63 lines
1.6 KiB
C
63 lines
1.6 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2023 Benjamin Tissoires
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*/
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#include "vmlinux.h"
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#include "hid_bpf.h"
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#include "hid_bpf_helpers.h"
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#include <bpf/bpf_tracing.h>
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#define VID_HP 0x03F0
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#define PID_ELITE_PRESENTER 0x464A
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HID_BPF_CONFIG(
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HID_DEVICE(BUS_BLUETOOTH, HID_GROUP_GENERIC, VID_HP, PID_ELITE_PRESENTER)
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);
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/*
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* Already fixed as of commit 0db117359e47 ("HID: add quirk for 03f0:464a
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* HP Elite Presenter Mouse") in the kernel, but this is a slightly better
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* fix.
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*
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* The HP Elite Presenter Mouse HID Record Descriptor shows
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* two mice (Report ID 0x1 and 0x2), one keypad (Report ID 0x5),
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* two Consumer Controls (Report IDs 0x6 and 0x3).
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* Prior to these fixes it registers one mouse, one keypad
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* and one Consumer Control, and it was usable only as a
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* digital laser pointer (one of the two mouses).
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* We replace the second mouse collection with a pointer collection,
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* allowing to use the device both as a mouse and a digital laser
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* pointer.
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*/
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SEC(HID_BPF_RDESC_FIXUP)
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int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx)
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{
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__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */);
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if (!data)
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return 0; /* EPERM check */
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/* replace application mouse by application pointer on the second collection */
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if (data[79] == 0x02)
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data[79] = 0x01;
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return 0;
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}
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HID_BPF_OPS(hp_elite_presenter) = {
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.hid_rdesc_fixup = (void *)hid_fix_rdesc,
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};
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SEC("syscall")
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int probe(struct hid_bpf_probe_args *ctx)
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{
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ctx->retval = ctx->rdesc_size != 264;
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if (ctx->retval)
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ctx->retval = -EINVAL;
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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