1 files changed, 142 insertions, 0 deletions
diff --git a/tests/sys/kern/sigsys.c b/tests/sys/kern/sigsys.c
new file mode 100644
index 000000000000..d135ed777498
--- /dev/null
+++ b/tests/sys/kern/sigsys.c
@@ -0,0 +1,142 @@
+/*-
+ * Copyright (c) 2023 The FreeBSD Foundation
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * This software were developed by Konstantin Belousov <kib@FreeBSD.org>
+ * under sponsorship from the FreeBSD Foundation.
+ */
+
+#include <sys/param.h>
+#include <sys/syscall.h>
+#include <sys/sysctl.h>
+
+#include <atf-c.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdatomic.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+static sig_atomic_t sigsys_cnt;
+
+#define	SAVEDVALUE	"savedsignosys"
+
+static void
+sigsys_handler(int signo, siginfo_t *si, void *ucp)
+{
+	sigsys_cnt++;
+}
+
+static void
+sigsys_test(int knob)
+{
+	struct sigaction sa;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_sigaction = sigsys_handler;
+	sa.sa_flags = SA_SIGINFO;
+	ATF_REQUIRE(sigaction(SIGSYS, &sa, NULL) == 0);
+
+	ATF_REQUIRE(syscall(273) == -1);	/* reserved */
+	ATF_CHECK_ERRNO(ENOSYS, true);
+	atomic_signal_fence(memory_order_seq_cst);
+	ATF_CHECK_EQ(1 * knob, sigsys_cnt);
+
+	ATF_REQUIRE(syscall(440) == -1);	/* SYS_kse_switchin */
+	ATF_CHECK_ERRNO(ENOSYS, true);
+	atomic_signal_fence(memory_order_seq_cst);
+	ATF_CHECK_EQ(2 * knob, sigsys_cnt);
+
+	/* Hope this is enough for say next two months */
+	ATF_REQUIRE(syscall(3000000) == -1);
+	ATF_CHECK_ERRNO(ENOSYS, true);
+	atomic_signal_fence(memory_order_seq_cst);
+	ATF_CHECK_EQ(3 * knob, sigsys_cnt);
+
+	ATF_REQUIRE(syscall(SYS_afs3_syscall) == -1);
+	ATF_CHECK_ERRNO(ENOSYS, true);
+	atomic_signal_fence(memory_order_seq_cst);
+	ATF_CHECK_EQ(4 * knob, sigsys_cnt);
+}
+
+static void
+sysctlset(const char *name, int val)
+{
+	size_t oldlen = sizeof(int);
+	int oldval;
+	char buf[80];
+
+	ATF_REQUIRE(sysctlbyname(name, &oldval, &oldlen, NULL, 0) == 0);
+
+	/* Store old %name in a symlink for cleanup */
+	snprintf(buf, sizeof(buf), "%d", oldval);
+	ATF_REQUIRE(symlink(buf, SAVEDVALUE) == 0);
+
+	ATF_REQUIRE(sysctlbyname(name, NULL, NULL, &val, sizeof(val)) == 0);
+}
+
+static void
+sysctlcleanup(const char *name)
+{
+	size_t oldlen;
+	int n, oldval;
+	char buf[80];
+
+	if ((n = readlink(SAVEDVALUE, buf, sizeof(buf))) > 0) {
+		buf[MIN((size_t)n, sizeof(buf) - 1)] = '\0';
+		if (sscanf(buf, "%d", &oldval) == 1) {
+			oldlen = sizeof(oldval);
+			(void)sysctlbyname(name, NULL, 0,
+			    &oldval, oldlen);
+		}
+	}
+	(void)unlink(SAVEDVALUE);
+}
+
+ATF_TC_WITH_CLEANUP(sigsys_test_on);
+ATF_TC_HEAD(sigsys_test_on, tc)
+{
+	atf_tc_set_md_var(tc, "require.user", "root");
+	atf_tc_set_md_var(tc, "require.config", "allow_sysctl_side_effects");
+	atf_tc_set_md_var(tc, "descr",
+	    "Testing delivery of SIGSYS on invalid syscalls");
+}
+
+ATF_TC_BODY(sigsys_test_on, tc)
+{
+	sysctlset("kern.signosys", 1);
+	sigsys_test(1);
+}
+
+ATF_TC_CLEANUP(sigsys_test_on, tc)
+{
+	sysctlcleanup("kern.signosys");
+}
+
+ATF_TC_WITH_CLEANUP(sigsys_test_off);
+ATF_TC_HEAD(sigsys_test_off, tc)
+{
+	atf_tc_set_md_var(tc, "require.user", "root");
+	atf_tc_set_md_var(tc, "require.config", "allow_sysctl_side_effects");
+	atf_tc_set_md_var(tc, "descr",
+	    "Testing SIGSYS silence on invalid syscalls");
+}
+
+ATF_TC_BODY(sigsys_test_off, tc)
+{
+	sysctlset("kern.signosys", 0);
+	sigsys_test(0);
+}
+
+ATF_TC_CLEANUP(sigsys_test_off, tc)
+{
+	sysctlcleanup("kern.signosys");
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+	ATF_TP_ADD_TC(tp, sigsys_test_on);
+	ATF_TP_ADD_TC(tp, sigsys_test_off);
+	return (atf_no_error());
+}