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![Alan Stern](/assets/img/avatar_default.png)
The syzbot fuzzer found a slab-out-of-bounds write bug in the hid-gaff driver. The problem is caused by the driver's assumption that the device must have an input report. While this will be true for all normal HID input devices, a suitably malicious device can violate the assumption. The same assumption is present in over a dozen other HID drivers. This patch fixes them by checking that the list of hid_inputs for the hid_device is nonempty before allowing it to be used. Reported-and-tested-by: syzbot+403741a091bf41d4ae79@syzkaller.appspotmail.com Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: <stable@vger.kernel.org> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
148 lines
3.2 KiB
C
148 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Force feedback support for EMS Trio Linker Plus II
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*
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* Copyright (c) 2010 Ignaz Forster <ignaz.forster@gmx.de>
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*/
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/*
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*/
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#include <linux/hid.h>
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#include <linux/input.h>
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#include <linux/module.h>
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#include "hid-ids.h"
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struct emsff_device {
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struct hid_report *report;
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};
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static int emsff_play(struct input_dev *dev, void *data,
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struct ff_effect *effect)
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{
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struct hid_device *hid = input_get_drvdata(dev);
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struct emsff_device *emsff = data;
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int weak, strong;
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weak = effect->u.rumble.weak_magnitude;
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strong = effect->u.rumble.strong_magnitude;
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dbg_hid("called with 0x%04x 0x%04x\n", strong, weak);
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weak = weak * 0xff / 0xffff;
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strong = strong * 0xff / 0xffff;
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emsff->report->field[0]->value[1] = weak;
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emsff->report->field[0]->value[2] = strong;
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dbg_hid("running with 0x%02x 0x%02x\n", strong, weak);
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hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT);
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return 0;
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}
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static int emsff_init(struct hid_device *hid)
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{
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struct emsff_device *emsff;
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struct hid_report *report;
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struct hid_input *hidinput;
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struct list_head *report_list =
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&hid->report_enum[HID_OUTPUT_REPORT].report_list;
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struct input_dev *dev;
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int error;
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if (list_empty(&hid->inputs)) {
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hid_err(hid, "no inputs found\n");
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return -ENODEV;
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}
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hidinput = list_first_entry(&hid->inputs, struct hid_input, list);
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dev = hidinput->input;
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if (list_empty(report_list)) {
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hid_err(hid, "no output reports found\n");
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return -ENODEV;
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}
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report = list_first_entry(report_list, struct hid_report, list);
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if (report->maxfield < 1) {
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hid_err(hid, "no fields in the report\n");
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return -ENODEV;
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}
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if (report->field[0]->report_count < 7) {
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hid_err(hid, "not enough values in the field\n");
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return -ENODEV;
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}
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emsff = kzalloc(sizeof(struct emsff_device), GFP_KERNEL);
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if (!emsff)
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return -ENOMEM;
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set_bit(FF_RUMBLE, dev->ffbit);
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error = input_ff_create_memless(dev, emsff, emsff_play);
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if (error) {
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kfree(emsff);
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return error;
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}
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emsff->report = report;
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emsff->report->field[0]->value[0] = 0x01;
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emsff->report->field[0]->value[1] = 0x00;
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emsff->report->field[0]->value[2] = 0x00;
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emsff->report->field[0]->value[3] = 0x00;
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emsff->report->field[0]->value[4] = 0x00;
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emsff->report->field[0]->value[5] = 0x00;
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emsff->report->field[0]->value[6] = 0x00;
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hid_hw_request(hid, emsff->report, HID_REQ_SET_REPORT);
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hid_info(hid, "force feedback for EMS based devices by Ignaz Forster <ignaz.forster@gmx.de>\n");
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return 0;
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}
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static int ems_probe(struct hid_device *hdev, const struct hid_device_id *id)
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{
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int ret;
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ret = hid_parse(hdev);
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if (ret) {
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hid_err(hdev, "parse failed\n");
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goto err;
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}
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ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT & ~HID_CONNECT_FF);
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if (ret) {
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hid_err(hdev, "hw start failed\n");
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goto err;
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}
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ret = emsff_init(hdev);
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if (ret) {
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dev_err(&hdev->dev, "force feedback init failed\n");
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hid_hw_stop(hdev);
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goto err;
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}
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return 0;
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err:
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return ret;
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}
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static const struct hid_device_id ems_devices[] = {
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{ HID_USB_DEVICE(USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II) },
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{ }
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};
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MODULE_DEVICE_TABLE(hid, ems_devices);
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static struct hid_driver ems_driver = {
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.name = "hkems",
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.id_table = ems_devices,
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.probe = ems_probe,
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};
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module_hid_driver(ems_driver);
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MODULE_LICENSE("GPL");
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