1  /*
       2   * Check decoding of signal delivery.
       3   *
       4   * Copyright (c) 2016-2020 The strace developers.
       5   * All rights reserved.
       6   *
       7   * SPDX-License-Identifier: GPL-2.0-or-later
       8   */
       9  
      10  #include "tests.h"
      11  #include "pidns.h"
      12  #include <signal.h>
      13  #include <stdio.h>
      14  #include <unistd.h>
      15  
      16  static volatile int s_sig, s_code, s_pid, s_uid;
      17  
      18  static void
      19  handler(int sig, siginfo_t *info, void *ucontext)
      20  {
      21  	s_sig = info->si_signo;
      22  	s_code = info->si_code;
      23  	s_pid = info->si_pid;
      24  	s_uid = info->si_uid;
      25  }
      26  
      27  int
      28  main(void)
      29  {
      30  	PIDNS_TEST_INIT;
      31  
      32  	static const char prefix[] = "KERNEL BUG";
      33  	int printed = 0;
      34  
      35  	const int pid = getpid();
      36  	const char *pid_str = pidns_pid2str(PT_TGID);
      37  	const int uid = geteuid();
      38  
      39  	for (int sig = 1; sig <= 31; ++sig) {
      40  		if (sig == SIGKILL || sig == SIGSTOP)
      41  			continue;
      42  
      43  		sigset_t mask;
      44  		sigemptyset(&mask);
      45  		sigaddset(&mask, sig);
      46  		if (sigprocmask(SIG_UNBLOCK, &mask, NULL))
      47  			perror_msg_and_fail("sigprocmask");
      48  
      49  		static const struct sigaction act = {
      50  			.sa_sigaction = handler,
      51  			.sa_flags = SA_SIGINFO
      52  		};
      53  		if (sigaction(sig, &act, NULL))
      54  			perror_msg_and_fail("sigaction: %d", sig);
      55  
      56  		if (kill(pid, sig) != 0)
      57  			perror_msg_and_fail("kill: %d", sig);
      58  
      59  #ifdef MPERS_IS_m32
      60  		/*
      61  		 * The tracee has received a compat siginfo_t but
      62  		 * the tracer has received a native siginfo_t.
      63  		 */
      64  		const int e_sig = sig;
      65  		const int e_pid = pid;
      66  		const int e_uid = uid;
      67  #else
      68  		/*
      69  		 * If the tracee is a native process,
      70  		 * then the tracer is also native.
      71  		 * If the tracee is a compat process,
      72  		 * then the tracer is also compat.
      73  		 * Anyway, both the tracee and the tracer
      74  		 * have received the same siginfo_t.
      75  		 */
      76  		const int e_sig = s_sig;
      77  		const int e_pid = s_pid;
      78  		const int e_uid = s_uid;
      79  #endif
      80  		pidns_print_leader();
      81  		printf("kill(%d%s, %s) = 0\n", pid, pid_str, signal2name(sig));
      82  		pidns_print_leader();
      83  		printf("--- %s {si_signo=%s, si_code=SI_USER, si_pid=%d%s"
      84  		       ", si_uid=%d} ---\n",
      85  		       signal2name(sig), signal2name(e_sig),
      86  		       e_pid, pid_str, e_uid);
      87  
      88  		if (s_code || sig != s_sig || pid != s_pid || uid != s_uid) {
      89  			/*
      90  			 * The kernel has failed to initialize siginfo_t
      91  			 * properly.  There is nothing that could be done
      92  			 * on the strace side to workaround the kernel bug,
      93  			 * so just print some useful diagnostics.
      94  			 */
      95  			if (!printed) {
      96  				printed = 1;
      97  				fprintf(stderr, "%s: siginfo_t\n", prefix);
      98  			}
      99  			fprintf(stderr,
     100  				"%s: expected: si_signo=%d, si_code=%d"
     101  				", si_pid=%d%s, si_uid=%d\n"
     102  				"%s: received: si_signo=%d, si_code=%d"
     103  				", si_pid=%d%s, si_uid=%d\n",
     104  				prefix, sig, SI_USER, pid, pid_str, uid,
     105  				prefix, sig, s_code, s_pid, pid_str, s_uid);
     106  		}
     107  	}
     108  
     109  	if (printed) {
     110  		fprintf(stderr, "%s: end of diagnostics\n"
     111  			"*** PLEASE FIX THE KERNEL ***\n", prefix);
     112  	}
     113  
     114  	pidns_print_leader();
     115  	puts("+++ exited with 0 +++");
     116  	return 0;
     117  }