[PATCH 4.14 19/45] qmi_wwan: do not steal interfaces from class drivers

Greg Kroah-Hartman
2018-05-18T08:15:36Z

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4.14-stable review patch. If anyone has any objections, please let me know.

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From: "Bjørn Mork" <bjorn@mork.no>

[ Upstream commit 5697db4a696c41601a1d15c1922150b4dbf5726c ]

The USB_DEVICE_INTERFACE_NUMBER matching macro assumes that
the { vendorid, productid, interfacenumber } set uniquely
identifies one specific function. This has proven to fail
for some configurable devices. One example is the Quectel
EM06/EP06 where the same interface number can be either
QMI or MBIM, without the device ID changing either.

Fix by requiring the vendor-specific class for interface number
based matching. Functions of other classes can and should use
class based matching instead.

Fixes: 03304bcb5ec4 ("net: qmi_wwan: use fixed interface number matching")
Signed-off-by: BjÃ¸rn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/usb/qmi_wwan.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

--- a/drivers/net/usb/qmi_wwan.c
+++ b/drivers/net/usb/qmi_wwan.c
@@ -1338,6 +1338,18 @@ static int qmi_wwan_probe(struct usb_int
id->driver_info = (unsigned long)&qmi_wwan_info;
}

+ /* There are devices where the same interface number can be
+ * configured as different functions. We should only bind to
+ * vendor specific functions when matching on interface number
+ */
+ if (id->match_flags & USB_DEVICE_ID_MATCH_INT_NUMBER &&
+ desc->bInterfaceClass != USB_CLASS_VENDOR_SPEC) {
+ dev_dbg(&intf->dev,
+ "Rejecting interface number match for class %02x\n",
+ desc->bInterfaceClass);
+ return -ENODEV;
+ }
+
/* Quectel EC20 quirk where we've QMI on interface 4 instead of 0 */
if (quectel_ec20_detected(intf) && desc->bInterfaceNumber == 0) {
dev_dbg(&intf->dev, "Quectel EC20 quirk, skipping interface 0\n");