[PATCH 3.2 071/199] USB: serial: iuu_phoenix: fix NULL-deref at open

[Ben Hutchings]

3.2.87-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Johan Hovold <jo...@kernel.org>

commit 90507d54f712d81b74815ef3a4bbb555cd9fab2f upstream.

Fix NULL-pointer dereference at open should the device lack a bulk-in or
bulk-out endpoint:

Unable to handle kernel NULL pointer dereference at virtual address 00000030
...
PC is at iuu_open+0x78/0x59c [iuu_phoenix]

Fixes: 07c3b1a10016 ("USB: remove broken usb-serial num_endpoints
check")
Signed-off-by: Johan Hovold <jo...@kernel.org>
[bwh: Backported to 3.2: add this check to the existing
 usb_serial_driver::attach implementation]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
--- a/drivers/usb/serial/iuu_phoenix.c
+++ b/drivers/usb/serial/iuu_phoenix.c
@@ -112,7 +112,12 @@ static int iuu_alloc_buf(struct iuu_priv
 
 static int iuu_startup(struct usb_serial *serial)
 {
+       unsigned char num_ports = serial->num_ports;
        struct iuu_private *priv;
+
+       if (serial->num_bulk_in < num_ports || serial->num_bulk_out < num_ports)
+               return -ENODEV;
+
        priv = kzalloc(sizeof(struct iuu_private), GFP_KERNEL);
        dbg("%s- priv allocation success", __func__);
        if (!priv)