- Linux-kselftest-mirror - lists.linaro.org

[PATCH v5 0/3] Some optimizations related to sgx

by Tianjia Zhang

This is an optimization of a set of sgx-related codes, each of which is independent of the patch. Because the second and third patches have conflicting dependencies, these patches are put together. --- v5 changes: * Remove the two patches with no actual value * Typo fix in commit message v4 changes: * Improvements suggested by review v3 changes: * split free_cnt count and spin lock optimization into two patches v2 changes: * review suggested changes Tianjia Zhang (3): selftests/x86: Use getauxval() to simplify the code in sgx x86/sgx: Allows ioctl PROVISION to execute before CREATE x86/sgx: Remove redundant if conditions in sgx_encl_create arch/x86/kernel/cpu/sgx/driver.c | 1 + arch/x86/kernel/cpu/sgx/ioctl.c | 8 ++++---- tools/testing/selftests/sgx/main.c | 24 ++++-------------------- 3 files changed, 9 insertions(+), 24 deletions(-) -- 2.19.1.3.ge56e4f7

4 years, 9 months

2
5
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[PATCH v3 0/8] Fork brute force attack mitigation

by John Wood

Attacks against vulnerable userspace applications with the purpose to break ASLR or bypass canaries traditionally use some level of brute force with the help of the fork system call. This is possible since when creating a new process using fork its memory contents are the same as those of the parent process (the process that called the fork system call). So, the attacker can test the memory infinite times to find the correct memory values or the correct memory addresses without worrying about crashing the application. Based on the above scenario it would be nice to have this detected and mitigated, and this is the goal of this patch serie. Specifically the following attacks are expected to be detected: 1.- Launching (fork()/exec()) a setuid/setgid process repeatedly until a desirable memory layout is got (e.g. Stack Clash). 2.- Connecting to an exec()ing network daemon (e.g. xinetd) repeatedly until a desirable memory layout is got (e.g. what CTFs do for simple network service). 3.- Launching processes without exec() (e.g. Android Zygote) and exposing state to attack a sibling. 4.- Connecting to a fork()ing network daemon (e.g. apache) repeatedly until the previously shared memory layout of all the other children is exposed (e.g. kind of related to HeartBleed). In each case, a privilege boundary has been crossed: Case 1: setuid/setgid process Case 2: network to local Case 3: privilege changes Case 4: network to local So, what will really be detected are fork/exec brute force attacks that cross any of the commented bounds. The implementation details and comparison against other existing implementations can be found in the "Documentation" patch. This v3 version has changed a lot from the v2. Basically the application crash period is now compute on an on-going basis using an exponential moving average (EMA), a detection of a brute force attack through the "execve" system call has been added and the crossing of the commented privilege bounds are taken into account. Also, the fine tune has also been removed and now, all this kind of attacks are detected without administrator intervention. In the v2 version Kees Cook suggested to study if the statistical data shared by all the fork hierarchy processes can be tracked in some other way. Specifically the question was if this info can be hold by the family hierarchy of the mm struct. After studying this hierarchy I think it is not suitable for the Brute LSM since they are totally copied on fork() and in this case we want that they are shared. So I leave this road. So, knowing all this information I will explain now the different patches: The 1/8 patch defines a new LSM hook to get the fatal signal of a task. This will be useful during the attack detection phase. The 2/8 patch defines a new LSM and manages the statistical data shared by all the fork hierarchy processes. The 3/8 patch detects a fork/exec brute force attack. The 4/8 patch narrows the detection taken into account the privilege boundary crossing. The 5/8 patch mitigates a brute force attack. The 6/8 patch adds self-tests to validate the Brute LSM expectations. The 7/8 patch adds the documentation to explain this implementation. The 8/8 patch updates the maintainers file. This patch serie is a task of the KSPP [1] and can also be accessed from my github tree [2] in the "brute_v3" branch. [1] https://github.com/KSPP/linux/issues/39 [2] https://github.com/johwood/linux/ The previous versions can be found in: https://lore.kernel.org/kernel-hardening/20200910202107.3799376-1-keescook@… https://lore.kernel.org/kernel-hardening/20201025134540.3770-1-john.wood@gm… Changelog RFC -> v2 ------------------- - Rename this feature with a more suitable name (Jann Horn, Kees Cook). - Convert the code to an LSM (Kees Cook). - Add locking to avoid data races (Jann Horn). - Add a new LSM hook to get the fatal signal of a task (Jann Horn, Kees Cook). - Add the last crashes timestamps list to avoid false positives in the attack detection (Jann Horn). - Use "period" instead of "rate" (Jann Horn). - Other minor changes suggested (Jann Horn, Kees Cook). Changelog v2 -> v3 ------------------ - Compute the application crash period on an on-going basis (Kees Cook). - Detect a brute force attack through the execve system call (Kees Cook). - Detect an slow brute force attack (Randy Dunlap). - Fine tuning the detection taken into account privilege boundary crossing (Kees Cook). - Taken into account only fatal signals delivered by the kernel (Kees Cook). - Remove the sysctl attributes to fine tuning the detection (Kees Cook). - Remove the prctls to allow per process enabling/disabling (Kees Cook). - Improve the documentation (Kees Cook). - Fix some typos in the documentation (Randy Dunlap). - Add self-test to validate the expectations (Kees Cook). John Wood (8): security: Add LSM hook at the point where a task gets a fatal signal security/brute: Define a LSM and manage statistical data securtiy/brute: Detect a brute force attack security/brute: Fine tuning the attack detection security/brute: Mitigate a brute force attack selftests/brute: Add tests for the Brute LSM Documentation: Add documentation for the Brute LSM MAINTAINERS: Add a new entry for the Brute LSM Documentation/admin-guide/LSM/Brute.rst | 224 +++++ Documentation/admin-guide/LSM/index.rst | 1 + MAINTAINERS | 7 + include/linux/lsm_hook_defs.h | 1 + include/linux/lsm_hooks.h | 4 + include/linux/security.h | 4 + kernel/signal.c | 1 + security/Kconfig | 11 +- security/Makefile | 4 + security/brute/Kconfig | 13 + security/brute/Makefile | 2 + security/brute/brute.c | 1102 ++++++++++++++++++++++ security/security.c | 5 + tools/testing/selftests/Makefile | 1 + tools/testing/selftests/brute/.gitignore | 2 + tools/testing/selftests/brute/Makefile | 5 + tools/testing/selftests/brute/config | 1 + tools/testing/selftests/brute/exec.c | 44 + tools/testing/selftests/brute/test.c | 507 ++++++++++ tools/testing/selftests/brute/test.sh | 226 +++++ 20 files changed, 2160 insertions(+), 5 deletions(-) create mode 100644 Documentation/admin-guide/LSM/Brute.rst create mode 100644 security/brute/Kconfig create mode 100644 security/brute/Makefile create mode 100644 security/brute/brute.c create mode 100644 tools/testing/selftests/brute/.gitignore create mode 100644 tools/testing/selftests/brute/Makefile create mode 100644 tools/testing/selftests/brute/config create mode 100644 tools/testing/selftests/brute/exec.c create mode 100644 tools/testing/selftests/brute/test.c create mode 100755 tools/testing/selftests/brute/test.sh -- 2.25.1

4 years, 9 months

2
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[PATCH] selftests: timers: remove unneeded semicolon

by Jiapeng Chong

Fix the following coccicheck warnings: ./tools/testing/selftests/timers/alarmtimer-suspend.c:82:2-3: Unneeded semicolon. Reported-by: Abaci Robot <abaci(a)linux.alibaba.com> Signed-off-by: Jiapeng Chong <jiapeng.chong(a)linux.alibaba.com> --- tools/testing/selftests/timers/alarmtimer-suspend.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/timers/alarmtimer-suspend.c b/tools/testing/selftests/timers/alarmtimer-suspend.c index 4da09db..54da4b08 100644 --- a/tools/testing/selftests/timers/alarmtimer-suspend.c +++ b/tools/testing/selftests/timers/alarmtimer-suspend.c @@ -79,7 +79,7 @@ char *clockstring(int clockid) return "CLOCK_BOOTTIME_ALARM"; case CLOCK_TAI: return "CLOCK_TAI"; - }; + } return "UNKNOWN_CLOCKID"; } -- 1.8.3.1

4 years, 9 months

1
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[PATCH v17 00/10] mm: introduce memfd_secret system call to create "secret" memory areas

by Mike Rapoport

From: Mike Rapoport <rppt(a)linux.ibm.com> Hi, @Andrew, this is based on v5.11-rc5-mmotm-2021-01-27-23-30, with secretmem and related patches dropped from there, I can rebase whatever way you prefer. This is an implementation of "secret" mappings backed by a file descriptor. The file descriptor backing secret memory mappings is created using a dedicated memfd_secret system call The desired protection mode for the memory is configured using flags parameter of the system call. The mmap() of the file descriptor created with memfd_secret() will create a "secret" memory mapping. The pages in that mapping will be marked as not present in the direct map and will be present only in the page table of the owning mm. Although normally Linux userspace mappings are protected from other users, such secret mappings are useful for environments where a hostile tenant is trying to trick the kernel into giving them access to other tenants mappings. Additionally, in the future the secret mappings may be used as a mean to protect guest memory in a virtual machine host. For demonstration of secret memory usage we've created a userspace library https://git.kernel.org/pub/scm/linux/kernel/git/jejb/secret-memory-preloade… that does two things: the first is act as a preloader for openssl to redirect all the OPENSSL_malloc calls to secret memory meaning any secret keys get automatically protected this way and the other thing it does is expose the API to the user who needs it. We anticipate that a lot of the use cases would be like the openssl one: many toolkits that deal with secret keys already have special handling for the memory to try to give them greater protection, so this would simply be pluggable into the toolkits without any need for user application modification. Hiding secret memory mappings behind an anonymous file allows usage of the page cache for tracking pages allocated for the "secret" mappings as well as using address_space_operations for e.g. page migration callbacks. The anonymous file may be also used implicitly, like hugetlb files, to implement mmap(MAP_SECRET) and use the secret memory areas with "native" mm ABIs in the future. Removing of the pages from the direct map may cause its fragmentation on architectures that use large pages to map the physical memory which affects the system performance. However, the original Kconfig text for CONFIG_DIRECT_GBPAGES said that gigabyte pages in the direct map "... can improve the kernel's performance a tiny bit ..." (commit 00d1c5e05736 ("x86: add gbpages switches")) and the recent report [1] showed that "... although 1G mappings are a good default choice, there is no compelling evidence that it must be the only choice". Hence, it is sufficient to have secretmem disabled by default with the ability of a system administrator to enable it at boot time. In addition, there is also a long term goal to improve management of the direct map. [1] https://lore.kernel.org/linux-mm/213b4567-46ce-f116-9cdf-bbd0c884eb3c@linux… v17: * Remove pool of large pages backing secretmem allocations, per Michal Hocko * Add secretmem pages to unevictable LRU, per Michal Hocko * Use GFP_HIGHUSER as secretmem mapping mask, per Michal Hocko * Make secretmem an opt-in feature that is disabled by default v16: * Fix memory leak intorduced in v15 * Clean the data left from previous page user before handing the page to the userspace v15: https://lore.kernel.org/lkml/20210120180612.1058-1-rppt@kernel.org * Add riscv/Kconfig update to disable set_memory operations for nommu builds (patch 3) * Update the code around add_to_page_cache() per Matthew's comments (patches 6,7) * Add fixups for build/checkpatch errors discovered by CI systems v14: https://lore.kernel.org/lkml/20201203062949.5484-1-rppt@kernel.org * Finally s/mod_node_page_state/mod_lruvec_page_state/ v13: https://lore.kernel.org/lkml/20201201074559.27742-1-rppt@kernel.org * Added Reviewed-by, thanks Catalin and David * s/mod_node_page_state/mod_lruvec_page_state/ as Shakeel suggested Older history: v12: https://lore.kernel.org/lkml/20201125092208.12544-1-rppt@kernel.org v11: https://lore.kernel.org/lkml/20201124092556.12009-1-rppt@kernel.org v10: https://lore.kernel.org/lkml/20201123095432.5860-1-rppt@kernel.org v9: https://lore.kernel.org/lkml/20201117162932.13649-1-rppt@kernel.org v8: https://lore.kernel.org/lkml/20201110151444.20662-1-rppt@kernel.org v7: https://lore.kernel.org/lkml/20201026083752.13267-1-rppt@kernel.org v6: https://lore.kernel.org/lkml/20200924132904.1391-1-rppt@kernel.org v5: https://lore.kernel.org/lkml/20200916073539.3552-1-rppt@kernel.org v4: https://lore.kernel.org/lkml/20200818141554.13945-1-rppt@kernel.org v3: https://lore.kernel.org/lkml/20200804095035.18778-1-rppt@kernel.org v2: https://lore.kernel.org/lkml/20200727162935.31714-1-rppt@kernel.org v1: https://lore.kernel.org/lkml/20200720092435.17469-1-rppt@kernel.org rfc-v2: https://lore.kernel.org/lkml/20200706172051.19465-1-rppt@kernel.org/ rfc-v1: https://lore.kernel.org/lkml/20200130162340.GA14232@rapoport-lnx/ rfc-v0: https://lore.kernel.org/lkml/1572171452-7958-1-git-send-email-rppt@kernel.o… Arnd Bergmann (1): arm64: kfence: fix header inclusion Mike Rapoport (9): mm: add definition of PMD_PAGE_ORDER mmap: make mlock_future_check() global riscv/Kconfig: make direct map manipulation options depend on MMU set_memory: allow set_direct_map_*_noflush() for multiple pages set_memory: allow querying whether set_direct_map_*() is actually enabled mm: introduce memfd_secret system call to create "secret" memory areas PM: hibernate: disable when there are active secretmem users arch, mm: wire up memfd_secret system call where relevant secretmem: test: add basic selftest for memfd_secret(2) arch/arm64/include/asm/Kbuild | 1 - arch/arm64/include/asm/cacheflush.h | 6 - arch/arm64/include/asm/kfence.h | 2 +- arch/arm64/include/asm/set_memory.h | 17 ++ arch/arm64/include/uapi/asm/unistd.h | 1 + arch/arm64/kernel/machine_kexec.c | 1 + arch/arm64/mm/mmu.c | 6 +- arch/arm64/mm/pageattr.c | 23 +- arch/riscv/Kconfig | 4 +- arch/riscv/include/asm/set_memory.h | 4 +- arch/riscv/include/asm/unistd.h | 1 + arch/riscv/mm/pageattr.c | 8 +- arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + arch/x86/include/asm/set_memory.h | 4 +- arch/x86/mm/pat/set_memory.c | 8 +- fs/dax.c | 11 +- include/linux/pgtable.h | 3 + include/linux/secretmem.h | 30 +++ include/linux/set_memory.h | 16 +- include/linux/syscalls.h | 1 + include/uapi/asm-generic/unistd.h | 6 +- include/uapi/linux/magic.h | 1 + kernel/power/hibernate.c | 5 +- kernel/power/snapshot.c | 4 +- kernel/sys_ni.c | 2 + mm/Kconfig | 3 + mm/Makefile | 1 + mm/gup.c | 10 + mm/internal.h | 3 + mm/mlock.c | 3 +- mm/mmap.c | 5 +- mm/secretmem.c | 261 +++++++++++++++++++ mm/vmalloc.c | 5 +- scripts/checksyscalls.sh | 4 + tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 3 +- tools/testing/selftests/vm/memfd_secret.c | 296 ++++++++++++++++++++++ tools/testing/selftests/vm/run_vmtests | 17 ++ 39 files changed, 726 insertions(+), 53 deletions(-) create mode 100644 arch/arm64/include/asm/set_memory.h create mode 100644 include/linux/secretmem.h create mode 100644 mm/secretmem.c create mode 100644 tools/testing/selftests/vm/memfd_secret.c -- 2.28.0

4 years, 9 months

7
72
0 0

[GIT PULL] Kselftest update for Linux 5.12-rc1

by Shuah Khan

Hi Linus, Please pull the following Kselftest update for Linux 5.12-rc1. This Kselftest update for Linux 5.12-rc1 consists of: - dmabuf-heaps test fixes and cleanups from John Stultz. - seccomp test fix to accept any valid fd in user_notification_addfd. - Minor fixes to breakpoints and vDSO tests. - Minor code cleanups to ipc and x86 tests. diff is attached. thanks, -- Shuah ---------------------------------------------------------------- The following changes since commit 92bf22614b21a2706f4993b278017e437f7785b3: Linux 5.11-rc7 (2021-02-07 13:57:38 -0800) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux-kselftest-next-5.12-rc1 for you to fetch changes up to e0c0840a46db9d50ba7391082d665d74f320c39f: selftests/seccomp: Accept any valid fd in user_notification_addfd (2021-02-09 17:39:01 -0700) ---------------------------------------------------------------- linux-kselftest-next-5.12-rc1 This Kselftest update for Linux 5.12-rc1 consists of: - dmabuf-heaps test fixes and cleanups from John Stultz. - seccomp test fix to accept any valid fd in user_notification_addfd. - Minor fixes to breakpoints and vDSO tests. - Minor code cleanups to ipc and x86 tests. ---------------------------------------------------------------- John Stultz (5): kselftests: dmabuf-heaps: Fix Makefile's inclusion of the kernel's usr/include dir kselftests: dmabuf-heaps: Add clearer checks on DMABUF_BEGIN/END_SYNC kselftests: dmabuf-heaps: Softly fail if don't find a vgem device kselftests: dmabuf-heaps: Cleanup test output kselftests: dmabuf-heaps: Add extra checking that allocated buffers are zeroed Seth Forshee (1): selftests/seccomp: Accept any valid fd in user_notification_addfd Tiezhu Yang (1): selftests: breakpoints: Use correct error messages in breakpoint_test_arm64.c Tobias Klauser (2): selftests/vDSO: fix ABI selftest on riscv selftests/timens: add futex binary to .gitignore Yang Li (2): selftests/ipc: remove unneeded semicolon selftests/x86/ldt_gdt: remove unneeded semicolon .../selftests/breakpoints/breakpoint_test_arm64.c | 4 +- tools/testing/selftests/dmabuf-heaps/Makefile | 2 +- tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c | 149 ++++++++++++++++----- tools/testing/selftests/ipc/msgque.c | 6 +- tools/testing/selftests/seccomp/seccomp_bpf.c | 8 +- tools/testing/selftests/timens/.gitignore | 1 + tools/testing/selftests/vDSO/vdso_config.h | 4 +- tools/testing/selftests/x86/ldt_gdt.c | 2 +- 8 files changed, 132 insertions(+), 44 deletions(-) ----------------------------------------------------------------

4 years, 9 months

2
1
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[GIT PULL] KUnit update for Linux 5.12-rc1

by Shuah Khan

Hi Linus, Please pull the following KUnit update for Linux 5.12-rc1. This KUnit update for Linux 5.12-rc1 consists of consists of: -- support for filtering test suites using glob from Daniel Latypov. "kunit_filter.glob" command line option is passed to the UML kernel, which currently only supports filtering by suite name. This support allows running different subsets of tests, e.g. $ ./tools/testing/kunit/kunit.py build $ ./tools/testing/kunit/kunit.py exec 'list*' $ ./tools/testing/kunit/kunit.py exec 'kunit*' -- several fixes and cleanups also from Daniel Latypov. diff is attached. thanks, -- Shuah ---------------------------------------------------------------- The following changes since commit 92bf22614b21a2706f4993b278017e437f7785b3: Linux 5.11-rc7 (2021-02-07 13:57:38 -0800) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux-kselftest-kunit-5.12-rc1 for you to fetch changes up to 7af29141a31a2a2350589471c8979ff5f22fb9b7: kunit: tool: fix unintentional statefulness in run_kernel() (2021-02-08 16:10:22 -0700) ---------------------------------------------------------------- linux-kselftest-kunit-5.12-rc1 This KUnit update for Linux 5.12-rc1 consists of consists of: -- support for filtering test suites using glob from Daniel Latypov. "kunit_filter.glob" command line option is passed to the UML kernel, which currently only supports filtering by suite name. This support allows running different subsets of tests, e.g. $ ./tools/testing/kunit/kunit.py build $ ./tools/testing/kunit/kunit.py exec 'list*' $ ./tools/testing/kunit/kunit.py exec 'kunit*' -- several fixes and cleanups also from Daniel Latypov. ---------------------------------------------------------------- Daniel Latypov (12): kunit: tool: fix unit test cleanup handling kunit: tool: stop using bare asserts in unit test kunit: tool: use `with open()` in unit test minor: kunit: tool: fix unit test so it can run from non-root dir kunit: tool: simplify kconfig is_subset_of() logic KUnit: Docs: make start.rst example Kconfig follow style.rst Documentation: kunit: add tips.rst for small examples kunit: make kunit_tool accept optional path to .kunitconfig fragment kunit: don't show `1 == 1` in failed assertion messages kunit: add kunit.filter_glob cmdline option to filter suites kunit: tool: add support for filtering suites by glob kunit: tool: fix unintentional statefulness in run_kernel() Documentation/dev-tools/kunit/index.rst | 2 + Documentation/dev-tools/kunit/start.rst | 7 +- Documentation/dev-tools/kunit/tips.rst | 115 ++++++++++++++++++ lib/kunit/Kconfig | 1 + lib/kunit/assert.c | 39 +++++- lib/kunit/executor.c | 93 +++++++++++++-- tools/testing/kunit/kunit.py | 30 +++-- tools/testing/kunit/kunit_config.py | 13 +- tools/testing/kunit/kunit_kernel.py | 18 ++- tools/testing/kunit/kunit_tool_test.py | 204 +++++++++++++++++--------------- 10 files changed, 390 insertions(+), 132 deletions(-) create mode 100644 Documentation/dev-tools/kunit/tips.rst ----------------------------------------------------------------

4 years, 9 months

2
1
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[PATCH v4 21/22] x86/fpu/xstate: Support dynamic user state in the signal handling path

by Chang S. Bae

Entering a signal handler, the kernel saves xstate in signal frame. The dynamic user state is better to be saved only when used. fpu->state_mask can help to exclude unused states. Returning from a signal handler, XRSTOR re-initializes the excluded state components. Add a test case to verify in the signal handler that the signal frame excludes AMX data when the signaled thread has initialized AMX state. Signed-off-by: Chang S. Bae <chang.seok.bae(a)intel.com> Reviewed-by: Len Brown <len.brown(a)intel.com> Cc: x86(a)kernel.org Cc: linux-kernel(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org --- Changes from v3: * Removed 'no functional changes' in the changelog. (Borislav Petkov) Changes from v1: * Made it revertable (moved close to the end of the series). * Included the test case. --- arch/x86/include/asm/fpu/internal.h | 2 +- tools/testing/selftests/x86/amx.c | 66 +++++++++++++++++++++++++++++ 2 files changed, 67 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index c467312d38d8..090eb5bb277b 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -354,7 +354,7 @@ static inline void copy_kernel_to_xregs(struct xregs_state *xstate, u64 mask) */ static inline int copy_xregs_to_user(struct xregs_state __user *buf) { - u64 mask = xfeatures_mask_user(); + u64 mask = current->thread.fpu.state_mask; u32 lmask = mask; u32 hmask = mask >> 32; int err; diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c index f4ecdfd27ae9..a7386b886532 100644 --- a/tools/testing/selftests/x86/amx.c +++ b/tools/testing/selftests/x86/amx.c @@ -650,6 +650,71 @@ static void test_ptrace(void) test_tile_state_write(ptracee_loads_tiles); } +/* Signal handling test */ + +static int sigtrapped; +struct tile_data sig_tiles, sighdl_tiles; + +static void handle_sigtrap(int sig, siginfo_t *info, void *ctx_void) +{ + ucontext_t *uctxt = (ucontext_t *)ctx_void; + struct xsave_data xdata; + struct tile_config cfg; + struct tile_data tiles; + u64 header; + + header = __get_xsave_xstate_bv((void *)uctxt->uc_mcontext.fpregs); + + if (header & (1 << XFEATURE_XTILE_DATA)) + printf("[FAIL]\ttile data was written in sigframe\n"); + else + printf("[OK]\ttile data was skipped in sigframe\n"); + + set_tilecfg(&cfg); + load_tilecfg(&cfg); + init_xdata(&xdata); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + restore_xdata(&xdata); + + save_xdata(&xdata); + if (compare_xdata_tiles(&xdata, &tiles)) + err(1, "tile load file"); + + printf("\tsignal handler: load tile data\n"); + + sigtrapped = sig; +} + +static void test_signal_handling(void) +{ + struct xsave_data xdata = { 0 }; + struct tile_data tiles = { 0 }; + + sethandler(SIGTRAP, handle_sigtrap, 0); + sigtrapped = 0; + + printf("[RUN]\tCheck tile state management in handling signal\n"); + + printf("\tbefore signal: initial tile data state\n"); + + raise(SIGTRAP); + + if (sigtrapped == 0) + err(1, "sigtrap"); + + save_xdata(&xdata); + if (compare_xdata_tiles(&xdata, &tiles)) { + printf("[FAIL]\ttile data was not loaded at sigreturn\n"); + nerrs++; + } else { + printf("[OK]\ttile data was re-initialized at sigreturn\n"); + } + + clearhandler(SIGTRAP); +} + int main(void) { /* Check hardware availability at first */ @@ -672,6 +737,7 @@ int main(void) test_fork(); test_context_switch(); test_ptrace(); + test_signal_handling(); return nerrs ? 1 : 0; } -- 2.17.1

4 years, 9 months

1
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[PATCH v4 20/22] selftest/x86/amx: Include test cases for the AMX state management

by Chang S. Bae

This selftest exercises the kernel's behavior not to inherit AMX state and the ability to switch the context by verifying that they retain unique data between multiple threads. Also, ptrace() is used to insert AMX state into existing threads -- both before and after the existing thread has initialized its AMX state. Collect the test cases of validating those operations together, as they share some common setup for the AMX state. These test cases do not depend on AMX compiler support, as they employ userspace-XSAVE directly to access AMX state. Signed-off-by: Chang S. Bae <chang.seok.bae(a)intel.com> Reviewed-by: Len Brown <len.brown(a)intel.com> Cc: linux-kernel(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org --- Changes from v2: * Updated the test messages and the changelog as tile data is not inherited to a child anymore. * Removed bytecode for the instructions already supported by binutils. * Changed to check the XSAVE availability in a reliable way. Changes from v1: * Removed signal testing code --- tools/testing/selftests/x86/Makefile | 2 +- tools/testing/selftests/x86/amx.c | 677 +++++++++++++++++++++++++++ 2 files changed, 678 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/x86/amx.c diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index 333980375bc7..2f7feb03867b 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -17,7 +17,7 @@ TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt test_mremap TARGETS_C_32BIT_ONLY := entry_from_vm86 test_syscall_vdso unwind_vdso \ test_FCMOV test_FCOMI test_FISTTP \ vdso_restorer -TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering +TARGETS_C_64BIT_ONLY := fsgsbase sysret_rip syscall_numbering amx # Some selftests require 32bit support enabled also on 64bit systems TARGETS_C_32BIT_NEEDED := ldt_gdt ptrace_syscall diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c new file mode 100644 index 000000000000..f4ecdfd27ae9 --- /dev/null +++ b/tools/testing/selftests/x86/amx.c @@ -0,0 +1,677 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define _GNU_SOURCE +#include <err.h> +#include <elf.h> +#include <pthread.h> +#include <sched.h> +#include <setjmp.h> +#include <signal.h> +#include <stdio.h> +#include <string.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdlib.h> +#include <time.h> +#include <malloc.h> +#include <unistd.h> +#include <ucontext.h> + +#include <linux/futex.h> + +#include <sys/ipc.h> +#include <sys/mman.h> +#include <sys/ptrace.h> +#include <sys/shm.h> +#include <sys/signal.h> +#include <sys/syscall.h> +#include <sys/time.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <sys/uio.h> +#include <sys/ucontext.h> + +#include <x86intrin.h> + +#ifndef __x86_64__ +# error This test is 64-bit only +#endif + +typedef uint8_t u8; +typedef uint16_t u16; +typedef uint32_t u32; +typedef uint64_t u64; + +#define PAGE_SIZE (1 << 12) + +#define NUM_TILES 8 +#define TILE_SIZE 1024 +#define XSAVE_SIZE ((NUM_TILES * TILE_SIZE) + PAGE_SIZE) + +struct xsave_data { + u8 area[XSAVE_SIZE]; +} __attribute__((aligned(64))); + +/* Tile configuration associated: */ +#define MAX_TILES 16 +#define RESERVED_BYTES 14 + +struct tile_config { + u8 palette_id; + u8 start_row; + u8 reserved[RESERVED_BYTES]; + u16 colsb[MAX_TILES]; + u8 rows[MAX_TILES]; +}; + +struct tile_data { + u8 data[NUM_TILES * TILE_SIZE]; +}; + +static inline u64 __xgetbv(u32 index) +{ + u32 eax, edx; + + asm volatile("xgetbv;" + : "=a" (eax), "=d" (edx) + : "c" (index)); + return eax + ((u64)edx << 32); +} + +static inline void __cpuid(u32 *eax, u32 *ebx, u32 *ecx, u32 *edx) +{ + asm volatile("cpuid;" + : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx) + : "0" (*eax), "2" (*ecx)); +} + +/* Load tile configuration */ +static inline void __ldtilecfg(void *cfg) +{ + asm volatile(".byte 0xc4,0xe2,0x78,0x49,0x00" + : : "a"(cfg)); +} + +/* Load tile data to %tmm0 register only */ +static inline void __tileloadd(void *tile) +{ + asm volatile(".byte 0xc4,0xe2,0x7b,0x4b,0x04,0x10" + : : "a"(tile), "d"(0)); +} + +/* Save extended states */ +static inline void __xsave(void *buffer, u32 lo, u32 hi) +{ + asm volatile("xsave (%%rdi)" + : : "D" (buffer), "a" (lo), "d" (hi) + : "memory"); +} + +/* Restore extended states */ +static inline void __xrstor(void *buffer, u32 lo, u32 hi) +{ + asm volatile("xrstor (%%rdi)" + : : "D" (buffer), "a" (lo), "d" (hi)); +} + +/* Release tile states to init values */ +static inline void __tilerelease(void) +{ + asm volatile(".byte 0xc4, 0xe2, 0x78, 0x49, 0xc0" ::); +} + +static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), + int flags) +{ + struct sigaction sa; + + memset(&sa, 0, sizeof(sa)); + sa.sa_sigaction = handler; + sa.sa_flags = SA_SIGINFO | flags; + sigemptyset(&sa.sa_mask); + if (sigaction(sig, &sa, 0)) + err(1, "sigaction"); +} + +static void clearhandler(int sig) +{ + struct sigaction sa; + + memset(&sa, 0, sizeof(sa)); + sa.sa_handler = SIG_DFL; + sigemptyset(&sa.sa_mask); + if (sigaction(sig, &sa, 0)) + err(1, "sigaction"); +} + +/* Hardware info check: */ + +static jmp_buf jmpbuf; +static bool xsave_disabled; + +static void handle_sigill(int sig, siginfo_t *si, void *ctx_void) +{ + xsave_disabled = true; + siglongjmp(jmpbuf, 1); +} + +#define XFEATURE_XTILE_CFG 17 +#define XFEATURE_XTILE_DATA 18 +#define XFEATURE_MASK_XTILE ((1 << XFEATURE_XTILE_DATA) | \ + (1 << XFEATURE_XTILE_CFG)) + +static inline bool check_xsave_supports_xtile(void) +{ + bool supported = false; + + sethandler(SIGILL, handle_sigill, 0); + + if (!sigsetjmp(jmpbuf, 1)) + supported = __xgetbv(0) & XFEATURE_MASK_XTILE; + + clearhandler(SIGILL); + return supported; +} + +struct xtile_hwinfo { + struct { + u16 bytes_per_tile; + u16 bytes_per_row; + u16 max_names; + u16 max_rows; + } spec; + + struct { + u32 offset; + u32 size; + } xsave; +}; + +static struct xtile_hwinfo xtile; + +static bool __enum_xtile_config(void) +{ + u32 eax, ebx, ecx, edx; + u16 bytes_per_tile; + bool valid = false; + +#define TILE_CPUID 0x1d +#define TILE_PALETTE_CPUID_SUBLEAVE 0x1 + + eax = TILE_CPUID; + ecx = TILE_PALETTE_CPUID_SUBLEAVE; + + __cpuid(&eax, &ebx, &ecx, &edx); + if (!eax || !ebx || !ecx) + return valid; + + xtile.spec.max_names = ebx >> 16; + if (xtile.spec.max_names < NUM_TILES) + return valid; + + bytes_per_tile = eax >> 16; + if (bytes_per_tile < TILE_SIZE) + return valid; + + xtile.spec.bytes_per_row = ebx; + xtile.spec.max_rows = ecx; + valid = true; + + return valid; +} + +static bool __enum_xsave_tile(void) +{ + u32 eax, ebx, ecx, edx; + bool valid = false; + +#define XSTATE_CPUID 0xd +#define XSTATE_USER_STATE_SUBLEAVE 0x0 + + eax = XSTATE_CPUID; + ecx = XFEATURE_XTILE_DATA; + + __cpuid(&eax, &ebx, &ecx, &edx); + if (!eax || !ebx) + return valid; + + xtile.xsave.offset = ebx; + xtile.xsave.size = eax; + valid = true; + + return valid; +} + +static bool __check_xsave_size(void) +{ + u32 eax, ebx, ecx, edx; + bool valid = false; + + eax = XSTATE_CPUID; + ecx = XSTATE_USER_STATE_SUBLEAVE; + + __cpuid(&eax, &ebx, &ecx, &edx); + if (ebx && ebx <= XSAVE_SIZE) + valid = true; + + return valid; +} + +/* + * Check the hardware-provided tile state info and cross-check it with the + * hard-coded values: XSAVE_SIZE, NUM_TILES, and TILE_SIZE. + */ +static int check_xtile_hwinfo(void) +{ + bool success = false; + + if (!__check_xsave_size()) + return success; + + if (!__enum_xsave_tile()) + return success; + + if (!__enum_xtile_config()) + return success; + + if (sizeof(struct tile_data) >= xtile.xsave.size) + success = true; + + return success; +} + +/* The helpers for managing XSAVE buffer and tile states: */ + +/* Use the uncompacted format without 'init optimization' */ +static void save_xdata(void *data) +{ + __xsave(data, -1, -1); +} + +static void restore_xdata(void *data) +{ + __xrstor(data, -1, -1); +} + +static inline u64 __get_xsave_xstate_bv(void *data) +{ +#define XSAVE_HDR_OFFSET 512 + return *(u64 *)(data + XSAVE_HDR_OFFSET); +} + +static void set_tilecfg(struct tile_config *cfg) +{ + int i; + + memset(cfg, 0, sizeof(*cfg)); + /* The first implementation has one significant palette with id 1 */ + cfg->palette_id = 1; + for (i = 0; i < xtile.spec.max_names; i++) { + cfg->colsb[i] = xtile.spec.bytes_per_row; + cfg->rows[i] = xtile.spec.max_rows; + } +} + +static void load_tilecfg(struct tile_config *cfg) +{ + __ldtilecfg(cfg); +} + +static void make_tiles(void *tiles) +{ + u32 iterations = xtile.xsave.size / sizeof(u32); + static u32 value = 1; + u32 *ptr = tiles; + int i; + + for (i = 0, ptr = tiles; i < iterations; i++, ptr++) + *ptr = value; + value++; +} + +/* + * Initialize the XSAVE buffer: + * + * Make sure tile configuration loaded already. Load limited tile data (%tmm0 only) + * and save all the states. XSAVE buffer is ready to complete tile data. + */ +static void init_xdata(void *data) +{ + struct tile_data tiles; + + make_tiles(&tiles); + __tileloadd(&tiles); + __xsave(data, -1, -1); +} + +static inline void *__get_xsave_tile_data_addr(void *data) +{ + return data + xtile.xsave.offset; +} + +static void copy_tiles_to_xdata(void *xdata, void *tiles) +{ + void *dst = __get_xsave_tile_data_addr(xdata); + + memcpy(dst, tiles, xtile.xsave.size); +} + +static int compare_xdata_tiles(void *xdata, void *tiles) +{ + void *tile_data = __get_xsave_tile_data_addr(xdata); + + if (memcmp(tile_data, tiles, xtile.xsave.size)) + return 1; + + return 0; +} + +static int nerrs, errs; + +/* Testing tile data inheritance */ + +static void test_tile_data_inheritance(void) +{ + struct xsave_data xdata; + struct tile_data tiles; + struct tile_config cfg; + pid_t child; + int status; + + set_tilecfg(&cfg); + load_tilecfg(&cfg); + init_xdata(&xdata); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + restore_xdata(&xdata); + + errs = 0; + + child = fork(); + if (child < 0) + err(1, "fork"); + + if (child == 0) { + memset(&xdata, 0, sizeof(xdata)); + save_xdata(&xdata); + if (compare_xdata_tiles(&xdata, &tiles)) { + printf("[OK]\tchild didn't inherit tile data at fork()\n"); + } else { + printf("[FAIL]\tchild inherited tile data at fork()\n"); + nerrs++; + } + _exit(0); + } + wait(&status); +} + +static void test_fork(void) +{ + pid_t child; + int status; + + child = fork(); + if (child < 0) + err(1, "fork"); + + if (child == 0) { + test_tile_data_inheritance(); + _exit(0); + } + + wait(&status); +} + +/* Context switching test */ + +#define ITERATIONS 10 +#define NUM_THREADS 5 + +struct futex_info { + int current; + int next; + int *futex; +}; + +static inline void command_wait(struct futex_info *info, int value) +{ + do { + sched_yield(); + } while (syscall(SYS_futex, info->futex, FUTEX_WAIT, value, 0, 0, 0)); +} + +static inline void command_wake(struct futex_info *info, int value) +{ + do { + *info->futex = value; + while (!syscall(SYS_futex, info->futex, FUTEX_WAKE, 1, 0, 0, 0)) + sched_yield(); + } while (0); +} + +static inline int get_iterative_value(int id) +{ + return ((id << 1) & ~0x1); +} + +static inline int get_endpoint_value(int id) +{ + return ((id << 1) | 0x1); +} + +static void *check_tiles(void *info) +{ + struct futex_info *finfo = (struct futex_info *)info; + struct xsave_data xdata; + struct tile_data tiles; + struct tile_config cfg; + int i; + + set_tilecfg(&cfg); + load_tilecfg(&cfg); + init_xdata(&xdata); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + restore_xdata(&xdata); + + for (i = 0; i < ITERATIONS; i++) { + command_wait(finfo, get_iterative_value(finfo->current)); + + memset(&xdata, 0, sizeof(xdata)); + save_xdata(&xdata); + errs += compare_xdata_tiles(&xdata, &tiles); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + restore_xdata(&xdata); + + command_wake(finfo, get_iterative_value(finfo->next)); + } + + command_wait(finfo, get_endpoint_value(finfo->current)); + __tilerelease(); + return NULL; +} + +static int create_children(int num, struct futex_info *finfo) +{ + const int shm_id = shmget(IPC_PRIVATE, sizeof(int), IPC_CREAT | 0666); + int *futex = shmat(shm_id, NULL, 0); + pthread_t thread; + int i; + + for (i = 0; i < num; i++) { + finfo[i].futex = futex; + finfo[i].current = i + 1; + finfo[i].next = (i + 2) % (num + 1); + + if (pthread_create(&thread, NULL, check_tiles, &finfo[i])) { + err(1, "pthread_create"); + return 1; + } + } + return 0; +} + +static void test_context_switch(void) +{ + struct futex_info *finfo; + cpu_set_t cpuset; + int i; + + printf("[RUN]\t%u context switches of tile states in %d threads\n", + ITERATIONS * NUM_THREADS, NUM_THREADS); + + errs = 0; + + CPU_ZERO(&cpuset); + CPU_SET(0, &cpuset); + if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) + err(1, "sched_setaffinity to CPU 0"); + + finfo = malloc(sizeof(*finfo) * NUM_THREADS); + + if (create_children(NUM_THREADS, finfo)) + return; + + for (i = 0; i < ITERATIONS; i++) { + command_wake(finfo, get_iterative_value(1)); + command_wait(finfo, get_iterative_value(0)); + } + + for (i = 1; i <= NUM_THREADS; i++) + command_wake(finfo, get_endpoint_value(i)); + + if (errs) { + printf("[FAIL]\t%u incorrect tile states\n", errs); + nerrs += errs; + return; + } + + printf("[OK]\tall tile states are correct\n"); +} + +/* Ptrace test */ + +static inline long get_tile_state(pid_t child, struct iovec *iov) +{ + return ptrace(PTRACE_GETREGSET, child, (u32)NT_X86_XSTATE, iov); +} + +static inline long set_tile_state(pid_t child, struct iovec *iov) +{ + return ptrace(PTRACE_SETREGSET, child, (u32)NT_X86_XSTATE, iov); +} + +static int write_tile_state(bool load_tile, pid_t child) +{ + struct xsave_data xdata; + struct tile_data tiles; + struct iovec iov; + + iov.iov_base = &xdata; + iov.iov_len = sizeof(xdata); + + if (get_tile_state(child, &iov)) + err(1, "PTRACE_GETREGSET"); + + make_tiles(&tiles); + copy_tiles_to_xdata(&xdata, &tiles); + if (set_tile_state(child, &iov)) + err(1, "PTRACE_SETREGSET"); + + memset(&xdata, 0, sizeof(xdata)); + if (get_tile_state(child, &iov)) + err(1, "PTRACE_GETREGSET"); + + if (!load_tile) + memset(&tiles, 0, sizeof(tiles)); + + return compare_xdata_tiles(&xdata, &tiles); +} + +static void test_tile_state_write(bool load_tile) +{ + pid_t child; + int status; + + child = fork(); + if (child < 0) + err(1, "fork"); + + if (child == 0) { + printf("[RUN]\tPtrace-induced tile state write, "); + printf("%s tile data loaded\n", load_tile ? "with" : "without"); + + if (ptrace(PTRACE_TRACEME, 0, NULL, NULL)) + err(1, "PTRACE_TRACEME"); + + if (load_tile) { + struct tile_config cfg; + struct tile_data tiles; + + set_tilecfg(&cfg); + load_tilecfg(&cfg); + make_tiles(&tiles); + /* Load only %tmm0 but inducing the #NM */ + __tileloadd(&tiles); + } + + raise(SIGTRAP); + _exit(0); + } + + do { + wait(&status); + } while (WSTOPSIG(status) != SIGTRAP); + + errs = write_tile_state(load_tile, child); + if (errs) { + nerrs++; + printf("[FAIL]\t%s write\n", load_tile ? "incorrect" : "unexpected"); + } else { + printf("[OK]\t%s write\n", load_tile ? "correct" : "no"); + } + + ptrace(PTRACE_DETACH, child, NULL, NULL); + wait(&status); +} + +static void test_ptrace(void) +{ + bool ptracee_loads_tiles; + + ptracee_loads_tiles = true; + test_tile_state_write(ptracee_loads_tiles); + + ptracee_loads_tiles = false; + test_tile_state_write(ptracee_loads_tiles); +} + +int main(void) +{ + /* Check hardware availability at first */ + + if (!check_xsave_supports_xtile()) { + if (xsave_disabled) + printf("XSAVE disabled.\n"); + else + printf("Tile data not available.\n"); + return 0; + } + + if (!check_xtile_hwinfo()) { + printf("Available tile state size is insufficient to test.\n"); + return 0; + } + + nerrs = 0; + + test_fork(); + test_context_switch(); + test_ptrace(); + + return nerrs ? 1 : 0; +} -- 2.17.1

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[PATCH v28 00/12] Landlock LSM

by Mickaël Salaün

Hi, This patch series fixes a corner-case with non-overlapping access rights coming from different layers. This is now handled in a generic way and verified with new tests. A stricter check is enforced for landlock_add_rule(2) to forbid useless rules. Finally, the previous landlock_enforce_ruleset_self(2) is renamed to landlock_restrict_self(2), which is more consistent. The SLOC count is 1314 for security/landlock/ and 2484 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-v28/userspace-api/landlock.html This series can be applied on top of v5.11-rc6 . 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-v28 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/20210121205119.793296-1-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.n… 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 | 307 ++ MAINTAINERS | 15 + 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 | 238 ++ 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 | 627 ++++ 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 | 473 +++ security/landlock/ruleset.h | 165 + security/landlock/setup.c | 40 + security/landlock/setup.h | 18 + security/landlock/syscalls.c | 444 +++ 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 | 169 ++ tools/testing/selftests/landlock/config | 6 + tools/testing/selftests/landlock/fs_test.c | 2664 +++++++++++++++++ .../testing/selftests/landlock/ptrace_test.c | 314 ++ tools/testing/selftests/landlock/true.c | 5 + 72 files changed, 6668 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: 1048ba83fb1c00cd24172e23e8263972f6b5d9ac -- 2.30.0

4 years, 9 months

3
26
0 0

[RFC PATCH 00/13] Add futex2 syscalls

by André Almeida

Hi, This patch series introduces the futex2 syscalls. * What happened to the current futex()? For some years now, developers have been trying to add new features to futex, but maintainers have been reluctant to accept then, given the multiplexed interface full of legacy features and tricky to do big changes. Some problems that people tried to address with patchsets are: NUMA-awareness[0], smaller sized futexes[1], wait on multiple futexes[2]. NUMA, for instance, just doesn't fit the current API in a reasonable way. Considering that, it's not possible to merge new features into the current futex. ** The NUMA problem At the current implementation, all futex kernel side infrastructure is stored on a single node. Given that, all futex() calls issued by processors that aren't located on that node will have a memory access penalty when doing it. ** The 32bit sized futex problem Embedded systems or anything with memory constrains would benefit of using smaller sizes for the futex userspace integer. Also, a mutex implementation can be done using just three values, so 8 bits is enough for various scenarios. ** The wait on multiple problem The use case lies in the Wine implementation of the Windows NT interface WaitMultipleObjects. This Windows API function allows a thread to sleep waiting on the first of a set of event sources (mutexes, timers, signal, console input, etc) to signal. Considering this is a primitive synchronization operation for Windows applications, being able to quickly signal events on the producer side, and quickly go to sleep on the consumer side is essential for good performance of those running over Wine. [0] https://lore.kernel.org/lkml/20160505204230.932454245@linutronix.de/ [1] https://lore.kernel.org/lkml/20191221155659.3159-2-malteskarupke@web.de/ [2] https://lore.kernel.org/lkml/20200213214525.183689-1-andrealmeid@collabora.… * The solution As proposed by Peter Zijlstra and Florian Weimer[3], a new interface is required to solve this, which must be designed with those features in mind. futex2() is that interface. As opposed to the current multiplexed interface, the new one should have one syscall per operation. This will allow the maintainability of the API if it gets extended, and will help users with type checking of arguments. In particular, the new interface is extended to support the ability to wait on any of a list of futexes at a time, which could be seen as a vectored extension of the FUTEX_WAIT semantics. [3] https://lore.kernel.org/lkml/20200303120050.GC2596@hirez.programming.kicks-… * The interface The new interface can be seen in details in the following patches, but this is a high level summary of what the interface can do: - Supports wake/wait semantics, as in futex() - Supports requeue operations, similarly as FUTEX_CMP_REQUEUE, but with individual flags for each address - Supports waiting for a vector of futexes, using a new syscall named futex_waitv() - Supports variable sized futexes (8bits, 16bits and 32bits) - Supports NUMA-awareness operations, where the user can specify on which memory node would like to operate * Implementation The internal implementation follows a similar design to the original futex. Given that we want to replicate the same external behavior of current futex, this should be somewhat expected. For some functions, like the init and the code to get a shared key, I literally copied code and comments from kernel/futex.c. I decided to do so instead of exposing the original function as a public function since in that way we can freely modify our implementation if required, without any impact on old futex. Also, the comments precisely describes the details and corner cases of the implementation. Each patch contains a brief description of implementation, but patch 6 "docs: locking: futex2: Add documentation" adds a more complete document about it. * The patchset This patchset can be also found at my git tree: https://gitlab.collabora.com/tonyk/linux/-/tree/futex2 - Patch 1: Implements wait/wake, and the basics foundations of futex2 - Patches 2-4: Implement the remaining features (shared, waitv, requeue). - Patch 5: Adds the x86_x32 ABI handling. I kept it in a separated patch since I'm not sure if x86_x32 is still a thing, or if it should return -ENOSYS. - Patch 6: Add a documentation file which details the interface and the internal implementation. - Patches 7-13: Selftests for all operations along with perf support for futex2. - Patch 14: While working on porting glibc for futex2, I found out that there's a futex_wake() call at the user thread exit path, if that thread was created with clone(..., CLONE_CHILD_SETTID, ...). In order to make pthreads work with futex2, it was required to add this patch. Note that this is more a proof-of-concept of what we will need to do in future, rather than part of the interface and shouldn't be merged as it is. * Testing: This patchset provides selftests for each operation and their flags. Along with that, the following work was done: ** Stability To stress the interface in "real world scenarios": - glibc[4]: nptl's low level locking was modified to use futex2 API (except for robust and PI things). All relevant nptl/ tests passed. - Wine[5]: Proton/Wine was modified in order to use futex2() for the emulation of Windows NT sync mechanisms based on futex, called "fsync". Triple-A games with huge CPU's loads and tons of parallel jobs worked as expected when compared with the previous FUTEX_WAIT_MULTIPLE implementation at futex(). Some games issue 42k futex2() calls per second. - Full GNU/Linux distro: I installed the modified glibc in my host machine, so all pthread's programs would use futex2(). After tweaking systemd[6] to allow futex2() calls at seccomp, everything worked as expected (web browsers do some syscall sandboxing and need some configuration as well). - perf: The perf benchmarks tests can also be used to stress the interface, and they can be found in this patchset. ** Performance - For comparing futex() and futex2() performance, I used the artificial benchmarks implemented at perf (wake, wake-parallel, hash and requeue). The setup was 200 runs for each test and using 8, 80, 800, 8000 for the number of threads, Note that for this test, I'm not using patch 14 ("kernel: Enable waitpid() for futex2") , for reasons explained at "The patchset" section. - For the first three ones, I measured an average of 4% gain in performance. This is not a big step, but it shows that the new interface is at least comparable in performance with the current one. - For requeue, I measured an average of 21% decrease in performance compared to the original futex implementation. This is expected given the new design with individual flags. The performance trade-offs are explained at patch 4 ("futex2: Implement requeue operation"). [4] https://gitlab.collabora.com/tonyk/glibc/-/tree/futex2 [5] https://gitlab.collabora.com/tonyk/wine/-/tree/proton_5.13 [6] https://gitlab.collabora.com/tonyk/systemd * FAQ ** "Where's the code for NUMA and FUTEX_8/16?" The current code is already complex enough to take some time for review, so I believe it's better to split that work out to a future iteration of this patchset. Besides that, this RFC is the core part of the infrastructure, and the following features will not pose big design changes to it, the work will be more about wiring up the flags and modifying some functions. ** "And what's about FUTEX_64?" By supporting 64 bit futexes, the kernel structure for futex would need to have a 64 bit field for the value, and that could defeat one of the purposes of having different sized futexes in the first place: supporting smaller ones to decrease memory usage. This might be something that could be disabled for 32bit archs (and even for CONFIG_BASE_SMALL). Which use case would benefit for FUTEX_64? Does it worth the trade-offs? ** "Where's the PI/robust stuff?" As said by Peter Zijlstra at [3], all those new features are related to the "simple" futex interface, that doesn't use PI or robust. Do we want to have this complexity at futex2() and if so, should it be part of this patchset or can it be future work? Thanks, André André Almeida (13): futex2: Implement wait and wake functions futex2: Add support for shared futexes futex2: Implement vectorized wait futex2: Implement requeue operation futex2: Add compatibility entry point for x86_x32 ABI docs: locking: futex2: Add documentation selftests: futex2: Add wake/wait test selftests: futex2: Add timeout test selftests: futex2: Add wouldblock test selftests: futex2: Add waitv test selftests: futex2: Add requeue test perf bench: Add futex2 benchmark tests kernel: Enable waitpid() for futex2 Documentation/locking/futex2.rst | 198 +++ Documentation/locking/index.rst | 1 + MAINTAINERS | 2 +- arch/arm/tools/syscall.tbl | 4 + arch/arm64/include/asm/unistd.h | 2 +- arch/arm64/include/asm/unistd32.h | 4 + arch/x86/entry/syscalls/syscall_32.tbl | 4 + arch/x86/entry/syscalls/syscall_64.tbl | 4 + fs/inode.c | 1 + include/linux/compat.h | 23 + include/linux/fs.h | 1 + include/linux/syscalls.h | 18 + include/uapi/asm-generic/unistd.h | 14 +- include/uapi/linux/futex.h | 56 + init/Kconfig | 7 + kernel/Makefile | 1 + kernel/fork.c | 2 + kernel/futex2.c | 1255 +++++++++++++++++ kernel/sys_ni.c | 6 + tools/arch/x86/include/asm/unistd_64.h | 12 + tools/include/uapi/asm-generic/unistd.h | 11 +- .../arch/x86/entry/syscalls/syscall_64.tbl | 3 + tools/perf/bench/bench.h | 4 + tools/perf/bench/futex-hash.c | 24 +- tools/perf/bench/futex-requeue.c | 57 +- tools/perf/bench/futex-wake-parallel.c | 41 +- tools/perf/bench/futex-wake.c | 37 +- tools/perf/bench/futex.h | 47 + tools/perf/builtin-bench.c | 18 +- .../selftests/futex/functional/.gitignore | 3 + .../selftests/futex/functional/Makefile | 8 +- .../futex/functional/futex2_requeue.c | 164 +++ .../selftests/futex/functional/futex2_wait.c | 209 +++ .../selftests/futex/functional/futex2_waitv.c | 157 +++ .../futex/functional/futex_wait_timeout.c | 58 +- .../futex/functional/futex_wait_wouldblock.c | 33 +- .../testing/selftests/futex/functional/run.sh | 6 + .../selftests/futex/include/futex2test.h | 121 ++ 38 files changed, 2563 insertions(+), 53 deletions(-) create mode 100644 Documentation/locking/futex2.rst create mode 100644 kernel/futex2.c create mode 100644 tools/testing/selftests/futex/functional/futex2_requeue.c create mode 100644 tools/testing/selftests/futex/functional/futex2_wait.c create mode 100644 tools/testing/selftests/futex/functional/futex2_waitv.c create mode 100644 tools/testing/selftests/futex/include/futex2test.h -- 2.30.1

4 years, 9 months

6
28
0 0

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