From: Johan Hovold <johan@kernel.org>
Date: Tue, 3 Jan 2017 15:39:55 +0000 (+0100)
Subject: USB: serial: mos7840: fix NULL-deref at open
X-Git-Tag: v3.2.87~125
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=9e818917657b4fd3b05c9654de90f007496b598e

USB: serial: mos7840: fix NULL-deref at open

commit 5c75633ef751dd4cd8f443dc35152c1ae563162e upstream.

Fix NULL-pointer dereference in open() should the device lack the
expected endpoints:

Unable to handle kernel NULL pointer dereference at virtual address 00000030
...
PC is at mos7840_open+0x88/0x8dc [mos7840]

Note that we continue to treat the interrupt-in endpoint as optional for
now.

Fixes: 3f5429746d91 ("USB: Moschip 7840 USB-Serial Driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
[bwh: Backported to 3.2: add this check to the existing
 usb_serial_driver::attach implementation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 59fdb84d016f..6469d30739de 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -2386,6 +2386,12 @@ static int mos7840_startup(struct usb_serial *serial)
 		return -1;
 	}
 
+	if (serial->num_bulk_in < serial->num_ports ||
+			serial->num_bulk_out < serial->num_ports) {
+		dev_err(&serial->interface->dev, "missing endpoints\n");
+		return -ENODEV;
+	}
+
 	dev = serial->dev;
 
 	dbg("%s", "Entering...");