[patch added to 3.12-stable] USB: usbtmc: add missing endpoint sanity check

[Jiri Slaby <jslaby@suse.cz>]

From: Johan Hovold <johan@kernel.org>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.

===============

commit 687e0687f71ec00e0132a21fef802dee88c2f1ad upstream.

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")
Signed-off-by: Johan Hovold <johan@kernel.org>
[ johan: backport to v4.4 ]
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/usb/class/usbtmc.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 72ed4ac2cfad..13583a2edba7 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -1102,7 +1102,7 @@ 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) {
 		dev_err(&intf->dev, "Unable to allocate kernel memory\n");
 		return -ENOMEM;
@@ -1162,6 +1162,12 @@ static int usbtmc_probe(struct usb_interface *intf,
 		}
 	}
 
+	if (!data->bulk_out || !data->bulk_in) {
+		dev_err(&intf->dev, "bulk endpoints not found\n");
+		retcode = -ENODEV;
+		goto err_put;
+	}
+
 	retcode = get_capabilities(data);
 	if (retcode)
 		dev_err(&intf->dev, "can't read capabilities\n");
@@ -1185,6 +1191,7 @@ static int usbtmc_probe(struct usb_interface *intf,
 error_register:
 	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
 	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
+err_put:
 	kref_put(&data->kref, usbtmc_delete);
 	return retcode;
 }
-- 
2.12.2