[PATCH 3.4 34/45] USB: serial: fix potential heap buffer overflow

Zefan Li
2014-09-23T02:40:40Z

From: Johan Hovold <johan@kernel.org>

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

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

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@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[lizf: Backported to 3.4: s/ddev/\&interface->dev/]
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
drivers/usb/serial/usb-serial.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 815d86d..a08230e 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -889,6 +889,11 @@ int usb_serial_probe(struct usb_interface *interface,
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;
--
1.7.9.5