[PATCH 3.2 094/131] USB: serial: fix potential heap buffer overflow

[Ben Hutchings]

3.2.63-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Johan Hovold <johan@xxxxxxxxxx>

commit 5654699fb38512bdbfc0f892ce54fce75bdc2bab upstream.

Make sure to verify the number of ports requested by subdriver to avoid
writing beyond the end of fixed-size array in interface data.

The current usb-serial implementation is limited to eight ports per
interface but failed to verify that the number of ports requested by a
subdriver (which could have been determined from device descriptors) did
not exceed this limit.

Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.2: s/ddev/\&interface->dev/]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/usb/serial/usb-serial.c | 5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -888,6 +888,11 @@ int usb_serial_probe(struct usb_interfac
 			num_ports = type->num_ports;
 	}
 
+	if (num_ports > MAX_NUM_PORTS) {
+		dev_warn(&interface->dev, "too many ports requested: %d\n", num_ports);
+		num_ports = MAX_NUM_PORTS;
+	}
+
 	serial->num_ports = num_ports;
 	serial->num_bulk_in = num_bulk_in;
 	serial->num_bulk_out = num_bulk_out;

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/