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

Cc: Oleg Nesterov oleg@redhat.com Cc: Andy Lutomirski luto@kernel.org Cc: Shuah Khan shuah@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 --- tools/testing/selftests/ptrace/.gitignore | 1 + tools/testing/selftests/ptrace/Makefile | 2 +- .../selftests/ptrace/get_syscall_info.c | 272 ++++++++++++++++++ 3 files changed, 274 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..21d1180d117e --- /dev/null +++ b/tools/testing/selftests/ptrace/get_syscall_info.c @@ -0,0 +1,272 @@ +/* + * SPDX-License-Identifier: GPL-2.0-or-later + * + * 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_LE(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_LE(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_LE(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