On Fri, Jun 21, 2024 at 1:56 AM Benjamin Tissoires bentiss@kernel.org wrote:
This allows to intercept and prevent or change the behavior of hid_hw_raw_request() from a bpf program.
The intent is to solve a couple of use case:
- firewalling a HID device: a firewall can monitor who opens the hidraw nodes and then prevent or allow access to write operations on that hidraw node.
- change the behavior of a device and emulate a new HID feature request
The hook is allowed to be run as sleepable so it can itself call hid_bpf_hw_request(), which allows to "convert" one feature request into another or even call the feature request on a different HID device on the same physical device.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org
Here checkpatch complains about: WARNING: use of RCU tasks trace is incorrect outside BPF or core RCU code
However, we are jumping in BPF code, so I think this is correct, but I'd like to have the opinion on the BPF folks.
drivers/hid/bpf/hid_bpf_dispatch.c | 36 ++++++++++++++++++++++++++++++++++++ drivers/hid/bpf/hid_bpf_struct_ops.c | 1 + drivers/hid/hid-core.c | 6 ++++++ include/linux/hid_bpf.h | 35 +++++++++++++++++++++++++++++++++++ 4 files changed, 78 insertions(+)
diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index 2df31decaac3..813b53119b85 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -74,6 +74,42 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type } EXPORT_SYMBOL_GPL(dispatch_hid_bpf_device_event);
+int dispatch_hid_bpf_raw_requests(struct hid_device *hdev,
unsigned char reportnum, u8 *buf,u32 size, enum hid_report_type rtype,enum hid_class_request reqtype,u64 source)+{
struct hid_bpf_ctx_kern ctx_kern = {.ctx = {.hid = hdev,.allocated_size = size,.size = size,},.data = buf,};struct hid_bpf_ops *e;int ret;if (rtype >= HID_REPORT_TYPES)return -EINVAL;rcu_read_lock_trace();
checkpatch is correct. What is this for?