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d9d4b1e46d
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>
152 lines
3.8 KiB
C
152 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Force feedback support for Logitech Flight System G940
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*
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* Copyright (c) 2009 Gary Stein <LordCnidarian@gmail.com>
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*/
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/*
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*/
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#include <linux/input.h>
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#include <linux/hid.h>
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#include "hid-lg.h"
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/*
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* G940 Theory of Operation (from experimentation)
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*
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* There are 63 fields (only 3 of them currently used)
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* 0 - seems to be command field
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* 1 - 30 deal with the x axis
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* 31 -60 deal with the y axis
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*
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* Field 1 is x axis constant force
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* Field 31 is y axis constant force
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*
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* other interesting fields 1,2,3,4 on x axis
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* (same for 31,32,33,34 on y axis)
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*
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* 0 0 127 127 makes the joystick autocenter hard
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*
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* 127 0 127 127 makes the joystick loose on the right,
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* but stops all movemnt left
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*
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* -127 0 -127 -127 makes the joystick loose on the left,
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* but stops all movement right
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*
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* 0 0 -127 -127 makes the joystick rattle very hard
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*
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* I'm sure these are effects that I don't know enough about them
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*/
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struct lg3ff_device {
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struct hid_report *report;
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};
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static int hid_lg3ff_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 list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
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struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
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int x, y;
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/*
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* Available values in the field should always be 63, but we only use up to
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* 35. Instead, clear the entire area, however big it is.
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*/
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memset(report->field[0]->value, 0,
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sizeof(__s32) * report->field[0]->report_count);
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switch (effect->type) {
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case FF_CONSTANT:
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/*
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* Already clamped in ff_memless
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* 0 is center (different then other logitech)
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*/
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x = effect->u.ramp.start_level;
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y = effect->u.ramp.end_level;
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/* send command byte */
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report->field[0]->value[0] = 0x51;
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/*
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* Sign backwards from other Force3d pro
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* which get recast here in two's complement 8 bits
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*/
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report->field[0]->value[1] = (unsigned char)(-x);
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report->field[0]->value[31] = (unsigned char)(-y);
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hid_hw_request(hid, report, HID_REQ_SET_REPORT);
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break;
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}
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return 0;
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}
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static void hid_lg3ff_set_autocenter(struct input_dev *dev, u16 magnitude)
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{
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struct hid_device *hid = input_get_drvdata(dev);
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struct list_head *report_list = &hid->report_enum[HID_OUTPUT_REPORT].report_list;
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struct hid_report *report = list_entry(report_list->next, struct hid_report, list);
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/*
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* Auto Centering probed from device
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* NOTE: deadman's switch on G940 must be covered
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* for effects to work
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*/
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report->field[0]->value[0] = 0x51;
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report->field[0]->value[1] = 0x00;
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report->field[0]->value[2] = 0x00;
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report->field[0]->value[3] = 0x7F;
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report->field[0]->value[4] = 0x7F;
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report->field[0]->value[31] = 0x00;
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report->field[0]->value[32] = 0x00;
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report->field[0]->value[33] = 0x7F;
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report->field[0]->value[34] = 0x7F;
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hid_hw_request(hid, report, HID_REQ_SET_REPORT);
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}
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static const signed short ff3_joystick_ac[] = {
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FF_CONSTANT,
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FF_AUTOCENTER,
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-1
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};
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int lg3ff_init(struct hid_device *hid)
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{
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struct hid_input *hidinput;
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struct input_dev *dev;
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const signed short *ff_bits = ff3_joystick_ac;
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int error;
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int i;
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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_entry(hid->inputs.next, struct hid_input, list);
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dev = hidinput->input;
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/* Check that the report looks ok */
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if (!hid_validate_values(hid, HID_OUTPUT_REPORT, 0, 0, 35))
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return -ENODEV;
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/* Assume single fixed device G940 */
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for (i = 0; ff_bits[i] >= 0; i++)
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set_bit(ff_bits[i], dev->ffbit);
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error = input_ff_create_memless(dev, NULL, hid_lg3ff_play);
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if (error)
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return error;
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if (test_bit(FF_AUTOCENTER, dev->ffbit))
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dev->ff->set_autocenter = hid_lg3ff_set_autocenter;
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hid_info(hid, "Force feedback for Logitech Flight System G940 by Gary Stein <LordCnidarian@gmail.com>\n");
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return 0;
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}
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