tests: Add stack grows tests

Reviewed by:		kib
Differential Revision:	https://reviews.freebsd.org/D41320
MFC after:		2 weeks

etc/mtree/BSD.tests.dist

@@ -897,6 +897,8 @@
         vfs
         ..
         vm
+            stack
+            ..
         ..
         vmm
         ..

tests/sys/vm/Makefile

@@ -17,4 +17,9 @@ ATF_TESTS_SH+=	mmap_map_32bit_test
 PROGS+=		mmap_map_32bit_helper
 .endif
 
+SUBDIR=		soxstack
+TESTS_SUBDIRS+=	stack
+
+SUBDIR_DEPENDS_stack=soxstack
+
 .include <bsd.test.mk>

tests/sys/vm/soxstack/Makefile

@@ -0,0 +1,17 @@
+# $FreeBSD$
+
+SHLIB=		soxstack
+SHLIB_NAME=	libsoxstack.so
+SHLIB_MAJOR=	1
+
+WITHOUT_STATIC=
+WITHOUT_PROFILE=
+WITHOUT_PIC=
+
+SRCS=		soxstack.c
+LDFLAGS+=	-Wl,-z,execstack
+LIBADD+=	procstat
+
+LIBDIR=		${TESTSBASE}/sys/vm/stack
+
+.include <bsd.lib.mk>

tests/sys/vm/soxstack/soxstack.c

@@ -0,0 +1,51 @@
+/*-
+ * Copyright (c) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <sys/user.h>
+
+#include <assert.h>
+#include <libprocstat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int	checkstack(void);
+
+#define	_STACK_FLAG_GROWS	KVME_FLAG_GROWS_UP | KVME_FLAG_GROWS_DOWN
+int
+checkstack(void)
+{
+	struct kinfo_vmentry *freep, *kve;
+	struct kinfo_proc *p;
+	struct procstat *prstat;
+	uint64_t stack;
+	int i, cnt;
+
+	prstat = procstat_open_sysctl();
+	assert(prstat != NULL);
+	p = procstat_getprocs(prstat, KERN_PROC_PID, getpid(), &cnt);
+	assert(p != NULL);
+	freep = procstat_getvmmap(prstat, p, &cnt);
+	assert(freep != NULL);
+
+	stack = (uint64_t)&i;
+	for (i = 0; i < cnt; i++) {
+		kve = &freep[i];
+		if (stack < kve->kve_start || stack > kve->kve_end)
+			continue;
+		if ((kve->kve_flags & _STACK_FLAG_GROWS) != 0 &&
+		    (kve->kve_protection & KVME_PROT_EXEC) != 0)
+			stack = 0;
+		break;
+	}
+
+	free(freep);
+	procstat_freeprocs(prstat, p);
+	procstat_close(prstat);
+	return (stack != 0);
+}

tests/sys/vm/stack/Makefile

@@ -0,0 +1,15 @@
+# $FreeBSD$
+
+PACKAGE=	tests
+
+TESTSDIR=	${TESTSBASE}/sys/vm/stack
+
+ATF_TESTS_C+=	stack_dt_need_exec_test
+ATF_TESTS_C+=	stack_dlopen_exec_test
+ATF_TESTS_C+=	stack_mprotect_exec_test
+
+LDFLAGS.stack_dt_need_exec_test+= -Wl,-rpath,${TESTSDIR} -L${.OBJDIR:H}/soxstack
+LDADD.stack_dt_need_exec_test+= -lsoxstack
+LDFLAGS.stack_dlopen_exec_test+= -Wl,-rpath,${TESTSDIR}
+
+.include <bsd.test.mk>

tests/sys/vm/stack/stack_dlopen_exec_test.c

@@ -0,0 +1,64 @@
+/*-
+ * Copyright (c) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <sys/systm.h>
+#include <vm/vm_param.h>
+
+#include <atf-c.h>
+#include <dlfcn.h>
+
+static int jumpstack0(void) __noinline;
+static int jumpstack1(void) __noinline;
+
+static int (*socheckstack)(void) = NULL;
+
+static int
+checkstack(void)
+{
+	void *fh;
+
+	if (socheckstack == NULL) {
+		fh = dlopen("libsoxstack.so", RTLD_LAZY);
+		ATF_REQUIRE(fh != NULL);
+		socheckstack = dlsym(fh, "checkstack");
+		ATF_REQUIRE(socheckstack != NULL);
+	}
+	return (socheckstack());
+}
+
+static int
+jumpstack0(void)
+{
+	char stack[SGROWSIZ];
+
+	explicit_bzero(stack, sizeof(stack));
+	return (checkstack());
+}
+
+static int
+jumpstack1(void)
+{
+	char stack[SGROWSIZ * 2];
+
+	explicit_bzero(stack, sizeof(stack));
+	return (checkstack());
+}
+
+ATF_TC_WITHOUT_HEAD(dlopen_test);
+ATF_TC_BODY(dlopen_test, tc)
+{
+
+	ATF_REQUIRE(jumpstack0() == 0);
+	ATF_REQUIRE(jumpstack1() == 0);
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+
+	ATF_TP_ADD_TC(tp, dlopen_test);
+
+	return (atf_no_error());
+}

tests/sys/vm/stack/stack_dt_need_exec_test.c

@@ -0,0 +1,50 @@
+/*-
+ * Copyright (c) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <sys/systm.h>
+#include <vm/vm_param.h>
+
+#include <atf-c.h>
+
+extern int checkstack(void);
+
+static int jumpstack0(void) __noinline;
+static int jumpstack1(void) __noinline;
+
+
+static int
+jumpstack0(void)
+{
+	char stack[SGROWSIZ];
+
+	explicit_bzero(stack, sizeof(stack));
+	return (checkstack());
+}
+
+static int
+jumpstack1(void)
+{
+	char stack[SGROWSIZ * 2];
+
+	explicit_bzero(stack, sizeof(stack));
+	return (checkstack());
+}
+
+ATF_TC_WITHOUT_HEAD(dt_need_test);
+ATF_TC_BODY(dt_need_test, tc)
+{
+
+	ATF_REQUIRE(jumpstack0() == 0);
+	ATF_REQUIRE(jumpstack1() == 0);
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+
+	ATF_TP_ADD_TC(tp, dt_need_test);
+
+	return (atf_no_error());
+}

tests/sys/vm/stack/stack_mprotect_exec_test.c

@@ -0,0 +1,48 @@
+/*-
+ * Copyright (c) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * PR:	272585
+ * Test provided by John F. Carr
+ */
+
+#include <sys/systm.h>
+#include <sys/mman.h>
+#include <vm/vm_param.h>
+
+#include <atf-c.h>
+#include <unistd.h>
+
+
+ATF_TC_WITHOUT_HEAD(mprotect_exec_test);
+ATF_TC_BODY(mprotect_exec_test, tc)
+{
+	long pagesize;
+	char *addr, *guard;
+	size_t alloc_size;
+
+	pagesize = sysconf(_SC_PAGESIZE);
+	ATF_REQUIRE(pagesize > 0);
+
+	alloc_size = SGROWSIZ * 2;
+	addr = mmap(NULL, alloc_size, PROT_READ | PROT_WRITE,
+	    MAP_STACK | MAP_PRIVATE | MAP_ANON, -1, 0);
+	ATF_REQUIRE(addr != MAP_FAILED);
+
+	/*
+	 * Change prot of the last page in the mmaped stack area.
+	 */
+	guard = addr + alloc_size - SGROWSIZ;
+	ATF_REQUIRE(mprotect(guard, pagesize, PROT_NONE) == 0);
+
+	((volatile char *)guard)[-1];
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+
+	ATF_TP_ADD_TC(tp, mprotect_exec_test);
+
+	return (atf_no_error());
+}