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Subject[PATCH v11 2/2] selftests: add tests for clone3() with *set_tid
Date
This tests clone3() with *set_tid to see if all desired PIDs are working
as expected. The tests are trying multiple invalid input parameters as
well as creating processes while specifying a certain PID in multiple
PID namespaces at the same time.

Additionally this moves common clone3() test code into clone3_selftests.h.

Signed-off-by: Adrian Reber <areber@redhat.com>
---
v9:
- applied all changes from Christian's review (except using the
NSpid: parsing code from selftests/pidfd/pidfd_fdinfo_test.c)

v10:
- added even more '\n' and include file fixes (Christian)

v11:
- added more return code checking at multiple places (Andrei)
- also add set_tid/set_tid_size to internal struct (Andrei)
---
tools/testing/selftests/clone3/.gitignore | 1 +
tools/testing/selftests/clone3/Makefile | 2 +-
tools/testing/selftests/clone3/clone3.c | 8 +-
.../selftests/clone3/clone3_clear_sighand.c | 20 +-
.../selftests/clone3/clone3_selftests.h | 35 ++
.../testing/selftests/clone3/clone3_set_tid.c | 381 ++++++++++++++++++
6 files changed, 421 insertions(+), 26 deletions(-)
create mode 100644 tools/testing/selftests/clone3/clone3_selftests.h
create mode 100644 tools/testing/selftests/clone3/clone3_set_tid.c

diff --git a/tools/testing/selftests/clone3/.gitignore b/tools/testing/selftests/clone3/.gitignore
index 2a30ae18b06e..0dc4f32c6cb8 100644
--- a/tools/testing/selftests/clone3/.gitignore
+++ b/tools/testing/selftests/clone3/.gitignore
@@ -1,2 +1,3 @@
clone3
clone3_clear_sighand
+clone3_set_tid
diff --git a/tools/testing/selftests/clone3/Makefile b/tools/testing/selftests/clone3/Makefile
index eb26eb793c80..cf976c732906 100644
--- a/tools/testing/selftests/clone3/Makefile
+++ b/tools/testing/selftests/clone3/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
CFLAGS += -g -I../../../../usr/include/

-TEST_GEN_PROGS := clone3 clone3_clear_sighand
+TEST_GEN_PROGS := clone3 clone3_clear_sighand clone3_set_tid

include ../lib.mk
diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selftests/clone3/clone3.c
index 0f8a9ef40117..4669b3d418e7 100644
--- a/tools/testing/selftests/clone3/clone3.c
+++ b/tools/testing/selftests/clone3/clone3.c
@@ -18,6 +18,7 @@
#include <sched.h>

#include "../kselftest.h"
+#include "clone3_selftests.h"

/*
* Different sizes of struct clone_args
@@ -35,11 +36,6 @@ enum test_mode {
CLONE3_ARGS_INVAL_EXIT_SIGNAL_NSIG,
};

-static pid_t raw_clone(struct clone_args *args, size_t size)
-{
- return syscall(__NR_clone3, args, size);
-}
-
static int call_clone3(uint64_t flags, size_t size, enum test_mode test_mode)
{
struct clone_args args = {
@@ -83,7 +79,7 @@ static int call_clone3(uint64_t flags, size_t size, enum test_mode test_mode)

memcpy(&args_ext.args, &args, sizeof(struct clone_args));

- pid = raw_clone((struct clone_args *)&args_ext, size);
+ pid = sys_clone3((struct clone_args *)&args_ext, size);
if (pid < 0) {
ksft_print_msg("%s - Failed to create new process\n",
strerror(errno));
diff --git a/tools/testing/selftests/clone3/clone3_clear_sighand.c b/tools/testing/selftests/clone3/clone3_clear_sighand.c
index 0d957be1bdc5..456783ad19d6 100644
--- a/tools/testing/selftests/clone3/clone3_clear_sighand.c
+++ b/tools/testing/selftests/clone3/clone3_clear_sighand.c
@@ -14,30 +14,12 @@
#include <sys/wait.h>

#include "../kselftest.h"
+#include "clone3_selftests.h"

#ifndef CLONE_CLEAR_SIGHAND
#define CLONE_CLEAR_SIGHAND 0x100000000ULL
#endif

-#ifndef __NR_clone3
-#define __NR_clone3 -1
-struct clone_args {
- __aligned_u64 flags;
- __aligned_u64 pidfd;
- __aligned_u64 child_tid;
- __aligned_u64 parent_tid;
- __aligned_u64 exit_signal;
- __aligned_u64 stack;
- __aligned_u64 stack_size;
- __aligned_u64 tls;
-};
-#endif
-
-static pid_t sys_clone3(struct clone_args *args, size_t size)
-{
- return syscall(__NR_clone3, args, size);
-}
-
static void test_clone3_supported(void)
{
pid_t pid;
diff --git a/tools/testing/selftests/clone3/clone3_selftests.h b/tools/testing/selftests/clone3/clone3_selftests.h
new file mode 100644
index 000000000000..1a270390766a
--- /dev/null
+++ b/tools/testing/selftests/clone3/clone3_selftests.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _CLONE3_SELFTESTS_H
+#define _CLONE3_SELFTESTS_H
+
+#define _GNU_SOURCE
+#include <sched.h>
+#include <stdint.h>
+#include <syscall.h>
+#include <linux/types.h>
+
+#define ptr_to_u64(ptr) ((__u64)((uintptr_t)(ptr)))
+
+#ifndef __NR_clone3
+#define __NR_clone3 -1
+struct clone_args {
+ __aligned_u64 flags;
+ __aligned_u64 pidfd;
+ __aligned_u64 child_tid;
+ __aligned_u64 parent_tid;
+ __aligned_u64 exit_signal;
+ __aligned_u64 stack;
+ __aligned_u64 stack_size;
+ __aligned_u64 tls;
+ __aligned_u64 set_tid;
+ __aligned_u64 set_tid_size;
+};
+#endif
+
+static pid_t sys_clone3(struct clone_args *args, size_t size)
+{
+ return syscall(__NR_clone3, args, size);
+}
+
+#endif /* _CLONE3_SELFTESTS_H */
diff --git a/tools/testing/selftests/clone3/clone3_set_tid.c b/tools/testing/selftests/clone3/clone3_set_tid.c
new file mode 100644
index 000000000000..3480e1c46983
--- /dev/null
+++ b/tools/testing/selftests/clone3/clone3_set_tid.c
@@ -0,0 +1,381 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Based on Christian Brauner's clone3() example.
+ * These tests are assuming to be running in the host's
+ * PID namespace.
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <sched.h>
+
+#include "../kselftest.h"
+#include "clone3_selftests.h"
+
+#ifndef MAX_PID_NS_LEVEL
+#define MAX_PID_NS_LEVEL 32
+#endif
+
+static int pipe_1[2];
+static int pipe_2[2];
+
+static int call_clone3_set_tid(pid_t *set_tid,
+ size_t set_tid_size,
+ int flags,
+ int expected_pid,
+ bool wait_for_it)
+{
+ int status;
+ pid_t pid = -1;
+
+ struct clone_args args = {
+ .flags = flags,
+ .exit_signal = SIGCHLD,
+ .set_tid = ptr_to_u64(set_tid),
+ .set_tid_size = set_tid_size,
+ };
+
+ pid = sys_clone3(&args, sizeof(struct clone_args));
+ if (pid < 0) {
+ ksft_print_msg("%s - Failed to create new process\n",
+ strerror(errno));
+ return -errno;
+ }
+
+ if (pid == 0) {
+ int ret;
+ char tmp = 0;
+ int exit_code = EXIT_SUCCESS;
+
+ ksft_print_msg("I am the child, my PID is %d (expected %d)\n",
+ getpid(), set_tid[0]);
+ if (wait_for_it) {
+ ksft_print_msg("[%d] Child is ready and waiting\n",
+ getpid());
+
+ /* Signal the parent that the child is ready */
+ close(pipe_1[0]);
+ ret = write(pipe_1[1], &tmp, 1);
+ if (ret != 1) {
+ ksft_print_msg(
+ "Writing to pipe returned %d", ret);
+ exit_code = EXIT_FAILURE;
+ }
+ close(pipe_1[1]);
+ close(pipe_2[1]);
+ ret = read(pipe_2[0], &tmp, 1);
+ if (ret != 1) {
+ ksft_print_msg(
+ "Reading from pipe returned %d", ret);
+ exit_code = EXIT_FAILURE;
+ }
+ close(pipe_2[0]);
+ }
+
+ if (set_tid[0] != getpid())
+ _exit(EXIT_FAILURE);
+ _exit(exit_code);
+ }
+
+ if (expected_pid == 0 || expected_pid == pid) {
+ ksft_print_msg("I am the parent (%d). My child's pid is %d\n",
+ getpid(), pid);
+ } else {
+ ksft_print_msg(
+ "Expected child pid %d does not match actual pid %d\n",
+ expected_pid, pid);
+ return -1;
+ }
+
+ if (waitpid(pid, &status, 0) < 0) {
+ ksft_print_msg("Child returned %s\n", strerror(errno));
+ return -errno;
+ }
+
+ if (!WIFEXITED(status))
+ return -1;
+
+ return WEXITSTATUS(status);
+}
+
+static void test_clone3_set_tid(pid_t *set_tid,
+ size_t set_tid_size,
+ int flags,
+ int expected,
+ int expected_pid,
+ bool wait_for_it)
+{
+ int ret;
+
+ ksft_print_msg(
+ "[%d] Trying clone3() with CLONE_SET_TID to %d and 0x%x\n",
+ getpid(), set_tid[0], flags);
+ ret = call_clone3_set_tid(set_tid, set_tid_size, flags, expected_pid,
+ wait_for_it);
+ ksft_print_msg(
+ "[%d] clone3() with CLONE_SET_TID %d says :%d - expected %d\n",
+ getpid(), set_tid[0], ret, expected);
+ if (ret != expected)
+ ksft_test_result_fail(
+ "[%d] Result (%d) is different than expected (%d)\n",
+ getpid(), ret, expected);
+ else
+ ksft_test_result_pass(
+ "[%d] Result (%d) matches expectation (%d)\n",
+ getpid(), ret, expected);
+}
+int main(int argc, char *argv[])
+{
+ FILE *f;
+ char buf;
+ char *line;
+ int status;
+ int ret = -1;
+ size_t len = 0;
+ int pid_max = 0;
+ uid_t uid = getuid();
+ char proc_path[100] = {0};
+ pid_t pid, ns1, ns2, ns3, ns_pid;
+ pid_t set_tid[MAX_PID_NS_LEVEL * 2];
+
+ if (pipe(pipe_1) < 0 || pipe(pipe_2) < 0)
+ ksft_exit_fail_msg("pipe() failed\n");
+
+ ksft_print_header();
+ ksft_set_plan(27);
+
+ f = fopen("/proc/sys/kernel/pid_max", "r");
+ if (f == NULL)
+ ksft_exit_fail_msg(
+ "%s - Could not open /proc/sys/kernel/pid_max\n",
+ strerror(errno));
+ fscanf(f, "%d", &pid_max);
+ fclose(f);
+ ksft_print_msg("/proc/sys/kernel/pid_max %d\n", pid_max);
+
+ /* Try invalid settings */
+ memset(&set_tid, 0, sizeof(set_tid));
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL + 1, 0, -EINVAL, 0, 0);
+
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2, 0, -EINVAL, 0, 0);
+
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2 + 1, 0,
+ -EINVAL, 0, 0);
+
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 42, 0, -EINVAL, 0, 0);
+
+ /*
+ * This can actually work if this test running in a MAX_PID_NS_LEVEL - 1
+ * nested PID namespace.
+ */
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL - 1, 0, -EINVAL, 0, 0);
+
+ memset(&set_tid, 0xff, sizeof(set_tid));
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL + 1, 0, -EINVAL, 0, 0);
+
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2, 0, -EINVAL, 0, 0);
+
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2 + 1, 0,
+ -EINVAL, 0, 0);
+
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 42, 0, -EINVAL, 0, 0);
+
+ /*
+ * This can actually work if this test running in a MAX_PID_NS_LEVEL - 1
+ * nested PID namespace.
+ */
+ test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL - 1, 0, -EINVAL, 0, 0);
+
+ memset(&set_tid, 0, sizeof(set_tid));
+ /* Try with an invalid PID */
+ set_tid[0] = 0;
+ test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
+
+ set_tid[0] = -1;
+ test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
+
+ /* Claim that the set_tid array actually contains 2 elements. */
+ test_clone3_set_tid(set_tid, 2, 0, -EINVAL, 0, 0);
+
+ /* Try it in a new PID namespace */
+ if (uid == 0)
+ test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, -EINVAL, 0, 0);
+ else
+ ksft_test_result_skip("Clone3() with set_tid requires root\n");
+
+ /* Try with a valid PID (1) this should return -EEXIST. */
+ set_tid[0] = 1;
+ if (uid == 0)
+ test_clone3_set_tid(set_tid, 1, 0, -EEXIST, 0, 0);
+ else
+ ksft_test_result_skip("Clone3() with set_tid requires root\n");
+
+ /* Try it in a new PID namespace */
+ if (uid == 0)
+ test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, 0, 0, 0);
+ else
+ ksft_test_result_skip("Clone3() with set_tid requires root\n");
+
+ /* pid_max should fail everywhere */
+ set_tid[0] = pid_max;
+ test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
+
+ if (uid == 0)
+ test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, -EINVAL, 0, 0);
+ else
+ ksft_test_result_skip("Clone3() with set_tid requires root\n");
+
+ if (uid != 0) {
+ /*
+ * All remaining tests require root. Tell the framework
+ * that all those tests are skipped as non-root.
+ */
+ ksft_cnt.ksft_xskip += ksft_plan - ksft_test_num();
+ goto out;
+ }
+
+ /* Find the current active PID */
+ pid = fork();
+ if (pid == 0) {
+ ksft_print_msg("Child has PID %d\n", getpid());
+ _exit(EXIT_SUCCESS);
+ }
+ if (waitpid(pid, &status, 0) < 0)
+ ksft_exit_fail_msg("Waiting for child %d failed", pid);
+
+ /* After the child has finished, its PID should be free. */
+ set_tid[0] = pid;
+ test_clone3_set_tid(set_tid, 1, 0, 0, 0, 0);
+
+ /* This should fail as there is no PID 1 in that namespace */
+ test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, -EINVAL, 0, 0);
+
+ /*
+ * Creating a process with PID 1 in the newly created most nested
+ * PID namespace and PID 'pid' in the parent PID namespace. This
+ * needs to work.
+ */
+ set_tid[0] = 1;
+ set_tid[1] = pid;
+ test_clone3_set_tid(set_tid, 2, CLONE_NEWPID, 0, pid, 0);
+
+ ksft_print_msg("unshare PID namespace\n");
+ if (unshare(CLONE_NEWPID) == -1)
+ ksft_exit_fail_msg("unshare(CLONE_NEWPID) failed: %s\n",
+ strerror(errno));
+
+ set_tid[0] = pid;
+
+ /* This should fail as there is no PID 1 in that namespace */
+ test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
+
+ /* Let's create a PID 1 */
+ ns_pid = fork();
+ if (ns_pid == 0) {
+ ksft_print_msg("Child in PID namespace has PID %d\n", getpid());
+ set_tid[0] = 2;
+ test_clone3_set_tid(set_tid, 1, 0, 0, 2, 0);
+
+ set_tid[0] = 1;
+ set_tid[1] = -1;
+ set_tid[2] = pid;
+ /* This should fail as there is invalid PID at level '1'. */
+ test_clone3_set_tid(set_tid, 3, CLONE_NEWPID, -EINVAL, 0, 0);
+
+ set_tid[0] = 1;
+ set_tid[1] = 42;
+ set_tid[2] = pid;
+ /*
+ * This should fail as there are not enough active PID
+ * namespaces. Again assuming this is running in the host's
+ * PID namespace. Not yet nested.
+ */
+ test_clone3_set_tid(set_tid, 4, CLONE_NEWPID, -EINVAL, 0, 0);
+
+ /*
+ * This should work and from the parent we should see
+ * something like 'NSpid: pid 42 1'.
+ */
+ test_clone3_set_tid(set_tid, 3, CLONE_NEWPID, 0, 42, true);
+
+ _exit(ksft_cnt.ksft_pass);
+ }
+
+ close(pipe_1[1]);
+ close(pipe_2[0]);
+ while (read(pipe_1[0], &buf, 1) > 0) {
+ ksft_print_msg("[%d] Child is ready and waiting\n", getpid());
+ break;
+ }
+
+ snprintf(proc_path, sizeof(proc_path), "/proc/%d/status", pid);
+ f = fopen(proc_path, "r");
+ if (f == NULL)
+ ksft_exit_fail_msg(
+ "%s - Could not open %s\n",
+ strerror(errno), proc_path);
+
+ while (getline(&line, &len, f) != -1) {
+ if (strstr(line, "NSpid")) {
+ int i;
+
+ /* Verify that all generated PIDs are as expected. */
+ i = sscanf(line, "NSpid:\t%d\t%d\t%d",
+ &ns3, &ns2, &ns1);
+ if (i != 3) {
+ ksft_print_msg(
+ "Unexpected 'NSPid:' entry: %s",
+ line);
+ ns1 = ns2 = ns3 = 0;
+ }
+ break;
+ }
+ }
+ fclose(f);
+ free(line);
+ close(pipe_2[0]);
+
+ /* Tell the clone3()'d child to finish. */
+ write(pipe_2[1], &buf, 1);
+ close(pipe_2[1]);
+
+ if (waitpid(ns_pid, &status, 0) < 0) {
+ ksft_print_msg("Child returned %s\n", strerror(errno));
+ ret = -errno;
+ goto out;
+ }
+
+ if (!WIFEXITED(status))
+ ksft_test_result_fail("Child error\n");
+
+ if (WEXITSTATUS(status))
+ /*
+ * Update the number of total tests with the tests from the
+ * child processes.
+ */
+ ksft_cnt.ksft_pass = WEXITSTATUS(status);
+
+ if (ns3 == pid && ns2 == 42 && ns1 == 1)
+ ksft_test_result_pass(
+ "PIDs in all namespaces as expected (%d,%d,%d)\n",
+ ns3, ns2, ns1);
+ else
+ ksft_test_result_fail(
+ "PIDs in all namespaces not as expected (%d,%d,%d)\n",
+ ns3, ns2, ns1);
+out:
+ ret = 0;
+
+ return !ret ? ksft_exit_pass() : ksft_exit_fail();
+}
--
2.23.0
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