[PATCH linux-next v10 7/7] selftests/ptrace: add a test case for PTRACE_GET_SYSCALL_INFO

Dmitry V. Levin
2019-04-15T23:45:14Z

Check whether PTRACE_GET_SYSCALL_INFO semantics implemented in the kernel
matches userspace expectations.

Acked-by: Shuah Khan <shuah@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Elvira Khabirova <lineprinter@altlinux.org>
Cc: Eugene Syromyatnikov <esyr@redhat.com>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
---

Notes:
v10: changed GPL-2.0-or-later to GPL-2.0+, added Acked-by
v9: unchanged
v8: unchanged
v7: unchanged
v6: made PTRACE_GET_SYSCALL_INFO return value checks strict
v5: initial revision

tools/testing/selftests/ptrace/.gitignore | 1 +
tools/testing/selftests/ptrace/Makefile | 2 +-
.../selftests/ptrace/get_syscall_info.c | 271 ++++++++++++++++++
3 files changed, 273 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/ptrace/get_syscall_info.c

diff --git a/tools/testing/selftests/ptrace/.gitignore b/tools/testing/selftests/ptrace/.gitignore
index b3e59d41fd82..cfcc49a7def7 100644
--- a/tools/testing/selftests/ptrace/.gitignore
+++ b/tools/testing/selftests/ptrace/.gitignore
@@ -1 +1,2 @@
+get_syscall_info
peeksiginfo
diff --git a/tools/testing/selftests/ptrace/Makefile b/tools/testing/selftests/ptrace/Makefile
index 8a2bc5562179..4bc550b6b845 100644
--- a/tools/testing/selftests/ptrace/Makefile
+++ b/tools/testing/selftests/ptrace/Makefile
@@ -1,5 +1,5 @@
CFLAGS += -iquote../../../../include/uapi -Wall

-TEST_GEN_PROGS := peeksiginfo
+TEST_GEN_PROGS := get_syscall_info peeksiginfo

include ../lib.mk
diff --git a/tools/testing/selftests/ptrace/get_syscall_info.c b/tools/testing/selftests/ptrace/get_syscall_info.c
new file mode 100644
index 000000000000..d1961c3ee72e
--- /dev/null
+++ b/tools/testing/selftests/ptrace/get_syscall_info.c
@@ -0,0 +1,271 @@
+/* SPDX-License-Identifier: GPL-2.0+
+ *
+ * Copyright (c) 2018 Dmitry V. Levin <ldv@altlinux.org>
+ * All rights reserved.
+ *
+ * Check whether PTRACE_GET_SYSCALL_INFO semantics implemented in the kernel
+ * matches userspace expectations.
+ */
+
+#include "../kselftest_harness.h"
+#include <err.h>
+#include <signal.h>
+#include <asm/unistd.h>
+#include "linux/ptrace.h"
+
+static int
+kill_tracee(pid_t pid)
+{
+ if (!pid)
+ return 0;
+
+ int saved_errno = errno;
+
+ int rc = kill(pid, SIGKILL);
+
+ errno = saved_errno;
+ return rc;
+}
+
+static long
+sys_ptrace(int request, pid_t pid, unsigned long addr, unsigned long data)
+{
+ return syscall(__NR_ptrace, request, pid, addr, data);
+}
+
+#define LOG_KILL_TRACEE(fmt, ...) \
+ do { \
+ kill_tracee(pid); \
+ TH_LOG("wait #%d: " fmt, \
+ ptrace_stop, ##__VA_ARGS__); \
+ } while (0)
+
+TEST(get_syscall_info)
+{
+ static const unsigned long args[][7] = {
+ /* a sequence of architecture-agnostic syscalls */
+ {
+ __NR_chdir,
+ (unsigned long) "",
+ 0xbad1fed1,
+ 0xbad2fed2,
+ 0xbad3fed3,
+ 0xbad4fed4,
+ 0xbad5fed5
+ },
+ {
+ __NR_gettid,
+ 0xcaf0bea0,
+ 0xcaf1bea1,
+ 0xcaf2bea2,
+ 0xcaf3bea3,
+ 0xcaf4bea4,
+ 0xcaf5bea5
+ },
+ {
+ __NR_exit_group,
+ 0,
+ 0xfac1c0d1,
+ 0xfac2c0d2,
+ 0xfac3c0d3,
+ 0xfac4c0d4,
+ 0xfac5c0d5
+ }
+ };
+ const unsigned long *exp_args;
+
+ pid_t pid = fork();
+
+ ASSERT_LE(0, pid) {
+ TH_LOG("fork: %m");
+ }
+
+ if (pid == 0) {
+ /* get the pid before PTRACE_TRACEME */
+ pid = getpid();
+ ASSERT_EQ(0, sys_ptrace(PTRACE_TRACEME, 0, 0, 0)) {
+ TH_LOG("PTRACE_TRACEME: %m");
+ }
+ ASSERT_EQ(0, kill(pid, SIGSTOP)) {
+ /* cannot happen */
+ TH_LOG("kill SIGSTOP: %m");
+ }
+ for (unsigned int i = 0; i < ARRAY_SIZE(args); ++i) {
+ syscall(args[i][0],
+ args[i][1], args[i][2], args[i][3],
+ args[i][4], args[i][5], args[i][6]);
+ }
+ /* unreachable */
+ _exit(1);
+ }
+
+ const struct {
+ unsigned int is_error;
+ int rval;
+ } *exp_param, exit_param[] = {
+ { 1, -ENOENT }, /* chdir */
+ { 0, pid } /* gettid */
+ };
+
+ unsigned int ptrace_stop;
+
+ for (ptrace_stop = 0; ; ++ptrace_stop) {
+ struct ptrace_syscall_info info = {
+ .op = 0xff /* invalid PTRACE_SYSCALL_INFO_* op */
+ };
+ const size_t size = sizeof(info);
+ const int expected_none_size =
+ (void *) &info.entry - (void *) &info;
+ const int expected_entry_size =
+ (void *) &info.entry.args[6] - (void *) &info;
+ const int expected_exit_size =
+ (void *) (&info.exit.is_error + 1) -
+ (void *) &info;
+ int status;
+ long rc;
+
+ ASSERT_EQ(pid, wait(&status)) {
+ /* cannot happen */
+ LOG_KILL_TRACEE("wait: %m");
+ }
+ if (WIFEXITED(status)) {
+ pid = 0; /* the tracee is no more */
+ ASSERT_EQ(0, WEXITSTATUS(status));
+ break;
+ }
+ ASSERT_FALSE(WIFSIGNALED(status)) {
+ pid = 0; /* the tracee is no more */
+ LOG_KILL_TRACEE("unexpected signal %u",
+ WTERMSIG(status));
+ }
+ ASSERT_TRUE(WIFSTOPPED(status)) {
+ /* cannot happen */
+ LOG_KILL_TRACEE("unexpected wait status %#x", status);
+ }
+
+ switch (WSTOPSIG(status)) {
+ case SIGSTOP:
+ ASSERT_EQ(0, ptrace_stop) {
+ LOG_KILL_TRACEE("unexpected signal stop");
+ }
+ ASSERT_EQ(0, sys_ptrace(PTRACE_SETOPTIONS, pid, 0,
+ PTRACE_O_TRACESYSGOOD)) {
+ LOG_KILL_TRACEE("PTRACE_SETOPTIONS: %m");
+ }
+ ASSERT_LT(0, (rc = sys_ptrace(PTRACE_GET_SYSCALL_INFO,
+ pid, size,
+ (unsigned long) &info))) {
+ LOG_KILL_TRACEE("PTRACE_GET_SYSCALL_INFO: %m");
+ }
+ ASSERT_EQ(expected_none_size, rc) {
+ LOG_KILL_TRACEE("signal stop mismatch");
+ }
+ ASSERT_EQ(PTRACE_SYSCALL_INFO_NONE, info.op) {
+ LOG_KILL_TRACEE("signal stop mismatch");
+ }
+ ASSERT_TRUE(info.arch) {
+ LOG_KILL_TRACEE("signal stop mismatch");
+ }
+ ASSERT_TRUE(info.instruction_pointer) {
+ LOG_KILL_TRACEE("signal stop mismatch");
+ }
+ ASSERT_TRUE(info.stack_pointer) {
+ LOG_KILL_TRACEE("signal stop mismatch");
+ }
+ break;
+
+ case SIGTRAP | 0x80:
+ ASSERT_LT(0, (rc = sys_ptrace(PTRACE_GET_SYSCALL_INFO,
+ pid, size,
+ (unsigned long) &info))) {
+ LOG_KILL_TRACEE("PTRACE_GET_SYSCALL_INFO: %m");
+ }
+ switch (ptrace_stop) {
+ case 1: /* entering chdir */
+ case 3: /* entering gettid */
+ case 5: /* entering exit_group */
+ exp_args = args[ptrace_stop / 2];
+ ASSERT_EQ(expected_entry_size, rc) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_EQ(PTRACE_SYSCALL_INFO_ENTRY, info.op) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_TRUE(info.arch) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_TRUE(info.instruction_pointer) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_TRUE(info.stack_pointer) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_EQ(exp_args[0], info.entry.nr) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_EQ(exp_args[1], info.entry.args[0]) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_EQ(exp_args[2], info.entry.args[1]) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_EQ(exp_args[3], info.entry.args[2]) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_EQ(exp_args[4], info.entry.args[3]) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_EQ(exp_args[5], info.entry.args[4]) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ ASSERT_EQ(exp_args[6], info.entry.args[5]) {
+ LOG_KILL_TRACEE("entry stop mismatch");
+ }
+ break;
+ case 2: /* exiting chdir */
+ case 4: /* exiting gettid */
+ exp_param = &exit_param[ptrace_stop / 2 - 1];
+ ASSERT_EQ(expected_exit_size, rc) {
+ LOG_KILL_TRACEE("exit stop mismatch");
+ }
+ ASSERT_EQ(PTRACE_SYSCALL_INFO_EXIT, info.op) {
+ LOG_KILL_TRACEE("exit stop mismatch");
+ }
+ ASSERT_TRUE(info.arch) {
+ LOG_KILL_TRACEE("exit stop mismatch");
+ }
+ ASSERT_TRUE(info.instruction_pointer) {
+ LOG_KILL_TRACEE("exit stop mismatch");
+ }
+ ASSERT_TRUE(info.stack_pointer) {
+ LOG_KILL_TRACEE("exit stop mismatch");
+ }
+ ASSERT_EQ(exp_param->is_error,
+ info.exit.is_error) {
+ LOG_KILL_TRACEE("exit stop mismatch");
+ }
+ ASSERT_EQ(exp_param->rval, info.exit.rval) {
+ LOG_KILL_TRACEE("exit stop mismatch");
+ }
+ break;
+ default:
+ LOG_KILL_TRACEE("unexpected syscall stop");
+ abort();
+ }
+ break;
+
+ default:
+ LOG_KILL_TRACEE("unexpected stop signal %#x",
+ WSTOPSIG(status));
+ abort();
+ }
+
+ ASSERT_EQ(0, sys_ptrace(PTRACE_SYSCALL, pid, 0, 0)) {
+ LOG_KILL_TRACEE("PTRACE_SYSCALL: %m");
+ }
+ }
+
+ ASSERT_EQ(ARRAY_SIZE(args) * 2, ptrace_stop);
+}
+
+TEST_HARNESS_MAIN
--
ldv