Hi,
This patch series adjusts the semantic of file hierarchy access-control per layer to get a more pragmatic and compatible approach. I updated the documentation to explain how layers, bind mounts and overlayfs are handled by Landlock. A syscall is also renamed to make it less ambiguous for future evolution. Last but not least, the test file layout cleanups are more resilient, and a lot of tests are added to cover bind mounts and overlayfs, which are fully supported.
The SLOC count is 1292 for security/landlock/ and 2425 for tools/testing/selftest/landlock/ . Test coverage for security/landlock/ is 94.7% of lines. The code not covered only deals with internal kernel errors (e.g. memory allocation) and race conditions. This series is being fuzzed by syzkaller, and patches are on their way: https://github.com/google/syzkaller/pull/2380
The compiled documentation is available here: https://landlock.io/linux-doc/landlock-v27/userspace-api/landlock.html
This series can be applied on top of v5.11-rc4 . This can be tested with CONFIG_SECURITY_LANDLOCK, CONFIG_SAMPLE_LANDLOCK and by prepending "landlock," to CONFIG_LSM. This patch series can be found in a Git repository here: https://github.com/landlock-lsm/linux/commits/landlock-v27 This patch series seems ready for upstream and I would really appreciate final reviews.
# Landlock LSM
The goal of Landlock is to enable to restrict ambient rights (e.g. global filesystem access) for a set of processes. Because Landlock is a stackable LSM [1], it makes possible to create safe security sandboxes as new security layers in addition to the existing system-wide access-controls. This kind of sandbox is expected to help mitigate the security impact of bugs or unexpected/malicious behaviors in user-space applications. Landlock empowers any process, including unprivileged ones, to securely restrict themselves.
Landlock is inspired by seccomp-bpf but instead of filtering syscalls and their raw arguments, a Landlock rule can restrict the use of kernel objects like file hierarchies, according to the kernel semantic. Landlock also takes inspiration from other OS sandbox mechanisms: XNU Sandbox, FreeBSD Capsicum or OpenBSD Pledge/Unveil.
In this current form, Landlock misses some access-control features. This enables to minimize this patch series and ease review. This series still addresses multiple use cases, especially with the combined use of seccomp-bpf: applications with built-in sandboxing, init systems, security sandbox tools and security-oriented APIs [2].
Previous version: https://lore.kernel.org/lkml/20201209192839.1396820-1-mic@digikod.net/
[1] https://lore.kernel.org/lkml/50db058a-7dde-441b-a7f9-f6837fe8b69f@schaufler-... [2] https://lore.kernel.org/lkml/f646e1c7-33cf-333f-070c-0a40ad0468cd@digikod.ne...
Casey Schaufler (1): LSM: Infrastructure management of the superblock
Mickaël Salaün (11): landlock: Add object management landlock: Add ruleset and domain management landlock: Set up the security framework and manage credentials landlock: Add ptrace restrictions fs,security: Add sb_delete hook landlock: Support filesystem access-control landlock: Add syscall implementations arch: Wire up Landlock syscalls selftests/landlock: Add user space tests samples/landlock: Add a sandbox manager example landlock: Add user and kernel documentation
Documentation/security/index.rst | 1 + Documentation/security/landlock.rst | 79 + Documentation/userspace-api/index.rst | 1 + Documentation/userspace-api/landlock.rst | 306 ++ MAINTAINERS | 13 + arch/Kconfig | 7 + arch/alpha/kernel/syscalls/syscall.tbl | 3 + arch/arm/tools/syscall.tbl | 3 + arch/arm64/include/asm/unistd.h | 2 +- arch/arm64/include/asm/unistd32.h | 6 + arch/ia64/kernel/syscalls/syscall.tbl | 3 + arch/m68k/kernel/syscalls/syscall.tbl | 3 + arch/microblaze/kernel/syscalls/syscall.tbl | 3 + arch/mips/kernel/syscalls/syscall_n32.tbl | 3 + arch/mips/kernel/syscalls/syscall_n64.tbl | 3 + arch/mips/kernel/syscalls/syscall_o32.tbl | 3 + arch/parisc/kernel/syscalls/syscall.tbl | 3 + arch/powerpc/kernel/syscalls/syscall.tbl | 3 + arch/s390/kernel/syscalls/syscall.tbl | 3 + arch/sh/kernel/syscalls/syscall.tbl | 3 + arch/sparc/kernel/syscalls/syscall.tbl | 3 + arch/um/Kconfig | 1 + arch/x86/entry/syscalls/syscall_32.tbl | 3 + arch/x86/entry/syscalls/syscall_64.tbl | 3 + arch/xtensa/kernel/syscalls/syscall.tbl | 3 + fs/super.c | 1 + include/linux/lsm_hook_defs.h | 1 + include/linux/lsm_hooks.h | 3 + include/linux/security.h | 4 + include/linux/syscalls.h | 7 + include/uapi/asm-generic/unistd.h | 8 +- include/uapi/linux/landlock.h | 128 + kernel/sys_ni.c | 5 + samples/Kconfig | 7 + samples/Makefile | 1 + samples/landlock/.gitignore | 1 + samples/landlock/Makefile | 13 + samples/landlock/sandboxer.c | 239 ++ security/Kconfig | 11 +- security/Makefile | 2 + security/landlock/Kconfig | 21 + security/landlock/Makefile | 4 + security/landlock/common.h | 20 + security/landlock/cred.c | 46 + security/landlock/cred.h | 58 + security/landlock/fs.c | 621 ++++ security/landlock/fs.h | 56 + security/landlock/limits.h | 21 + security/landlock/object.c | 67 + security/landlock/object.h | 91 + security/landlock/ptrace.c | 120 + security/landlock/ptrace.h | 14 + security/landlock/ruleset.c | 466 +++ security/landlock/ruleset.h | 161 + security/landlock/setup.c | 40 + security/landlock/setup.h | 18 + security/landlock/syscalls.c | 429 +++ security/security.c | 51 +- security/selinux/hooks.c | 58 +- security/selinux/include/objsec.h | 6 + security/selinux/ss/services.c | 3 +- security/smack/smack.h | 6 + security/smack/smack_lsm.c | 35 +- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/landlock/.gitignore | 2 + tools/testing/selftests/landlock/Makefile | 24 + tools/testing/selftests/landlock/base_test.c | 219 ++ tools/testing/selftests/landlock/common.h | 166 ++ tools/testing/selftests/landlock/config | 6 + tools/testing/selftests/landlock/fs_test.c | 2585 +++++++++++++++++ .../testing/selftests/landlock/ptrace_test.c | 314 ++ tools/testing/selftests/landlock/true.c | 5 + 72 files changed, 6552 insertions(+), 77 deletions(-) create mode 100644 Documentation/security/landlock.rst create mode 100644 Documentation/userspace-api/landlock.rst create mode 100644 include/uapi/linux/landlock.h create mode 100644 samples/landlock/.gitignore create mode 100644 samples/landlock/Makefile create mode 100644 samples/landlock/sandboxer.c create mode 100644 security/landlock/Kconfig create mode 100644 security/landlock/Makefile create mode 100644 security/landlock/common.h create mode 100644 security/landlock/cred.c create mode 100644 security/landlock/cred.h create mode 100644 security/landlock/fs.c create mode 100644 security/landlock/fs.h create mode 100644 security/landlock/limits.h create mode 100644 security/landlock/object.c create mode 100644 security/landlock/object.h create mode 100644 security/landlock/ptrace.c create mode 100644 security/landlock/ptrace.h create mode 100644 security/landlock/ruleset.c create mode 100644 security/landlock/ruleset.h create mode 100644 security/landlock/setup.c create mode 100644 security/landlock/setup.h create mode 100644 security/landlock/syscalls.c create mode 100644 tools/testing/selftests/landlock/.gitignore create mode 100644 tools/testing/selftests/landlock/Makefile create mode 100644 tools/testing/selftests/landlock/base_test.c create mode 100644 tools/testing/selftests/landlock/common.h create mode 100644 tools/testing/selftests/landlock/config create mode 100644 tools/testing/selftests/landlock/fs_test.c create mode 100644 tools/testing/selftests/landlock/ptrace_test.c create mode 100644 tools/testing/selftests/landlock/true.c
base-commit: 19c329f6808995b142b3966301f217c831e7cf31