[PATCH 6/6] thunderbolt: test: add KUnit tests for property parser bounds checks

[Michael Bommarito]

Add regression tests for the zero-length entry and root directory
bounds fixes:

- tb_test_property_parse_zero_length: TEXT entry with length 0
  must be rejected by the validator.

- tb_test_property_parse_rootdir_overflow: root directory whose
  content_offset + content_len exceeds block_len must be rejected.

Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@xxxxxxxxx>
---
 drivers/thunderbolt/test.c | 40 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/thunderbolt/test.c b/drivers/thunderbolt/test.c
index 1f4318249c226..345f39ecd233f 100644
--- a/drivers/thunderbolt/test.c
+++ b/drivers/thunderbolt/test.c
@@ -2852,6 +2852,44 @@ static void tb_test_property_copy(struct kunit *test)
 	tb_property_free_dir(src);
 }
 
+static void tb_test_property_parse_zero_length(struct kunit *test)
+{
+	u32 *block = kunit_kzalloc(test, 6 * sizeof(u32), GFP_KERNEL);
+	struct tb_property_dir *dir;
+
+	KUNIT_ASSERT_NOT_NULL(test, block);
+
+	block[0] = 0x55584401;	/* rootdir magic */
+	block[1] = 0x00000004;	/* root length: one entry */
+
+	block[2] = 0x61616161;	/* key_hi */
+	block[3] = 0x61616161;	/* key_lo */
+	block[4] = 0x74000000;	/* type=TEXT, reserved=0, length=0 */
+	block[5] = 0x00000000;	/* value */
+
+	dir = tb_property_parse_dir(block, 6);
+	KUNIT_EXPECT_NULL(test, dir);
+	tb_property_free_dir(dir);
+}
+
+static void tb_test_property_parse_rootdir_overflow(struct kunit *test)
+{
+	u32 *block = kunit_kzalloc(test, 4 * sizeof(u32), GFP_KERNEL);
+	struct tb_property_dir *dir;
+
+	KUNIT_ASSERT_NOT_NULL(test, block);
+
+	block[0] = 0x55584401;	/* rootdir magic */
+	block[1] = 0x00000004;	/* root length claims 4 dwords of content */
+	block[2] = 0x61616161;
+	block[3] = 0x61616161;
+
+	/* content_offset(2) + content_len(4) = 6 > block_len(4) */
+	dir = tb_property_parse_dir(block, 4);
+	KUNIT_EXPECT_NULL(test, dir);
+	tb_property_free_dir(dir);
+}
+
 static struct kunit_case tb_test_cases[] = {
 	KUNIT_CASE(tb_test_path_basic),
 	KUNIT_CASE(tb_test_path_not_connected_walk),
@@ -2892,6 +2930,8 @@ static struct kunit_case tb_test_cases[] = {
 	KUNIT_CASE(tb_test_property_parse),
 	KUNIT_CASE(tb_test_property_format),
 	KUNIT_CASE(tb_test_property_copy),
+	KUNIT_CASE(tb_test_property_parse_zero_length),
+	KUNIT_CASE(tb_test_property_parse_rootdir_overflow),
 	{ }
 };
 
-- 
2.53.0