According to the test environment, the mount point of the test's working directory may be shared or not, which changes the visibility of the nested "tmp" mount point for the test's parent process calling umount("tmp").

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

Cc: Günther Noack gnoack@google.com Cc: Shuah Khan skhan@linuxfoundation.org Link: https://github.com/landlock-lsm/landlock-test-tools/pull/4 [1] Fixes: 41cca0542d7c ("selftests/harness: Fix TEST_F()'s vfork handling") Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: Mickaël Salaün mic@digikod.net Link: https://lore.kernel.org/r/20240511171445.904356-3-mic@digikod.net ---

Changes since v1: * Update commit description. --- tools/testing/selftests/landlock/fs_test.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index 9a6036fbf289..46b9effd53e4 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -293,7 +293,15 @@ static void prepare_layout(struct __test_metadata *const _metadata) static void cleanup_layout(struct __test_metadata *const _metadata) { set_cap(_metadata, CAP_SYS_ADMIN); - EXPECT_EQ(0, umount(TMP_DIR)); + if (umount(TMP_DIR)) { + /* + * According to the test environment, the mount point of the + * current directory may be shared or not, which changes the + * visibility of the nested TMP_DIR mount point for the test's + * parent process doing this cleanup. + */ + ASSERT_EQ(EINVAL, errno); + } clear_cap(_metadata, CAP_SYS_ADMIN); EXPECT_EQ(0, remove_path(TMP_DIR)); }

Fix a race condition when running several FIXTURE_TEARDOWN() managing the same resource. This fixes a race condition in the Landlock file system tests when creating or unmounting the same directory.

Using clone3() with CLONE_VFORK guarantees that the child and grandchild test processes are sequentially scheduled. This is implemented with a new clone3_vfork() helper replacing the fork() call.

This avoids triggering this error in __wait_for_test(): Test ended in some other way [127]

Cc: Christian Brauner brauner@kernel.org Cc: David S. Miller davem@davemloft.net Cc: Günther Noack gnoack@google.com Cc: Jakub Kicinski kuba@kernel.org Cc: Mark Brown broonie@kernel.org Cc: Shuah Khan shuah@kernel.org Cc: Will Drewry wad@chromium.org Fixes: 41cca0542d7c ("selftests/harness: Fix TEST_F()'s vfork handling") Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: Mickaël Salaün mic@digikod.net Link: https://lore.kernel.org/r/20240511171445.904356-5-mic@digikod.net ---

Changes since v2: * Replace __attribute__((__unused__)) with inline for clone3_vfork() (suggested by Kees and Jakub) --- tools/testing/selftests/kselftest_harness.h | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index 55699a762c45..9d7178a71c2c 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -66,6 +66,8 @@ #include <sys/wait.h> #include <unistd.h> #include <setjmp.h> +#include <syscall.h> +#include <linux/sched.h>

#include "kselftest.h"

@@ -80,6 +82,17 @@ # define TH_LOG_ENABLED 1 #endif

+/* Wait for the child process to end but without sharing memory mapping. */ +static inline pid_t clone3_vfork(void) +{ + struct clone_args args = { + .flags = CLONE_VFORK, + .exit_signal = SIGCHLD, + }; + + return syscall(__NR_clone3, &args, sizeof(args)); +} + /** * TH_LOG() * @@ -1183,7 +1196,7 @@ void __run_test(struct __fixture_metadata *f, fflush(stdout); fflush(stderr);

- t->pid = fork(); + t->pid = clone3_vfork(); if (t->pid < 0) { ksft_print_msg("ERROR SPAWNING TEST CHILD\n"); t->exit_code = KSFT_FAIL;

Do not allocate self->dir_path in the test process because this would not be visible in the FIXTURE_TEARDOWN() process when relying on fork()/clone3() instead of vfork().

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

Cc: Günther Noack gnoack@google.com Cc: Shuah Khan skhan@linuxfoundation.org Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: Mickaël Salaün mic@digikod.net Link: https://lore.kernel.org/r/20240511171445.904356-6-mic@digikod.net ---

Changes since v1: * Extract change from a bigger patch (suggested by Kees). --- tools/testing/selftests/landlock/fs_test.c | 57 +++++++++++++--------- 1 file changed, 35 insertions(+), 22 deletions(-)

diff --git a/tools/testing/selftests/landlock/fs_test.c b/tools/testing/selftests/landlock/fs_test.c index 46b9effd53e4..1e2cffde02b5 100644 --- a/tools/testing/selftests/landlock/fs_test.c +++ b/tools/testing/selftests/landlock/fs_test.c @@ -9,6 +9,7 @@

#define _GNU_SOURCE #include <fcntl.h> +#include <libgen.h> #include <linux/landlock.h> #include <linux/magic.h> #include <sched.h> @@ -4624,7 +4625,6 @@ FIXTURE(layout3_fs) { bool has_created_dir; bool has_created_file; - char *dir_path; bool skip_test; };

@@ -4683,11 +4683,24 @@ FIXTURE_VARIANT_ADD(layout3_fs, hostfs) { .cwd_fs_magic = HOSTFS_SUPER_MAGIC, };

+static char *dirname_alloc(const char *path) +{ + char *dup; + + if (!path) + return NULL; + + dup = strdup(path); + if (!dup) + return NULL; + + return dirname(dup); +} + FIXTURE_SETUP(layout3_fs) { struct stat statbuf; - const char *slash; - size_t dir_len; + char *dir_path = dirname_alloc(variant->file_path);

if (!supports_filesystem(variant->mnt.type) || !cwd_matches_fs(variant->cwd_fs_magic)) { @@ -4697,25 +4710,15 @@ FIXTURE_SETUP(layout3_fs)

_metadata->teardown_parent = true;

- slash = strrchr(variant->file_path, '/'); - ASSERT_NE(slash, NULL); - dir_len = (size_t)slash - (size_t)variant->file_path; - ASSERT_LT(0, dir_len); - self->dir_path = malloc(dir_len + 1); - self->dir_path[dir_len] = '\0'; - strncpy(self->dir_path, variant->file_path, dir_len); - prepare_layout_opt(_metadata, &variant->mnt);

/* Creates directory when required. */ - if (stat(self->dir_path, &statbuf)) { + if (stat(dir_path, &statbuf)) { set_cap(_metadata, CAP_DAC_OVERRIDE); - EXPECT_EQ(0, mkdir(self->dir_path, 0700)) + EXPECT_EQ(0, mkdir(dir_path, 0700)) { TH_LOG("Failed to create directory "%s": %s", - self->dir_path, strerror(errno)); - free(self->dir_path); - self->dir_path = NULL; + dir_path, strerror(errno)); } self->has_created_dir = true; clear_cap(_metadata, CAP_DAC_OVERRIDE); @@ -4736,6 +4739,8 @@ FIXTURE_SETUP(layout3_fs) self->has_created_file = true; clear_cap(_metadata, CAP_DAC_OVERRIDE); } + + free(dir_path); }

FIXTURE_TEARDOWN(layout3_fs) @@ -4754,16 +4759,17 @@ FIXTURE_TEARDOWN(layout3_fs) }

if (self->has_created_dir) { + char *dir_path = dirname_alloc(variant->file_path); + set_cap(_metadata, CAP_DAC_OVERRIDE); /* * Don't check for error because the directory might already * have been removed (cf. release_inode test). */ - rmdir(self->dir_path); + rmdir(dir_path); clear_cap(_metadata, CAP_DAC_OVERRIDE); + free(dir_path); } - free(self->dir_path); - self->dir_path = NULL;

cleanup_layout(_metadata); } @@ -4830,7 +4836,10 @@ TEST_F_FORK(layout3_fs, tag_inode_dir_mnt)

TEST_F_FORK(layout3_fs, tag_inode_dir_child) { - layer3_fs_tag_inode(_metadata, self, variant, self->dir_path); + char *dir_path = dirname_alloc(variant->file_path); + + layer3_fs_tag_inode(_metadata, self, variant, dir_path); + free(dir_path); }

TEST_F_FORK(layout3_fs, tag_inode_file) @@ -4857,9 +4866,13 @@ TEST_F_FORK(layout3_fs, release_inodes) if (self->has_created_file) EXPECT_EQ(0, remove_path(variant->file_path));

- if (self->has_created_dir) + if (self->has_created_dir) { + char *dir_path = dirname_alloc(variant->file_path); + /* Don't check for error because of cgroup specificities. */ - remove_path(self->dir_path); + remove_path(dir_path); + free(dir_path); + }

ruleset_fd = create_ruleset(_metadata, LANDLOCK_ACCESS_FS_READ_DIR, layer1);

Replace a wrong EXPECT_GT(self->child_pid_exited, 0) with EXPECT_GE(), which will be actually tested on the parent and child sides with a following commit.

Cc: Shuah Khan skhan@linuxfoundation.org Reviewed-by: Kees Cook keescook@chromium.org Reviewed-by: Christian Brauner brauner@kernel.org Signed-off-by: Mickaël Salaün mic@digikod.net Link: https://lore.kernel.org/r/20240511171445.904356-8-mic@digikod.net ---

Changes since v1: * Extract change from a bigger patch (suggested by Kees). --- tools/testing/selftests/pidfd/pidfd_setns_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/pidfd/pidfd_setns_test.c b/tools/testing/selftests/pidfd/pidfd_setns_test.c index 6e2f2cd400ca..47746b0c6acd 100644 --- a/tools/testing/selftests/pidfd/pidfd_setns_test.c +++ b/tools/testing/selftests/pidfd/pidfd_setns_test.c @@ -158,7 +158,7 @@ FIXTURE_SETUP(current_nsset) /* Create task that exits right away. */ self->child_pid_exited = create_child(&self->child_pidfd_exited, CLONE_NEWUSER | CLONE_NEWNET); - EXPECT_GT(self->child_pid_exited, 0); + EXPECT_GE(self->child_pid_exited, 0);

if (self->child_pid_exited == 0) _exit(EXIT_SUCCESS);

Unconditionally share _metadata between all forked processes, which enables to actually catch errors which were previously ignored.

This is required for a following commit replacing vfork() with clone3() and CLONE_VFORK (i.e. not sharing the full memory) . It should also be useful to share _metadata to extend expectations to test process's forks. For instance, this change identified a wrong expectation in pidfd_setns_test.

Because this _metadata is used by the new XFAIL_ADD(), use a global pointer initialized in TEST_F(). This is OK because only XFAIL_ADD() use it, and XFAIL_ADD() already depends on TEST_F().

Cc: Jakub Kicinski kuba@kernel.org Cc: Shuah Khan skhan@linuxfoundation.org Cc: Will Drewry wad@chromium.org Reviewed-by: Kees Cook keescook@chromium.org Signed-off-by: Mickaël Salaün mic@digikod.net Link: https://lore.kernel.org/r/20240511171445.904356-9-mic@digikod.net ---

Changes since v6: * Use a global pointer per TEST_F() and complete build of the __test_xfail object in the xfail constructor to fix XFAIL_ADD(): https://lore.kernel.org/r/202405100339.vfBe0t9C-lkp@intel.com/

Changes since v4: * Reset _metadata's aborted and setup_completed fields.

Changes since v1: * Extract change from a bigger patch (suggested by Kees). --- tools/testing/selftests/kselftest_harness.h | 26 ++++++++++++--------- 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index 201040207c85..28415798fa60 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -430,19 +430,19 @@ static inline pid_t clone3_vfork(void) kill(getpid(), WTERMSIG(status)); \ __test_check_assert(_metadata); \ } \ - static struct __test_metadata \ - _##fixture_name##_##test_name##_object = { \ - .name = #test_name, \ - .fn = &wrapper_##fixture_name##_##test_name, \ - .fixture = &_##fixture_name##_fixture_object, \ - .termsig = signal, \ - .timeout = tmout, \ - .teardown_parent = false, \ - }; \ + static struct __test_metadata *_##fixture_name##_##test_name##_object; \ static void __attribute__((constructor)) \ _register_##fixture_name##_##test_name(void) \ { \ - __register_test(&_##fixture_name##_##test_name##_object); \ + struct __test_metadata *object = mmap(NULL, sizeof(*object), \ + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0); \ + object->name = #test_name; \ + object->fn = &wrapper_##fixture_name##_##test_name; \ + object->fixture = &_##fixture_name##_fixture_object; \ + object->termsig = signal; \ + object->timeout = tmout; \ + _##fixture_name##_##test_name##_object = object; \ + __register_test(object); \ } \ static void fixture_name##_##test_name( \ struct __test_metadata __attribute__((unused)) *_metadata, \ @@ -850,11 +850,12 @@ struct __test_xfail { { \ .fixture = &_##fixture_name##_fixture_object, \ .variant = &_##fixture_name##_##variant_name##_object, \ - .test = &_##fixture_name##_##test_name##_object, \ }; \ static void __attribute__((constructor)) \ _register_##fixture_name##_##variant_name##_##test_name##_xfail(void) \ { \ + _##fixture_name##_##variant_name##_##test_name##_xfail.test = \ + _##fixture_name##_##test_name##_object; \ __register_xfail(&_##fixture_name##_##variant_name##_##test_name##_xfail); \ }

@@ -1181,6 +1182,9 @@ void __run_test(struct __fixture_metadata *f, /* reset test struct */ t->exit_code = KSFT_PASS; t->trigger = 0; + t->aborted = false; + t->setup_completed = false; + memset(t->env, 0, sizeof(t->env)); memset(t->results->reason, 0, sizeof(t->results->reason));

if (asprintf(&test_name, "%s%s%s.%s", f->name,

If TEST_F() explicitly calls exit(code) with code different than 0, then _metadata->exit_code is set to this code (e.g. KVM_ONE_VCPU_TEST()). We need to keep in mind that _metadata->exit_code can be KSFT_SKIP while the process exit code is 0.

Cc: Jakub Kicinski kuba@kernel.org Cc: Kees Cook keescook@chromium.org Cc: Mark Brown broonie@kernel.org Cc: Shuah Khan shuah@kernel.org Cc: Will Drewry wad@chromium.org Reported-by: Sean Christopherson seanjc@google.com Tested-by: Sean Christopherson seanjc@google.com Closes: https://lore.kernel.org/r/ZjPelW6-AbtYvslu@google.com Fixes: 0710a1a73fb4 ("selftests/harness: Merge TEST_F_FORK() into TEST_F()") Signed-off-by: Mickaël Salaün mic@digikod.net Link: https://lore.kernel.org/r/20240511171445.904356-11-mic@digikod.net ---

Changes since v5: * Update commit message as suggested by Sean.

Changes since v4: * Check abort status when the grandchild exited. * Keep the _exit(0) calls because _metadata->exit_code is always checked. * Only set _metadata->exit_code to WEXITSTATUS() if it is not zero.

Changes since v3: * New patch mainly from Sean Christopherson. --- tools/testing/selftests/kselftest_harness.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index cbedb4a6cf7b..3c8f2965c285 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -462,9 +462,13 @@ static inline pid_t clone3_vfork(void) munmap(teardown, sizeof(*teardown)); \ if (self && fixture_name##_teardown_parent) \ munmap(self, sizeof(*self)); \ - if (!WIFEXITED(status) && WIFSIGNALED(status)) \ + if (WIFEXITED(status)) { \ + if (WEXITSTATUS(status)) \ + _metadata->exit_code = WEXITSTATUS(status); \ + } else if (WIFSIGNALED(status)) { \ /* Forward signal to __wait_for_test(). */ \ kill(getpid(), WTERMSIG(status)); \ + } \ __test_check_assert(_metadata); \ } \ static struct __test_metadata *_##fixture_name##_##test_name##_object; \