lib: stackinit: Convert to KUnit

Convert stackinit unit tests to KUnit, for better integration
into the kernel self test framework. Includes a rename of
test_stackinit.c to stackinit_kunit.c, and CONFIG_TEST_STACKINIT to
CONFIG_STACKINIT_KUNIT_TEST.

Adjust expected test results based on which stack initialization method
was chosen:

 $ CMD="./tools/testing/kunit/kunit.py run stackinit --raw_output \
        --arch=x86_64 --kconfig_add"

 $ $CMD | grep stackinit:
 # stackinit: pass:36 fail:0 skip:29 total:65

 $ $CMD CONFIG_GCC_PLUGIN_STRUCTLEAK_USER=y | grep stackinit:
 # stackinit: pass:37 fail:0 skip:28 total:65

 $ $CMD CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF=y | grep stackinit:
 # stackinit: pass:55 fail:0 skip:10 total:65

 $ $CMD CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL=y | grep stackinit:
 # stackinit: pass:62 fail:0 skip:3 total:65

 $ $CMD CONFIG_INIT_STACK_ALL_PATTERN=y --make_option LLVM=1 | grep stackinit:
 # stackinit: pass:60 fail:0 skip:5 total:65

 $ $CMD CONFIG_INIT_STACK_ALL_ZERO=y --make_option LLVM=1 | grep stackinit:
 # stackinit: pass:60 fail:0 skip:5 total:65

Temporarily remove the userspace-build mode, which will be restored in a
later patch.

Expand the size of the pre-case switch variable so it doesn't get
accidentally cleared.

Cc: David Gow <davidgow@google.com>
Cc: Daniel Latypov <dlatypov@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
v1: https://lore.kernel.org/lkml/20220224055145.1853657-1-keescook@chromium.org
v2:
 - split "userspace KUnit stub" into separate header and patch (Daniel)
 - Improve commit log and comments (David)
 - Provide mapping of expected XFAIL tests to CONFIGs (David)

1 files changed, 0 insertions, 514 deletions

diff --git a/lib/test_stackinit.c b/lib/test_stackinit.c
deleted file mode 100644
index a3c74e6a21ff..000000000000
--- a/lib/test_stackinit.c
+++ /dev/null
@@ -1,514 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * Test cases for compiler-based stack variable zeroing via
- * -ftrivial-auto-var-init={zero,pattern} or CONFIG_GCC_PLUGIN_STRUCTLEAK*.
- *
- * External build example:
- *	clang -O2 -Wall -ftrivial-auto-var-init=pattern \
- *		-o test_stackinit test_stackinit.c
- */
-#ifdef __KERNEL__
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/string.h>
-
-#else
-
-/* Userspace headers. */
-#include <stdio.h>
-#include <stdint.h>
-#include <string.h>
-#include <stdbool.h>
-#include <errno.h>
-#include <sys/types.h>
-
-/* Linux kernel-ism stubs for stand-alone userspace build. */
-#define KBUILD_MODNAME		"stackinit"
-#define pr_fmt(fmt)		KBUILD_MODNAME ": " fmt
-#define pr_err(fmt, ...)	fprintf(stderr, pr_fmt(fmt), ##__VA_ARGS__)
-#define pr_warn(fmt, ...)	fprintf(stderr, pr_fmt(fmt), ##__VA_ARGS__)
-#define pr_info(fmt, ...)	fprintf(stdout, pr_fmt(fmt), ##__VA_ARGS__)
-#define __init			/**/
-#define __exit			/**/
-#define __user			/**/
-#define noinline		__attribute__((__noinline__))
-#define __aligned(x)		__attribute__((__aligned__(x)))
-#ifdef __clang__
-# define __compiletime_error(message) /**/
-#else
-# define __compiletime_error(message) __attribute__((__error__(message)))
-#endif
-#define __compiletime_assert(condition, msg, prefix, suffix)		\
-	do {								\
-		extern void prefix ## suffix(void) __compiletime_error(msg); \
-		if (!(condition))					\
-			prefix ## suffix();				\
-	} while (0)
-#define _compiletime_assert(condition, msg, prefix, suffix) \
-	__compiletime_assert(condition, msg, prefix, suffix)
-#define compiletime_assert(condition, msg) \
-	_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
-#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
-#define BUILD_BUG_ON(condition) \
-	BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
-typedef uint8_t			u8;
-typedef uint16_t		u16;
-typedef uint32_t		u32;
-typedef uint64_t		u64;
-
-#define module_init(func)	static int (*do_init)(void) = func
-#define module_exit(func)	static void (*do_exit)(void) = func
-#define MODULE_LICENSE(str)	int main(void) {		\
-					int rc;			\
-					/* License: str */	\
-					rc = do_init();		\
-					if (rc == 0)		\
-						do_exit();	\
-					return rc;		\
-				}
-
-#endif /* __KERNEL__ */
-
-/* Exfiltration buffer. */
-#define MAX_VAR_SIZE	128
-static u8 check_buf[MAX_VAR_SIZE];
-
-/* Character array to trigger stack protector in all functions. */
-#define VAR_BUFFER	 32
-
-/* Volatile mask to convince compiler to copy memory with 0xff. */
-static volatile u8 forced_mask = 0xff;
-
-/* Location and size tracking to validate fill and test are colocated. */
-static void *fill_start, *target_start;
-static size_t fill_size, target_size;
-
-static bool range_contains(char *haystack_start, size_t haystack_size,
-			   char *needle_start, size_t needle_size)
-{
-	if (needle_start >= haystack_start &&
-	    needle_start + needle_size <= haystack_start + haystack_size)
-		return true;
-	return false;
-}
-
-/* Whether the test is expected to fail. */
-#define WANT_SUCCESS				0
-#define XFAIL					1
-
-#define DO_NOTHING_TYPE_SCALAR(var_type)	var_type
-#define DO_NOTHING_TYPE_STRING(var_type)	void
-#define DO_NOTHING_TYPE_STRUCT(var_type)	void
-
-#define DO_NOTHING_RETURN_SCALAR(ptr)		*(ptr)
-#define DO_NOTHING_RETURN_STRING(ptr)		/**/
-#define DO_NOTHING_RETURN_STRUCT(ptr)		/**/
-
-#define DO_NOTHING_CALL_SCALAR(var, name)			\
-		(var) = do_nothing_ ## name(&(var))
-#define DO_NOTHING_CALL_STRING(var, name)			\
-		do_nothing_ ## name(var)
-#define DO_NOTHING_CALL_STRUCT(var, name)			\
-		do_nothing_ ## name(&(var))
-
-#define FETCH_ARG_SCALAR(var)		&var
-#define FETCH_ARG_STRING(var)		var
-#define FETCH_ARG_STRUCT(var)		&var
-
-#define FILL_SIZE_STRING		16
-
-#define INIT_CLONE_SCALAR		/**/
-#define INIT_CLONE_STRING		[FILL_SIZE_STRING]
-#define INIT_CLONE_STRUCT		/**/
-
-#define ZERO_CLONE_SCALAR(zero)		memset(&(zero), 0x00, sizeof(zero))
-#define ZERO_CLONE_STRING(zero)		memset(&(zero), 0x00, sizeof(zero))
-/*
- * For the struct, intentionally poison padding to see if it gets
- * copied out in direct assignments.
- * */
-#define ZERO_CLONE_STRUCT(zero)				\
-	do {						\
-		memset(&(zero), 0xFF, sizeof(zero));	\
-		zero.one = 0;				\
-		zero.two = 0;				\
-		zero.three = 0;				\
-		zero.four = 0;				\
-	} while (0)
-
-#define INIT_SCALAR_none(var_type)	/**/
-#define INIT_SCALAR_zero(var_type)	= 0
-
-#define INIT_STRING_none(var_type)	[FILL_SIZE_STRING] /**/
-#define INIT_STRING_zero(var_type)	[FILL_SIZE_STRING] = { }
-
-#define INIT_STRUCT_none(var_type)	/**/
-#define INIT_STRUCT_zero(var_type)	= { }
-
-
-#define __static_partial		{ .two = 0, }
-#define __static_all			{ .one = 0,			\
-					  .two = 0,			\
-					  .three = 0,			\
-					  .four = 0,			\
-					}
-#define __dynamic_partial		{ .two = arg->two, }
-#define __dynamic_all			{ .one = arg->one,		\
-					  .two = arg->two,		\
-					  .three = arg->three,		\
-					  .four = arg->four,		\
-					}
-#define __runtime_partial		var.two = 0
-#define __runtime_all			var.one = 0;			\
-					var.two = 0;			\
-					var.three = 0;			\
-					var.four = 0
-
-#define INIT_STRUCT_static_partial(var_type)				\
-					= __static_partial
-#define INIT_STRUCT_static_all(var_type)				\
-					= __static_all
-#define INIT_STRUCT_dynamic_partial(var_type)				\
-					= __dynamic_partial
-#define INIT_STRUCT_dynamic_all(var_type)				\
-					= __dynamic_all
-#define INIT_STRUCT_runtime_partial(var_type)				\
-					; __runtime_partial
-#define INIT_STRUCT_runtime_all(var_type)				\
-					; __runtime_all
-
-#define INIT_STRUCT_assigned_static_partial(var_type)			\
-					; var = (var_type)__static_partial
-#define INIT_STRUCT_assigned_static_all(var_type)			\
-					; var = (var_type)__static_all
-#define INIT_STRUCT_assigned_dynamic_partial(var_type)			\
-					; var = (var_type)__dynamic_partial
-#define INIT_STRUCT_assigned_dynamic_all(var_type)			\
-					; var = (var_type)__dynamic_all
-
-#define INIT_STRUCT_assigned_copy(var_type)				\
-					; var = *(arg)
-
-/*
- * @name: unique string name for the test
- * @var_type: type to be tested for zeroing initialization
- * @which: is this a SCALAR, STRING, or STRUCT type?
- * @init_level: what kind of initialization is performed
- * @xfail: is this test expected to fail?
- */
-#define DEFINE_TEST_DRIVER(name, var_type, which, xfail)	\
-/* Returns 0 on success, 1 on failure. */			\
-static noinline __init int test_ ## name (void)			\
-{								\
-	var_type zero INIT_CLONE_ ## which;			\
-	int ignored;						\
-	u8 sum = 0, i;						\
-								\
-	/* Notice when a new test is larger than expected. */	\
-	BUILD_BUG_ON(sizeof(zero) > MAX_VAR_SIZE);		\
-								\
-	/* Fill clone type with zero for per-field init. */	\
-	ZERO_CLONE_ ## which(zero);				\
-	/* Clear entire check buffer for 0xFF overlap test. */	\
-	memset(check_buf, 0x00, sizeof(check_buf));		\
-	/* Fill stack with 0xFF. */				\
-	ignored = leaf_ ##name((unsigned long)&ignored, 1,	\
-				FETCH_ARG_ ## which(zero));	\
-	/* Verify all bytes overwritten with 0xFF. */		\
-	for (sum = 0, i = 0; i < target_size; i++)		\
-		sum += (check_buf[i] != 0xFF);			\
-	if (sum) {						\
-		pr_err(#name ": leaf fill was not 0xFF!?\n");	\
-		return 1;					\
-	}							\
-	/* Clear entire check buffer for later bit tests. */	\
-	memset(check_buf, 0x00, sizeof(check_buf));		\
-	/* Extract stack-defined variable contents. */		\
-	ignored = leaf_ ##name((unsigned long)&ignored, 0,	\
-				FETCH_ARG_ ## which(zero));	\
-								\
-	/* Validate that compiler lined up fill and target. */	\
-	if (!range_contains(fill_start, fill_size,		\
-			    target_start, target_size)) {	\
-		pr_err(#name ": stack fill missed target!?\n");	\
-		pr_err(#name ": fill %zu wide\n", fill_size);	\
-		pr_err(#name ": target offset by %d\n",	\
-			(int)((ssize_t)(uintptr_t)fill_start -	\
-			(ssize_t)(uintptr_t)target_start));	\
-		return 1;					\
-	}							\
-								\
-	/* Look for any bytes still 0xFF in check region. */	\
-	for (sum = 0, i = 0; i < target_size; i++)		\
-		sum += (check_buf[i] == 0xFF);			\
-								\
-	if (sum == 0) {						\
-		pr_info(#name " ok\n");				\
-		return 0;					\
-	} else {						\
-		pr_warn(#name " %sFAIL (uninit bytes: %d)\n",	\
-			(xfail) ? "X" : "", sum);		\
-		return (xfail) ? 0 : 1;				\
-	}							\
-}
-#define DEFINE_TEST(name, var_type, which, init_level, xfail)	\
-/* no-op to force compiler into ignoring "uninitialized" vars */\
-static noinline __init DO_NOTHING_TYPE_ ## which(var_type)	\
-do_nothing_ ## name(var_type *ptr)				\
-{								\
-	/* Will always be true, but compiler doesn't know. */	\
-	if ((unsigned long)ptr > 0x2)				\
-		return DO_NOTHING_RETURN_ ## which(ptr);	\
-	else							\
-		return DO_NOTHING_RETURN_ ## which(ptr + 1);	\
-}								\
-static noinline __init int leaf_ ## name(unsigned long sp,	\
-					 bool fill,		\
-					 var_type *arg)		\
-{								\
-	char buf[VAR_BUFFER];					\
-	var_type var						\
-		INIT_ ## which ## _ ## init_level(var_type);	\
-								\
-	target_start = &var;					\
-	target_size = sizeof(var);				\
-	/*							\
-	 * Keep this buffer around to make sure we've got a	\
-	 * stack frame of SOME kind...				\
-	 */							\
-	memset(buf, (char)(sp & 0xff), sizeof(buf));		\
-	/* Fill variable with 0xFF. */				\
-	if (fill) {						\
-		fill_start = &var;				\
-		fill_size = sizeof(var);			\
-		memset(fill_start,				\
-		       (char)((sp & 0xff) | forced_mask),	\
-		       fill_size);				\
-	}							\
-								\
-	/* Silence "never initialized" warnings. */		\
-	DO_NOTHING_CALL_ ## which(var, name);			\
-								\
-	/* Exfiltrate "var". */					\
-	memcpy(check_buf, target_start, target_size);		\
-								\
-	return (int)buf[0] | (int)buf[sizeof(buf) - 1];		\
-}								\
-DEFINE_TEST_DRIVER(name, var_type, which, xfail)
-
-/* Structure with no padding. */
-struct test_packed {
-	unsigned long one;
-	unsigned long two;
-	unsigned long three;
-	unsigned long four;
-};
-
-/* Simple structure with padding likely to be covered by compiler. */
-struct test_small_hole {
-	size_t one;
-	char two;
-	/* 3 byte padding hole here. */
-	int three;
-	unsigned long four;
-};
-
-/* Trigger unhandled padding in a structure. */
-struct test_big_hole {
-	u8 one;
-	u8 two;
-	u8 three;
-	/* 61 byte padding hole here. */
-	u8 four __aligned(64);
-} __aligned(64);
-
-struct test_trailing_hole {
-	char *one;
-	char *two;
-	char *three;
-	char four;
-	/* "sizeof(unsigned long) - 1" byte padding hole here. */
-};
-
-/* Test if STRUCTLEAK is clearing structs with __user fields. */
-struct test_user {
-	u8 one;
-	unsigned long two;
-	char __user *three;
-	unsigned long four;
-};
-
-#define DEFINE_SCALAR_TEST(name, init, xfail)			\
-		DEFINE_TEST(name ## _ ## init, name, SCALAR,	\
-			    init, xfail)
-
-#define DEFINE_SCALAR_TESTS(init, xfail)			\
-		DEFINE_SCALAR_TEST(u8, init, xfail);		\
-		DEFINE_SCALAR_TEST(u16, init, xfail);		\
-		DEFINE_SCALAR_TEST(u32, init, xfail);		\
-		DEFINE_SCALAR_TEST(u64, init, xfail);		\
-		DEFINE_TEST(char_array_ ## init, unsigned char,	\
-			    STRING, init, xfail)
-
-#define DEFINE_STRUCT_TEST(name, init, xfail)			\
-		DEFINE_TEST(name ## _ ## init,			\
-			    struct test_ ## name, STRUCT, init, \
-			    xfail)
-
-#define DEFINE_STRUCT_TESTS(init, xfail)			\
-		DEFINE_STRUCT_TEST(small_hole, init, xfail);	\
-		DEFINE_STRUCT_TEST(big_hole, init, xfail);	\
-		DEFINE_STRUCT_TEST(trailing_hole, init, xfail);	\
-		DEFINE_STRUCT_TEST(packed, init, xfail)
-
-#define DEFINE_STRUCT_INITIALIZER_TESTS(base)			\
-		DEFINE_STRUCT_TESTS(base ## _ ## partial,	\
-				    WANT_SUCCESS);		\
-		DEFINE_STRUCT_TESTS(base ## _ ## all,		\
-				    WANT_SUCCESS)
-
-/* These should be fully initialized all the time! */
-DEFINE_SCALAR_TESTS(zero, WANT_SUCCESS);
-DEFINE_STRUCT_TESTS(zero, WANT_SUCCESS);
-/* Struct initializers: padding may be left uninitialized. */
-DEFINE_STRUCT_INITIALIZER_TESTS(static);
-DEFINE_STRUCT_INITIALIZER_TESTS(dynamic);
-DEFINE_STRUCT_INITIALIZER_TESTS(runtime);
-DEFINE_STRUCT_INITIALIZER_TESTS(assigned_static);
-DEFINE_STRUCT_INITIALIZER_TESTS(assigned_dynamic);
-DEFINE_STRUCT_TESTS(assigned_copy, XFAIL);
-/* No initialization without compiler instrumentation. */
-DEFINE_SCALAR_TESTS(none, WANT_SUCCESS);
-DEFINE_STRUCT_TESTS(none, WANT_SUCCESS);
-/* Initialization of members with __user attribute. */
-DEFINE_TEST(user, struct test_user, STRUCT, none, WANT_SUCCESS);
-
-/*
- * Check two uses through a variable declaration outside either path,
- * which was noticed as a special case in porting earlier stack init
- * compiler logic.
- */
-static int noinline __leaf_switch_none(int path, bool fill)
-{
-	switch (path) {
-		/*
-		 * This is intentionally unreachable. To silence the
-		 * warning, build with -Wno-switch-unreachable
-		 */
-		uint64_t var;
-
-	case 1:
-		target_start = &var;
-		target_size = sizeof(var);
-		if (fill) {
-			fill_start = &var;
-			fill_size = sizeof(var);
-
-			memset(fill_start, forced_mask | 0x55, fill_size);
-		}
-		memcpy(check_buf, target_start, target_size);
-		break;
-	case 2:
-		target_start = &var;
-		target_size = sizeof(var);
-		if (fill) {
-			fill_start = &var;
-			fill_size = sizeof(var);
-
-			memset(fill_start, forced_mask | 0xaa, fill_size);
-		}
-		memcpy(check_buf, target_start, target_size);
-		break;
-	default:
-		var = 5;
-		return var & forced_mask;
-	}
-	return 0;
-}
-
-static noinline __init int leaf_switch_1_none(unsigned long sp, bool fill,
-					      uint64_t *arg)
-{
-	return __leaf_switch_none(1, fill);
-}
-
-static noinline __init int leaf_switch_2_none(unsigned long sp, bool fill,
-					      uint64_t *arg)
-{
-	return __leaf_switch_none(2, fill);
-}
-
-/*
- * These are expected to fail for most configurations because neither
- * GCC nor Clang have a way to perform initialization of variables in
- * non-code areas (i.e. in a switch statement before the first "case").
- * https://bugs.llvm.org/show_bug.cgi?id=44916
- */
-DEFINE_TEST_DRIVER(switch_1_none, uint64_t, SCALAR, XFAIL);
-DEFINE_TEST_DRIVER(switch_2_none, uint64_t, SCALAR, XFAIL);
-
-static int __init test_stackinit_init(void)
-{
-	unsigned int failures = 0;
-
-#define test_scalars(init)	do {				\
-		failures += test_u8_ ## init ();		\
-		failures += test_u16_ ## init ();		\
-		failures += test_u32_ ## init ();		\
-		failures += test_u64_ ## init ();		\
-		failures += test_char_array_ ## init ();	\
-	} while (0)
-
-#define test_structs(init)	do {				\
-		failures += test_small_hole_ ## init ();	\
-		failures += test_big_hole_ ## init ();		\
-		failures += test_trailing_hole_ ## init ();	\
-		failures += test_packed_ ## init ();		\
-	} while (0)
-
-	/* These are explicitly initialized and should always pass. */
-	test_scalars(zero);
-	test_structs(zero);
-	/* Padding here appears to be accidentally always initialized? */
-	test_structs(dynamic_partial);
-	test_structs(assigned_dynamic_partial);
-	/* Padding initialization depends on compiler behaviors. */
-	test_structs(static_partial);
-	test_structs(static_all);
-	test_structs(dynamic_all);
-	test_structs(runtime_partial);
-	test_structs(runtime_all);
-	test_structs(assigned_static_partial);
-	test_structs(assigned_static_all);
-	test_structs(assigned_dynamic_all);
-	/* Everything fails this since it effectively performs a memcpy(). */
-	test_structs(assigned_copy);
-
-	/* STRUCTLEAK_BYREF_ALL should cover everything from here down. */
-	test_scalars(none);
-	failures += test_switch_1_none();
-	failures += test_switch_2_none();
-
-	/* STRUCTLEAK_BYREF should cover from here down. */
-	test_structs(none);
-
-	/* STRUCTLEAK will only cover this. */
-	failures += test_user();
-
-	if (failures == 0)
-		pr_info("all tests passed!\n");
-	else
-		pr_err("failures: %u\n", failures);
-
-	return failures ? -EINVAL : 0;
-}
-module_init(test_stackinit_init);
-
-static void __exit test_stackinit_exit(void)
-{ }
-module_exit(test_stackinit_exit);
-
-MODULE_LICENSE("GPL");