[PATCH bpf-next v2 07/28] bpf/hid: add a new attach type to change the report descriptor
flat view
STALE1679d
SUPERSEDED
From: Benjamin Tissoires <hidden>
Date: 2022-03-04 17:31:58
Also in:
bpf, linux-input, linux-kselftest, lkml
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Revision v2 of 9 in this series.
Revisions (9)
The report descriptor is the dictionary of the HID protocol specific to the given device. Changing it is a common habit in the HID world, and making that feature accessible from eBPF allows to fix devices without having to install a new kernel. However, the report descriptor is supposed to be static on a device. To be able to change it, we need to reconnect the device at the HID level. So whenever the report descriptor program type is attached or detached, we call on a hook on HID to notify it that there is something to be done. Signed-off-by: Benjamin Tissoires <redacted> --- changes in v2: - split the series by bpf/libbpf/hid/selftests and samples - unsigned long -> __u16 in uapi/linux/bpf_hid.h --- include/linux/bpf-hid.h | 4 ++++ include/uapi/linux/bpf.h | 1 + include/uapi/linux/bpf_hid.h | 1 + kernel/bpf/hid.c | 5 +++++ kernel/bpf/syscall.c | 2 ++ tools/include/uapi/linux/bpf.h | 1 + 6 files changed, 14 insertions(+)
diff --git a/include/linux/bpf-hid.h b/include/linux/bpf-hid.h
index 3cda78051b5f..0c5000b28b20 100644
--- a/include/linux/bpf-hid.h
+++ b/include/linux/bpf-hid.h@@ -15,6 +15,7 @@ struct hid_device; enum bpf_hid_attach_type { BPF_HID_ATTACH_INVALID = -1, BPF_HID_ATTACH_DEVICE_EVENT = 0, + BPF_HID_ATTACH_RDESC_FIXUP, MAX_BPF_HID_ATTACH_TYPE };
@@ -32,6 +33,8 @@ to_bpf_hid_attach_type(enum bpf_attach_type attach_type) switch (attach_type) { case BPF_HID_DEVICE_EVENT: return BPF_HID_ATTACH_DEVICE_EVENT; + case BPF_HID_RDESC_FIXUP: + return BPF_HID_ATTACH_RDESC_FIXUP; default: return BPF_HID_ATTACH_INVALID; }
@@ -88,6 +91,7 @@ static inline bool bpf_hid_link_empty(struct bpf_hid *bpf, struct bpf_hid_hooks { struct hid_device *(*hdev_from_fd)(int fd); int (*link_attach)(struct hid_device *hdev, enum bpf_hid_attach_type type); + void (*link_attached)(struct hid_device *hdev, enum bpf_hid_attach_type type); void (*array_detached)(struct hid_device *hdev, enum bpf_hid_attach_type type); };
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 5978b92cacd3..a7a8d9cfcf24 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -999,6 +999,7 @@ enum bpf_attach_type { BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, BPF_PERF_EVENT, BPF_HID_DEVICE_EVENT, + BPF_HID_RDESC_FIXUP, __MAX_BPF_ATTACH_TYPE };
diff --git a/include/uapi/linux/bpf_hid.h b/include/uapi/linux/bpf_hid.h
index 975ca5bd526f..634f17c0b1cb 100644
--- a/include/uapi/linux/bpf_hid.h
+++ b/include/uapi/linux/bpf_hid.h@@ -24,6 +24,7 @@ struct hid_device; enum hid_bpf_event { HID_BPF_UNDEF = 0, HID_BPF_DEVICE_EVENT, /* when attach type is BPF_HID_DEVICE_EVENT */ + HID_BPF_RDESC_FIXUP, /* ................... BPF_HID_RDESC_FIXUP */ }; struct hid_bpf_ctx {
diff --git a/kernel/bpf/hid.c b/kernel/bpf/hid.c
index db7f75a0a812..37500313e270 100644
--- a/kernel/bpf/hid.c
+++ b/kernel/bpf/hid.c@@ -315,6 +315,8 @@ static int bpf_hid_max_progs(enum bpf_hid_attach_type type) switch (type) { case BPF_HID_ATTACH_DEVICE_EVENT: return 64; + case BPF_HID_ATTACH_RDESC_FIXUP: + return 1; default: return 0; }
@@ -355,6 +357,9 @@ static int bpf_hid_link_attach(struct hid_device *hdev, struct bpf_link *link, lockdep_is_held(&bpf_hid_mutex)); bpf_prog_array_free(run_array); + if (hid_hooks.link_attached) + hid_hooks.link_attached(hdev, type); + out_unlock: mutex_unlock(&bpf_hid_mutex); return err;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a94e78ec3211..7428a1a512c6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c@@ -3203,6 +3203,7 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type) case BPF_XDP: return BPF_PROG_TYPE_XDP; case BPF_HID_DEVICE_EVENT: + case BPF_HID_RDESC_FIXUP: return BPF_PROG_TYPE_HID; default: return BPF_PROG_TYPE_UNSPEC;
@@ -3348,6 +3349,7 @@ static int bpf_prog_query(const union bpf_attr *attr, case BPF_SK_SKB_VERDICT: return sock_map_bpf_prog_query(attr, uattr); case BPF_HID_DEVICE_EVENT: + case BPF_HID_RDESC_FIXUP: return bpf_hid_prog_query(attr, uattr); default: return -EINVAL;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 5978b92cacd3..a7a8d9cfcf24 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h@@ -999,6 +999,7 @@ enum bpf_attach_type { BPF_SK_REUSEPORT_SELECT_OR_MIGRATE, BPF_PERF_EVENT, BPF_HID_DEVICE_EVENT, + BPF_HID_RDESC_FIXUP, __MAX_BPF_ATTACH_TYPE };
--
2.35.1