[PATCH v2] kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller

[Nihar Chaithanya]

The Kunit tests for kmalloc_track_caller and kmalloc_node_track_caller
were missing in kasan_test_c.c, which check that these functions poison
the memory properly.

Add a Kunit test:
-> kmalloc_tracker_caller_oob_right(): This includes out-of-bounds
   access test for kmalloc_track_caller and kmalloc_node_track_caller.

Signed-off-by: Nihar Chaithanya <niharchaithanya@xxxxxxxxx>
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=216509
---
v1->v2: Simplified the three separate out-of-bounds tests to a single test for
kmalloc_track_caller.

Link to v1: https://lore.kernel.org/all/20241013172912.1047136-1-niharchaithanya@xxxxxxxxx/

 mm/kasan/kasan_test_c.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c
index a181e4780d9d..62efc1ee9612 100644
--- a/mm/kasan/kasan_test_c.c
+++ b/mm/kasan/kasan_test_c.c
@@ -213,6 +213,37 @@ static void kmalloc_node_oob_right(struct kunit *test)
 	kfree(ptr);
 }
 
+static void kmalloc_track_caller_oob_right(struct kunit *test)
+{
+	char *ptr;
+	size_t size = 128 - KASAN_GRANULE_SIZE;
+
+	/*
+	 * Check that KASAN detects out-of-bounds access for object allocated via
+	 * kmalloc_track_caller().
+	 */
+	ptr = kmalloc_track_caller(size, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+
+	OPTIMIZER_HIDE_VAR(ptr);
+	KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 'y');
+
+	kfree(ptr);
+
+	/*
+	 * Check that KASAN detects out-of-bounds access for object allocated via
+	 * kmalloc_node_track_caller().
+	 */
+	size = 4096;
+	ptr = kmalloc_node_track_caller(size, GFP_KERNEL, 0);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+
+	OPTIMIZER_HIDE_VAR(ptr);
+	KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 'y');
+
+	kfree(ptr);
+}
+
 /*
  * Check that KASAN detects an out-of-bounds access for a big object allocated
  * via kmalloc(). But not as big as to trigger the page_alloc fallback.
@@ -1958,6 +1989,7 @@ static struct kunit_case kasan_kunit_test_cases[] = {
 	KUNIT_CASE(kmalloc_oob_right),
 	KUNIT_CASE(kmalloc_oob_left),
 	KUNIT_CASE(kmalloc_node_oob_right),
+	KUNIT_CASE(kmalloc_track_caller_oob_right),
 	KUNIT_CASE(kmalloc_big_oob_right),
 	KUNIT_CASE(kmalloc_large_oob_right),
 	KUNIT_CASE(kmalloc_large_uaf),
-- 
2.34.1