1 /*
2  * Check decoding of signal delivery.
3  *
4  * Copyright (c) 2016-2018 The strace developers.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include "tests.h"
31 #include <signal.h>
32 #include <stdio.h>
33 #include <unistd.h>
34 
35 static volatile int s_sig, s_code, s_pid, s_uid;
36 
37 static void
handler(int sig,siginfo_t * info,void * ucontext)38 handler(int sig, siginfo_t *info, void *ucontext)
39 {
40 	s_sig = info->si_signo;
41 	s_code = info->si_code;
42 	s_pid = info->si_pid;
43 	s_uid = info->si_uid;
44 }
45 
46 int
main(void)47 main(void)
48 {
49 	static const char prefix[] = "KERNEL BUG";
50 	int printed = 0;
51 
52 	const int pid = getpid();
53 	const int uid = geteuid();
54 
55 	for (int sig = 1; sig <= 31; ++sig) {
56 		if (sig == SIGKILL || sig == SIGSTOP)
57 			continue;
58 
59 		sigset_t mask;
60 		sigemptyset(&mask);
61 		sigaddset(&mask, sig);
62 		if (sigprocmask(SIG_UNBLOCK, &mask, NULL))
63 			perror_msg_and_fail("sigprocmask");
64 
65 		static const struct sigaction act = {
66 			.sa_sigaction = handler,
67 			.sa_flags = SA_SIGINFO
68 		};
69 		if (sigaction(sig, &act, NULL))
70 			perror_msg_and_fail("sigaction: %d", sig);
71 
72 		if (kill(pid, sig) != 0)
73 			perror_msg_and_fail("kill: %d", sig);
74 
75 #ifdef MPERS_IS_m32
76 		/*
77 		 * The tracee has received a compat siginfo_t but
78 		 * the tracer has received a native siginfo_t.
79 		 */
80 		const int e_sig = sig;
81 		const int e_pid = pid;
82 		const int e_uid = uid;
83 #else
84 		/*
85 		 * If the tracee is a native process,
86 		 * then the tracer is also native.
87 		 * If the tracee is a compat process,
88 		 * then the tracer is also compat.
89 		 * Anyway, both the tracee and the tracer
90 		 * have received the same siginfo_t.
91 		 */
92 		const int e_sig = s_sig;
93 		const int e_pid = s_pid;
94 		const int e_uid = s_uid;
95 #endif
96 		printf("kill(%d, %s) = 0\n", pid, signal2name(sig));
97 		printf("--- %s {si_signo=%s, si_code=SI_USER, si_pid=%d"
98 		       ", si_uid=%d} ---\n",
99 		       signal2name(sig), signal2name(e_sig), e_pid, e_uid);
100 
101 		if (s_code || sig != s_sig || pid != s_pid || uid != s_uid) {
102 			/*
103 			 * The kernel has failed to initialize siginfo_t
104 			 * properly.  There is nothing that could be done
105 			 * on the strace side to workaround the kernel bug,
106 			 * so just print some useful diagnostics.
107 			 */
108 			if (!printed) {
109 				printed = 1;
110 				fprintf(stderr, "%s: siginfo_t\n", prefix);
111 			}
112 			fprintf(stderr,
113 				"%s: expected: si_signo=%d, si_code=%d"
114 				", si_pid=%d, si_uid=%d\n"
115 				"%s: received: si_signo=%d, si_code=%d"
116 				", si_pid=%d, si_uid=%d\n",
117 				prefix, sig, SI_USER, pid, uid,
118 				prefix, sig, s_code, s_pid, s_uid);
119 		}
120 	}
121 
122 	if (printed) {
123 		fprintf(stderr, "%s: end of diagnostics\n"
124 			"*** PLEASE FIX THE KERNEL ***\n", prefix);
125 	}
126 
127 	puts("+++ exited with 0 +++");
128 	return 0;
129 }
130