[PATCH v3] kasan: add kunit tests for kmalloc_track_caller, kmalloc_node_track_caller

Nihar Chaithanya
2024-10-14T19:08:56Z

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@gmail.com>
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.

v2->v3: Used the same size for both the test cases.

Link to v1: https://lore.kernel.org/all/20241013172912.1047136-1-niharchaithanya@gmail.com/
Link to v2: https://lore.kernel.org/all/20241014041130.1768674-1-niharchaithanya@gmail.com/

mm/kasan/kasan_test_c.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)

diff --git a/mm/kasan/kasan_test_c.c b/mm/kasan/kasan_test_c.c
index a181e4780d9d..7e7076e71de0 100644
--- a/mm/kasan/kasan_test_c.c
+++ b/mm/kasan/kasan_test_c.c
@@ -213,6 +213,36 @@ 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().
+ */
+ 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 +1988,7 @@ 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