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-rw-r--r--mm/kasan/kasan_test_c.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c
index 3ea317837c2d..5f922dd38ffa 100644
--- a/mm/kasan/kasan_test_c.c
+++ b/mm/kasan/kasan_test_c.c
@@ -1567,6 +1567,7 @@ static void kasan_memcmp(struct kunit *test)
static void kasan_strings(struct kunit *test)
{
char *ptr;
+ char *src;
size_t size = 24;
/*
@@ -1578,6 +1579,25 @@ static void kasan_strings(struct kunit *test)
ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ src = kmalloc(KASAN_GRANULE_SIZE, GFP_KERNEL | __GFP_ZERO);
+ strscpy(src, "f0cacc1a0000000", KASAN_GRANULE_SIZE);
+
+ /*
+ * Make sure that strscpy() does not trigger KASAN if it overreads into
+ * poisoned memory.
+ *
+ * The expected size does not include the terminator '\0'
+ * so it is (KASAN_GRANULE_SIZE - 2) ==
+ * KASAN_GRANULE_SIZE - ("initial removed character" + "\0").
+ */
+ KUNIT_EXPECT_EQ(test, KASAN_GRANULE_SIZE - 2,
+ strscpy(ptr, src + 1, KASAN_GRANULE_SIZE));
+
+ /* strscpy should fail if the first byte is unreadable. */
+ KUNIT_EXPECT_KASAN_FAIL(test, strscpy(ptr, src + KASAN_GRANULE_SIZE,
+ KASAN_GRANULE_SIZE));
+
+ kfree(src);
kfree(ptr);
/*
@@ -2127,4 +2147,5 @@ static struct kunit_suite kasan_kunit_test_suite = {
kunit_test_suite(kasan_kunit_test_suite);
+MODULE_DESCRIPTION("KUnit tests for checking KASAN bug-detection capabilities");
MODULE_LICENSE("GPL");