thunderbolt: test: add KUnit regression tests for XDomain property parser

Add three KUnit cases that exercise the defects fixed by the sibling
commits in this series by feeding crafted XDomain property blocks to
tb_property_parse_dir():

  tb_test_property_parse_u32_wrap - entry->value = 0xffffff00 and
    entry->length = 0x100 so their u32 sum 0x100000000 wraps to 0
    under the block_len guard; without the fix the subsequent
    parse_dwdata() reads attacker-directed OOB memory.

  tb_test_property_parse_recursion - two DIRECTORY entries pointing
    at each other, driving __tb_property_parse_dir() recursion;
    without the fix the kernel stack is exhausted.

  tb_test_property_parse_dir_len_underflow - a DIRECTORY entry with
    length < 4 placed near the end of the block so the non-root UUID
    kmemdup of 4 dwords from dir_offset reads OOB before the later
    content_len = dir_len - 4 underflow path is reached.

Each test asserts tb_property_parse_dir() returns NULL on the
crafted input.  With CONFIG_KASAN=y, running these on the pre-fix
kernel produces an oops inside __tb_property_parse_dir or its
callees: u32_wrap takes a page fault on the KASAN shadow lookup for
the wild ~16 GiB OOB offset; recursion trips a KASAN out-of-bounds
report in __unwind_start as the per-task kernel stack is consumed;
dir_len_underflow trips a KASAN slab-out-of-bounds report in
kmemdup_noprof reading 16 bytes past the 28-byte block.  Post-fix
they pass cleanly.

The crafted blocks are populated by writing u32 dwords directly,
matching the existing root_directory[] style used elsewhere in
this file rather than imposing a private struct overlay.

Run with:
  ./tools/testing/kunit/kunit.py run --arch=x86_64 \
    --kconfig_add CONFIG_PCI=y --kconfig_add CONFIG_NVMEM=y \
    --kconfig_add CONFIG_USB4=y --kconfig_add CONFIG_USB4_KUNIT_TEST=y \
    --kconfig_add CONFIG_KASAN=y 'thunderbolt.tb_test_property_parse_*'

Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

0 files changed, 0 insertions, 0 deletions