From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Pengpeng Hou <pengpeng@iscas.ac.cn>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>
Subject: [PATCH 5.15 018/272] Input: iforce - validate input packet lengths
Date: Thu, 20 Aug 2026 16:53:22 +0200
Message-ID: <20260820145231.780682390@linuxfoundation.org>
In-Reply-To: <20260820145231.229664293@linuxfoundation.org>
References: <20260820145231.229664293@linuxfoundation.org>
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5.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Pengpeng Hou <pengpeng@iscas.ac.cn>

commit 5751c781d3c97ab6ce0e2a966156ed882152c415 upstream.

iforce_process_packet() reads fixed fields from joystick, wheel and
status packets without first checking their lengths. In particular, the
shared hats-and-buttons helper unconditionally reads data[6]. The status
tail is a sequence of 16-bit effect addresses, but an incomplete final
address is also consumed. A successful zero-length USB URB additionally
reads the packet ID before the common parser is called.

Reject the zero-length USB transfer, require the seven-byte joystick and
wheel prefixes and the two-byte status prefix, and consume only complete
status-tail addresses.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Link: https://patch.msgid.link/20260720115018.75045-1-pengpeng@iscas.ac.cn
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/input/joystick/iforce/iforce-packets.c |   11 ++++++++++-
 drivers/input/joystick/iforce/iforce-usb.c     |    3 +++
 2 files changed, 13 insertions(+), 1 deletion(-)

--- a/drivers/input/joystick/iforce/iforce-packets.c
+++ b/drivers/input/joystick/iforce/iforce-packets.c
@@ -161,6 +161,9 @@ void iforce_process_packet(struct iforce
 	switch (packet_id) {
 
 	case 0x01:	/* joystick position data */
+		if (len < 7)
+			break;
+
 		input_report_abs(dev, ABS_X,
 				 (__s16) get_unaligned_le16(data));
 		input_report_abs(dev, ABS_Y,
@@ -176,6 +179,9 @@ void iforce_process_packet(struct iforce
 		break;
 
 	case 0x03:	/* wheel position data */
+		if (len < 7)
+			break;
+
 		input_report_abs(dev, ABS_WHEEL,
 				 (__s16) get_unaligned_le16(data));
 		input_report_abs(dev, ABS_GAS,   255 - data[2]);
@@ -187,6 +193,9 @@ void iforce_process_packet(struct iforce
 		break;
 
 	case 0x02:	/* status report */
+		if (len < 2)
+			break;
+
 		input_report_key(dev, BTN_DEAD, data[0] & 0x02);
 		input_sync(dev);
 
@@ -206,7 +215,7 @@ void iforce_process_packet(struct iforce
 			}
 		}
 
-		for (j = 3; j < len; j += 2)
+		for (j = 3; j + sizeof(u16) <= len; j += sizeof(u16))
 			mark_core_as_ready(iforce, get_unaligned_le16(data + j));
 
 		break;
--- a/drivers/input/joystick/iforce/iforce-usb.c
+++ b/drivers/input/joystick/iforce/iforce-usb.c
@@ -159,6 +159,9 @@ static void iforce_usb_irq(struct urb *u
 		goto exit;
 	}
 
+	if (!urb->actual_length)
+		goto exit;
+
 	iforce_process_packet(iforce, iforce_usb->data_in[0],
 			      iforce_usb->data_in + 1, urb->actual_length - 1);