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From:   Adrian Reber <areber@redhat.com>
To:     Christian Brauner <christian.brauner@ubuntu.com>,
        Eric Biederman <ebiederm@xmission.com>,
        Pavel Emelyanov <ovzxemul@gmail.com>,
        Jann Horn <jannh@google.com>, Oleg Nesterov <oleg@redhat.com>,
        Dmitry Safonov <0x7f454c46@gmail.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc:     linux-kernel@vger.kernel.org, Andrei Vagin <avagin@gmail.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Radostin Stoyanov <rstoyanov1@gmail.com>,
        Adrian Reber <areber@redhat.com>
Subject: [PATCH v9 2/2] selftests: add tests for clone3() with *set_tid
Date:   Thu, 14 Nov 2019 08:07:09 +0100
Message-Id: <20191114070709.1504202-2-areber@redhat.com>
In-Reply-To: <20191114070709.1504202-1-areber@redhat.com>
References: <20191114070709.1504202-1-areber@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=WINDOWS-1252
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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)
---
 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       |  29 ++
 .../testing/selftests/clone3/clone3_set_tid.c | 355 ++++++++++++++++++
 6 files changed, 389 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/self=
tests/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/selfte=
sts/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 +=3D -g -I../../../../usr/include/
=20
-TEST_GEN_PROGS :=3D clone3 clone3_clear_sighand
+TEST_GEN_PROGS :=3D clone3 clone3_clear_sighand clone3_set_tid
=20
 include ../lib.mk
diff --git a/tools/testing/selftests/clone3/clone3.c b/tools/testing/selfte=
sts/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>
=20
 #include "../kselftest.h"
+#include "clone3_selftests.h"
=20
 /*
  * Different sizes of struct clone_args
@@ -35,11 +36,6 @@ enum test_mode {
 =09CLONE3_ARGS_INVAL_EXIT_SIGNAL_NSIG,
 };
=20
-static pid_t raw_clone(struct clone_args *args, size_t size)
-{
-=09return syscall(__NR_clone3, args, size);
-}
-
 static int call_clone3(uint64_t flags, size_t size, enum test_mode test_mo=
de)
 {
 =09struct clone_args args =3D {
@@ -83,7 +79,7 @@ static int call_clone3(uint64_t flags, size_t size, enum =
test_mode test_mode)
=20
 =09memcpy(&args_ext.args, &args, sizeof(struct clone_args));
=20
-=09pid =3D raw_clone((struct clone_args *)&args_ext, size);
+=09pid =3D sys_clone3((struct clone_args *)&args_ext, size);
 =09if (pid < 0) {
 =09=09ksft_print_msg("%s - Failed to create new process\n",
 =09=09=09=09strerror(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>
=20
 #include "../kselftest.h"
+#include "clone3_selftests.h"
=20
 #ifndef CLONE_CLEAR_SIGHAND
 #define CLONE_CLEAR_SIGHAND 0x100000000ULL
 #endif
=20
-#ifndef __NR_clone3
-#define __NR_clone3 -1
-struct clone_args {
-=09__aligned_u64 flags;
-=09__aligned_u64 pidfd;
-=09__aligned_u64 child_tid;
-=09__aligned_u64 parent_tid;
-=09__aligned_u64 exit_signal;
-=09__aligned_u64 stack;
-=09__aligned_u64 stack_size;
-=09__aligned_u64 tls;
-};
-#endif
-
-static pid_t sys_clone3(struct clone_args *args, size_t size)
-{
-=09return syscall(__NR_clone3, args, size);
-}
-
 static void test_clone3_supported(void)
 {
 =09pid_t pid;
diff --git a/tools/testing/selftests/clone3/clone3_selftests.h b/tools/test=
ing/selftests/clone3/clone3_selftests.h
new file mode 100644
index 000000000000..793e719d781d
--- /dev/null
+++ b/tools/testing/selftests/clone3/clone3_selftests.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _CLONE3_SELFTESTS_H
+#define _CLONE3_SELFTESTS_H
+
+#include <stdint.h>
+
+#define ptr_to_u64(ptr) ((__u64)((uintptr_t)(ptr)))
+
+#ifndef __NR_clone3
+#define __NR_clone3 -1
+struct clone_args {
+=09__aligned_u64 flags;
+=09__aligned_u64 pidfd;
+=09__aligned_u64 child_tid;
+=09__aligned_u64 parent_tid;
+=09__aligned_u64 exit_signal;
+=09__aligned_u64 stack;
+=09__aligned_u64 stack_size;
+=09__aligned_u64 tls;
+};
+#endif
+
+static pid_t sys_clone3(struct clone_args *args, size_t size)
+{
+=09return syscall(__NR_clone3, args, size);
+}
+
+#endif /* _CLONE3_SELFTESTS_H */
diff --git a/tools/testing/selftests/clone3/clone3_set_tid.c b/tools/testin=
g/selftests/clone3/clone3_set_tid.c
new file mode 100644
index 000000000000..e73d01aea5db
--- /dev/null
+++ b/tools/testing/selftests/clone3/clone3_set_tid.c
@@ -0,0 +1,355 @@
+// 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,
+=09=09=09       size_t set_tid_size,
+=09=09=09       int flags,
+=09=09=09       int expected_pid,
+=09=09=09       bool wait_for_it)
+{
+=09int status;
+=09int ret =3D 0;
+=09pid_t pid =3D -1;
+
+=09struct clone_args args =3D {
+=09=09.flags =3D flags,
+=09=09.exit_signal =3D SIGCHLD,
+=09=09.set_tid =3D ptr_to_u64(set_tid),
+=09=09.set_tid_size =3D set_tid_size,
+=09};
+
+=09pid =3D sys_clone3(&args, sizeof(struct clone_args));
+=09if (pid < 0) {
+=09=09ksft_print_msg("%s - Failed to create new process\n",
+=09=09=09       strerror(errno));
+=09=09return -errno;
+=09}
+
+=09if (pid =3D=3D 0) {
+=09=09char tmp =3D 0;
+
+=09=09ksft_print_msg("I am the child, my PID is %d (expected %d)\n",
+=09=09=09       getpid(), set_tid[0]);
+=09=09if (wait_for_it) {
+=09=09=09ksft_print_msg("[%d] Child is ready and waiting\n",
+=09=09=09=09       getpid());
+
+=09=09=09/* Signal the parent that the child is ready */
+=09=09=09close(pipe_1[0]);
+=09=09=09write(pipe_1[1], &tmp, 1);
+=09=09=09close(pipe_1[1]);
+=09=09=09close(pipe_2[1]);
+=09=09=09read(pipe_2[0], &tmp, 1);
+=09=09=09close(pipe_2[0]);
+=09=09}
+
+=09=09if (set_tid[0] !=3D getpid())
+=09=09=09_exit(EXIT_FAILURE);
+=09=09_exit(EXIT_SUCCESS);
+=09}
+
+=09if (expected_pid =3D=3D 0 || expected_pid =3D=3D pid) {
+=09=09ksft_print_msg("I am the parent (%d). My child's pid is %d\n",
+=09=09=09       getpid(), pid);
+=09} else {
+=09=09ksft_print_msg(
+=09=09=09"Expected child pid %d does not match actual pid %d\n",
+=09=09=09expected_pid, pid);
+=09=09ret =3D -1;
+=09}
+
+=09if (wait(&status) < 0) {
+=09=09ksft_print_msg("Child returned %s\n", strerror(errno));
+=09=09return -errno;
+=09}
+
+=09if (!WIFEXITED(status))
+=09=09return -1;
+
+=09return WEXITSTATUS(status);
+}
+
+static void test_clone3_set_tid(pid_t *set_tid,
+=09=09=09=09size_t set_tid_size,
+=09=09=09=09int flags,
+=09=09=09=09int expected,
+=09=09=09=09int expected_pid,
+=09=09=09=09bool wait_for_it)
+{
+=09int ret;
+
+=09ksft_print_msg(
+=09=09"[%d] Trying clone3() with CLONE_SET_TID to %d and 0x%x\n",
+=09=09getpid(), set_tid[0], flags);
+=09ret =3D call_clone3_set_tid(set_tid, set_tid_size, flags, expected_pid,
+=09=09=09=09  wait_for_it);
+=09ksft_print_msg(
+=09=09"[%d] clone3() with CLONE_SET_TID %d says :%d - expected %d\n",
+=09=09getpid(), set_tid[0], ret, expected);
+=09if (ret !=3D expected)
+=09=09ksft_test_result_fail(
+=09=09=09"[%d] Result (%d) is different than expected (%d)\n",
+=09=09=09getpid(), ret, expected);
+=09else
+=09=09ksft_test_result_pass(
+=09=09=09"[%d] Result (%d) matches expectation (%d)\n",
+=09=09=09getpid(), ret, expected);
+}
+int main(int argc, char *argv[])
+{
+=09FILE *f;
+=09char buf;
+=09char *line;
+=09int status;
+=09int ret =3D -1;
+=09size_t len =3D 0;
+=09int pid_max =3D 0;
+=09uid_t uid =3D getuid();
+=09char proc_path[100] =3D {0};
+=09pid_t pid, ns1, ns2, ns3, ns_pid;
+=09pid_t set_tid[MAX_PID_NS_LEVEL * 2];
+
+=09if (pipe(pipe_1) < 0 || pipe(pipe_2) < 0)
+=09=09ksft_exit_fail_msg("pipe() failed\n");
+
+=09ksft_print_header();
+=09ksft_set_plan(26);
+
+=09f =3D fopen("/proc/sys/kernel/pid_max", "r");
+=09if (f =3D=3D NULL)
+=09=09ksft_exit_fail_msg(
+=09=09=09"%s - Could not open /proc/sys/kernel/pid_max\n",
+=09=09=09strerror(errno));
+=09fscanf(f, "%d", &pid_max);
+=09fclose(f);
+=09ksft_print_msg("/proc/sys/kernel/pid_max %d\n", pid_max);
+
+=09/* Try invalid settings */
+=09memset(&set_tid, 0, sizeof(set_tid));
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL + 1, 0, -EINVAL, 0, 0);
+
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2, 0, -EINVAL, 0, 0);
+
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2 + 1, 0,
+=09=09=09-EINVAL, 0, 0);
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 42, 0, -EINVAL, 0, 0);
+
+=09/*
+=09 * This can actually work if this test running in a MAX_PID_NS_LEVEL - =
1
+=09 * nested PID namespace.
+=09 */
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL - 1, 0, -EINVAL, 0, 0);
+
+=09memset(&set_tid, 0xff, sizeof(set_tid));
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL + 1, 0, -EINVAL, 0, 0);
+
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2, 0, -EINVAL, 0, 0);
+
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 2 + 1, 0,
+=09=09=09-EINVAL, 0, 0);
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL * 42, 0, -EINVAL, 0, 0);
+=09/*
+=09 * This can actually work if this test running in a MAX_PID_NS_LEVEL - =
1
+=09 * nested PID namespace.
+=09 */
+=09test_clone3_set_tid(set_tid, MAX_PID_NS_LEVEL - 1, 0, -EINVAL, 0, 0);
+
+=09memset(&set_tid, 0, sizeof(set_tid));
+=09/* Try with an invalid PID */
+=09set_tid[0] =3D 0;
+=09test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
+=09set_tid[0] =3D -1;
+=09test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
+=09/* Claim that the set_tid array actually contains 2 elements. */
+=09test_clone3_set_tid(set_tid, 2, 0, -EINVAL, 0, 0);
+=09/* Try it in a new PID namespace */
+=09if (uid =3D=3D 0)
+=09=09test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, -EINVAL, 0, 0);
+=09else
+=09=09ksft_test_result_skip("Clone3() with set_tid requires root\n");
+
+=09/*
+=09 * Try with a valid PID (1) but as non-root. This should fail
+=09 * with -EPERM if running in the initial user namespace.
+=09 * As root it should tell us -EEXIST.
+=09 */
+=09set_tid[0] =3D 1;
+=09if (uid =3D=3D 0)
+=09=09test_clone3_set_tid(set_tid, 1, 0, -EEXIST, 0, 0);
+=09else
+=09=09ksft_test_result_skip("Clone3() with set_tid requires root\n");
+
+=09/* Try it in a new PID namespace */
+=09if (uid =3D=3D 0)
+=09=09test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, 0, 0, 0);
+=09else
+=09=09ksft_test_result_skip("Clone3() with set_tid requires root\n");
+
+=09/* pid_max should fail everywhere */
+=09set_tid[0] =3D pid_max;
+=09test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
+=09if (uid =3D=3D 0)
+=09=09test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, -EINVAL, 0, 0);
+=09else
+=09=09ksft_test_result_skip("Clone3() with set_tid requires root\n");
+
+=09if (uid !=3D 0) {
+=09=09/*
+=09=09 * All remaining tests require root. Tell the framework
+=09=09 * that all those tests are skipped as non-root.
+=09=09 */
+=09=09ksft_cnt.ksft_xskip +=3D ksft_plan - ksft_test_num();
+=09=09goto out;
+=09}
+
+=09/* Find the current active PID */
+=09pid =3D fork();
+=09if (pid =3D=3D 0) {
+=09=09ksft_print_msg("Child has PID %d\n", getpid());
+=09=09_exit(EXIT_SUCCESS);
+=09}
+=09(void)wait(NULL);
+
+=09/* After the child has finished, its PID should be free. */
+=09set_tid[0] =3D pid;
+=09test_clone3_set_tid(set_tid, 1, 0, 0, 0, 0);
+
+=09/* This should fail as there is no PID 1 in that namespace */
+=09test_clone3_set_tid(set_tid, 1, CLONE_NEWPID, -EINVAL, 0, 0);
+
+=09/*
+=09 * Creating a process with PID 1 in the newly created most nested
+=09 * PID namespace and PID 'pid' in the parent PID namespace. This
+=09 * needs to work.
+=09 */
+=09set_tid[0] =3D 1;
+=09set_tid[1] =3D pid;
+=09test_clone3_set_tid(set_tid, 2, CLONE_NEWPID, 0, pid, 0);
+
+=09ksft_print_msg("unshare PID namespace\n");
+=09if (unshare(CLONE_NEWPID) =3D=3D -1)
+=09=09ksft_exit_fail_msg("unshare(CLONE_NEWPID) failed: %s\n",
+=09=09=09=09strerror(errno));
+
+=09set_tid[0] =3D pid;
+
+=09/* This should fail as there is no PID 1 in that namespace */
+=09test_clone3_set_tid(set_tid, 1, 0, -EINVAL, 0, 0);
+
+=09/* Let's create a PID 1 */
+=09ns_pid =3D fork();
+=09if (ns_pid =3D=3D 0) {
+=09=09ksft_print_msg("Child in PID namespace has PID %d\n", getpid());
+=09=09set_tid[0] =3D 2;
+=09=09test_clone3_set_tid(set_tid, 1, 0, 0, 2, 0);
+=09=09set_tid[0] =3D 1;
+=09=09set_tid[1] =3D 42;
+=09=09set_tid[2] =3D pid;
+=09=09/*
+=09=09 * This should fail as there are not enough active PID
+=09=09 * namespaces. Again assuming this is running in the host's
+=09=09 * PID namespace. Not yet nested.
+=09=09 */
+=09=09test_clone3_set_tid(set_tid, 4, CLONE_NEWPID, -EINVAL, 0, 0);
+
+=09=09/*
+=09=09 * This should work and from the parent we should see
+=09=09 * something like 'NSpid:=09pid=0942=091'.
+=09=09 */
+=09=09test_clone3_set_tid(set_tid, 3, CLONE_NEWPID, 0, 42, 1);
+
+=09=09_exit(ksft_cnt.ksft_pass);
+=09}
+
+=09close(pipe_1[1]);
+=09close(pipe_2[0]);
+=09while (read(pipe_1[0], &buf, 1) > 0) {
+=09=09ksft_print_msg("[%d] Child is ready and waiting\n", getpid());
+=09=09break;
+=09}
+
+=09snprintf(proc_path, sizeof(proc_path), "/proc/%d/status", pid);
+=09f =3D fopen(proc_path, "r");
+=09if (f =3D=3D NULL)
+=09=09ksft_exit_fail_msg(
+=09=09=09"%s - Could not open %s\n",
+=09=09=09strerror(errno), proc_path);
+
+=09while (getline(&line, &len, f) !=3D -1) {
+=09=09if (strstr(line, "NSpid")) {
+=09=09=09int i;
+
+=09=09=09/* Verify that all generated PIDs are as expected. */
+=09=09=09i =3D sscanf(line, "NSpid:\t%d\t%d\t%d",
+=09=09=09=09   &ns3, &ns2, &ns1);
+=09=09=09if (i !=3D 3)
+=09=09=09=09ns1 =3D ns2 =3D ns3 =3D 0;
+=09=09=09break;
+=09=09}
+=09}
+=09fclose(f);
+=09free(line);
+=09close(pipe_2[0]);
+
+=09/* Tell the clone3()'d child to finish. */
+=09write(pipe_2[1], &buf, 1);
+=09close(pipe_2[1]);
+
+=09if (wait(&status) < 0) {
+=09=09ksft_print_msg("Child returned %s\n", strerror(errno));
+=09=09ret =3D -errno;
+=09=09goto out;
+=09}
+
+=09if (!WIFEXITED(status))
+=09=09ksft_test_result_fail("Child error\n");
+
+=09if (WEXITSTATUS(status))
+=09=09/*
+=09=09 * Update the number of total tests with the tests from the
+=09=09 * child processes.
+=09=09 */
+=09=09ksft_cnt.ksft_pass =3D WEXITSTATUS(status);
+
+=09if (ns3 =3D=3D pid && ns2 =3D=3D 42 && ns1 =3D=3D 1)
+=09=09ksft_test_result_pass(
+=09=09=09"PIDs in all namespaces as expected (%d,%d,%d)\n",
+=09=09=09ns3, ns2, ns1);
+=09else
+=09=09ksft_test_result_fail(
+=09=09=09"PIDs in all namespaces not as expected (%d,%d,%d)\n",
+=09=09=09ns3, ns2, ns1);
+out:
+=09ret =3D 0;
+
+=09return !ret ? ksft_exit_pass() : ksft_exit_fail();
+}
--=20
2.23.0