FAILED: patch "[PATCH] USB: usbtmc: add missing endpoint sanity check" failed to apply to 4.4-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 687e0687f71ec00e0132a21fef802dee88c2f1ad Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan@xxxxxxxxxx>
Date: Tue, 14 Mar 2017 17:55:45 +0100
Subject: [PATCH] USB: usbtmc: add missing endpoint sanity check

USBTMC devices are required to have a bulk-in and a bulk-out endpoint,
but the driver failed to verify this, something which could lead to the
endpoint addresses being taken from uninitialised memory.

Make sure to zero all private data as part of allocation, and add the
missing endpoint sanity check.

Note that this also addresses a more recently introduced issue, where
the interrupt-in-presence flag would also be uninitialised whenever the
optional interrupt-in endpoint is not present. This in turn could lead
to an interrupt urb being allocated, initialised and submitted based on
uninitialised values.

Fixes: dbf3e7f654c0 ("Implement an ioctl to support the USMTMC-USB488 READ_STATUS_BYTE operation.")
Fixes: 5b775f672cc9 ("USB: add USB test and measurement class driver")
Cc: stable <stable@xxxxxxxxxxxxxxx>     # 2.6.28
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index f03692ec5520..5e3446db4513 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -1381,7 +1381,7 @@ static int usbtmc_probe(struct usb_interface *intf,
 
 	dev_dbg(&intf->dev, "%s called\n", __func__);
 
-	data = kmalloc(sizeof(*data), GFP_KERNEL);
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
 
@@ -1444,6 +1444,13 @@ static int usbtmc_probe(struct usb_interface *intf,
 			break;
 		}
 	}
+
+	if (!data->bulk_out || !data->bulk_in) {
+		dev_err(&intf->dev, "bulk endpoints not found\n");
+		retcode = -ENODEV;
+		goto err_put;
+	}
+
 	/* Find int endpoint */
 	for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
 		endpoint = &iface_desc->endpoint[n].desc;
@@ -1512,6 +1519,7 @@ static int usbtmc_probe(struct usb_interface *intf,
 	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
 	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
 	usbtmc_free_int(data);
+err_put:
 	kref_put(&data->kref, usbtmc_delete);
 	return retcode;
 }