[PATCH] hwmon: valid the data size before reading the sensor data

[Edward Adam Davis]

The user-forged sensor data is only 65 bytes long; however, aqc_raw_event()
fails to handle cases where the sensor data length is smaller than the buffer
size when reading the data, resulting in [1] during the read process.

Add a check for the data size, if it less than the buffer size, the sensor
data read is aborted.

[1]
BUG: KASAN: slab-out-of-bounds in aqc_raw_event+0x213e/0x25d0 drivers/hwmon/aquacomputer_d5next.c:1327
Read of size 2 at addr ffff888108aba257 by task swapper/1/0
Call Trace:
 get_unaligned_be16 include/linux/unaligned.h:48 [inline]
 aqc_raw_event drivers/hwmon/aquacomputer_d5next.c:1345 [inline]
 aqc_raw_event+0x213e/0x25d0 drivers/hwmon/aquacomputer_d5next.c:1327
 __hid_input_report.constprop.0+0x319/0x470 drivers/hid/hid-core.c:2168
 hid_irq_in+0x55d/0x710 drivers/hid/usbhid/hid-core.c:287
 __usb_hcd_giveback_urb+0x38d/0x610 drivers/usb/core/hcd.c:1657
 usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741

Fixes: 0e35f63f7f4e ("hwmon: add driver for Aquacomputer D5 Next")
Reported-by: syzbot+9ee5f5dc18673d6b2f37@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=9ee5f5dc18673d6b2f37
Tested-by: syzbot+9ee5f5dc18673d6b2f37@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
 drivers/hwmon/aquacomputer_d5next.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hwmon/aquacomputer_d5next.c b/drivers/hwmon/aquacomputer_d5next.c
index 1ca70e726298..1cc6c220ffe9 100644
--- a/drivers/hwmon/aquacomputer_d5next.c
+++ b/drivers/hwmon/aquacomputer_d5next.c
@@ -1334,6 +1334,9 @@ static int aqc_raw_event(struct hid_device *hdev, struct hid_report *report, u8
 
 	priv = hid_get_drvdata(hdev);
 
+	if (size < priv->buffer_size)
+		return 0;
+
 	/* Info provided with every report */
 	priv->serial_number[0] = get_unaligned_be16(data + priv->serial_number_start_offset);
 	priv->serial_number[1] = get_unaligned_be16(data + priv->serial_number_start_offset +
-- 
2.43.0