hid_bpf_get_data() exposes a pointer into the HID-BPF context data when
the caller-provided offset and size fit inside ctx->allocated_size.
The helper currently checks that range with:
rdwr_buf_size + offset > ctx->allocated_size
Since both operands are unsigned, a very large size can wrap the sum and
make an out-of-range request look valid.
Patch 1 changes the helper to use check_add_overflow() for the range end
and then compare the computed end against ctx->allocated_size.
Patch 2 updates the HID selftest loader to create only the struct_ops
maps requested by the current test, so unrelated programs from the shared
HID-BPF skeleton are not autoloaded.
Patch 3 adds a HID-BPF regression check that asks hid_bpf_get_data() for
offset 2 and size ~0ULL from an rdesc_fixup callback and expects NULL.
It also adds KHDR_INCLUDES to the HID selftest build so the userspace
test sees current kernel UAPI HID definitions.
Changes in v4:
- Use check_add_overflow() in hid_bpf_get_data() before comparing the
computed range end against ctx->allocated_size.
- Update the fix commit message to describe the overflow-helper check.
Changes in v3:
- Split out a HID selftest loader fix that disables autocreate for
unrelated struct_ops maps.
- Add a Fixes tag to the selftest patch.
- Keep the BSS result flag in the rdesc fixup callback and explain why
the callback must still return 0.
Changes in v2:
- Drop the temporary data variable around the overflow
hid_bpf_get_data() call in the selftest callback.
- Correct the Fixes tag to commit 658ee5a64fcf ("HID: bpf: allocate
data memory for device_event BPF programs").
v3:
https://lore.kernel.org/bpf/[email protected]/
v2:
https://lore.kernel.org/bpf/[email protected]/
v1:
https://lore.kernel.org/bpf/[email protected]/
Yiyang Chen (3):
HID: bpf: Fix hid_bpf_get_data() range check
selftests/hid: Load only requested struct_ops maps
selftests/hid: Cover hid_bpf_get_data() size overflow
drivers/hid/bpf/hid_bpf_dispatch.c | 5 +++-
tools/testing/selftests/hid/Makefile | 2 +-
tools/testing/selftests/hid/hid_bpf.c | 36 ++++++++++++++++++++-----
tools/testing/selftests/hid/progs/hid.c | 15 +++++++++++
4 files changed, 49 insertions(+), 9 deletions(-)
base-commit: a975094bf98ca97be9146f9d3b5681a6f9cf5ce3
--
2.34.1
