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 26 sigsys_handler(int signo, siginfo_t *si, void *ucp) 27 { 28 sigsys_cnt++; 29 } 30 31 static void 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 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 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); 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 } 105 106 ATF_TC_BODY(sigsys_test_on, tc) 107 { 108 sysctlset("kern.signosys", 1); 109 sigsys_test(1); 110 } 111 112 ATF_TC_CLEANUP(sigsys_test_on, tc) 113 { 114 sysctlcleanup("kern.signosys"); 115 } 116 117 ATF_TC_WITH_CLEANUP(sigsys_test_off); 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 } 125 126 ATF_TC_BODY(sigsys_test_off, tc) 127 { 128 sysctlset("kern.signosys", 0); 129 sigsys_test(0); 130 } 131 132 ATF_TC_CLEANUP(sigsys_test_off, tc) 133 { 134 sysctlcleanup("kern.signosys"); 135 } 136 137 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