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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: fe3ee1ec00 ("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: Sam Bazely <sambazley@fastmail.com>
Signed-off-by: Andrey 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: Benjamin Tissoires <benjamin.tissoires@redhat.com>
This commit is contained in:
Andrey Smirnov 2019-10-17 21:45:16 -07:00 committed by Benjamin Tissoires
parent abdd3d0b34
commit 905d754c53
1 changed files with 37 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
drivers/hid/hid-logitech-hidpp.c
View File

@ -3498,34 +3498,45 @@ static int hidpp_get_report_length(struct hid_device *hdev, int id)
return report->field[0]->report_count + 1;
}
static bool hidpp_validate_report(struct hid_device *hdev, int id,
int expected_length, bool optional)
{
int report_length;
if (id >= HID_MAX_IDS || id < 0) {
hid_err(hdev, "invalid HID report id %u\n", id);
return false;
}
report_length = hidpp_get_report_length(hdev, id);
if (!report_length)
return optional;
if (report_length < expected_length) {
hid_warn(hdev, "not enough values in hidpp report %d\n", id);
return false;
}
return true;
}
static bool hidpp_validate_device(struct hid_device *hdev)
{
return hidpp_validate_report(hdev, REPORT_ID_HIDPP_SHORT,
HIDPP_REPORT_SHORT_LENGTH, false) &&
hidpp_validate_report(hdev, REPORT_ID_HIDPP_LONG,
HIDPP_REPORT_LONG_LENGTH, true);
struct hidpp_device *hidpp = hid_get_drvdata(hdev);
int id, report_length, supported_reports = 0;
id = REPORT_ID_HIDPP_SHORT;
report_length = hidpp_get_report_length(hdev, id);
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);
if (report_length) {
if (report_length < HIDPP_REPORT_LONG_LENGTH)
goto bad_device;
supported_reports++;
}
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;
}
return supported_reports;
bad_device:
hid_warn(hdev, "not enough values in hidpp report %d\n", id);
return false;
}
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);
}
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)
hidpp->quirks |= HIDPP_QUIRK_UNIFYING;