1 /* $NetBSD: t_sig_backtrace.c,v 1.8 2025/04/17 14:18:40 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2021 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __RCSID("$NetBSD: t_sig_backtrace.c,v 1.8 2025/04/17 14:18:40 riastradh Exp $");
34
35 #include <sys/mman.h>
36 #include <execinfo.h>
37 #include <setjmp.h>
38 #include <stdbool.h>
39 #include <signal.h>
40 #include <stdio.h>
41 #include <stddef.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <unistd.h>
45
46 #include <atf-c.h>
47
48 stack_t sig_stack;
49
50 char *foo;
51 char *(*bar)(void);
52
53 static int the_loop_deref(int);
54 static int the_loop_jump(int);
55
56 #ifdef NOINLINE_HACK
57 volatile int noinline;
58 #endif
59
60 static int __noinline
func1(int i)61 func1(int i)
62 {
63 if (i > 100) {
64 return the_loop_deref(i);
65 }
66 return i + 1;
67 }
68
69 static int __noinline
func2(int i)70 func2(int i)
71 {
72 return func1(i) << 1;
73 }
74
75 static int __noinline
func3(int i)76 func3(int i)
77 {
78 if (func1(i) < 10) {
79 return func2(i);
80 } else {
81 return func1(i);
82 }
83 }
84
85 static int __noinline
the_loop_deref(int i0)86 the_loop_deref(int i0)
87 {
88 volatile int i = i0;
89
90 while (*foo != 0) {
91 i = func3(i);
92 i = func1(i);
93 i = func2(i);
94 }
95
96 #ifdef NOINLINE_HACK
97 if (noinline)
98 vfork();
99 #endif
100
101 return i;
102 }
103
104 static int __noinline
the_loop_jump(int i0)105 the_loop_jump(int i0)
106 {
107 volatile int i = i0;
108
109 while ((*bar)() != 0) {
110 i = func3(i);
111 i = func1(i);
112 i = func2(i);
113 }
114
115 #ifdef NOINLINE_HACK
116 if (noinline)
117 vfork();
118 #endif
119
120 return i;
121 }
122
123 jmp_buf env;
124
125 static void
handler(int s)126 handler(int s)
127 {
128 printf("signal: %d\n", s);
129
130 void *array[10];
131 size_t size = backtrace(array, 10);
132 ATF_REQUIRE(size != 0);
133
134 printf("Backtrace %zd stack frames.\n", size);
135 fflush(stdout);
136 backtrace_symbols_fd(array, size, STDOUT_FILENO);
137
138 char **strings = backtrace_symbols_fmt(array, size, "%n");
139 bool found_handler = false;
140 bool found_sigtramp = false;
141 bool found_the_loop = false;
142 bool found_main = false;
143 size_t i;
144
145 /*
146 * We must find the symbols in the following order:
147 *
148 * handler -> __sigtramp_siginfo_* -> the_loop -> main
149 */
150 for (i = 0; i < size; i++) {
151 if (!found_handler &&
152 strcmp(strings[i], "handler") == 0) {
153 found_handler = true;
154 continue;
155 }
156 if (found_handler && !found_sigtramp &&
157 strncmp(strings[i], "__sigtramp_siginfo_",
158 strlen("__sigtramp_siginfo_")) == 0) {
159 found_sigtramp = true;
160 continue;
161 }
162 if (found_sigtramp && !found_the_loop &&
163 strncmp(strings[i], "the_loop", strlen("the_loop")) == 0) {
164 found_the_loop = true;
165 continue;
166 }
167 if (found_the_loop && !found_main &&
168 strcmp(strings[i], "atf_tp_main") == 0) {
169 found_main = true;
170 break;
171 }
172 }
173
174 ATF_CHECK(found_handler);
175 ATF_CHECK(found_sigtramp);
176 ATF_CHECK(found_the_loop);
177 ATF_CHECK(found_main);
178
179 longjmp(env, 1);
180 }
181
182 ATF_TC(sig_backtrace_deref);
ATF_TC_HEAD(sig_backtrace_deref,tc)183 ATF_TC_HEAD(sig_backtrace_deref, tc)
184 {
185 atf_tc_set_md_var(tc, "descr",
186 "Test backtrace(3) across signal handlers, null pointer deref");
187 }
188
ATF_TC_BODY(sig_backtrace_deref,tc)189 ATF_TC_BODY(sig_backtrace_deref, tc)
190 {
191 sig_stack.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
192 MAP_ANON | MAP_STACK, -1, 0);
193 ATF_REQUIRE(sig_stack.ss_sp != MAP_FAILED);
194
195 sig_stack.ss_size = SIGSTKSZ;
196 sig_stack.ss_flags = 0;
197 ATF_REQUIRE(sigaltstack(&sig_stack, NULL) == 0);
198
199 struct sigaction sa = {
200 .sa_handler = handler,
201 .sa_flags = SA_ONSTACK,
202 };
203 ATF_REQUIRE(sigaction(SIGSEGV, &sa, NULL) == 0);
204
205 #ifdef __sparc__ /* 32 or 64 */
206 atf_tc_expect_fail("PR port-sparc64/59313:"
207 " t_sig_backtrace tests are failing");
208 #endif
209
210 if (setjmp(env) == 0) {
211 printf("%d\n", the_loop_deref(0));
212 }
213 }
214
215 ATF_TC(sig_backtrace_jump);
ATF_TC_HEAD(sig_backtrace_jump,tc)216 ATF_TC_HEAD(sig_backtrace_jump, tc)
217 {
218 atf_tc_set_md_var(tc, "descr",
219 "Test backtrace(3) across signal handlers, null pointer jump");
220 }
221
ATF_TC_BODY(sig_backtrace_jump,tc)222 ATF_TC_BODY(sig_backtrace_jump, tc)
223 {
224 sig_stack.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
225 MAP_ANON | MAP_STACK, -1, 0);
226 ATF_REQUIRE(sig_stack.ss_sp != MAP_FAILED);
227
228 sig_stack.ss_size = SIGSTKSZ;
229 sig_stack.ss_flags = 0;
230 ATF_REQUIRE(sigaltstack(&sig_stack, NULL) == 0);
231
232 struct sigaction sa = {
233 .sa_handler = handler,
234 .sa_flags = SA_ONSTACK,
235 };
236 ATF_REQUIRE(sigaction(SIGSEGV, &sa, NULL) == 0);
237
238 atf_tc_expect_fail("PR lib/56940");
239
240 if (setjmp(env) == 0) {
241 printf("%d\n", the_loop_jump(0));
242 }
243 }
244
ATF_TP_ADD_TCS(tp)245 ATF_TP_ADD_TCS(tp)
246 {
247 ATF_TP_ADD_TC(tp, sig_backtrace_deref);
248 ATF_TP_ADD_TC(tp, sig_backtrace_jump);
249
250 return atf_no_error();
251 }
252