Commit 41eefc46 authored by Kees Cook's avatar Kees Cook
Browse files

string: Convert strscpy() self-test to KUnit 



Convert the strscpy() self-test to a KUnit test.

Cc: David Gow <davidgow@google.com>
Cc: Tobin C. Harding <tobin@kernel.org>
Tested-by: default avatarNathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/lkml/Y072ZMk/hNkfwqMv@dev-arch.thelio-3990X


Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent 9e4a6177

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -8045,6 +8045,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/har 
F:	include/linux/fortify-string.h

F:	lib/fortify_kunit.c

F:	lib/memcpy_kunit.c

F:	lib/strscpy_kunit.c

F:	lib/test_fortify/*

F:	scripts/test_fortify.sh

K:	\b__NO_FORTIFY\b

lib/Kconfig.debug

+5 −3
Original line number Diff line number Diff line
@@ -2215,9 +2215,6 @@ config STRING_SELFTEST 
config TEST_STRING_HELPERS

	tristate "Test functions located in the string_helpers module at runtime"



config TEST_STRSCPY

	tristate "Test strscpy*() family of functions at runtime"



config TEST_KSTRTOX

	tristate "Test kstrto*() family of functions at runtime"
@@ -2583,6 +2580,11 @@ config HW_BREAKPOINT_KUNIT_TEST 


	  If unsure, say N.



config STRSCPY_KUNIT_TEST

	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS

	depends on KUNIT

	default KUNIT_ALL_TESTS



config TEST_UDELAY

	tristate "udelay test driver"

	help

lib/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -82,7 +82,6 @@ obj-$(CONFIG_TEST_DYNAMIC_DEBUG) += test_dynamic_debug.o 
obj-$(CONFIG_TEST_PRINTF) += test_printf.o

obj-$(CONFIG_TEST_SCANF) += test_scanf.o

obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o

obj-$(CONFIG_TEST_STRSCPY) += test_strscpy.o

obj-$(CONFIG_TEST_UUID) += test_uuid.o

obj-$(CONFIG_TEST_XARRAY) += test_xarray.o

obj-$(CONFIG_TEST_PARMAN) += test_parman.o
@@ -380,6 +379,7 @@ obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o 
CFLAGS_stackinit_kunit.o += $(call cc-disable-warning, switch-unreachable)

obj-$(CONFIG_STACKINIT_KUNIT_TEST) += stackinit_kunit.o

obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o

obj-$(CONFIG_STRSCPY_KUNIT_TEST) += strscpy_kunit.o



obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o

lib/test_strscpy.c→lib/strscpy_kunit.c

+129 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0+



#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/string.h>



#include "../tools/testing/selftests/kselftest_module.h"



/*

 * Kernel module for testing 'strscpy' family of functions.

 */



KSTM_MODULE_GLOBALS();

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <kunit/test.h>

#include <linux/string.h>



/*

 * tc() - Run a specific test case.
@@ -26,7 +22,7 @@ KSTM_MODULE_GLOBALS(); 
 * Calls strscpy_pad() and verifies the return value and state of the

 * destination buffer after the call returns.

 */

static int __init tc(char *src, int count, int expected,

static void tc(struct kunit *test, char *src, int count, int expected,

	       int chars, int terminator, int pad)

{

	int nr_bytes_poison;
@@ -37,81 +33,53 @@ static int __init tc(char *src, int count, int expected, 
	int index, i;

	const char POISON = 'z';



	total_tests++;



	if (!src) {

		pr_err("null source string not supported\n");

		return -1;

	}

	KUNIT_ASSERT_TRUE_MSG(test, src != NULL,

			      "null source string not supported");



	memset(buf, POISON, sizeof(buf));

	/* Future proofing test suite, validate args */

	max_count = sizeof(buf) - 2; /* Space for null and to verify overflow */

	max_expected = count - 1;    /* Space for the null */

	if (count > max_count) {

		pr_err("count (%d) is too big (%d) ... aborting", count, max_count);

		return -1;

	}

	if (expected > max_expected) {

		pr_warn("expected (%d) is bigger than can possibly be returned (%d)",



	KUNIT_ASSERT_LE_MSG(test, count, max_count,

		"count (%d) is too big (%d) ... aborting", count, max_count);

	KUNIT_EXPECT_LE_MSG(test, expected, max_expected,

		"expected (%d) is bigger than can possibly be returned (%d)",

		expected, max_expected);

	}



	written = strscpy_pad(buf, src, count);

	if ((written) != (expected)) {

		pr_err("%d != %d (written, expected)\n", written, expected);

		goto fail;

	}

	KUNIT_ASSERT_EQ(test, written, expected);



	if (count && written == -E2BIG) {

		if (strncmp(buf, src, count - 1) != 0) {

			pr_err("buffer state invalid for -E2BIG\n");

			goto fail;

		}

		if (buf[count - 1] != '\0') {

			pr_err("too big string is not null terminated correctly\n");

			goto fail;

		}

		KUNIT_ASSERT_EQ_MSG(test, 0, strncmp(buf, src, count - 1),

			"buffer state invalid for -E2BIG");

		KUNIT_ASSERT_EQ_MSG(test, buf[count - 1], '\0',

			"too big string is not null terminated correctly");

	}



	for (i = 0; i < chars; i++) {

		if (buf[i] != src[i]) {

			pr_err("buf[i]==%c != src[i]==%c\n", buf[i], src[i]);

			goto fail;

		}

	}

	for (i = 0; i < chars; i++)

		KUNIT_ASSERT_EQ_MSG(test, buf[i], src[i],

			"buf[i]==%c != src[i]==%c", buf[i], src[i]);



	if (terminator) {

		if (buf[count - 1] != '\0') {

			pr_err("string is not null terminated correctly\n");

			goto fail;

		}

	}

	if (terminator)

		KUNIT_ASSERT_EQ_MSG(test, buf[count - 1], '\0',

			"string is not null terminated correctly");



	for (i = 0; i < pad; i++) {

		index = chars + terminator + i;

		if (buf[index] != '\0') {

			pr_err("padding missing at index: %d\n", i);

			goto fail;

		}

		KUNIT_ASSERT_EQ_MSG(test, buf[index], '\0',

			"padding missing at index: %d", i);

	}



	nr_bytes_poison = sizeof(buf) - chars - terminator - pad;

	for (i = 0; i < nr_bytes_poison; i++) {

		index = sizeof(buf) - 1 - i; /* Check from the end back */

		if (buf[index] != POISON) {

			pr_err("poison value missing at index: %d\n", i);

			goto fail;

		}

		KUNIT_ASSERT_EQ_MSG(test, buf[index], POISON,

			"poison value missing at index: %d", i);

	}



	return 0;

fail:

	failed_tests++;

	return -1;

}



static void __init selftest(void)

static void strscpy_test(struct kunit *test)

{

	/*

	 * tc() uses a destination buffer of size 6 and needs at
@@ -122,29 +90,40 @@ static void __init selftest(void) 
	 * the buffer size in tc().

	 */



	/* tc(src, count, expected, chars, terminator, pad) */

	KSTM_CHECK_ZERO(tc("a", 0, -E2BIG, 0, 0, 0));

	KSTM_CHECK_ZERO(tc("", 0, -E2BIG, 0, 0, 0));

	/* tc(test, src, count, expected, chars, terminator, pad) */

	tc(test, "a", 0, -E2BIG, 0, 0, 0);

	tc(test, "",  0, -E2BIG, 0, 0, 0);



	KSTM_CHECK_ZERO(tc("a", 1, -E2BIG, 0, 1, 0));

	KSTM_CHECK_ZERO(tc("", 1, 0, 0, 1, 0));

	tc(test, "a", 1, -E2BIG, 0, 1, 0);

	tc(test, "",  1, 0,	 0, 1, 0);



	KSTM_CHECK_ZERO(tc("ab", 2, -E2BIG, 1, 1, 0));

	KSTM_CHECK_ZERO(tc("a", 2, 1, 1, 1, 0));

	KSTM_CHECK_ZERO(tc("", 2, 0, 0, 1, 1));

	tc(test, "ab", 2, -E2BIG, 1, 1, 0);

	tc(test, "a",  2, 1,	  1, 1, 0);

	tc(test, "",   2, 0,	  0, 1, 1);



	KSTM_CHECK_ZERO(tc("abc", 3, -E2BIG, 2, 1, 0));

	KSTM_CHECK_ZERO(tc("ab", 3, 2, 2, 1, 0));

	KSTM_CHECK_ZERO(tc("a", 3, 1, 1, 1, 1));

	KSTM_CHECK_ZERO(tc("", 3, 0, 0, 1, 2));

	tc(test, "abc", 3, -E2BIG, 2, 1, 0);

	tc(test, "ab",  3, 2,	   2, 1, 0);

	tc(test, "a",   3, 1,	   1, 1, 1);

	tc(test, "",    3, 0,	   0, 1, 2);



	KSTM_CHECK_ZERO(tc("abcd", 4, -E2BIG, 3, 1, 0));

	KSTM_CHECK_ZERO(tc("abc", 4, 3, 3, 1, 0));

	KSTM_CHECK_ZERO(tc("ab", 4, 2, 2, 1, 1));

	KSTM_CHECK_ZERO(tc("a", 4, 1, 1, 1, 2));

	KSTM_CHECK_ZERO(tc("", 4, 0, 0, 1, 3));

	tc(test, "abcd", 4, -E2BIG, 3, 1, 0);

	tc(test, "abc",  4, 3,	    3, 1, 0);

	tc(test, "ab",   4, 2,	    2, 1, 1);

	tc(test, "a",    4, 1,	    1, 1, 2);

	tc(test, "",     4, 0,	    0, 1, 3);

}



KSTM_MODULE_LOADERS(test_strscpy);

static struct kunit_case strscpy_test_cases[] = {

	KUNIT_CASE(strscpy_test),

	{}

};



static struct kunit_suite strscpy_test_suite = {

	.name = "strscpy",

	.test_cases = strscpy_test_cases,

};



kunit_test_suite(strscpy_test_suite);



MODULE_AUTHOR("Tobin C. Harding <tobin@kernel.org>");

MODULE_LICENSE("GPL");