[PATCH] HID: intel-thc-hid: reject oversized QuickSPI GET_REPORT responses

["Jérémy Jean" <Jeremy.Jean@oss.cyber.gouv.fr>]

Thread the HID core caller length into quickspi_get_report() and reject
responses that exceed the caller-provided buffer before the final copy.
Snapshot the completed response length once so the bound check, copy, and
returned byte count all use the same value.

Fixes: 9d8d51735a3a ("HID: intel-thc-hid: intel-quickspi: Add HIDSPI protocol implementation")
Assisted-by: Codex:gpt-5
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
---
 .../intel-thc-hid/intel-quickspi/quickspi-hid.c   |  2 +-
 .../intel-quickspi/quickspi-protocol.c            | 15 ++++++++++++---
 .../intel-quickspi/quickspi-protocol.h            |  2 +-
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-hid.c b/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-hid.c
index 91d5807b4a83..a60a0a7f16aa 100644
--- a/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-hid.c
+++ b/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-hid.c
@@ -61,7 +61,7 @@ static int quickspi_hid_raw_request(struct hid_device *hid,
 
 	switch (reqtype) {
 	case HID_REQ_GET_REPORT:
-		ret = quickspi_get_report(qsdev, rtype, reportnum, buf);
+		ret = quickspi_get_report(qsdev, rtype, reportnum, buf, len);
 		break;
 	case HID_REQ_SET_REPORT:
 		ret = quickspi_set_report(qsdev, rtype, reportnum, buf, len);
diff --git a/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-protocol.c b/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-protocol.c
index cb19057f1191..acc9d67c53ca 100644
--- a/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-protocol.c
+++ b/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-protocol.c
@@ -342,10 +342,12 @@ int reset_tic(struct quickspi_device *qsdev)
 }
 
 int quickspi_get_report(struct quickspi_device *qsdev,
-			u8 report_type, unsigned int report_id, void *buf)
+			u8 report_type, unsigned int report_id,
+			void *buf, size_t buf_len)
 {
 	int rep_type;
 	int ret;
+	u32 report_len;
 
 	if (report_type == HID_INPUT_REPORT) {
 		rep_type = GET_INPUT_REPORT;
@@ -371,10 +373,17 @@ int quickspi_get_report(struct quickspi_device *qsdev,
 		return -ETIMEDOUT;
 	}
 	qsdev->get_report_cmpl = false;
+	report_len = READ_ONCE(qsdev->report_len);
+
+	if (report_len > buf_len) {
+		dev_err_once(qsdev->dev, "Get report response too large: %u vs %zu\n",
+			     report_len, buf_len);
+		return -EINVAL;
+	}
 
-	memcpy(buf, qsdev->report_buf, qsdev->report_len);
+	memcpy(buf, qsdev->report_buf, report_len);
 
-	return qsdev->report_len;
+	return report_len;
 }
 
 int quickspi_set_report(struct quickspi_device *qsdev,
diff --git a/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-protocol.h b/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-protocol.h
index 775e29c1ed13..aa2c935dafe8 100644
--- a/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-protocol.h
+++ b/drivers/hid/intel-thc-hid/intel-quickspi/quickspi-protocol.h
@@ -12,7 +12,7 @@ struct quickspi_device;
 
 void quickspi_handle_input_data(struct quickspi_device *qsdev, u32 buf_len);
 int quickspi_get_report(struct quickspi_device *qsdev, u8 report_type,
-			unsigned int report_id, void *buf);
+			unsigned int report_id, void *buf, size_t buf_len);
 int quickspi_set_report(struct quickspi_device *qsdev, u8 report_type,
 			unsigned int report_id, void *buf, u32 buf_len);
 int quickspi_get_report_descriptor(struct quickspi_device *qsdev);
-- 
2.47.3