1927 lines according to
LLVM 20.

Cc: Günther Noack <gnoack@google.com>
Cc: Song Liu <song@kernel.org>
Cc: Tingmao Wang <m@maowtm.org>
Link: https://lore.kernel.org/r/20251128172200.760753-5-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-11-28 18:27:07 +01:00
Tingmao Wang
a18ee3f31f
selftests/landlock: Add tests for access through disconnected paths
This adds tests for the edge case discussed in [1], with specific ones
for rename and link operations when the operands are through
disconnected paths, as that go through a separate code path in Landlock.

This has resulted in a warning, due to collect_domain_accesses() not
expecting to reach a different root from path->mnt:

  #  RUN           layout1_bind.path_disconnected ...
  #            OK  layout1_bind.path_disconnected
  ok 96 layout1_bind.path_disconnected
  #  RUN           layout1_bind.path_disconnected_rename ...
  [..] ------------[ cut here ]------------
  [..] WARNING: CPU: 3 PID: 385 at security/landlock/fs.c:1065 collect_domain_accesses
  [..] ...
  [..] RIP: 0010:collect_domain_accesses (security/landlock/fs.c:1065 (discriminator 2) security/landlock/fs.c:1031 (discriminator 2))
  [..] current_check_refer_path (security/landlock/fs.c:1205)
  [..] ...
  [..] hook_path_rename (security/landlock/fs.c:1526)
  [..] security_path_rename (security/security.c:2026 (discriminator 1))
  [..] do_renameat2 (fs/namei.c:5264)
  #            OK  layout1_bind.path_disconnected_rename
  ok 97 layout1_bind.path_disconnected_rename

Move the const char definitions a bit above so that we can use the path
for s4d1 in cleanup code.

Cc: Günther Noack <gnoack@google.com>
Cc: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/027d5190-b37a-40a8-84e9-4ccbc352bcdf@maowtm.org [1]
Signed-off-by: Tingmao Wang <m@maowtm.org>
Link: https://lore.kernel.org/r/20251128172200.760753-4-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-11-28 18:27:06 +01:00
Mickaël Salaün
dae01387e6
selftests/landlock: Add test to check rule tied to covered mount point
This test checks that a rule on a directory used as a mount point does
not grant access to the mount covering it.  It is a generalization of
the bind mount case in layout3_fs.hostfs.release_inodes [1] that tests
hidden mount points.

Cc: Günther Noack <gnoack@google.com>
Cc: Song Liu <song@kernel.org>
Cc: Tingmao Wang <m@maowtm.org>
Link: https://lore.kernel.org/r/20250606.zo5aekae6Da6@digikod.net [1]
Link: https://lore.kernel.org/r/20250606110811.211297-1-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-06-19 13:55:41 +02:00
Mickaël Salaün
6b4566400a
selftests/landlock: Add PID tests for audit records
Add audit.thread tests to check that the PID tied to a domain is not a
thread ID but the thread group ID.  These new tests would not pass
without the previous TGID fix.

Extend matches_log_domain_allocated() to check against the PID that
created the domain.

Test coverage for security/landlock is 93.6% of 1524 lines according to
gcc/gcov-14.

Cc: Christian Brauner <brauner@kernel.org>
Cc: Günther Noack <gnoack@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20250410171725.1265860-3-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-04-11 12:53:22 +02:00
Mickaël Salaün
316d06b011
selftests/landlock: Add audit tests for filesystem
Test all filesystem blockers, including events with several records, and
record with several blockers:
- fs.execute
- fs.write_file
- fs.read_file
- fs_read_dir
- fs.remove_dir
- fs.remove_file
- fs.make_char
- fs.make_dir
- fs.make_reg
- fs.make_sock
- fs.make_fifo
- fs.make_block
- fs.make_sym
- fs.refer
- fs.truncate
- fs.ioctl_dev
- fs.change_topology

Cc: Günther Noack <gnoack@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20250320190717.2287696-27-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-03-26 13:59:48 +01:00
Linus Torvalds
bdd4f86c97 AT_EXECVE_CHECK update for v6.14-rc1 (fix1)
- selftests: Handle old glibc without execveat(2) (Mickaël Salaün)
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Merge tag 'AT_EXECVE_CHECK-v6.14-rc1-fix1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull AT_EXECVE_CHECK selftest fix from Kees Cook:
 "Fixes the AT_EXECVE_CHECK selftests which didn't run on old versions
  of glibc"

* tag 'AT_EXECVE_CHECK-v6.14-rc1-fix1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  selftests: Handle old glibc without execveat(2)
2025-01-31 17:12:31 -08:00
Mickaël Salaün
38567b972a selftests: Handle old glibc without execveat(2)
Add an execveat(2) wrapper because glibc < 2.34 does not have one.  This
fixes the check-exec tests and samples.

Cc: Günther Noack <gnoack@google.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Roberto Sassu <roberto.sassu@huawei.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Stefan Berger <stefanb@linux.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://lore.kernel.org/r/20250114205645.GA2825031@ax162
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20250115144753.311152-1-mic@digikod.net
Signed-off-by: Kees Cook <kees@kernel.org>
2025-01-27 11:37:18 -08:00
Linus Torvalds
21266b8df5 AT_EXECVE_CHECK introduction for v6.14-rc1
- Implement AT_EXECVE_CHECK flag to execveat(2) (Mickaël Salaün)
 
 - Implement EXEC_RESTRICT_FILE and EXEC_DENY_INTERACTIVE securebits
   (Mickaël Salaün)
 
 - Add selftests and samples for AT_EXECVE_CHECK (Mickaël Salaün)
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Merge tag 'AT_EXECVE_CHECK-v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull AT_EXECVE_CHECK from Kees Cook:

 - Implement AT_EXECVE_CHECK flag to execveat(2) (Mickaël Salaün)

 - Implement EXEC_RESTRICT_FILE and EXEC_DENY_INTERACTIVE securebits
   (Mickaël Salaün)

 - Add selftests and samples for AT_EXECVE_CHECK (Mickaël Salaün)

* tag 'AT_EXECVE_CHECK-v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  ima: instantiate the bprm_creds_for_exec() hook
  samples/check-exec: Add an enlighten "inc" interpreter and 28 tests
  selftests: ktap_helpers: Fix uninitialized variable
  samples/check-exec: Add set-exec
  selftests/landlock: Add tests for execveat + AT_EXECVE_CHECK
  selftests/exec: Add 32 tests for AT_EXECVE_CHECK and exec securebits
  security: Add EXEC_RESTRICT_FILE and EXEC_DENY_INTERACTIVE securebits
  exec: Add a new AT_EXECVE_CHECK flag to execveat(2)
2025-01-22 20:34:42 -08:00
Mickaël Salaün
2a794ee613
selftests/landlock: Add layout1.umount_sandboxer tests
Check that a domain is not tied to the executable file that created it.
For instance, that could happen if a Landlock domain took a reference to
a struct path.

Move global path names to common.h and replace copy_binary() with a more
generic copy_file() helper.

Test coverage for security/landlock is 92.7% of 1133 lines according to
gcc/gcov-14.

Cc: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20250108154338.1129069-23-mic@digikod.net
[mic: Update date and add test coverage]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-01-17 19:05:38 +01:00
Mickaël Salaün
2107c35128
selftests/landlock: Fix error message
The global variable errno may not be set in test_execute().  Do not use
it in related error message.

Cc: Günther Noack <gnoack@google.com>
Fixes: e1199815b4 ("selftests/landlock: Add user space tests")
Link: https://lore.kernel.org/r/20250108154338.1129069-21-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-01-17 19:05:37 +01:00
Mickaël Salaün
12264f721f
selftests/landlock: Add test to check partial access in a mount tree
Add layout1.refer_part_mount_tree_is_allowed to test the masked logical
issue regarding collect_domain_accesses() calls followed by the
is_access_to_paths_allowed() check in current_check_refer_path().  See
previous commit.

This test should work without the previous fix as well, but it enables
us to make sure future changes will not have impact regarding this
behavior.

Cc: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20250108154338.1129069-13-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2025-01-17 19:05:36 +01:00
Mickaël Salaün
0e7f90f34c selftests/landlock: Add tests for execveat + AT_EXECVE_CHECK
Extend layout1.execute with the new AT_EXECVE_CHECK flag.  The semantic
with AT_EXECVE_CHECK is the same as with a simple execve(2),
LANDLOCK_ACCESS_FS_EXECUTE is enforced the same way.

Cc: Günther Noack <gnoack@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20241212174223.389435-5-mic@digikod.net
Signed-off-by: Kees Cook <kees@kernel.org>
2024-12-18 17:00:29 -08:00
Tahera Fahimi
4f9a5b50d3
selftests/landlock: Test UNIX sockets with any address formats
Expand abstract UNIX socket restriction tests by examining different
scenarios for UNIX sockets with pathname or unnamed address formats
connection with scoped domain.

The various_address_sockets tests ensure that UNIX sockets bound to a
filesystem pathname and unnamed sockets created by socketpair can still
connect to a socket outside of their scoped domain, meaning that even if
the domain is scoped with LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET, the
socket can connect to a socket outside the scoped domain.

Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com>
Link: https://lore.kernel.org/r/a9e8016aaa5846252623b158c8f1ce0d666944f4.1725494372.git.fahimitahera@gmail.com
[mic: Remove useless clang-format tags, fix unlink/rmdir calls, drop
capabilities, rename variables, remove useless mknod/unlink calls, clean
up fixture, test write/read on sockets, test sendto() on datagram
sockets, close sockets as soon as possible]
Co-developed-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-09-16 23:50:49 +02:00
Mickaël Salaün
0055f53aac
selftests/landlock: Add layout1.refer_mount_root
Add tests to check error codes when linking or renaming a mount root
directory.  This previously triggered a kernel warning, but it is fixed
with the previous commit.

Cc: Günther Noack <gnoack@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20240516181935.1645983-3-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-31 16:41:54 +02:00
Günther Noack
bce605e0cf
selftests/landlock: Exhaustive test for the IOCTL allow-list
This test checks all IOCTL commands implemented in do_vfs_ioctl().

Test coverage for security/landlock is 90.9% of 722 lines according to
gcc/gcov-13.

Suggested-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20240419161122.2023765-8-gnoack@google.com
[mic: Add test coverage]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-13 06:58:33 +02:00
Günther Noack
f83d51a5bd
selftests/landlock: Check IOCTL restrictions for named UNIX domain sockets
The LANDLOCK_ACCESS_FS_IOCTL_DEV right should have no effect on the use of
named UNIX domain sockets.

Suggested-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20240419161122.2023765-7-gnoack@google.com
[mic: Add missing stddef.h for offsetof()]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-13 06:58:32 +02:00
Günther Noack
56ffd377c7
selftests/landlock: Test IOCTLs on named pipes
Named pipes should behave like pipes created with pipe(2),
so we don't want to restrict IOCTLs on them.

Suggested-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20240419161122.2023765-6-gnoack@google.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-13 06:58:31 +02:00
Günther Noack
7954a1d155
selftests/landlock: Test ioctl(2) and ftruncate(2) with open(O_PATH)
ioctl(2) and ftruncate(2) operations on files opened with O_PATH
should always return EBADF, independent of the
LANDLOCK_ACCESS_FS_TRUNCATE and LANDLOCK_ACCESS_FS_IOCTL_DEV access
rights in that file hierarchy.

Suggested-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20240419161122.2023765-5-gnoack@google.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-13 06:58:31 +02:00
Günther Noack
dd6d32afdf
selftests/landlock: Test IOCTL with memfds
Because the LANDLOCK_ACCESS_FS_IOCTL_DEV right is associated with the
opened file during open(2), IOCTLs are supposed to work with files
which are opened by means other than open(2).

Signed-off-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20240419161122.2023765-4-gnoack@google.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-13 06:58:30 +02:00
Günther Noack
3ecf19e568
selftests/landlock: Test IOCTL support
Exercises Landlock's IOCTL feature in different combinations of
handling and permitting the LANDLOCK_ACCESS_FS_IOCTL_DEV right, and in
different combinations of using files and directories.

Signed-off-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20240419161122.2023765-3-gnoack@google.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-13 06:58:30 +02:00
Günther Noack
b25f7415eb
landlock: Add IOCTL access right for character and block devices
Introduces the LANDLOCK_ACCESS_FS_IOCTL_DEV right
and increments the Landlock ABI version to 5.

This access right applies to device-custom IOCTL commands
when they are invoked on block or character device files.

Like the truncate right, this right is associated with a file
descriptor at the time of open(2), and gets respected even when the
file descriptor is used outside of the thread which it was originally
opened in.

Therefore, a newly enabled Landlock policy does not apply to file
descriptors which are already open.

If the LANDLOCK_ACCESS_FS_IOCTL_DEV right is handled, only a small
number of safe IOCTL commands will be permitted on newly opened device
files.  These include FIOCLEX, FIONCLEX, FIONBIO and FIOASYNC, as well
as other IOCTL commands for regular files which are implemented in
fs/ioctl.c.

Noteworthy scenarios which require special attention:

TTY devices are often passed into a process from the parent process,
and so a newly enabled Landlock policy does not retroactively apply to
them automatically.  In the past, TTY devices have often supported
IOCTL commands like TIOCSTI and some TIOCLINUX subcommands, which were
letting callers control the TTY input buffer (and simulate
keypresses).  This should be restricted to CAP_SYS_ADMIN programs on
modern kernels though.

Known limitations:

The LANDLOCK_ACCESS_FS_IOCTL_DEV access right is a coarse-grained
control over IOCTL commands.

Landlock users may use path-based restrictions in combination with
their knowledge about the file system layout to control what IOCTLs
can be done.

Cc: Paul Moore <paul@paul-moore.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20240419161122.2023765-2-gnoack@google.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-13 06:58:29 +02:00
Mickaël Salaün
f453cc3002
selftests/harness: Fix vfork() side effects
Setting the time namespace with CLONE_NEWTIME returns -EUSERS if the
calling thread shares memory with another thread (because of the shared
vDSO), which is the case when it is created with vfork().

Fix pidfd_setns_test by replacing test harness's vfork() call with a
clone3() call with CLONE_VFORK, and an explicit sharing of the
_metadata and self objects.

Replace _metadata->teardown_parent with a new FIXTURE_TEARDOWN_PARENT()
helper that can replace FIXTURE_TEARDOWN().  This is a cleaner approach
and it enables to selectively share the fixture data between the child
process running tests and the parent process running the fixture
teardown.  This also avoids updating several tests to not rely on the
self object's copy-on-write property (e.g. storing the returned value of
a fork() call).

Cc: Christian Brauner <brauner@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Günther Noack <gnoack@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Will Drewry <wad@chromium.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202403291015.1fcfa957-oliver.sang@intel.com
Fixes: 0710a1a73f ("selftests/harness: Merge TEST_F_FORK() into TEST_F()")
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240511171445.904356-10-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-11 19:18:47 +02:00
Mickaël Salaün
3656bc2342
selftests/landlock: Do not allocate memory in fixture data
Do not allocate self->dir_path in the test process because this would
not be visible in the FIXTURE_TEARDOWN() process when relying on
fork()/clone3() instead of vfork().

This change is required for a following commit removing vfork() call to
not break the layout3_fs.* test cases.

Cc: Günther Noack <gnoack@google.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240511171445.904356-6-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-11 19:18:44 +02:00
Mickaël Salaün
7e4042abe2
selftests/landlock: Fix FS tests when run on a private mount point
According to the test environment, the mount point of the test's working
directory may be shared or not, which changes the visibility of the
nested "tmp" mount point for the test's parent process calling
umount("tmp").

This was spotted while running tests in containers [1], where mount
points are private.

Cc: Günther Noack <gnoack@google.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Link: https://github.com/landlock-lsm/landlock-test-tools/pull/4 [1]
Fixes: 41cca0542d ("selftests/harness: Fix TEST_F()'s vfork handling")
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240511171445.904356-3-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-05-11 19:18:42 +02:00
Mickaël Salaün
41cca0542d selftests/harness: Fix TEST_F()'s vfork handling
Always run fixture setup in the grandchild process, and by default also
run the teardown in the same process.  However, this change makes it
possible to run the teardown in a parent process when
_metadata->teardown_parent is set to true (e.g. in fixture setup).

Fix TEST_SIGNAL() by forwarding grandchild's signal to its parent.  Fix
seccomp tests by running the test setup in the parent of the test
thread, as expected by the related test code.  Fix Landlock tests by
waiting for the grandchild before processing _metadata.

Use of exit(3) in tests should be OK because the environment in which
the vfork(2) call happen is already dedicated to the running test (with
flushed stdio, setpgrp() call), see __run_test() and the call to fork(2)
just before running the setup/test/teardown.  Even if the test
configures its own exit handlers, they will not be run by the parent
because it never calls exit(3), and the test function either ends with a
call to _exit(2) or a signal.

Cc: Günther Noack <gnoack@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Will Drewry <wad@chromium.org>
Fixes: 0710a1a73f ("selftests/harness: Merge TEST_F_FORK() into TEST_F()")
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Reported-by: Mark Brown <broonie@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20240305201029.1331333-1-mic@digikod.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-03-06 20:31:50 -08:00
Jakub Kicinski
69fe8ec4f6 selftests: kselftest_harness: save full exit code in metadata
Instead of tracking passed = 0/1 rename the field to exit_code
and invert the values so that they match the KSFT_* exit codes.
This will allow us to fold SKIP / XFAIL into the same value.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2024-03-01 10:30:28 +00:00
Hu Yadi
40b7835e74
selftests/landlock: Fix fs_test build with old libc
One issue comes up while building selftest/landlock/fs_test on my side
(gcc 7.3/glibc-2.28/kernel-4.19).

gcc -Wall -O2 -isystem   fs_test.c -lcap -o selftests/landlock/fs_test
fs_test.c:4575:9: error: initializer element is not constant
  .mnt = mnt_tmp,
         ^~~~~~~

Signed-off-by: Hu Yadi <hu.yadi@h3c.com>
Suggested-by: Jiao <jiaoxupo@h3c.com>
Reviewed-by: Berlin <berlin@h3c.com>
Link: https://lore.kernel.org/r/20240124022908.42100-1-hu.yadi@h3c.com
Fixes: 04f9070e99 ("selftests/landlock: Add tests for pseudo filesystems")
[mic: Factor out mount's data string and make mnt_tmp static]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-01-25 16:49:08 +01:00
Günther Noack
b838dd7612
selftests/landlock: Rename "permitted" to "allowed" in ftruncate tests
Suggested-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20231208155121.1943775-3-gnoack@google.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2024-01-03 12:07:58 +01:00
Mickaël Salaün
e2780a0b95
selftests/landlock: Add tests to check unhandled rule's access rights
Add two tests to make sure that we cannot add a rule to a ruleset if the
rule's access rights that are not handled by the ruleset:
* fs: layout1.rule_with_unhandled_access
* net: mini.rule_with_unhandled_access

Cc: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Reviewed-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20231130093616.67340-3-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-12-22 16:35:22 +01:00
Mickaël Salaün
6471c9c4c4
selftests/landlock: Add tests to check unknown rule's access rights
Add two tests to make sure that we cannot add a rule with access
rights that are unknown:
* fs: layout0.rule_with_unknown_access
* net: mini.rule_with_unknown_access

Rename unknown_access_rights tests to ruleset_with_unknown_access .

Cc: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Reviewed-by: Günther Noack <gnoack@google.com>
Link: https://lore.kernel.org/r/20231130093616.67340-2-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-12-22 16:35:17 +01:00
Mickaël Salaün
f12f8f8450
selftests/landlock: Add tests for FS topology changes with network rules
Add 2 tests to the layout1 fixture:
* topology_changes_with_net_only: Checks that FS topology
  changes are not denied by network-only restrictions.
* topology_changes_with_net_and_fs: Make sure that FS topology
  changes are still denied with FS and network restrictions.

This specifically test commit d722036403 ("landlock: Allow FS topology
changes for domains without such rule type").

Cc: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Link: https://lore.kernel.org/r/20231027154615.815134-1-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-10-27 17:53:31 +02:00
Konstantin Meskhidze
1fa335209f
selftests/landlock: Share enforce_ruleset() helper
Move enforce_ruleset() helper function to common.h so that it can be
used both by filesystem tests and network ones.

Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze@huawei.com>
Link: https://lore.kernel.org/r/20231026014751.414649-10-konstantin.meskhidze@huawei.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-10-26 21:07:15 +02:00
Ding Xiang
2a20154951
selftests/landlock: Fix a resource leak
The opened file should be closed before return, otherwise resource leak
will occur.

Signed-off-by: Ding Xiang <dingxiang@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20230830101148.3738-1-dingxiang@cmss.chinamobile.com
Fixes: 3de64b656b ("selftests/landlock: Add supports_filesystem() helper")
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-08-30 18:53:08 +02:00
Mickaël Salaün
35ca423992
selftests/landlock: Add hostfs tests
Add tests for the hostfs filesystems to make sure it has a consistent
inode management, which is required for Landlock's file hierarchy
identification.  This adds 5 new tests for layout3_fs with the hostfs
variant.

Add hostfs to the new (architecture-specific) config.um file.

The hostfs filesystem, only available for an User-Mode Linux kernel, is
special because we cannot explicitly mount it.  The layout3_fs.hostfs
variant tests are skipped if the current test directory is not backed by
this filesystem.

The layout3_fs.hostfs.tag_inode_dir_child and
layout3_fs.hostfs.tag_inode_file tests pass thanks to a previous commit
fixing hostfs inode management.  Without this fix, the deny-by-default
policy would apply and all access requests would be denied.

Link: https://lore.kernel.org/r/20230612191430.339153-7-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-06-12 21:26:23 +02:00
Mickaël Salaün
04f9070e99
selftests/landlock: Add tests for pseudo filesystems
Add generic and read-only tests for 6 pseudo filesystems to make sure
they have a consistent inode management, which is required for
Landlock's file hierarchy identification:
- tmpfs
- ramfs
- cgroup2
- proc
- sysfs

Update related kernel configuration to support these new filesystems,
remove useless CONFIG_SECURITY_PATH, and sort all entries.  If these
filesystems are not supported by the kernel running tests, the related
tests are skipped.

Expanding variants, this adds 25 new tests for layout3_fs:
- tag_inode_dir_parent
- tag_inode_dir_mnt
- tag_inode_dir_child
- tag_inode_dir_file
- release_inodes

Test coverage for security/landlock with kernel debug code:
- 94.7% of 835 lines according to gcc/gcov-12
- 93.0% of 852 lines according to gcc/gcov-13

Test coverage for security/landlock without kernel debug code:
- 95.5% of 624 lines according to gcc/gcov-12
- 93.1% of 641 lines according to gcc/gcov-13

Link: https://lore.kernel.org/r/20230612191430.339153-6-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-06-12 21:26:23 +02:00
Mickaël Salaün
55ab3fbe83
selftests/landlock: Make mounts configurable
Add a new struct mnt_opt to define a mount point with the mount_opt()
helper.  This doesn't change tests but prepare for the next commit.

Link: https://lore.kernel.org/r/20230612191430.339153-5-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-06-12 21:26:22 +02:00
Mickaël Salaün
3de64b656b
selftests/landlock: Add supports_filesystem() helper
Replace supports_overlayfs() with supports_filesystem() to be able to
check several filesystems.  This will be useful in a following commit.

Only check for overlay filesystem once in the setup step, and then rely
on self->skip_test.

Cc: Guenter Roeck <groeck@chromium.org>
Cc: Jeff Xu <jeffxu@google.com>
Link: https://lore.kernel.org/r/20230612191430.339153-4-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-06-12 21:26:21 +02:00
Mickaël Salaün
592efeb4a0
selftests/landlock: Don't create useless file layouts
Add and use a layout0 test fixture to not populate the tmpfs filesystem
if it is not required for tests: unknown_access_rights, proc_nsfs,
unpriv and max_layers.

This doesn't change these tests but it speeds up their setup and makes
them less prone to error.  This prepare the ground for a next commit.

Link: https://lore.kernel.org/r/20230612191430.339153-3-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-06-12 21:26:21 +02:00
Jeff Xu
366617a69e
selftests/landlock: Skip overlayfs tests when not supported
overlayfs may be disabled in the kernel configuration, causing related
tests to fail.  Check that overlayfs is supported at runtime, so we can
skip layout2_overlay.* accordingly.

Signed-off-by: Jeff Xu <jeffxu@google.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230113053229.1281774-2-jeffxu@google.com
[mic: Reword comments and constify variables]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2023-01-13 21:23:22 +01:00
Günther Noack
0d8c658be2
selftests/landlock: Test ftruncate on FDs created by memfd_create(2)
All file descriptors that are truncatable need to have the Landlock
access rights set correctly on the file's Landlock security blob. This
is also the case for files that are opened by other means than
open(2).

Test coverage for security/landlock is 94.7% of 838 lines according to
gcc/gcov-11.

Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20221018182216.301684-10-gnoack3000@gmail.com
[mic: Add test coverage in commit message]
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2022-10-19 09:01:47 +02:00