HID: bpf: allow to change the report descriptor

Add a new tracepoint hid_bpf_rdesc_fixup() so we can trigger a
report descriptor fixup in the bpf world.

Whenever the program gets attached/detached, the device is reconnected
meaning that userspace will see it disappearing and reappearing with
the new report descriptor.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Benjamin Tissoires
2022-11-03 16:57:51 +01:00
committed by Jiri Kosina
parent 4f7153cf46
commit ad190df11a
5 changed files with 97 additions and 2 deletions

View File

@@ -74,6 +74,7 @@ enum hid_bpf_attach_flags {
/* Following functions are tracepoints that BPF programs can attach to */
int hid_bpf_device_event(struct hid_bpf_ctx *ctx);
int hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx);
/* Following functions are kfunc that we export to BPF programs */
/* available everywhere in HID-BPF */
@@ -100,6 +101,7 @@ int __hid_bpf_tail_call(struct hid_bpf_ctx *ctx);
enum hid_bpf_prog_type {
HID_BPF_PROG_TYPE_UNDEF = -1,
HID_BPF_PROG_TYPE_DEVICE_EVENT, /* an event is emitted from the device */
HID_BPF_PROG_TYPE_RDESC_FIXUP,
HID_BPF_PROG_TYPE_MAX,
};
@@ -143,6 +145,7 @@ int hid_bpf_connect_device(struct hid_device *hdev);
void hid_bpf_disconnect_device(struct hid_device *hdev);
void hid_bpf_destroy_device(struct hid_device *hid);
void hid_bpf_device_init(struct hid_device *hid);
u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size);
#else /* CONFIG_HID_BPF */
static inline u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type,
u8 *data, u32 *size, int interrupt) { return NULL; }
@@ -150,6 +153,11 @@ static inline int hid_bpf_connect_device(struct hid_device *hdev) { return 0; }
static inline void hid_bpf_disconnect_device(struct hid_device *hdev) {}
static inline void hid_bpf_destroy_device(struct hid_device *hid) {}
static inline void hid_bpf_device_init(struct hid_device *hid) {}
static inline u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size)
{
return kmemdup(rdesc, *size, GFP_KERNEL);
}
#endif /* CONFIG_HID_BPF */
#endif /* __HID_BPF_H */