1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2023 Benjamin Tissoires 3 */ 4 5 #include "vmlinux.h" 6 #include "hid_bpf.h" 7 #include "hid_bpf_helpers.h" 8 #include <bpf/bpf_tracing.h> 9 10 #define VID_HP 0x03F0 11 #define PID_ELITE_PRESENTER 0x464A 12 13 HID_BPF_CONFIG( 14 HID_DEVICE(BUS_BLUETOOTH, HID_GROUP_GENERIC, VID_HP, PID_ELITE_PRESENTER) 15 ); 16 17 /* 18 * Already fixed as of commit 0db117359e47 ("HID: add quirk for 03f0:464a 19 * HP Elite Presenter Mouse") in the kernel, but this is a slightly better 20 * fix. 21 * 22 * The HP Elite Presenter Mouse HID Record Descriptor shows 23 * two mice (Report ID 0x1 and 0x2), one keypad (Report ID 0x5), 24 * two Consumer Controls (Report IDs 0x6 and 0x3). 25 * Prior to these fixes it registers one mouse, one keypad 26 * and one Consumer Control, and it was usable only as a 27 * digital laser pointer (one of the two mouses). 28 * We replace the second mouse collection with a pointer collection, 29 * allowing to use the device both as a mouse and a digital laser 30 * pointer. 31 */ 32 33 SEC("fmod_ret/hid_bpf_rdesc_fixup") 34 int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx) 35 { 36 __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */); 37 38 if (!data) 39 return 0; /* EPERM check */ 40 41 /* replace application mouse by application pointer on the second collection */ 42 if (data[79] == 0x02) 43 data[79] = 0x01; 44 45 return 0; 46 } 47 48 SEC("syscall") 49 int probe(struct hid_bpf_probe_args *ctx) 50 { 51 ctx->retval = ctx->rdesc_size != 264; 52 if (ctx->retval) 53 ctx->retval = -EINVAL; 54 55 return 0; 56 } 57 58 char _license[] SEC("license") = "GPL"; 59