From fc35ef12dc8ba8633a99c9d9df03a5bb53f1dda3 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 20 Sep 2018 13:45:07 -0300 Subject: selftests/powerpc: New PTRACE_SYSEMU test This patch adds a new test for the new PTRACE_SYSEMU ptrace request. This test also relies on PTRACE_GETREGS and PTRACE_SETREGS requests to run properly, since the trace instruction (gettid() syscall) is being modified at run-time (by PTRACE_SETREGS) and re-executed three times. PTRACE_GETREGS is being used to check that the registers are still sane. This test basically creates a child process that executes syscalls and the parent process check if it is being traced appropriately. The parent process guarantees that the SYSCALLs are being traced, with PTRACE_SYSEMU, and ptrace stops the child application before a syscall is executed. The way the tests validates it, is by guaranteeing that the system calls arguments, as argv[0] (r3) which is the same register that will have the syscall return value on powerpc, are not being corrupted on PTRACE_SYSEMU with a return value, i.e, it continues to have the current arguments instead, meaning that the registers where not clobbered. This test is basically the same test for x86 located at tools/testing/selftests/x86/ptrace_syscall.c, limited to test PTRACE_SYSEMU request, and ported to PowerPC. Signed-off-by: Breno Leitao Signed-off-by: Michael Ellerman --- tools/testing/selftests/powerpc/ptrace/Makefile | 2 +- .../selftests/powerpc/ptrace/ptrace-syscall.c | 228 +++++++++++++++++++++ 2 files changed, 229 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/powerpc/ptrace/ptrace-syscall.c (limited to 'tools/testing/selftests/powerpc/ptrace') diff --git a/tools/testing/selftests/powerpc/ptrace/Makefile b/tools/testing/selftests/powerpc/ptrace/Makefile index 28f5b781a553..1ee59978508d 100644 --- a/tools/testing/selftests/powerpc/ptrace/Makefile +++ b/tools/testing/selftests/powerpc/ptrace/Makefile @@ -2,7 +2,7 @@ TEST_PROGS := ptrace-gpr ptrace-tm-gpr ptrace-tm-spd-gpr \ ptrace-tar ptrace-tm-tar ptrace-tm-spd-tar ptrace-vsx ptrace-tm-vsx \ ptrace-tm-spd-vsx ptrace-tm-spr ptrace-hwbreak ptrace-pkey core-pkey \ - perf-hwbreak + perf-hwbreak ptrace-syscall include ../../lib.mk diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-syscall.c b/tools/testing/selftests/powerpc/ptrace/ptrace-syscall.c new file mode 100644 index 000000000000..3353210dcdbd --- /dev/null +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-syscall.c @@ -0,0 +1,228 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A ptrace test for testing PTRACE_SYSEMU, PTRACE_SETREGS and + * PTRACE_GETREG. This test basically create a child process that executes + * syscalls and the parent process check if it is being traced appropriated. + * + * This test is heavily based on tools/testing/selftests/x86/ptrace_syscall.c + * test, and it was adapted to run on Powerpc by + * Breno Leitao + */ +#define _GNU_SOURCE + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "utils.h" + +/* Bitness-agnostic defines for user_regs_struct fields. */ +#define user_syscall_nr gpr[0] +#define user_arg0 gpr[3] +#define user_arg1 gpr[4] +#define user_arg2 gpr[5] +#define user_arg3 gpr[6] +#define user_arg4 gpr[7] +#define user_arg5 gpr[8] +#define user_ip nip + +#define PTRACE_SYSEMU 0x1d + +static int nerrs; + +static void wait_trap(pid_t chld) +{ + siginfo_t si; + + if (waitid(P_PID, chld, &si, WEXITED|WSTOPPED) != 0) + err(1, "waitid"); + if (si.si_pid != chld) + errx(1, "got unexpected pid in event\n"); + if (si.si_code != CLD_TRAPPED) + errx(1, "got unexpected event type %d\n", si.si_code); +} + +static void test_ptrace_syscall_restart(void) +{ + int status; + struct pt_regs regs; + pid_t chld; + + printf("[RUN]\tptrace-induced syscall restart\n"); + + chld = fork(); + if (chld < 0) + err(1, "fork"); + + /* + * Child process is running 4 syscalls after ptrace. + * + * 1) getpid() + * 2) gettid() + * 3) tgkill() -> Send SIGSTOP + * 4) gettid() -> Where the tests will happen essentially + */ + if (chld == 0) { + if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0) + err(1, "PTRACE_TRACEME"); + + pid_t pid = getpid(), tid = syscall(SYS_gettid); + + printf("\tChild will make one syscall\n"); + syscall(SYS_tgkill, pid, tid, SIGSTOP); + + syscall(SYS_gettid, 10, 11, 12, 13, 14, 15); + _exit(0); + } + /* Parent process below */ + + /* Wait for SIGSTOP sent by tgkill above. */ + if (waitpid(chld, &status, 0) != chld || !WIFSTOPPED(status)) + err(1, "waitpid"); + + printf("[RUN]\tSYSEMU\n"); + if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0) + err(1, "PTRACE_SYSEMU"); + wait_trap(chld); + + if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_GETREGS"); + + /* + * Ptrace trapped prior to executing the syscall, thus r3 still has + * the syscall number instead of the sys_gettid() result + */ + if (regs.user_syscall_nr != SYS_gettid || + regs.user_arg0 != 10 || regs.user_arg1 != 11 || + regs.user_arg2 != 12 || regs.user_arg3 != 13 || + regs.user_arg4 != 14 || regs.user_arg5 != 15) { + printf("[FAIL]\tInitial args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", + (unsigned long)regs.user_syscall_nr, + (unsigned long)regs.user_arg0, + (unsigned long)regs.user_arg1, + (unsigned long)regs.user_arg2, + (unsigned long)regs.user_arg3, + (unsigned long)regs.user_arg4, + (unsigned long)regs.user_arg5); + nerrs++; + } else { + printf("[OK]\tInitial nr and args are correct\n"); } + + printf("[RUN]\tRestart the syscall (ip = 0x%lx)\n", + (unsigned long)regs.user_ip); + + /* + * Rewind to retry the same syscall again. This will basically test + * the rewind process together with PTRACE_SETREGS and PTRACE_GETREGS. + */ + regs.user_ip -= 4; + if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_SETREGS"); + + if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0) + err(1, "PTRACE_SYSEMU"); + wait_trap(chld); + + if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_GETREGS"); + + if (regs.user_syscall_nr != SYS_gettid || + regs.user_arg0 != 10 || regs.user_arg1 != 11 || + regs.user_arg2 != 12 || regs.user_arg3 != 13 || + regs.user_arg4 != 14 || regs.user_arg5 != 15) { + printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", + (unsigned long)regs.user_syscall_nr, + (unsigned long)regs.user_arg0, + (unsigned long)regs.user_arg1, + (unsigned long)regs.user_arg2, + (unsigned long)regs.user_arg3, + (unsigned long)regs.user_arg4, + (unsigned long)regs.user_arg5); + nerrs++; + } else { + printf("[OK]\tRestarted nr and args are correct\n"); + } + + printf("[RUN]\tChange nr and args and restart the syscall (ip = 0x%lx)\n", + (unsigned long)regs.user_ip); + + /* + * Inject a new syscall (getpid) in the same place the previous + * syscall (gettid), rewind and re-execute. + */ + regs.user_syscall_nr = SYS_getpid; + regs.user_arg0 = 20; + regs.user_arg1 = 21; + regs.user_arg2 = 22; + regs.user_arg3 = 23; + regs.user_arg4 = 24; + regs.user_arg5 = 25; + regs.user_ip -= 4; + + if (ptrace(PTRACE_SETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_SETREGS"); + + if (ptrace(PTRACE_SYSEMU, chld, 0, 0) != 0) + err(1, "PTRACE_SYSEMU"); + wait_trap(chld); + + if (ptrace(PTRACE_GETREGS, chld, 0, ®s) != 0) + err(1, "PTRACE_GETREGS"); + + /* Check that ptrace stopped at the new syscall that was + * injected, and guarantee that it haven't executed, i.e, user_args + * contain the arguments and not the syscall return value, for + * instance. + */ + if (regs.user_syscall_nr != SYS_getpid + || regs.user_arg0 != 20 || regs.user_arg1 != 21 + || regs.user_arg2 != 22 || regs.user_arg3 != 23 + || regs.user_arg4 != 24 || regs.user_arg5 != 25) { + + printf("[FAIL]\tRestart nr or args are wrong (nr=%lu, args=%lu %lu %lu %lu %lu %lu)\n", + (unsigned long)regs.user_syscall_nr, + (unsigned long)regs.user_arg0, + (unsigned long)regs.user_arg1, + (unsigned long)regs.user_arg2, + (unsigned long)regs.user_arg3, + (unsigned long)regs.user_arg4, + (unsigned long)regs.user_arg5); + nerrs++; + } else { + printf("[OK]\tReplacement nr and args are correct\n"); + } + + if (ptrace(PTRACE_CONT, chld, 0, 0) != 0) + err(1, "PTRACE_CONT"); + + if (waitpid(chld, &status, 0) != chld) + err(1, "waitpid"); + + /* Guarantee that the process executed properly, returning 0 */ + if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { + printf("[FAIL]\tChild failed\n"); + nerrs++; + } else { + printf("[OK]\tChild exited cleanly\n"); + } +} + +int ptrace_syscall(void) +{ + test_ptrace_syscall_restart(); + + return nerrs; +} + +int main(void) +{ + return test_harness(ptrace_syscall, "ptrace_syscall"); +} -- cgit v1.2.3-59-g8ed1b