From 4362ddaba8634a5ac6b4add0eaf25eec5f7315f5 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?=C3=81kos=20Uzonyi?= <uzonyi.akos@gmail.com>

Date: Fri, 26 Jun 2020 20:13:28 +0200

Subject: [PATCH 137/138] Implement testing framework for pidns

* tests/pidns.c: New file.

* tests/pidns.h: New file.

* tests/Makefile.am (libtests_a_SOURCES): Add pidns.c, pidns.h.

* tests/init.sh (test_pidns, test_pidns_run_strace): New functions.

---

 tests/Makefile.am |   2 +

 tests/init.sh     |  30 +++++++

 tests/pidns.c     | 237 ++++++++++++++++++++++++++++++++++++++++++++++++++++++

 tests/pidns.h     |  56 +++++++++++++

 4 files changed, 325 insertions(+)

 create mode 100644 tests/pidns.c

 create mode 100644 tests/pidns.h

Index: strace-5.7/tests/Makefile.am

===================================================================

--- strace-5.7.orig/tests/Makefile.am	2020-09-09 19:32:50.846965498 +0200

+++ strace-5.7/tests/Makefile.am	2020-09-09 19:49:54.008575349 +0200

@@ -44,6 +44,8 @@

 	libsocketcall.c \

 	lock_file.c \

 	overflowuid.c \

+	pidns.c \

+	pidns.h \

 	pipe_maxfd.c \

 	print_quoted_string.c \

 	print_time.c \

Index: strace-5.7/tests/init.sh

===================================================================

--- strace-5.7.orig/tests/init.sh	2020-09-09 19:32:50.846965498 +0200

+++ strace-5.7/tests/init.sh	2020-09-09 19:49:54.008575349 +0200

@@ -387,6 +387,36 @@

 	test_pure_prog_set "$@" < "$srcdir/$NAME.in"

 }

+test_pidns_run_strace()

+{

+	local parent_pid init_pid

+

+	check_prog tail

+	check_prog cut

+	check_prog grep

+

+	run_prog > /dev/null

+	run_strace --pidns-translation -f $@ $args > "$EXP"

+

+	# filter out logs made by the parent or init process of the pidns test

+	parent_pid="$(tail -n 2 $LOG | head -n 1 | cut -d' ' -f1)"

+	init_pid="$(tail -n 1 $LOG | cut -d' ' -f1)"

+	grep -E -v "^($parent_pid|$init_pid) " "$LOG" > "$OUT"

+	match_diff "$OUT" "$EXP"

+}

+

+test_pidns()

+{

+	check_prog unshare

+	unshare -Urpf true || framework_skip_ "unshare -Urpf true failed"

+

+	test_pidns_run_strace "$@"

+

+	# test PID translation when /proc is mounted from an other namespace

+	STRACE="unshare -Urpf $STRACE"

+	test_pidns_run_strace "$@"

+}

+

 check_prog cat

 check_prog rm

Index: strace-5.7/tests/pidns.c

===================================================================

--- /dev/null	1970-01-01 00:00:00.000000000 +0000

+++ strace-5.7/tests/pidns.c	2020-09-09 19:49:54.009575350 +0200

@@ -0,0 +1,237 @@

+/*

+ * Testing framework for PID namespace translation

+ *

+ * Copyright (c) 2020 Ákos Uzonyi <uzonyi.akos@gmail.com>

+ * All rights reserved.

+ *

+ * SPDX-License-Identifier: LGPL-2.1-or-later

+ */

+#include "tests.h"

+#include "pidns.h"

+#include "nsfs.h"

+

+#include <errno.h>

+#include <stdio.h>

+#include <string.h>

+#include <sys/types.h>

+#include <signal.h>

+#include <stdlib.h>

+#include <sched.h>

+#include <unistd.h>

+#include <sys/wait.h>

+#include <linux/sched.h>

+#include <fcntl.h>

+#include <sys/ioctl.h>

+

+#ifndef CLONE_NEWUSER

+# define CLONE_NEWUSER 0x10000000

+#endif

+

+#ifndef CLONE_NEWPID

+# define CLONE_NEWPID 0x20000000

+#endif

+

+static bool pidns_translation = false;

+static bool pidns_unshared = false;

+

+/* Our PIDs in strace's namespace */

+static pid_t pidns_strace_ids[PT_COUNT];

+

+void

+pidns_print_leader(void)

+{

+	if (pidns_translation)

+		printf("%-5d ", pidns_strace_ids[PT_TID]);

+}

+

+const char *

+pidns_pid2str(enum pid_type type)

+{

+	static const char format[] = " /* %d in strace's PID NS */";

+	static char buf[PT_COUNT][sizeof(format) + sizeof(int) * 3];

+

+	if (type < 0 || type >= PT_COUNT)

+		return "";

+

+	if (!pidns_unshared || !pidns_strace_ids[type])

+		return "";

+

+	snprintf(buf[type], sizeof(buf[type]), format, pidns_strace_ids[type]);

+	return buf[type];

+}

+

+/**

+ * This function is like fork, but does a few more things. It sets up the

+ * child's PGID and SID according to the parameters. Also it fills the

+ * pidns_strace_ids array in the child's memory with the PIDs of the child in

+ * parent's PID namespace. In the parent it waits for the child to terminate

+ * (but leaves the zombie to use it later as a process group). If the child

+ * terminates with nonzero exit status, the test is failed.

+ *

+ * @param pgid     The process group the child should be moved to. It's expected

+ *                 to be a PID of a zombie process (will be reaped). If

+ *                 negative, leave the child in the process group of the parent.

+ *                 If 0, move the process to its own process group.

+ * @param new_sid  Wheather child should be moved to a new session.

+ */

+static pid_t

+pidns_fork(pid_t pgid, bool new_sid)

+{

+	int strace_ids_pipe[2];

+	if (pipe(strace_ids_pipe) < 0)

+		perror_msg_and_fail("pipe");

+

+	fflush(stdout);

+	pid_t pid = fork();

+	if (pid < 0)

+		perror_msg_and_fail("fork");

+

+	if (!pid) {

+		close(strace_ids_pipe[1]);

+

+		ssize_t len = read(strace_ids_pipe[0], pidns_strace_ids,

+				sizeof(pidns_strace_ids));

+		if (len < 0)

+			perror_msg_and_fail("read");

+		if (len != sizeof(pidns_strace_ids))

+			error_msg_and_fail("read returned < sizeof(pidns_strace_ids)");

+

+		close(strace_ids_pipe[0]);

+

+		if (pidns_strace_ids[PT_SID])

+			setsid();

+

+		return 0;

+	}

+

+	pidns_strace_ids[PT_TID] = pid;

+	pidns_strace_ids[PT_TGID] = pid;

+	pidns_strace_ids[PT_PGID] = 0;

+	pidns_strace_ids[PT_SID] = 0;

+

+	if (!pgid)

+		pgid = pid;

+

+	if (pgid > 0) {

+		if (setpgid(pid, pgid) < 0)

+			perror_msg_and_fail("setpgid");

+

+		pidns_strace_ids[PT_PGID] = pgid;

+	}

+

+	/* Reap group leader to test PGID decoding */

+	if (pgid > 0 && pgid != pid) {

+		int ret = waitpid(pgid, NULL, WNOHANG);

+		if (ret < 0)

+			perror_msg_and_fail("wait");

+		if (!ret)

+			error_msg_and_fail("could not reap group leader");

+	}

+

+	if (new_sid) {

+		pidns_strace_ids[PT_SID] = pid;

+		pidns_strace_ids[PT_PGID] = pid;

+	}

+

+	ssize_t len = write(strace_ids_pipe[1], pidns_strace_ids,

+	                     sizeof(pidns_strace_ids));

+	if (len < 0)

+		perror_msg_and_fail("write");

+	if (len != sizeof(pidns_strace_ids))

+		error_msg_and_fail("write returned < sizeof(pidns_strace_ids)");

+

+	close(strace_ids_pipe[0]);

+	close(strace_ids_pipe[1]);

+

+	/* WNOWAIT: leave the zombie, to be able to use it as a process group */

+	siginfo_t siginfo;

+	if (waitid(P_PID, pid, &siginfo, WEXITED | WNOWAIT) < 0)

+		perror_msg_and_fail("wait");

+	if (siginfo.si_code != CLD_EXITED || siginfo.si_status)

+		error_msg_and_fail("child terminated with nonzero exit status");

+

+	return pid;

+}

+

+static void

+create_init_process(void)

+{

+	int child_pipe[2];

+	if (pipe(child_pipe) < 0)

+		perror_msg_and_fail("pipe");

+

+	pid_t pid = fork();

+	if (pid < 0)

+		perror_msg_and_fail("fork");

+

+	if (!pid) {

+		close(child_pipe[1]);

+		if (read(child_pipe[0], &child_pipe[1], sizeof(int)) != 0)

+			_exit(1);

+		_exit(0);

+	}

+

+	close(child_pipe[0]);

+}

+

+void

+check_ns_ioctl(void)

+{

+	int fd = open("/proc/self/ns/pid", O_RDONLY);

+	if (fd < 0) {

+		if (errno == ENOENT)

+			perror_msg_and_skip("opening /proc/self/ns/pid");

+		else

+			perror_msg_and_fail("opening /proc/self/ns/pid");

+	}

+

+	int userns_fd = ioctl(fd, NS_GET_USERNS);

+	if (userns_fd < 0) {

+		if (errno == ENOTTY)

+			error_msg_and_skip("NS_* ioctl commands are not "

+			                   "supported by the kernel");

+		else

+			perror_msg_and_fail("ioctl(NS_GET_USERNS)");

+	}

+

+	close(userns_fd);

+	close(fd);

+}

+

+void

+pidns_test_init(void)

+{

+	pidns_translation = true;

+

+	check_ns_ioctl();

+

+	if (!pidns_fork(-1, false))

+		return;

+

+	/* Unshare user namespace too, so we do not need to be root */

+	if (unshare(CLONE_NEWUSER | CLONE_NEWPID) < 0) {

+		if (errno == EPERM)

+			perror_msg_and_skip("unshare");

+

+		perror_msg_and_fail("unshare");

+	}

+

+	pidns_unshared = true;

+

+	create_init_process();

+

+	if (!pidns_fork(-1, false))

+		return;

+

+	if (!pidns_fork(-1, true))

+		return;

+

+	pid_t pgid;

+	if (!(pgid = pidns_fork(0, false)))

+		return;

+

+	if (!pidns_fork(pgid, false))

+		return;

+

+	exit(0);

+}

Index: strace-5.7/tests/pidns.h

===================================================================

--- /dev/null	1970-01-01 00:00:00.000000000 +0000

+++ strace-5.7/tests/pidns.h	2020-09-09 19:49:54.009575350 +0200

@@ -0,0 +1,56 @@

+/*

+ * Test PID namespace translation

+ *

+ * Copyright (c) 2020 Ákos Uzonyi <uzonyi.akos@gmail.com>

+ * All rights reserved.

+ *

+ * SPDX-License-Identifier: LGPL-2.1-or-later

+ */

+#ifndef STRACE_PIDNS_H

+#define STRACE_PIDNS_H

+

+#ifdef PIDNS_TRANSLATION

+# define PIDNS_TEST_INIT pidns_test_init()

+#else

+# define PIDNS_TEST_INIT

+#endif

+

+#include <sys/types.h>

+

+enum pid_type {

+	PT_TID,

+	PT_TGID,

+	PT_PGID,

+	PT_SID,

+

+	PT_COUNT,

+	PT_NONE = -1

+};

+

+/* Prints leader (process tid) if pidns_test_init was called */

+void pidns_print_leader(void);

+

+/*

+ * Returns a static buffer containing the translation string of our PID.

+ */

+const char *pidns_pid2str(enum pid_type type);

+

+/**

+ * Skips the test if NS_* ioctl commands are not supported by the kernel.

+ */

+void check_ns_ioctl(void);

+

+/**

+ * Init pidns testing.

+ *

+ * Should be called at the beginning of the test's main function

+ *

+ * This function calls fork a couple of times, and returns in the child

+ * processes. These child processes are in a new PID namespace with different

+ * PID configurations (group leader, session leader, ...). If any child

+ * terminates with nonzero exit status the test is failed. Otherwise the test is

+ * succesful, and the parent process exits with 0.

+ */

+void pidns_test_init(void);

+

+#endif

\ No newline at end of file

Index: strace-5.7/tests-m32/Makefile.am

===================================================================

--- strace-5.7.orig/tests-m32/Makefile.am	2020-09-09 19:32:50.846965498 +0200

+++ strace-5.7/tests-m32/Makefile.am	2020-09-09 19:49:54.009575350 +0200

@@ -7,14 +7,14 @@

 # SPDX-License-Identifier: GPL-2.0-or-later

 OS = linux

-CC = @CC_FOR_M32@

-ARCH = @arch_m32@

+CC = @CC@

+ARCH = @arch@

 NATIVE_ARCH = @arch_native@

-SIZEOF_KERNEL_LONG_T = 4

-SIZEOF_LONG = 4

-MPERS_NAME = m32

-MPERS_CC_FLAGS = @CFLAGS_FOR_M32@ @cc_flags_m32@

-ARCH_MFLAGS = -DMPERS_IS_$(MPERS_NAME) $(MPERS_CC_FLAGS)

+SIZEOF_KERNEL_LONG_T = @SIZEOF_KERNEL_LONG_T@

+SIZEOF_LONG = @SIZEOF_LONG@

+MPERS_NAME =

+MPERS_CC_FLAGS =

+ARCH_MFLAGS =

 AM_CFLAGS = $(WARN_CFLAGS)

 AM_CPPFLAGS = $(ARCH_MFLAGS) \

 	      -I$(builddir) \

@@ -44,6 +44,8 @@

 	libsocketcall.c \

 	lock_file.c \

 	overflowuid.c \

+	pidns.c \

+	pidns.h \

 	pipe_maxfd.c \

 	print_quoted_string.c \

 	print_time.c \

Index: strace-5.7/tests-m32/init.sh

===================================================================

--- strace-5.7.orig/tests-m32/init.sh	2020-09-09 19:32:50.846965498 +0200

+++ strace-5.7/tests-m32/init.sh	2020-09-09 19:49:54.009575350 +0200

@@ -387,6 +387,36 @@

 	test_pure_prog_set "$@" < "$srcdir/$NAME.in"

 }

+test_pidns_run_strace()

+{

+	local parent_pid init_pid

+

+	check_prog tail

+	check_prog cut

+	check_prog grep

+

+	run_prog > /dev/null

+	run_strace --pidns-translation -f $@ $args > "$EXP"

+

+	# filter out logs made by the parent or init process of the pidns test

+	parent_pid="$(tail -n 2 $LOG | head -n 1 | cut -d' ' -f1)"

+	init_pid="$(tail -n 1 $LOG | cut -d' ' -f1)"

+	grep -E -v "^($parent_pid|$init_pid) " "$LOG" > "$OUT"

+	match_diff "$OUT" "$EXP"

+}

+

+test_pidns()

+{

+	check_prog unshare

+	unshare -Urpf true || framework_skip_ "unshare -Urpf true failed"

+

+	test_pidns_run_strace "$@"

+

+	# test PID translation when /proc is mounted from an other namespace

+	STRACE="unshare -Urpf $STRACE"

+	test_pidns_run_strace "$@"

+}

+

 check_prog cat

 check_prog rm

Index: strace-5.7/tests-m32/pidns.c

===================================================================

--- /dev/null	1970-01-01 00:00:00.000000000 +0000

+++ strace-5.7/tests-m32/pidns.c	2020-09-09 19:49:54.009575350 +0200

@@ -0,0 +1,237 @@

+/*

+ * Testing framework for PID namespace translation

+ *

+ * Copyright (c) 2020 Ákos Uzonyi <uzonyi.akos@gmail.com>

+ * All rights reserved.

+ *

+ * SPDX-License-Identifier: LGPL-2.1-or-later

+ */

+#include "tests.h"

+#include "pidns.h"

+#include "nsfs.h"

+

+#include <errno.h>

+#include <stdio.h>

+#include <string.h>

+#include <sys/types.h>

+#include <signal.h>

+#include <stdlib.h>

+#include <sched.h>

+#include <unistd.h>

+#include <sys/wait.h>

+#include <linux/sched.h>

+#include <fcntl.h>

+#include <sys/ioctl.h>

+

+#ifndef CLONE_NEWUSER

+# define CLONE_NEWUSER 0x10000000

+#endif

+

+#ifndef CLONE_NEWPID

+# define CLONE_NEWPID 0x20000000

+#endif

+

+static bool pidns_translation = false;

+static bool pidns_unshared = false;

+

+/* Our PIDs in strace's namespace */

+static pid_t pidns_strace_ids[PT_COUNT];

+

+void

+pidns_print_leader(void)

+{

+	if (pidns_translation)

+		printf("%-5d ", pidns_strace_ids[PT_TID]);

+}

+

+const char *

+pidns_pid2str(enum pid_type type)

+{

+	static const char format[] = " /* %d in strace's PID NS */";

+	static char buf[PT_COUNT][sizeof(format) + sizeof(int) * 3];

+

+	if (type < 0 || type >= PT_COUNT)

+		return "";

+

+	if (!pidns_unshared || !pidns_strace_ids[type])

+		return "";

+

+	snprintf(buf[type], sizeof(buf[type]), format, pidns_strace_ids[type]);

+	return buf[type];

+}

+

+/**

+ * This function is like fork, but does a few more things. It sets up the

+ * child's PGID and SID according to the parameters. Also it fills the

+ * pidns_strace_ids array in the child's memory with the PIDs of the child in

+ * parent's PID namespace. In the parent it waits for the child to terminate

+ * (but leaves the zombie to use it later as a process group). If the child

+ * terminates with nonzero exit status, the test is failed.

+ *

+ * @param pgid     The process group the child should be moved to. It's expected

+ *                 to be a PID of a zombie process (will be reaped). If

+ *                 negative, leave the child in the process group of the parent.

+ *                 If 0, move the process to its own process group.

+ * @param new_sid  Wheather child should be moved to a new session.

+ */

+static pid_t

+pidns_fork(pid_t pgid, bool new_sid)

+{

+	int strace_ids_pipe[2];

+	if (pipe(strace_ids_pipe) < 0)

+		perror_msg_and_fail("pipe");

+

+	fflush(stdout);

+	pid_t pid = fork();

+	if (pid < 0)

+		perror_msg_and_fail("fork");

+

+	if (!pid) {

+		close(strace_ids_pipe[1]);

+

+		ssize_t len = read(strace_ids_pipe[0], pidns_strace_ids,

+				sizeof(pidns_strace_ids));

+		if (len < 0)

+			perror_msg_and_fail("read");

+		if (len != sizeof(pidns_strace_ids))

+			error_msg_and_fail("read returned < sizeof(pidns_strace_ids)");

+

+		close(strace_ids_pipe[0]);

+

+		if (pidns_strace_ids[PT_SID])

+			setsid();

+

+		return 0;

+	}

+

+	pidns_strace_ids[PT_TID] = pid;

+	pidns_strace_ids[PT_TGID] = pid;

+	pidns_strace_ids[PT_PGID] = 0;

+	pidns_strace_ids[PT_SID] = 0;

+

+	if (!pgid)

+		pgid = pid;

+

+	if (pgid > 0) {

+		if (setpgid(pid, pgid) < 0)

+			perror_msg_and_fail("setpgid");

+

+		pidns_strace_ids[PT_PGID] = pgid;

+	}

+

+	/* Reap group leader to test PGID decoding */

+	if (pgid > 0 && pgid != pid) {

+		int ret = waitpid(pgid, NULL, WNOHANG);

+		if (ret < 0)

+			perror_msg_and_fail("wait");

+		if (!ret)

+			error_msg_and_fail("could not reap group leader");

+	}

+

+	if (new_sid) {

+		pidns_strace_ids[PT_SID] = pid;

+		pidns_strace_ids[PT_PGID] = pid;

+	}

+

+	ssize_t len = write(strace_ids_pipe[1], pidns_strace_ids,

+	                     sizeof(pidns_strace_ids));

+	if (len < 0)

+		perror_msg_and_fail("write");

+	if (len != sizeof(pidns_strace_ids))

+		error_msg_and_fail("write returned < sizeof(pidns_strace_ids)");

+

+	close(strace_ids_pipe[0]);

+	close(strace_ids_pipe[1]);

+

+	/* WNOWAIT: leave the zombie, to be able to use it as a process group */

+	siginfo_t siginfo;

+	if (waitid(P_PID, pid, &siginfo, WEXITED | WNOWAIT) < 0)

+		perror_msg_and_fail("wait");

+	if (siginfo.si_code != CLD_EXITED || siginfo.si_status)

+		error_msg_and_fail("child terminated with nonzero exit status");

+

+	return pid;

+}

+

+static void

+create_init_process(void)

+{

+	int child_pipe[2];

+	if (pipe(child_pipe) < 0)

+		perror_msg_and_fail("pipe");

+

+	pid_t pid = fork();

+	if (pid < 0)

+		perror_msg_and_fail("fork");

+

+	if (!pid) {

+		close(child_pipe[1]);

+		if (read(child_pipe[0], &child_pipe[1], sizeof(int)) != 0)

+			_exit(1);

+		_exit(0);

+	}

+

+	close(child_pipe[0]);

+}

+

+void

+check_ns_ioctl(void)

+{

+	int fd = open("/proc/self/ns/pid", O_RDONLY);

+	if (fd < 0) {

+		if (errno == ENOENT)

+			perror_msg_and_skip("opening /proc/self/ns/pid");

+		else

+			perror_msg_and_fail("opening /proc/self/ns/pid");

+	}

+

+	int userns_fd = ioctl(fd, NS_GET_USERNS);

+	if (userns_fd < 0) {

+		if (errno == ENOTTY)

+			error_msg_and_skip("NS_* ioctl commands are not "

+			                   "supported by the kernel");

+		else

+			perror_msg_and_fail("ioctl(NS_GET_USERNS)");

+	}

+

+	close(userns_fd);

+	close(fd);

+}

+

+void

+pidns_test_init(void)

+{

+	pidns_translation = true;

+

+	check_ns_ioctl();

+

+	if (!pidns_fork(-1, false))

+		return;

+

+	/* Unshare user namespace too, so we do not need to be root */

+	if (unshare(CLONE_NEWUSER | CLONE_NEWPID) < 0) {

+		if (errno == EPERM)

+			perror_msg_and_skip("unshare");

+

+		perror_msg_and_fail("unshare");

+	}

+

+	pidns_unshared = true;

+

+	create_init_process();

+

+	if (!pidns_fork(-1, false))

+		return;

+

+	if (!pidns_fork(-1, true))

+		return;

+

+	pid_t pgid;

+	if (!(pgid = pidns_fork(0, false)))

+		return;

+

+	if (!pidns_fork(pgid, false))

+		return;

+

+	exit(0);

+}

Index: strace-5.7/tests-m32/pidns.h

===================================================================

--- /dev/null	1970-01-01 00:00:00.000000000 +0000

+++ strace-5.7/tests-m32/pidns.h	2020-09-09 19:49:54.010575350 +0200

@@ -0,0 +1,56 @@

+/*

+ * Test PID namespace translation

+ *

+ * Copyright (c) 2020 Ákos Uzonyi <uzonyi.akos@gmail.com>

+ * All rights reserved.

+ *

+ * SPDX-License-Identifier: LGPL-2.1-or-later

+ */

+#ifndef STRACE_PIDNS_H

+#define STRACE_PIDNS_H

+

+#ifdef PIDNS_TRANSLATION

+# define PIDNS_TEST_INIT pidns_test_init()

+#else

+# define PIDNS_TEST_INIT

+#endif

+

+#include <sys/types.h>

+

+enum pid_type {

+	PT_TID,