lib/test_kasan: add bitops tests

Patch series "Bitops instrumentation for KASAN", v5.

This patch (of 3):

This adds bitops tests to the test_kasan module.  In a follow-up patch,
support for bitops instrumentation will be added.

Link: http://lkml.kernel.org/r/20190613125950.197667-2-elver@google.comSigned-off-by: Marco Elver <elver@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/test_kasan.c

@@ -7,16 +7,17 @@
 
 #define pr_fmt(fmt) "kasan test: %s " fmt, __func__
 
+#include <linux/bitops.h>
 #include <linux/delay.h>
+#include <linux/kasan.h>
 #include <linux/kernel.h>
-#include <linux/mman.h>
 #include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/module.h>
 #include <linux/printk.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/uaccess.h>
-#include <linux/module.h>
-#include <linux/kasan.h>
 
 /*
  * Note: test functions are marked noinline so that their names appear in
@@ -619,6 +620,79 @@ static noinline void __init kasan_strings(void)
 	strnlen(ptr, 1);
 }
 
+static noinline void __init kasan_bitops(void)
+{
+	/*
+	 * Allocate 1 more byte, which causes kzalloc to round up to 16-bytes;
+	 * this way we do not actually corrupt other memory.
+	 */
+	long *bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);
+	if (!bits)
+		return;
+
+	/*
+	 * Below calls try to access bit within allocated memory; however, the
+	 * below accesses are still out-of-bounds, since bitops are defined to
+	 * operate on the whole long the bit is in.
+	 */
+	pr_info("out-of-bounds in set_bit\n");
+	set_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in __set_bit\n");
+	__set_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in clear_bit\n");
+	clear_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in __clear_bit\n");
+	__clear_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in clear_bit_unlock\n");
+	clear_bit_unlock(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in __clear_bit_unlock\n");
+	__clear_bit_unlock(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in change_bit\n");
+	change_bit(BITS_PER_LONG, bits);
+
+	pr_info("out-of-bounds in __change_bit\n");
+	__change_bit(BITS_PER_LONG, bits);
+
+	/*
+	 * Below calls try to access bit beyond allocated memory.
+	 */
+	pr_info("out-of-bounds in test_and_set_bit\n");
+	test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in __test_and_set_bit\n");
+	__test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in test_and_set_bit_lock\n");
+	test_and_set_bit_lock(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in test_and_clear_bit\n");
+	test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in __test_and_clear_bit\n");
+	__test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in test_and_change_bit\n");
+	test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in __test_and_change_bit\n");
+	__test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+	pr_info("out-of-bounds in test_bit\n");
+	(void)test_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
+
+#if defined(clear_bit_unlock_is_negative_byte)
+	pr_info("out-of-bounds in clear_bit_unlock_is_negative_byte\n");
+	clear_bit_unlock_is_negative_byte(BITS_PER_LONG + BITS_PER_BYTE, bits);
+#endif
+	kfree(bits);
+}
+
 static int __init kmalloc_tests_init(void)
 {
 	/*
@@ -660,6 +734,7 @@ static int __init kmalloc_tests_init(void)
 	kasan_memchr();
 	kasan_memcmp();
 	kasan_strings();
+	kasan_bitops();
 
 	kasan_restore_multi_shot(multishot);