March 2021 - Linux-kselftest-mirror

[PATCH v6 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. 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_v6" branch. [1] https://github.com/KSPP/linux/issues/39 [2] https://github.com/johwood/linux/ The previous versions can be found in: RFC https://lore.kernel.org/kernel-hardening/20200910202107.3799376-1-keescook@… Version 2 https://lore.kernel.org/kernel-hardening/20201025134540.3770-1-john.wood@gm… Version 3 https://lore.kernel.org/lkml/20210221154919.68050-1-john.wood@gmx.com/ Version 4 https://lore.kernel.org/lkml/20210227150956.6022-1-john.wood@gmx.com/ Version 5 https://lore.kernel.org/kernel-hardening/20210227153013.6747-1-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). Changelog v3 -> v4 ------------------ - Fix all the warnings shown by the tool "scripts/kernel-doc" (Randy Dunlap). Changelog v4 -> v5 ------------------ - Fix some typos (Randy Dunlap). Changelog v5 -> v6 ------------------ - Fix a reported deadlock (kernel test robot). - Add high level details to the documentation (Andi Kleen). Any constructive comments are welcome. Thanks. 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 | 278 ++++++ 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 | 1107 ++++++++++++++++++++++ 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, 2219 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

3 years, 1 month

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[PATCH -next] treewide: Remove duplicated include from tm-vmx-unavail.c

by Zheng Yongjun

Remove duplicated include. Reported-by: Hulk Robot <hulkci(a)huawei.com> Signed-off-by: Zheng Yongjun <zhengyongjun3(a)huawei.com> --- tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c | 1 - 1 file changed, 1 deletion(-) diff --git a/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c b/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c index e2a0c07e8362..9ef37a9836ac 100644 --- a/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c +++ b/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c @@ -17,7 +17,6 @@ #include <pthread.h> #include <sys/mman.h> #include <unistd.h> -#include <pthread.h> #include "tm.h" #include "utils.h"

3 years, 1 month

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[PATCH] [v2] tools: testing: Remove duplicate includes

by Wan Jiabing

sched.h has been included at line 33, so remove the duplicate one at line 36. inttypes.h has been included at line 19, so remove the duplicate one at line 23. pthread.h has been included at line 17,so remove the duplicate one at line 20. Signed-off-by: Wan Jiabing <wanjiabing(a)vivo.com> --- tools/testing/selftests/powerpc/mm/tlbie_test.c | 1 - tools/testing/selftests/powerpc/tm/tm-poison.c | 1 - tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c | 1 - 3 files changed, 3 deletions(-) diff --git a/tools/testing/selftests/powerpc/mm/tlbie_test.c b/tools/testing/selftests/powerpc/mm/tlbie_test.c index f85a0938ab25..48344a74b212 100644 --- a/tools/testing/selftests/powerpc/mm/tlbie_test.c +++ b/tools/testing/selftests/powerpc/mm/tlbie_test.c @@ -33,7 +33,6 @@ #include <sched.h> #include <time.h> #include <stdarg.h> -#include <sched.h> #include <pthread.h> #include <signal.h> #include <sys/prctl.h> diff --git a/tools/testing/selftests/powerpc/tm/tm-poison.c b/tools/testing/selftests/powerpc/tm/tm-poison.c index 29e5f26af7b9..27c083a03d1f 100644 --- a/tools/testing/selftests/powerpc/tm/tm-poison.c +++ b/tools/testing/selftests/powerpc/tm/tm-poison.c @@ -20,7 +20,6 @@ #include <sched.h> #include <sys/types.h> #include <signal.h> -#include <inttypes.h> #include "tm.h" diff --git a/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c b/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c index e2a0c07e8362..9ef37a9836ac 100644 --- a/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c +++ b/tools/testing/selftests/powerpc/tm/tm-vmx-unavail.c @@ -17,7 +17,6 @@ #include <pthread.h> #include <sys/mman.h> #include <unistd.h> -#include <pthread.h> #include "tm.h" #include "utils.h" -- 2.25.1

3 years, 1 month

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Re: [PATCH v31 10/12] selftests/landlock: Add user space tests

by Kees Cook

On Wed, Mar 24, 2021 at 08:15:18PM +0100, Mickaël Salaün wrote: > From: Mickaël Salaün <mic(a)linux.microsoft.com> > > Test all Landlock system calls, ptrace hooks semantic and filesystem > access-control with multiple layouts. > > Test coverage for security/landlock/ is 93.6% of lines. The code not > covered only deals with internal kernel errors (e.g. memory allocation) > and race conditions. > > Cc: James Morris <jmorris(a)namei.org> > Cc: Jann Horn <jannh(a)google.com> > Cc: Kees Cook <keescook(a)chromium.org> > Cc: Serge E. Hallyn <serge(a)hallyn.com> > Cc: Shuah Khan <shuah(a)kernel.org> > Signed-off-by: Mickaël Salaün <mic(a)linux.microsoft.com> Reviewed-by: Kees Cook <keescook(a)chromium.org> -- Kees Cook

3 years, 1 month

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[PATCH v30 00/12] Landlock LSM

by Mickaël Salaün

Hi, This patch series is mainly a rebase on top of v5.12-rc3 and a synchronization with the new mount_setattr(2). A light cleanup of hook_sb_delete() and new tests are also included. The SLOC count is 1329 for security/landlock/ and 2556 for tools/testing/selftest/landlock/ . Test coverage for security/landlock/ is 93.6% 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 (which may cover internal kernel errors), 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-v30/userspace-api/landlock.html This series can be applied on top of v5.12-rc3 . 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-v30 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]. [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… Previous versions: v29: https://lore.kernel.org/lkml/20210225190614.2181147-1-mic@digikod.net/ v28: https://lore.kernel.org/lkml/20210202162710.657398-1-mic@digikod.net/ v27: https://lore.kernel.org/lkml/20210121205119.793296-1-mic@digikod.net/ v26: https://lore.kernel.org/lkml/20201209192839.1396820-1-mic@digikod.net/ v25: https://lore.kernel.org/lkml/20201201192322.213239-1-mic@digikod.net/ v24: https://lore.kernel.org/lkml/20201112205141.775752-1-mic@digikod.net/ v23: https://lore.kernel.org/lkml/20201103182109.1014179-1-mic@digikod.net/ v22: https://lore.kernel.org/lkml/20201027200358.557003-1-mic@digikod.net/ v21: https://lore.kernel.org/lkml/20201008153103.1155388-1-mic@digikod.net/ v20: https://lore.kernel.org/lkml/20200802215903.91936-1-mic@digikod.net/ v19: https://lore.kernel.org/lkml/20200707180955.53024-1-mic@digikod.net/ v18: https://lore.kernel.org/lkml/20200526205322.23465-1-mic@digikod.net/ v17: https://lore.kernel.org/lkml/20200511192156.1618284-1-mic@digikod.net/ v16: https://lore.kernel.org/lkml/20200416103955.145757-1-mic@digikod.net/ v15: https://lore.kernel.org/lkml/20200326202731.693608-1-mic@digikod.net/ v14: https://lore.kernel.org/lkml/20200224160215.4136-1-mic@digikod.net/ v13: https://lore.kernel.org/lkml/20191104172146.30797-1-mic@digikod.net/ v12: https://lore.kernel.org/lkml/20191031164445.29426-1-mic@digikod.net/ v11: https://lore.kernel.org/lkml/20191029171505.6650-1-mic@digikod.net/ v10: https://lore.kernel.org/lkml/20190721213116.23476-1-mic@digikod.net/ v9: https://lore.kernel.org/lkml/20190625215239.11136-1-mic@digikod.net/ v8: https://lore.kernel.org/lkml/20180227004121.3633-1-mic@digikod.net/ v7: https://lore.kernel.org/lkml/20170821000933.13024-1-mic@digikod.net/ v6: https://lore.kernel.org/lkml/20170328234650.19695-1-mic@digikod.net/ v5: https://lore.kernel.org/lkml/20170222012632.4196-1-mic@digikod.net/ v4: https://lore.kernel.org/lkml/20161026065654.19166-1-mic@digikod.net/ v3: https://lore.kernel.org/lkml/20160914072415.26021-1-mic@digikod.net/ v2: https://lore.kernel.org/lkml/1472121165-29071-1-git-send-email-mic@digikod.… v1: https://lore.kernel.org/kernel-hardening/1458784008-16277-1-git-send-email-… 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 | 4 + 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 | 687 ++++ 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 | 445 +++ 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 | 183 ++ tools/testing/selftests/landlock/config | 7 + tools/testing/selftests/landlock/fs_test.c | 2792 +++++++++++++++++ .../testing/selftests/landlock/ptrace_test.c | 337 ++ tools/testing/selftests/landlock/true.c | 5 + 72 files changed, 6896 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: 1e28eed17697bcf343c6743f0028cc3b5dd88bf0 -- 2.30.2

3 years, 1 month

4
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[PATCH] userfaultfd/shmem: fix minor fault page leak

by Axel Rasmussen

This fix is analogous to Peter Xu's fix for hugetlb [0]. If we don't put_page() after getting the page out of the page cache, we leak the reference. The fix can be verified by checking /proc/meminfo and running the userfaultfd selftest in shmem mode. Without the fix, we see MemFree / MemAvailable steadily decreasing with each run of the test. With the fix, memory is correctly freed after the test program exits. Fixes: 00da60b9d0a0 ("userfaultfd: support minor fault handling for shmem") Signed-off-by: Axel Rasmussen <axelrasmussen(a)google.com> --- mm/shmem.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/shmem.c b/mm/shmem.c index ef8c9f5e92fc..d2e0e81b7d2e 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1831,6 +1831,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, if (page && vma && userfaultfd_minor(vma)) { unlock_page(page); + put_page(page); *fault_type = handle_userfault(vmf, VM_UFFD_MINOR); return 0; } -- 2.31.0.rc2.261.g7f71774620-goog

3 years, 1 month

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[PATCH] tools: testing: Remove duplicate include of string.h

by Wan Jiabing

string.h has been included at line 15.So we remove the duplicate one at line 17. Signed-off-by: Wan Jiabing <wanjiabing(a)vivo.com> --- tools/testing/selftests/mincore/mincore_selftest.c | 1 - 1 file changed, 1 deletion(-) diff --git a/tools/testing/selftests/mincore/mincore_selftest.c b/tools/testing/selftests/mincore/mincore_selftest.c index 5a1e85ff5d32..e54106643337 100644 --- a/tools/testing/selftests/mincore/mincore_selftest.c +++ b/tools/testing/selftests/mincore/mincore_selftest.c @@ -14,7 +14,6 @@ #include <sys/mman.h> #include <string.h> #include <fcntl.h> -#include <string.h> #include "../kselftest.h" #include "../kselftest_harness.h" -- 2.25.1

3 years, 1 month

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[PATCH v6 1/2] mm: huge_memory: a new debugfs interface for splitting THP tests.

by Zi Yan

From: Zi Yan <ziy(a)nvidia.com> We did not have a direct user interface of splitting the compound page backing a THP and there is no need unless we want to expose the THP implementation details to users. Make <debugfs>/split_huge_pages accept a new command to do that. By writing "<pid>,<vaddr_start>,<vaddr_end>" to <debugfs>/split_huge_pages, THPs within the given virtual address range from the process with the given pid are split. It is used to test split_huge_page function. In addition, a selftest program is added to tools/testing/selftests/vm to utilize the interface by splitting PMD THPs and PTE-mapped THPs. This does not change the old behavior, i.e., writing 1 to the interface to split all THPs in the system. Changelog: >From v5: 1. Skipped special VMAs and other fixes. (suggested by Yang Shi) >From v4: 1. Fixed the error code return issue, spotted by kernel test robot <lkp(a)intel.com>. >From v3: 1. Factored out split huge pages in the given pid code to a separate function. 2. Added the missing put_page for not split pages. 3. pr_debug -> pr_info, make reading results simpler. >From v2: 1. Reused existing <debugfs>/split_huge_pages interface. (suggested by Yang Shi) >From v1: 1. Removed unnecessary calling to vma_migratable, spotted by kernel test robot <lkp(a)intel.com>. 2. Dropped the use of find_mm_struct and code it directly, since there is no need for the permission check in that function and the function is only available when migration is on. 3. Added some comments in the selftest program to clarify how PTE-mapped THPs are formed. Signed-off-by: Zi Yan <ziy(a)nvidia.com> Reviewed-by: Yang Shi <shy828301(a)gmail.com> --- mm/huge_memory.c | 151 ++++++++- tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 1 + .../selftests/vm/split_huge_page_test.c | 318 ++++++++++++++++++ 4 files changed, 464 insertions(+), 7 deletions(-) create mode 100644 tools/testing/selftests/vm/split_huge_page_test.c diff --git a/mm/huge_memory.c b/mm/huge_memory.c index bff92dea5ab3..b653255a548e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -7,6 +7,7 @@ #include <linux/mm.h> #include <linux/sched.h> +#include <linux/sched/mm.h> #include <linux/sched/coredump.h> #include <linux/sched/numa_balancing.h> #include <linux/highmem.h> @@ -2922,16 +2923,14 @@ static struct shrinker deferred_split_shrinker = { }; #ifdef CONFIG_DEBUG_FS -static int split_huge_pages_set(void *data, u64 val) +static void split_huge_pages_all(void) { struct zone *zone; struct page *page; unsigned long pfn, max_zone_pfn; unsigned long total = 0, split = 0; - if (val != 1) - return -EINVAL; - + pr_info("Split all THPs\n"); for_each_populated_zone(zone) { max_zone_pfn = zone_end_pfn(zone); for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) { @@ -2959,11 +2958,149 @@ static int split_huge_pages_set(void *data, u64 val) } pr_info("%lu of %lu THP split\n", split, total); +} - return 0; +static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma) +{ + return vma_is_special_huge(vma) || (vma->vm_flags & VM_IO) || + is_vm_hugetlb_page(vma); } -DEFINE_DEBUGFS_ATTRIBUTE(split_huge_pages_fops, NULL, split_huge_pages_set, - "%llu\n"); + +static int split_huge_pages_pid(int pid, unsigned long vaddr_start, + unsigned long vaddr_end) +{ + int ret = 0; + struct task_struct *task; + struct mm_struct *mm; + unsigned long total = 0, split = 0; + unsigned long addr; + + vaddr_start &= PAGE_MASK; + vaddr_end &= PAGE_MASK; + + /* Find the task_struct from pid */ + rcu_read_lock(); + task = find_task_by_vpid(pid); + if (!task) { + rcu_read_unlock(); + ret = -ESRCH; + goto out; + } + get_task_struct(task); + rcu_read_unlock(); + + /* Find the mm_struct */ + mm = get_task_mm(task); + put_task_struct(task); + + if (!mm) { + ret = -EINVAL; + goto out; + } + + pr_info("Split huge pages in pid: %d, vaddr: [0x%lx - 0x%lx]\n", + pid, vaddr_start, vaddr_end); + + mmap_read_lock(mm); + /* + * always increase addr by PAGE_SIZE, since we could have a PTE page + * table filled with PTE-mapped THPs, each of which is distinct. + */ + for (addr = vaddr_start; addr < vaddr_end; addr += PAGE_SIZE) { + struct vm_area_struct *vma = find_vma(mm, addr); + unsigned int follflags; + struct page *page; + + if (!vma || addr < vma->vm_start) + break; + + /* skip special VMA and hugetlb VMA */ + if (vma_not_suitable_for_thp_split(vma)) { + addr = vma->vm_end; + continue; + } + + /* FOLL_DUMP to ignore special (like zero) pages */ + follflags = FOLL_GET | FOLL_DUMP; + page = follow_page(vma, addr, follflags); + + if (IS_ERR(page)) + continue; + if (!page) + continue; + + if (!is_transparent_hugepage(page)) + goto next; + + total++; + if (!can_split_huge_page(compound_head(page), NULL)) + goto next; + + if (!trylock_page(page)) + goto next; + + if (!split_huge_page(page)) + split++; + + unlock_page(page); +next: + put_page(page); + } + mmap_read_unlock(mm); + mmput(mm); + + pr_info("%lu of %lu THP split\n", split, total); + +out: + return ret; +} + +#define MAX_INPUT_BUF_SZ 255 + +static ssize_t split_huge_pages_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppops) +{ + static DEFINE_MUTEX(split_debug_mutex); + ssize_t ret; + char input_buf[MAX_INPUT_BUF_SZ]; /* hold pid, start_vaddr, end_vaddr */ + int pid; + unsigned long vaddr_start, vaddr_end; + + ret = mutex_lock_interruptible(&split_debug_mutex); + if (ret) + return ret; + + ret = -EFAULT; + + memset(input_buf, 0, MAX_INPUT_BUF_SZ); + if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ))) + goto out; + + input_buf[MAX_INPUT_BUF_SZ - 1] = '\0'; + ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end); + if (ret == 1 && pid == 1) { + split_huge_pages_all(); + ret = strlen(input_buf); + goto out; + } else if (ret != 3) { + ret = -EINVAL; + goto out; + } + + ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end); + if (!ret) + ret = strlen(input_buf); +out: + mutex_unlock(&split_debug_mutex); + return ret; + +} + +static const struct file_operations split_huge_pages_fops = { + .owner = THIS_MODULE, + .write = split_huge_pages_write, + .llseek = no_llseek, +}; static int __init split_huge_pages_debugfs(void) { diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore index 9a35c3f6a557..1f651e85ed60 100644 --- a/tools/testing/selftests/vm/.gitignore +++ b/tools/testing/selftests/vm/.gitignore @@ -22,3 +22,4 @@ map_fixed_noreplace write_to_hugetlbfs hmm-tests local_config.* +split_huge_page_test diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile index d42115e4284d..4cbc91d6869f 100644 --- a/tools/testing/selftests/vm/Makefile +++ b/tools/testing/selftests/vm/Makefile @@ -42,6 +42,7 @@ TEST_GEN_FILES += on-fault-limit TEST_GEN_FILES += thuge-gen TEST_GEN_FILES += transhuge-stress TEST_GEN_FILES += userfaultfd +TEST_GEN_FILES += split_huge_page_test ifeq ($(MACHINE),x86_64) CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_32bit_program.c -m32) diff --git a/tools/testing/selftests/vm/split_huge_page_test.c b/tools/testing/selftests/vm/split_huge_page_test.c new file mode 100644 index 000000000000..2c0c18e60c57 --- /dev/null +++ b/tools/testing/selftests/vm/split_huge_page_test.c @@ -0,0 +1,318 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A test of splitting PMD THPs and PTE-mapped THPs from a specified virtual + * address range in a process via <debugfs>/split_huge_pages interface. + */ + +#define _GNU_SOURCE +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <inttypes.h> +#include <string.h> +#include <fcntl.h> +#include <sys/mman.h> +#include <malloc.h> +#include <stdbool.h> + +uint64_t pagesize; +unsigned int pageshift; +uint64_t pmd_pagesize; + +#define PMD_SIZE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size" +#define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages" +#define SMAP_PATH "/proc/self/smaps" +#define INPUT_MAX 80 + +#define PFN_MASK ((1UL<<55)-1) +#define KPF_THP (1UL<<22) + +int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file) +{ + uint64_t paddr; + uint64_t page_flags; + + if (pagemap_file) { + pread(pagemap_file, &paddr, sizeof(paddr), + ((long)vaddr >> pageshift) * sizeof(paddr)); + + if (kpageflags_file) { + pread(kpageflags_file, &page_flags, sizeof(page_flags), + (paddr & PFN_MASK) * sizeof(page_flags)); + + return !!(page_flags & KPF_THP); + } + } + return 0; +} + + +static uint64_t read_pmd_pagesize(void) +{ + int fd; + char buf[20]; + ssize_t num_read; + + fd = open(PMD_SIZE_PATH, O_RDONLY); + if (fd == -1) { + perror("Open hpage_pmd_size failed"); + exit(EXIT_FAILURE); + } + num_read = read(fd, buf, 19); + if (num_read < 1) { + close(fd); + perror("Read hpage_pmd_size failed"); + exit(EXIT_FAILURE); + } + buf[num_read] = '\0'; + close(fd); + + return strtoul(buf, NULL, 10); +} + +static int write_file(const char *path, const char *buf, size_t buflen) +{ + int fd; + ssize_t numwritten; + + fd = open(path, O_WRONLY); + if (fd == -1) + return 0; + + numwritten = write(fd, buf, buflen - 1); + close(fd); + if (numwritten < 1) + return 0; + + return (unsigned int) numwritten; +} + +static void write_debugfs(int pid, uint64_t vaddr_start, uint64_t vaddr_end) +{ + char input[INPUT_MAX]; + int ret; + + ret = snprintf(input, INPUT_MAX, "%d,0x%lx,0x%lx", pid, vaddr_start, + vaddr_end); + if (ret >= INPUT_MAX) { + printf("%s: Debugfs input is too long\n", __func__); + exit(EXIT_FAILURE); + } + + if (!write_file(SPLIT_DEBUGFS, input, ret + 1)) { + perror(SPLIT_DEBUGFS); + exit(EXIT_FAILURE); + } +} + +#define MAX_LINE_LENGTH 500 + +static bool check_for_pattern(FILE *fp, const char *pattern, char *buf) +{ + while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) { + if (!strncmp(buf, pattern, strlen(pattern))) + return true; + } + return false; +} + +static uint64_t check_huge(void *addr) +{ + uint64_t thp = 0; + int ret; + FILE *fp; + char buffer[MAX_LINE_LENGTH]; + char addr_pattern[MAX_LINE_LENGTH]; + + ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-", + (unsigned long) addr); + if (ret >= MAX_LINE_LENGTH) { + printf("%s: Pattern is too long\n", __func__); + exit(EXIT_FAILURE); + } + + + fp = fopen(SMAP_PATH, "r"); + if (!fp) { + printf("%s: Failed to open file %s\n", __func__, SMAP_PATH); + exit(EXIT_FAILURE); + } + if (!check_for_pattern(fp, addr_pattern, buffer)) + goto err_out; + + /* + * Fetch the AnonHugePages: in the same block and check the number of + * hugepages. + */ + if (!check_for_pattern(fp, "AnonHugePages:", buffer)) + goto err_out; + + if (sscanf(buffer, "AnonHugePages:%10ld kB", &thp) != 1) { + printf("Reading smap error\n"); + exit(EXIT_FAILURE); + } + +err_out: + fclose(fp); + return thp; +} + +void split_pmd_thp(void) +{ + char *one_page; + size_t len = 4 * pmd_pagesize; + uint64_t thp_size; + size_t i; + + one_page = memalign(pmd_pagesize, len); + + if (!one_page) { + printf("Fail to allocate memory\n"); + exit(EXIT_FAILURE); + } + + madvise(one_page, len, MADV_HUGEPAGE); + + for (i = 0; i < len; i++) + one_page[i] = (char)i; + + thp_size = check_huge(one_page); + if (!thp_size) { + printf("No THP is allocated\n"); + exit(EXIT_FAILURE); + } + + /* split all THPs */ + write_debugfs(getpid(), (uint64_t)one_page, (uint64_t)one_page + len); + + for (i = 0; i < len; i++) + if (one_page[i] != (char)i) { + printf("%ld byte corrupted\n", i); + exit(EXIT_FAILURE); + } + + + thp_size = check_huge(one_page); + if (thp_size) { + printf("Still %ld kB AnonHugePages not split\n", thp_size); + exit(EXIT_FAILURE); + } + + printf("Split huge pages successful\n"); + free(one_page); +} + +void split_pte_mapped_thp(void) +{ + char *one_page, *pte_mapped, *pte_mapped2; + size_t len = 4 * pmd_pagesize; + uint64_t thp_size; + size_t i; + const char *pagemap_template = "/proc/%d/pagemap"; + const char *kpageflags_proc = "/proc/kpageflags"; + char pagemap_proc[255]; + int pagemap_fd; + int kpageflags_fd; + + if (snprintf(pagemap_proc, 255, pagemap_template, getpid()) < 0) { + perror("get pagemap proc error"); + exit(EXIT_FAILURE); + } + pagemap_fd = open(pagemap_proc, O_RDONLY); + + if (pagemap_fd == -1) { + perror("read pagemap:"); + exit(EXIT_FAILURE); + } + + kpageflags_fd = open(kpageflags_proc, O_RDONLY); + + if (kpageflags_fd == -1) { + perror("read kpageflags:"); + exit(EXIT_FAILURE); + } + + one_page = mmap((void *)(1UL << 30), len, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + + madvise(one_page, len, MADV_HUGEPAGE); + + for (i = 0; i < len; i++) + one_page[i] = (char)i; + + thp_size = check_huge(one_page); + if (!thp_size) { + printf("No THP is allocated\n"); + exit(EXIT_FAILURE); + } + + /* remap the first pagesize of first THP */ + pte_mapped = mremap(one_page, pagesize, pagesize, MREMAP_MAYMOVE); + + /* remap the Nth pagesize of Nth THP */ + for (i = 1; i < 4; i++) { + pte_mapped2 = mremap(one_page + pmd_pagesize * i + pagesize * i, + pagesize, pagesize, + MREMAP_MAYMOVE|MREMAP_FIXED, + pte_mapped + pagesize * i); + if (pte_mapped2 == (char *)-1) { + perror("mremap failed"); + exit(EXIT_FAILURE); + } + } + + /* smap does not show THPs after mremap, use kpageflags instead */ + thp_size = 0; + for (i = 0; i < pagesize * 4; i++) + if (i % pagesize == 0 && + is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) + thp_size++; + + if (thp_size != 4) { + printf("Some THPs are missing during mremap\n"); + exit(EXIT_FAILURE); + } + + /* split all remapped THPs */ + write_debugfs(getpid(), (uint64_t)pte_mapped, + (uint64_t)pte_mapped + pagesize * 4); + + /* smap does not show THPs after mremap, use kpageflags instead */ + thp_size = 0; + for (i = 0; i < pagesize * 4; i++) { + if (pte_mapped[i] != (char)i) { + printf("%ld byte corrupted\n", i); + exit(EXIT_FAILURE); + } + if (i % pagesize == 0 && + is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd)) + thp_size++; + } + + if (thp_size) { + printf("Still %ld THPs not split\n", thp_size); + exit(EXIT_FAILURE); + } + + printf("Split PTE-mapped huge pages successful\n"); + munmap(one_page, len); + close(pagemap_fd); + close(kpageflags_fd); +} + +int main(int argc, char **argv) +{ + if (geteuid() != 0) { + printf("Please run the benchmark as root\n"); + exit(EXIT_FAILURE); + } + + pagesize = getpagesize(); + pageshift = ffs(pagesize) - 1; + pmd_pagesize = read_pmd_pagesize(); + + split_pmd_thp(); + split_pte_mapped_thp(); + + return 0; +} -- 2.30.2

3 years, 1 month

3
3
0 0

[PATCH v6] selftests/x86: Use getauxval() to simplify the code in sgx

by Tianjia Zhang

Simplify the sgx code implemntation by using library function getauxval() instead of a custom function to get the base address of vDSO. Signed-off-by: Tianjia Zhang <tianjia.zhang(a)linux.alibaba.com> Reviewed-by: Jarkko Sakkinen <jarkko(a)kernel.org> Acked-by: Shuah Khan <skhan(a)linuxfoundation.org> --- tools/testing/selftests/sgx/main.c | 24 ++++-------------------- 1 file changed, 4 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/sgx/main.c b/tools/testing/selftests/sgx/main.c index 724cec700926..5167505fbb46 100644 --- a/tools/testing/selftests/sgx/main.c +++ b/tools/testing/selftests/sgx/main.c @@ -15,6 +15,7 @@ #include <sys/stat.h> #include <sys/time.h> #include <sys/types.h> +#include <sys/auxv.h> #include "defines.h" #include "main.h" #include "../kselftest.h" @@ -28,24 +29,6 @@ struct vdso_symtab { Elf64_Word *elf_hashtab; }; -static void *vdso_get_base_addr(char *envp[]) -{ - Elf64_auxv_t *auxv; - int i; - - for (i = 0; envp[i]; i++) - ; - - auxv = (Elf64_auxv_t *)&envp[i + 1]; - - for (i = 0; auxv[i].a_type != AT_NULL; i++) { - if (auxv[i].a_type == AT_SYSINFO_EHDR) - return (void *)auxv[i].a_un.a_val; - } - - return NULL; -} - static Elf64_Dyn *vdso_get_dyntab(void *addr) { Elf64_Ehdr *ehdr = addr; @@ -162,7 +145,7 @@ static int user_handler(long rdi, long rsi, long rdx, long ursp, long r8, long r return 0; } -int main(int argc, char *argv[], char *envp[]) +int main(int argc, char *argv[]) { struct sgx_enclave_run run; struct vdso_symtab symtab; @@ -203,7 +186,8 @@ int main(int argc, char *argv[], char *envp[]) memset(&run, 0, sizeof(run)); run.tcs = encl.encl_base; - addr = vdso_get_base_addr(envp); + /* Get vDSO base address */ + addr = (void *)getauxval(AT_SYSINFO_EHDR); if (!addr) goto err; -- 2.19.1.3.ge56e4f7

3 years, 1 month

3
5
0 0

[PATCH RFC v2 0/8] Add support for synchronous signals on perf events

by Marco Elver

The perf subsystem today unifies various tracing and monitoring features, from both software and hardware. One benefit of the perf subsystem is automatically inheriting events to child tasks, which enables process-wide events monitoring with low overheads. By default perf events are non-intrusive, not affecting behaviour of the tasks being monitored. For certain use-cases, however, it makes sense to leverage the generality of the perf events subsystem and optionally allow the tasks being monitored to receive signals on events they are interested in. This patch series adds the option to synchronously signal user space on events. To better support process-wide synchronous self-monitoring, without events propagating to children that do not share the current process's shared environment, two pre-requisite patches are added to optionally restrict inheritance to CLONE_THREAD, and remove events on exec (without affecting the parent). Examples how to use these features can be found in the two kselftests at the end of the series. The kselftests verify and stress test the basic functionality. The discussion at [1] led to the changes proposed in this series. The approach taken in patch "Add support for SIGTRAP on perf events" to use 'event_limit' to trigger the signal was kindly suggested by Peter Zijlstra in [2]. [1] https://lore.kernel.org/lkml/CACT4Y+YPrXGw+AtESxAgPyZ84TYkNZdP0xpocX2jwVAbZ… [2] https://lore.kernel.org/lkml/YBv3rAT566k+6zjg@hirez.programming.kicks-ass.n… Motivation and example uses: 1. Our immediate motivation is low-overhead sampling-based race detection for user space [3]. By using perf_event_open() at process initialization, we can create hardware breakpoint/watchpoint events that are propagated automatically to all threads in a process. As far as we are aware, today no existing kernel facility (such as ptrace) allows us to set up process-wide watchpoints with minimal overheads (that are comparable to mprotect() of whole pages). [3] https://llvm.org/devmtg/2020-09/slides/Morehouse-GWP-Tsan.pdf 2. Other low-overhead error detectors that rely on detecting accesses to certain memory locations or code, process-wide and also only in a specific set of subtasks or threads. Other ideas for use-cases we found interesting, but should only illustrate the range of potential to further motivate the utility (we're sure there are more): 3. Code hot patching without full stop-the-world. Specifically, by setting a code breakpoint to entry to the patched routine, then send signals to threads and check that they are not in the routine, but without stopping them further. If any of the threads will enter the routine, it will receive SIGTRAP and pause. 4. Safepoints without mprotect(). Some Java implementations use "load from a known memory location" as a safepoint. When threads need to be stopped, the page containing the location is mprotect()ed and threads get a signal. This could be replaced with a watchpoint, which does not require a whole page nor DTLB shootdowns. 5. Threads receiving signals on performance events to throttle/unthrottle themselves. 6. Tracking data flow globally. --- v2: * Patch "Support only inheriting events if cloned with CLONE_THREAD" added to series. * Patch "Add support for event removal on exec" added to series. * Patch "Add kselftest for process-wide sigtrap handling" added to series. * Patch "Add kselftest for remove_on_exec" added to series. * Implicitly restrict inheriting events if sigtrap, but the child was cloned with CLONE_CLEAR_SIGHAND, because it is not generally safe if the child cleared all signal handlers to continue sending SIGTRAP. * Various minor fixes (see details in patches). v1: https://lkml.kernel.org/r/20210223143426.2412737-1-elver@google.com Marco Elver (8): perf/core: Apply PERF_EVENT_IOC_MODIFY_ATTRIBUTES to children perf/core: Support only inheriting events if cloned with CLONE_THREAD perf/core: Add support for event removal on exec signal: Introduce TRAP_PERF si_code and si_perf to siginfo perf/core: Add support for SIGTRAP on perf events perf/core: Add breakpoint information to siginfo on SIGTRAP selftests/perf: Add kselftest for process-wide sigtrap handling selftests/perf: Add kselftest for remove_on_exec arch/m68k/kernel/signal.c | 3 + arch/x86/kernel/signal_compat.c | 5 +- fs/signalfd.c | 4 + include/linux/compat.h | 2 + include/linux/perf_event.h | 5 +- include/linux/signal.h | 1 + include/uapi/asm-generic/siginfo.h | 6 +- include/uapi/linux/perf_event.h | 5 +- include/uapi/linux/signalfd.h | 4 +- kernel/events/core.c | 130 ++++++++- kernel/fork.c | 2 +- kernel/signal.c | 11 + .../testing/selftests/perf_events/.gitignore | 3 + tools/testing/selftests/perf_events/Makefile | 6 + tools/testing/selftests/perf_events/config | 1 + .../selftests/perf_events/remove_on_exec.c | 256 ++++++++++++++++++ tools/testing/selftests/perf_events/settings | 1 + .../selftests/perf_events/sigtrap_threads.c | 202 ++++++++++++++ 18 files changed, 632 insertions(+), 15 deletions(-) create mode 100644 tools/testing/selftests/perf_events/.gitignore create mode 100644 tools/testing/selftests/perf_events/Makefile create mode 100644 tools/testing/selftests/perf_events/config create mode 100644 tools/testing/selftests/perf_events/remove_on_exec.c create mode 100644 tools/testing/selftests/perf_events/settings create mode 100644 tools/testing/selftests/perf_events/sigtrap_threads.c -- 2.30.1.766.gb4fecdf3b7-goog

3 years, 1 month

3
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Linux-kselftest-mirror March 2021