Commit 905d754c authored by Andrey Smirnov's avatar Andrey Smirnov Committed by Benjamin Tissoires
Browse files

HID: logitech-hidpp: rework device validation 

G920 device only advertises REPORT_ID_HIDPP_LONG and
REPORT_ID_HIDPP_VERY_LONG in its HID report descriptor, so querying
for REPORT_ID_HIDPP_SHORT with optional=false will always fail and
prevent G920 to be recognized as a valid HID++ device.

To fix this and improve some other aspects, modify
hidpp_validate_device() as follows:

  - Inline the code of hidpp_validate_report() to simplify
    distingushing between non-present and invalid report descriptors

  - Drop the check for id >= HID_MAX_IDS || id < 0 since all of our
    IDs are static and known to satisfy that at compile time

  - Change the algorithms to check all possible report
    types (including very long report) and deem the device as a valid
    HID++ device if it supports at least one

  - Treat invalid report length as a hard stop for the validation
    algorithm, meaning that if any of the supported reports has
    invalid length we assume the worst and treat the device as a
    generic HID device.

  - Fold initialization of hidpp->very_long_report_length into
    hidpp_validate_device() since it already fetches very long report
    length and validates its value

Fixes: fe3ee1ec ("HID: logitech-hidpp: allow non HID++ devices to be handled by this module")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204191


Reported-by: default avatarSam Bazely <sambazley@fastmail.com>
Signed-off-by: default avatarAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Henrik Rydberg <rydberg@bitmath.org>
Cc: Pierre-Loup A. Griffais <pgriffais@valvesoftware.com>
Cc: Austin Palmer <austinp@valvesoftware.com>
Cc: linux-input@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # 5.2+
Signed-off-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
parent abdd3d0b

drivers/hid/hid-logitech-hidpp.c

+30 −24
Original line number Original line Diff line number Diff line
@@ -3498,34 +3498,45 @@ static int hidpp_get_report_length(struct hid_device *hdev, int id) 
	return report->field[0]->report_count + 1;

	return report->field[0]->report_count + 1;

}

}





static bool hidpp_validate_report(struct hid_device *hdev, int id,

static bool hidpp_validate_device(struct hid_device *hdev)

				  int expected_length, bool optional)

{

{

	int report_length;

	struct hidpp_device *hidpp = hid_get_drvdata(hdev);

	int id, report_length, supported_reports = 0;





	if (id >= HID_MAX_IDS || id < 0) {

	id = REPORT_ID_HIDPP_SHORT;

		hid_err(hdev, "invalid HID report id %u\n", id);

	report_length = hidpp_get_report_length(hdev, id);

		return false;

	if (report_length) {

		if (report_length < HIDPP_REPORT_SHORT_LENGTH)

			goto bad_device;



		supported_reports++;

	}

	}





	id = REPORT_ID_HIDPP_LONG;

	report_length = hidpp_get_report_length(hdev, id);

	report_length = hidpp_get_report_length(hdev, id);

	if (!report_length)

	if (report_length) {

		return optional;

		if (report_length < HIDPP_REPORT_LONG_LENGTH)

			goto bad_device;





	if (report_length < expected_length) {

		supported_reports++;

		hid_warn(hdev, "not enough values in hidpp report %d\n", id);

		return false;

	}

	}





	return true;

	id = REPORT_ID_HIDPP_VERY_LONG;

	report_length = hidpp_get_report_length(hdev, id);

	if (report_length) {

		if (report_length < HIDPP_REPORT_LONG_LENGTH ||

		    report_length > HIDPP_REPORT_VERY_LONG_MAX_LENGTH)

			goto bad_device;



		supported_reports++;

		hidpp->very_long_report_length = report_length;

	}

	}





static bool hidpp_validate_device(struct hid_device *hdev)

	return supported_reports;

{



	return hidpp_validate_report(hdev, REPORT_ID_HIDPP_SHORT,

bad_device:

				     HIDPP_REPORT_SHORT_LENGTH, false) &&

	hid_warn(hdev, "not enough values in hidpp report %d\n", id);

	       hidpp_validate_report(hdev, REPORT_ID_HIDPP_LONG,

	return false;

				     HIDPP_REPORT_LONG_LENGTH, true);

}

}





static bool hidpp_application_equals(struct hid_device *hdev,

static bool hidpp_application_equals(struct hid_device *hdev,
@@ -3572,11 +3583,6 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id) 
		return hid_hw_start(hdev, HID_CONNECT_DEFAULT);

		return hid_hw_start(hdev, HID_CONNECT_DEFAULT);

	}

	}





	hidpp->very_long_report_length =

		hidpp_get_report_length(hdev, REPORT_ID_HIDPP_VERY_LONG);

	if (hidpp->very_long_report_length > HIDPP_REPORT_VERY_LONG_MAX_LENGTH)

		hidpp->very_long_report_length = HIDPP_REPORT_VERY_LONG_MAX_LENGTH;



	if (id->group == HID_GROUP_LOGITECH_DJ_DEVICE)

	if (id->group == HID_GROUP_LOGITECH_DJ_DEVICE)

		hidpp->quirks |= HIDPP_QUIRK_UNIFYING;

		hidpp->quirks |= HIDPP_QUIRK_UNIFYING;

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