3 files changed, 153 insertions, 0 deletions

diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index a669c193b878..19d42ea75ec2 100644
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -46,3 +46,10 @@ config UBSAN_NULL
         help
           This option enables detection of memory accesses via a
           null pointer.
+
+config TEST_UBSAN
+        tristate "Module for testing for undefined behavior detection"
+        depends on m && UBSAN
+        help
+          This is a test module for UBSAN.
+          It triggers various undefined behavior, and detect it.
diff --git a/lib/Makefile b/lib/Makefile
index 6200f978740d..ce20696d5a92 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -54,6 +54,8 @@ obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o
 obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o
 obj-$(CONFIG_TEST_KASAN) += test_kasan.o
 CFLAGS_test_kasan.o += -fno-builtin
+obj-$(CONFIG_TEST_UBSAN) += test_ubsan.o
+UBSAN_SANITIZE_test_ubsan.o := y
 obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o
 obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o
 obj-$(CONFIG_TEST_LKM) += test_module.o
diff --git a/lib/test_ubsan.c b/lib/test_ubsan.c
new file mode 100644
index 000000000000..58dedff36b17
--- /dev/null
+++ b/lib/test_ubsan.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+typedef void(*test_ubsan_fp)(void);
+
+static void test_ubsan_add_overflow(void)
+{
+        volatile int val = INT_MAX;
+
+        val += 2;
+}
+
+static void test_ubsan_sub_overflow(void)
+{
+        volatile int val = INT_MIN;
+        volatile int val2 = 2;
+
+        val -= val2;
+}
+
+static void test_ubsan_mul_overflow(void)
+{
+        volatile int val = INT_MAX / 2;
+
+        val *= 3;
+}
+
+static void test_ubsan_negate_overflow(void)
+{
+        volatile int val = INT_MIN;
+
+        val = -val;
+}
+
+static void test_ubsan_divrem_overflow(void)
+{
+        volatile int val = 16;
+        volatile int val2 = 0;
+
+        val /= val2;
+}
+
+static void test_ubsan_vla_bound_not_positive(void)
+{
+        volatile int size = -1;
+        char buf[size];
+
+        (void)buf;
+}
+
+static void test_ubsan_shift_out_of_bounds(void)
+{
+        volatile int val = -1;
+        int val2 = 10;
+
+        val2 <<= val;
+}
+
+static void test_ubsan_out_of_bounds(void)
+{
+        volatile int i = 4, j = 5;
+        volatile int arr[i];
+
+        arr[j] = i;
+}
+
+static void test_ubsan_load_invalid_value(void)
+{
+        volatile char *dst, *src;
+        bool val, val2, *ptr;
+        char c = 4;
+
+        dst = (char *)&val;
+        src = &c;
+        *dst = *src;
+
+        ptr = &val2;
+        val2 = val;
+}
+
+static void test_ubsan_null_ptr_deref(void)
+{
+        volatile int *ptr = NULL;
+        int val;
+
+        val = *ptr;
+}
+
+void test_ubsan_misaligned_access(void)
+{
+        volatile char arr[5] __aligned(4) = {1, 2, 3, 4, 5};
+        volatile int *ptr, val = 6;
+
+        ptr = (int *)(arr + 1);
+        *ptr = val;
+}
+
+static void test_ubsan_object_size_mismatch(void)
+{
+        /* "((aligned(8)))" helps this not into be misaligned for ptr-access. */
+        volatile int val __aligned(8) = 4;
+        volatile long long *ptr, val2;
+
+        ptr = (long long *)&val;
+        val2 = *ptr;
+}
+
+static const test_ubsan_fp test_ubsan_array[] = {
+        test_ubsan_add_overflow,
+        test_ubsan_sub_overflow,
+        test_ubsan_mul_overflow,
+        test_ubsan_negate_overflow,
+        test_ubsan_divrem_overflow,
+        test_ubsan_vla_bound_not_positive,
+        test_ubsan_shift_out_of_bounds,
+        test_ubsan_out_of_bounds,
+        test_ubsan_load_invalid_value,
+        //test_ubsan_null_ptr_deref, /* exclude it because there is a crash */
+        test_ubsan_misaligned_access,
+        test_ubsan_object_size_mismatch,
+};
+
+static int __init test_ubsan_init(void)
+{
+        unsigned int i;
+
+        for (i = 0; i < ARRAY_SIZE(test_ubsan_array); i++)
+                test_ubsan_array[i]();
+
+        (void)test_ubsan_null_ptr_deref; /* to avoid unsed-function warning */
+        return 0;
+}
+module_init(test_ubsan_init);
+
+static void __exit test_ubsan_exit(void)
+{
+        /* do nothing */
+}
+module_exit(test_ubsan_exit);
+
+MODULE_AUTHOR("Jinbum Park <jinb.park7@gmail.com>");
+MODULE_LICENSE("GPL v2");