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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>,
        "Johan Hovold" <johan@kernel.org>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>
Date:   Fri, 24 Apr 2020 00:07:01 +0100
Message-ID: <lsq.1587683028.950875048@decadent.org.uk>
Subject: [PATCH 3.16 194/245] USB: serial: io_edgeport: handle unbound
 ports on URB completion
In-Reply-To: <lsq.1587683027.831233700@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
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3.16.83-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Johan Hovold <johan@kernel.org>

commit e37d1aeda737a20b1846a91a3da3f8b0f00cf690 upstream.

Check for NULL port data in the shared interrupt and bulk completion
callbacks to avoid dereferencing a NULL pointer in case a device sends
data for a port device which isn't bound to a driver (e.g. due to a
malicious device having unexpected endpoints or after an allocation
failure on port probe).

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/usb/serial/io_edgeport.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -638,7 +638,7 @@ static void edge_interrupt_callback(stru
 			if (txCredits) {
 				port = edge_serial->serial->port[portNumber];
 				edge_port = usb_get_serial_port_data(port);
-				if (edge_port->open) {
+				if (edge_port && edge_port->open) {
 					spin_lock(&edge_port->ep_lock);
 					edge_port->txCredits += txCredits;
 					spin_unlock(&edge_port->ep_lock);
@@ -1775,7 +1775,7 @@ static void process_rcvd_data(struct edg
 				port = edge_serial->serial->port[
 							edge_serial->rxPort];
 				edge_port = usb_get_serial_port_data(port);
-				if (edge_port->open) {
+				if (edge_port && edge_port->open) {
 					dev_dbg(dev, "%s - Sending %d bytes to TTY for port %d\n",
 						__func__, rxLen,
 						edge_serial->rxPort);