string: Merge strscpy KUnit tests into string_kunit.c

Move the strscpy() tests into string_kunit.c. Remove the separate
Kconfig and Makefile rule.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20240419140155.3028912-2-keescook@chromium.orgSigned-off-by: Kees Cook <keescook@chromium.org>

MAINTAINERS

@@ -8442,7 +8442,6 @@ F:	include/linux/fortify-string.h
 F:	lib/fortify_kunit.c
 F:	lib/memcpy_kunit.c
 F:	lib/strcat_kunit.c
-F:	lib/strscpy_kunit.c
 F:	lib/test_fortify/*
 F:	scripts/test_fortify.sh
 K:	\b__NO_FORTIFY\b

lib/Kconfig.debug

@@ -2763,11 +2763,6 @@ config STRCAT_KUNIT_TEST
 	depends on KUNIT
 	default KUNIT_ALL_TESTS
 
-config STRSCPY_KUNIT_TEST
-	tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
-	depends on KUNIT
-	default KUNIT_ALL_TESTS
-
 config SIPHASH_KUNIT_TEST
 	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
 	depends on KUNIT

lib/Makefile

@@ -404,7 +404,6 @@ CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-truncation)
 CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN)
 obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
 obj-$(CONFIG_STRCAT_KUNIT_TEST) += strcat_kunit.o
-obj-$(CONFIG_STRSCPY_KUNIT_TEST) += strscpy_kunit.o
 obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o
 
 obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o

lib/string_kunit.c

@@ -326,6 +326,125 @@ static void test_strncasecmp_long_strings(struct kunit *test)
 				   strcmp_buffer2, STRCMP_CHANGE_POINT + 1);
 }
 
+/**
+ * strscpy_check() - Run a specific test case.
+ * @test: KUnit test context pointer
+ * @src: Source string, argument to strscpy_pad()
+ * @count: Size of destination buffer, argument to strscpy_pad()
+ * @expected: Expected return value from call to strscpy_pad()
+ * @chars: Number of characters from the src string expected to be
+ *         written to the dst buffer.
+ * @terminator: 1 if there should be a terminating null byte 0 otherwise.
+ * @pad: Number of pad characters expected (in the tail of dst buffer).
+ *       (@pad does not include the null terminator byte.)
+ *
+ * Calls strscpy_pad() and verifies the return value and state of the
+ * destination buffer after the call returns.
+ */
+static void strscpy_check(struct kunit *test, char *src, int count,
+			  int expected, int chars, int terminator, int pad)
+{
+	int nr_bytes_poison;
+	int max_expected;
+	int max_count;
+	int written;
+	char buf[6];
+	int index, i;
+	const char POISON = 'z';
+
+	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 */
+
+	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);
+	KUNIT_ASSERT_EQ(test, written, expected);
+
+	if (count && written == -E2BIG) {
+		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++)
+		KUNIT_ASSERT_EQ_MSG(test, buf[i], src[i],
+			"buf[i]==%c != src[i]==%c", buf[i], src[i]);
+
+	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;
+		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 */
+		KUNIT_ASSERT_EQ_MSG(test, buf[index], POISON,
+			"poison value missing at index: %d", i);
+	}
+}
+
+static void test_strscpy(struct kunit *test)
+{
+	char dest[8];
+
+	/*
+	 * strscpy_check() uses a destination buffer of size 6 and needs at
+	 * least 2 characters spare (one for null and one to check for
+	 * overflow).  This means we should only call tc() with
+	 * strings up to a maximum of 4 characters long and 'count'
+	 * should not exceed 4.  To test with longer strings increase
+	 * the buffer size in tc().
+	 */
+
+	/* strscpy_check(test, src, count, expected, chars, terminator, pad) */
+	strscpy_check(test, "a", 0, -E2BIG, 0, 0, 0);
+	strscpy_check(test, "",  0, -E2BIG, 0, 0, 0);
+
+	strscpy_check(test, "a", 1, -E2BIG, 0, 1, 0);
+	strscpy_check(test, "",  1, 0,	 0, 1, 0);
+
+	strscpy_check(test, "ab", 2, -E2BIG, 1, 1, 0);
+	strscpy_check(test, "a",  2, 1,	  1, 1, 0);
+	strscpy_check(test, "",   2, 0,	  0, 1, 1);
+
+	strscpy_check(test, "abc", 3, -E2BIG, 2, 1, 0);
+	strscpy_check(test, "ab",  3, 2,	   2, 1, 0);
+	strscpy_check(test, "a",   3, 1,	   1, 1, 1);
+	strscpy_check(test, "",    3, 0,	   0, 1, 2);
+
+	strscpy_check(test, "abcd", 4, -E2BIG, 3, 1, 0);
+	strscpy_check(test, "abc",  4, 3,	    3, 1, 0);
+	strscpy_check(test, "ab",   4, 2,	    2, 1, 1);
+	strscpy_check(test, "a",    4, 1,	    1, 1, 2);
+	strscpy_check(test, "",     4, 0,	    0, 1, 3);
+
+	/* Compile-time-known source strings. */
+	KUNIT_EXPECT_EQ(test, strscpy(dest, "", ARRAY_SIZE(dest)), 0);
+	KUNIT_EXPECT_EQ(test, strscpy(dest, "", 3), 0);
+	KUNIT_EXPECT_EQ(test, strscpy(dest, "", 1), 0);
+	KUNIT_EXPECT_EQ(test, strscpy(dest, "", 0), -E2BIG);
+	KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", ARRAY_SIZE(dest)), 5);
+	KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 3), -E2BIG);
+	KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 1), -E2BIG);
+	KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 0), -E2BIG);
+	KUNIT_EXPECT_EQ(test, strscpy(dest, "This is too long", ARRAY_SIZE(dest)), -E2BIG);
+}
+
 static struct kunit_case string_test_cases[] = {
 	KUNIT_CASE(test_memset16),
 	KUNIT_CASE(test_memset32),
@@ -341,6 +460,7 @@ static struct kunit_case string_test_cases[] = {
 	KUNIT_CASE(test_strcasecmp_long_strings),
 	KUNIT_CASE(test_strncasecmp),
 	KUNIT_CASE(test_strncasecmp_long_strings),
+	KUNIT_CASE(test_strscpy),
 	{}
 };
 

lib/strscpy_kunit.c

-// SPDX-License-Identifier: GPL-2.0+
-/*
- * Kernel module for testing 'strscpy' family of functions.
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <kunit/test.h>
-#include <linux/string.h>
-
-/**
- * strscpy_check() - Run a specific test case.
- * @test: KUnit test context pointer
- * @src: Source string, argument to strscpy_pad()
- * @count: Size of destination buffer, argument to strscpy_pad()
- * @expected: Expected return value from call to strscpy_pad()
- * @chars: Number of characters from the src string expected to be
- *         written to the dst buffer.
- * @terminator: 1 if there should be a terminating null byte 0 otherwise.
- * @pad: Number of pad characters expected (in the tail of dst buffer).
- *       (@pad does not include the null terminator byte.)
- *
- * Calls strscpy_pad() and verifies the return value and state of the
- * destination buffer after the call returns.
- */
-static void strscpy_check(struct kunit *test, char *src, int count,
-			  int expected, int chars, int terminator, int pad)
-{
-	int nr_bytes_poison;
-	int max_expected;
-	int max_count;
-	int written;
-	char buf[6];
-	int index, i;
-	const char POISON = 'z';
-
-	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 */
-
-	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);
-	KUNIT_ASSERT_EQ(test, written, expected);
-
-	if (count && written == -E2BIG) {
-		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++)
-		KUNIT_ASSERT_EQ_MSG(test, buf[i], src[i],
-			"buf[i]==%c != src[i]==%c", buf[i], src[i]);
-
-	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;
-		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 */
-		KUNIT_ASSERT_EQ_MSG(test, buf[index], POISON,
-			"poison value missing at index: %d", i);
-	}
-}
-
-static void test_strscpy(struct kunit *test)
-{
-	char dest[8];
-
-	/*
-	 * strscpy_check() uses a destination buffer of size 6 and needs at
-	 * least 2 characters spare (one for null and one to check for
-	 * overflow).  This means we should only call tc() with
-	 * strings up to a maximum of 4 characters long and 'count'
-	 * should not exceed 4.  To test with longer strings increase
-	 * the buffer size in tc().
-	 */
-
-	/* strscpy_check(test, src, count, expected, chars, terminator, pad) */
-	strscpy_check(test, "a", 0, -E2BIG, 0, 0, 0);
-	strscpy_check(test, "",  0, -E2BIG, 0, 0, 0);
-
-	strscpy_check(test, "a", 1, -E2BIG, 0, 1, 0);
-	strscpy_check(test, "",  1, 0,	 0, 1, 0);
-
-	strscpy_check(test, "ab", 2, -E2BIG, 1, 1, 0);
-	strscpy_check(test, "a",  2, 1,	  1, 1, 0);
-	strscpy_check(test, "",   2, 0,	  0, 1, 1);
-
-	strscpy_check(test, "abc", 3, -E2BIG, 2, 1, 0);
-	strscpy_check(test, "ab",  3, 2,	   2, 1, 0);
-	strscpy_check(test, "a",   3, 1,	   1, 1, 1);
-	strscpy_check(test, "",    3, 0,	   0, 1, 2);
-
-	strscpy_check(test, "abcd", 4, -E2BIG, 3, 1, 0);
-	strscpy_check(test, "abc",  4, 3,	    3, 1, 0);
-	strscpy_check(test, "ab",   4, 2,	    2, 1, 1);
-	strscpy_check(test, "a",    4, 1,	    1, 1, 2);
-	strscpy_check(test, "",     4, 0,	    0, 1, 3);
-
-	/* Compile-time-known source strings. */
-	KUNIT_EXPECT_EQ(test, strscpy(dest, "", ARRAY_SIZE(dest)), 0);
-	KUNIT_EXPECT_EQ(test, strscpy(dest, "", 3), 0);
-	KUNIT_EXPECT_EQ(test, strscpy(dest, "", 1), 0);
-	KUNIT_EXPECT_EQ(test, strscpy(dest, "", 0), -E2BIG);
-	KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", ARRAY_SIZE(dest)), 5);
-	KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 3), -E2BIG);
-	KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 1), -E2BIG);
-	KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 0), -E2BIG);
-	KUNIT_EXPECT_EQ(test, strscpy(dest, "This is too long", ARRAY_SIZE(dest)), -E2BIG);
-}
-
-static struct kunit_case strscpy_test_cases[] = {
-	KUNIT_CASE(test_strscpy),
-	{}
-};
-
-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");