1 /*-
2 * Copyright (c) 2023 The FreeBSD Foundation
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 *
6 * This software were developed by Konstantin Belousov <kib@FreeBSD.org>
7 * under sponsorship from the FreeBSD Foundation.
8 */
9
10 #include <sys/param.h>
11 #include <sys/syscall.h>
12 #include <sys/sysctl.h>
13
14 #include <atf-c.h>
15 #include <errno.h>
16 #include <signal.h>
17 #include <stdatomic.h>
18 #include <stdbool.h>
19 #include <stdio.h>
20
21 static sig_atomic_t sigsys_cnt;
22
23 #define SAVEDVALUE "savedsignosys"
24
25 static void
sigsys_handler(int signo,siginfo_t * si,void * ucp)26 sigsys_handler(int signo, siginfo_t *si, void *ucp)
27 {
28 sigsys_cnt++;
29 }
30
31 static void
sigsys_test(int knob)32 sigsys_test(int knob)
33 {
34 struct sigaction sa;
35
36 memset(&sa, 0, sizeof(sa));
37 sa.sa_sigaction = sigsys_handler;
38 sa.sa_flags = SA_SIGINFO;
39 ATF_REQUIRE(sigaction(SIGSYS, &sa, NULL) == 0);
40
41 ATF_REQUIRE(syscall(273) == -1); /* reserved */
42 ATF_CHECK_ERRNO(ENOSYS, true);
43 atomic_signal_fence(memory_order_seq_cst);
44 ATF_CHECK_EQ(1 * knob, sigsys_cnt);
45
46 ATF_REQUIRE(syscall(440) == -1); /* SYS_kse_switchin */
47 ATF_CHECK_ERRNO(ENOSYS, true);
48 atomic_signal_fence(memory_order_seq_cst);
49 ATF_CHECK_EQ(2 * knob, sigsys_cnt);
50
51 /* Hope this is enough for say next two months */
52 ATF_REQUIRE(syscall(3000000) == -1);
53 ATF_CHECK_ERRNO(ENOSYS, true);
54 atomic_signal_fence(memory_order_seq_cst);
55 ATF_CHECK_EQ(3 * knob, sigsys_cnt);
56
57 ATF_REQUIRE(syscall(SYS_afs3_syscall) == -1);
58 ATF_CHECK_ERRNO(ENOSYS, true);
59 atomic_signal_fence(memory_order_seq_cst);
60 ATF_CHECK_EQ(4 * knob, sigsys_cnt);
61 }
62
63 static void
sysctlset(const char * name,int val)64 sysctlset(const char *name, int val)
65 {
66 size_t oldlen = sizeof(int);
67 int oldval;
68 char buf[80];
69
70 ATF_REQUIRE(sysctlbyname(name, &oldval, &oldlen, NULL, 0) == 0);
71
72 /* Store old %name in a symlink for cleanup */
73 snprintf(buf, sizeof(buf), "%d", oldval);
74 ATF_REQUIRE(symlink(buf, SAVEDVALUE) == 0);
75
76 ATF_REQUIRE(sysctlbyname(name, NULL, NULL, &val, sizeof(val)) == 0);
77 }
78
79 static void
sysctlcleanup(const char * name)80 sysctlcleanup(const char *name)
81 {
82 size_t oldlen;
83 int n, oldval;
84 char buf[80];
85
86 if ((n = readlink(SAVEDVALUE, buf, sizeof(buf))) > 0) {
87 buf[MIN((size_t)n, sizeof(buf) - 1)] = '\0';
88 if (sscanf(buf, "%d", &oldval) == 1) {
89 oldlen = sizeof(oldval);
90 (void)sysctlbyname(name, NULL, 0,
91 &oldval, oldlen);
92 }
93 }
94 (void)unlink(SAVEDVALUE);
95 }
96
97 ATF_TC_WITH_CLEANUP(sigsys_test_on);
ATF_TC_HEAD(sigsys_test_on,tc)98 ATF_TC_HEAD(sigsys_test_on, tc)
99 {
100 atf_tc_set_md_var(tc, "require.user", "root");
101 atf_tc_set_md_var(tc, "require.config", "allow_sysctl_side_effects");
102 atf_tc_set_md_var(tc, "descr",
103 "Testing delivery of SIGSYS on invalid syscalls");
104 }
105
ATF_TC_BODY(sigsys_test_on,tc)106 ATF_TC_BODY(sigsys_test_on, tc)
107 {
108 sysctlset("kern.signosys", 1);
109 sigsys_test(1);
110 }
111
ATF_TC_CLEANUP(sigsys_test_on,tc)112 ATF_TC_CLEANUP(sigsys_test_on, tc)
113 {
114 sysctlcleanup("kern.signosys");
115 }
116
117 ATF_TC_WITH_CLEANUP(sigsys_test_off);
ATF_TC_HEAD(sigsys_test_off,tc)118 ATF_TC_HEAD(sigsys_test_off, tc)
119 {
120 atf_tc_set_md_var(tc, "require.user", "root");
121 atf_tc_set_md_var(tc, "require.config", "allow_sysctl_side_effects");
122 atf_tc_set_md_var(tc, "descr",
123 "Testing SIGSYS silence on invalid syscalls");
124 }
125
ATF_TC_BODY(sigsys_test_off,tc)126 ATF_TC_BODY(sigsys_test_off, tc)
127 {
128 sysctlset("kern.signosys", 0);
129 sigsys_test(0);
130 }
131
ATF_TC_CLEANUP(sigsys_test_off,tc)132 ATF_TC_CLEANUP(sigsys_test_off, tc)
133 {
134 sysctlcleanup("kern.signosys");
135 }
136
ATF_TP_ADD_TCS(tp)137 ATF_TP_ADD_TCS(tp)
138 {
139 ATF_TP_ADD_TC(tp, sigsys_test_on);
140 ATF_TP_ADD_TC(tp, sigsys_test_off);
141 return (atf_no_error());
142 }
143