[PATCH 6.6 007/160] HID: multitouch: Check to ensure report responses match the request

Greg Kroah-Hartman
2026-04-08T18:21:39Z

From: Lee Jones <lee@kernel.org>

[ Upstream commit e716edafedad4952fe3a4a273d2e039a84e8681a ]

It is possible for a malicious (or clumsy) device to respond to a
specific report's feature request using a completely different report
ID. This can cause confusion in the HID core resulting in nasty
side-effects such as OOB writes.

Add a check to ensure that the report ID in the response, matches the
one that was requested. If it doesn't, omit reporting the raw event and
return early.

Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hid/hid-multitouch.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index b6c2cb7153fde..0039508943626 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -472,12 +472,19 @@ static void mt_get_feature(struct hid_device *hdev, struct hid_report *report)
dev_warn(&hdev->dev, "failed to fetch feature %d\n",
report->id);
} else {
+ /* The report ID in the request and the response should match */
+ if (report->id != buf[0]) {
+ hid_err(hdev, "Returned feature report did not match the request\n");
+ goto free;
+ }
+
ret = hid_report_raw_event(hdev, HID_FEATURE_REPORT, buf,
size, 0);
if (ret)
dev_warn(&hdev->dev, "failed to report feature\n");
}

+free:
kfree(buf);
}

--
2.53.0