Merge tag 'linux-kselftest-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kselftest updates from Shuah Khan:

 - fixes to seccomp test, and kselftest framework

 - cleanups to remove duplicate header defines

 - fixes to efivarfs "make clean" target

 - cgroup cleanup path

 - Moving the IMA kexec_load selftest to selftests/kexec work from Mimi
   Johar and Petr Vorel

 - A framework to kselftest for writing kernel test modules addition
   from Tobin C. Harding

* tag 'linux-kselftest-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (29 commits)
  selftests: build and run gpio when output directory is the src dir
  selftests/ipc: Fix msgque compiler warnings
  selftests/efivarfs: clean up test files from test_create*()
  selftests: fix headers_install circular dependency
  selftests/kexec: update get_secureboot_mode
  selftests/kexec: make kexec_load test independent of IMA being enabled
  selftests/kexec: check kexec_load and kexec_file_load are enabled
  selftests/kexec: Add missing '=y' to config options
  selftests/kexec: kexec_file_load syscall test
  selftests/kexec: define "require_root_privileges"
  selftests/kexec: define common logging functions
  selftests/kexec: define a set of common functions
  selftests/kexec: cleanup the kexec selftest
  selftests/kexec: move the IMA kexec_load selftest to selftests/kexec
  selftests/harness: Add 30 second timeout per test
  selftests/seccomp: Handle namespace failures gracefully
  selftests: cgroup: fix cleanup path in test_memcg_subtree_control()
  selftests: efivarfs: remove the test_create_read file if it was exist
  rseq/selftests: Adapt number of threads to the number of detected cpus
  lib: Add test module for strscpy_pad
  ...

6 files changed, 203 insertions, 35 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d5a4a4036d2f..4c54a89f06ee 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1769,6 +1769,9 @@ config TEST_HEXDUMP
 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"
 
diff --git a/lib/Makefile b/lib/Makefile
index e16e7aadc41a..07506e3891a0 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
 obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
 obj-$(CONFIG_TEST_PRINTF) += test_printf.o
 obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
+obj-$(CONFIG_TEST_STRSCPY) += test_strscpy.o
 obj-$(CONFIG_TEST_BITFIELD) += test_bitfield.o
 obj-$(CONFIG_TEST_UUID) += test_uuid.o
 obj-$(CONFIG_TEST_XARRAY) += test_xarray.o
diff --git a/lib/string.c b/lib/string.c
index 3ab861c1a857..6016eb3ac73d 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -159,11 +159,9 @@ EXPORT_SYMBOL(strlcpy);
  * @src: Where to copy the string from
  * @count: Size of destination buffer
  *
- * Copy the string, or as much of it as fits, into the dest buffer.
- * The routine returns the number of characters copied (not including
- * the trailing NUL) or -E2BIG if the destination buffer wasn't big enough.
- * The behavior is undefined if the string buffers overlap.
- * The destination buffer is always NUL terminated, unless it's zero-sized.
+ * Copy the string, or as much of it as fits, into the dest buffer.  The
+ * behavior is undefined if the string buffers overlap.  The destination
+ * buffer is always NUL terminated, unless it's zero-sized.
  *
  * Preferred to strlcpy() since the API doesn't require reading memory
  * from the src string beyond the specified "count" bytes, and since
@@ -173,8 +171,10 @@ EXPORT_SYMBOL(strlcpy);
  *
  * Preferred to strncpy() since it always returns a valid string, and
  * doesn't unnecessarily force the tail of the destination buffer to be
- * zeroed.  If the zeroing is desired, it's likely cleaner to use strscpy()
- * with an overflow test, then just memset() the tail of the dest buffer.
+ * zeroed.  If zeroing is desired please use strscpy_pad().
+ *
+ * Return: The number of characters copied (not including the trailing
+ *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
  */
 ssize_t strscpy(char *dest, const char *src, size_t count)
 {
@@ -237,6 +237,39 @@ ssize_t strscpy(char *dest, const char *src, size_t count)
 EXPORT_SYMBOL(strscpy);
 #endif
 
+/**
+ * strscpy_pad() - Copy a C-string into a sized buffer
+ * @dest: Where to copy the string to
+ * @src: Where to copy the string from
+ * @count: Size of destination buffer
+ *
+ * Copy the string, or as much of it as fits, into the dest buffer.  The
+ * behavior is undefined if the string buffers overlap.  The destination
+ * buffer is always %NUL terminated, unless it's zero-sized.
+ *
+ * If the source string is shorter than the destination buffer, zeros
+ * the tail of the destination buffer.
+ *
+ * For full explanation of why you may want to consider using the
+ * 'strscpy' functions please see the function docstring for strscpy().
+ *
+ * Return: The number of characters copied (not including the trailing
+ *         %NUL) or -E2BIG if the destination buffer wasn't big enough.
+ */
+ssize_t strscpy_pad(char *dest, const char *src, size_t count)
+{
+	ssize_t written;
+
+	written = strscpy(dest, src, count);
+	if (written < 0 || written == count - 1)
+		return written;
+
+	memset(dest + written + 1, 0, count - written - 1);
+
+	return written;
+}
+EXPORT_SYMBOL(strscpy_pad);
+
 #ifndef __HAVE_ARCH_STRCAT
 /**
  * strcat - Append one %NUL-terminated string to another
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 6cd7d0740005..792d90608052 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -12,6 +12,8 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 
+#include "../tools/testing/selftests/kselftest_module.h"
+
 static unsigned total_tests __initdata;
 static unsigned failed_tests __initdata;
 
@@ -361,7 +363,7 @@ static void noinline __init test_mem_optimisations(void)
 	}
 }
 
-static int __init test_bitmap_init(void)
+static void __init selftest(void)
 {
 	test_zero_clear();
 	test_fill_set();
@@ -369,22 +371,8 @@ static int __init test_bitmap_init(void)
 	test_bitmap_arr32();
 	test_bitmap_parselist();
 	test_mem_optimisations();
-
-	if (failed_tests == 0)
-		pr_info("all %u tests passed\n", total_tests);
-	else
-		pr_warn("failed %u out of %u tests\n",
-			failed_tests, total_tests);
-
-	return failed_tests ? -EINVAL : 0;
 }
 
-static void __exit test_bitmap_cleanup(void)
-{
-}
-
-module_init(test_bitmap_init);
-module_exit(test_bitmap_cleanup);
-
+KSTM_MODULE_LOADERS(test_bitmap);
 MODULE_AUTHOR("david decotigny <david.decotigny@googlers.com>");
 MODULE_LICENSE("GPL");
diff --git a/lib/test_printf.c b/lib/test_printf.c
index 659b6cc0d483..f4fcc1c43739 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -21,6 +21,8 @@
 #include <linux/gfp.h>
 #include <linux/mm.h>
 
+#include "../tools/testing/selftests/kselftest_module.h"
+
 #define BUF_SIZE 256
 #define PAD_SIZE 16
 #define FILL_CHAR '$'
@@ -590,12 +592,11 @@ test_pointer(void)
 	flags();
 }
 
-static int __init
-test_printf_init(void)
+static void __init selftest(void)
 {
 	alloced_buffer = kmalloc(BUF_SIZE + 2*PAD_SIZE, GFP_KERNEL);
 	if (!alloced_buffer)
-		return -ENOMEM;
+		return;
 	test_buffer = alloced_buffer + PAD_SIZE;
 
 	test_basic();
@@ -604,16 +605,8 @@ test_printf_init(void)
 	test_pointer();
 
 	kfree(alloced_buffer);
-
-	if (failed_tests == 0)
-		pr_info("all %u tests passed\n", total_tests);
-	else
-		pr_warn("failed %u out of %u tests\n", failed_tests, total_tests);
-
-	return failed_tests ? -EINVAL : 0;
 }
 
-module_init(test_printf_init);
-
+KSTM_MODULE_LOADERS(test_printf);
 MODULE_AUTHOR("Rasmus Villemoes <linux@rasmusvillemoes.dk>");
 MODULE_LICENSE("GPL");
diff --git a/lib/test_strscpy.c b/lib/test_strscpy.c
new file mode 100644
index 000000000000..a827f94601f5
--- /dev/null
+++ b/lib/test_strscpy.c
@@ -0,0 +1,150 @@
+// 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();
+
+/*
+ * tc() - Run a specific test case.
+ * @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()
+ * @terminator: 1 if there should be a terminating null byte 0 otherwise.
+ * @chars: Number of characters from the src string expected to be
+ *         written to the dst buffer.
+ * @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 int __init tc(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';
+
+	total_tests++;
+
+	if (!src) {
+		pr_err("null source string not supported\n");
+		return -1;
+	}
+
+	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)",
+			expected, max_expected);
+	}
+
+	written = strscpy_pad(buf, src, count);
+	if ((written) != (expected)) {
+		pr_err("%d != %d (written, expected)\n", written, expected);
+		goto fail;
+	}
+
+	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;
+		}
+	}
+
+	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;
+		}
+	}
+
+	if (terminator) {
+		if (buf[count - 1] != '\0') {
+			pr_err("string is not null terminated correctly\n");
+			goto fail;
+		}
+	}
+
+	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;
+		}
+	}
+
+	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;
+		}
+	}
+
+	return 0;
+fail:
+	failed_tests++;
+	return -1;
+}
+
+static void __init selftest(void)
+{
+	/*
+	 * tc() 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().
+	 */
+
+	/* 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));
+
+	KSTM_CHECK_ZERO(tc("a", 1, -E2BIG, 0, 1, 0));
+	KSTM_CHECK_ZERO(tc("", 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));
+
+	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));
+
+	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));
+}
+
+KSTM_MODULE_LOADERS(test_strscpy);
+MODULE_AUTHOR("Tobin C. Harding <tobin@kernel.org>");
+MODULE_LICENSE("GPL");