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By allowing the drivers to return a "const *" they can constify their static report arrays. This makes it clear to driver authors that the HID core will not modify those reports and they can be reused for multiple devices. Furthermore security is slightly improved as those reports are protected against accidental or malicious modifications. [bentiss: fixup hid-cougar.c and hid-multitouch.c for latest version of the master branch] Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://patch.msgid.link/20240803-hid-const-fixup-v2-6-f53d7a7b29d8@weissschuh.net Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
114 lines
3.2 KiB
C
114 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* HID driver for Gembird Joypad, "PC Game Controller"
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*
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* Copyright (c) 2015 Red Hat, Inc
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* Copyright (c) 2015 Benjamin Tissoires
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*/
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/*
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*/
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#include <linux/device.h>
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#include <linux/hid.h>
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#include <linux/module.h>
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#include "hid-ids.h"
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#define GEMBIRD_START_FAULTY_RDESC 8
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static const __u8 gembird_jpd_faulty_rdesc[] = {
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0x75, 0x08, /* Report Size (8) */
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0x95, 0x05, /* Report Count (5) */
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0x15, 0x00, /* Logical Minimum (0) */
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0x26, 0xff, 0x00, /* Logical Maximum (255) */
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0x35, 0x00, /* Physical Minimum (0) */
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0x46, 0xff, 0x00, /* Physical Maximum (255) */
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0x09, 0x30, /* Usage (X) */
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0x09, 0x31, /* Usage (Y) */
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0x09, 0x32, /* Usage (Z) */
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0x09, 0x32, /* Usage (Z) */
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0x09, 0x35, /* Usage (Rz) */
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0x81, 0x02, /* Input (Data,Var,Abs) */
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};
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/*
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* we fix the report descriptor by:
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* - marking the first Z axis as constant (so it is ignored by HID)
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* - assign the original second Z to Rx
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* - assign the original Rz to Ry
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*/
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static const __u8 gembird_jpd_fixed_rdesc[] = {
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0x75, 0x08, /* Report Size (8) */
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0x95, 0x02, /* Report Count (2) */
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0x15, 0x00, /* Logical Minimum (0) */
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0x26, 0xff, 0x00, /* Logical Maximum (255) */
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0x35, 0x00, /* Physical Minimum (0) */
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0x46, 0xff, 0x00, /* Physical Maximum (255) */
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0x09, 0x30, /* Usage (X) */
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0x09, 0x31, /* Usage (Y) */
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0x81, 0x02, /* Input (Data,Var,Abs) */
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0x95, 0x01, /* Report Count (1) */
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0x09, 0x32, /* Usage (Z) */
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0x81, 0x01, /* Input (Cnst,Arr,Abs) */
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0x95, 0x02, /* Report Count (2) */
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0x09, 0x33, /* Usage (Rx) */
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0x09, 0x34, /* Usage (Ry) */
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0x81, 0x02, /* Input (Data,Var,Abs) */
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};
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static const __u8 *gembird_report_fixup(struct hid_device *hdev, __u8 *rdesc,
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unsigned int *rsize)
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{
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__u8 *new_rdesc;
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/* delta_size is > 0 */
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size_t delta_size = sizeof(gembird_jpd_fixed_rdesc) -
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sizeof(gembird_jpd_faulty_rdesc);
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size_t new_size = *rsize + delta_size;
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if (*rsize >= 31 && !memcmp(&rdesc[GEMBIRD_START_FAULTY_RDESC],
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gembird_jpd_faulty_rdesc,
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sizeof(gembird_jpd_faulty_rdesc))) {
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new_rdesc = devm_kzalloc(&hdev->dev, new_size, GFP_KERNEL);
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if (new_rdesc == NULL)
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return rdesc;
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dev_info(&hdev->dev,
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"fixing Gembird JPD-DualForce 2 report descriptor.\n");
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/* start by copying the end of the rdesc */
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memcpy(new_rdesc + delta_size, rdesc, *rsize);
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/* add the correct beginning */
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memcpy(new_rdesc, rdesc, GEMBIRD_START_FAULTY_RDESC);
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/* replace the faulty part with the fixed one */
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memcpy(new_rdesc + GEMBIRD_START_FAULTY_RDESC,
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gembird_jpd_fixed_rdesc,
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sizeof(gembird_jpd_fixed_rdesc));
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*rsize = new_size;
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rdesc = new_rdesc;
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}
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return rdesc;
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}
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static const struct hid_device_id gembird_devices[] = {
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{ HID_USB_DEVICE(USB_VENDOR_ID_GEMBIRD,
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USB_DEVICE_ID_GEMBIRD_JPD_DUALFORCE2) },
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{ }
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};
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MODULE_DEVICE_TABLE(hid, gembird_devices);
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static struct hid_driver gembird_driver = {
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.name = "gembird",
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.id_table = gembird_devices,
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.report_fixup = gembird_report_fixup,
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};
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module_hid_driver(gembird_driver);
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MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@gmail.com>");
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MODULE_DESCRIPTION("HID Gembird joypad driver");
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MODULE_LICENSE("GPL");
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