USB: serial: keyspan_pda: verify endpoints at probe

Check for the expected endpoints in attach() and fail loudly if not
present.

Note that failing to do this appears to be benign since da280e348866
("USB: keyspan_pda: clean up write-urb busy handling") which prevents a
NULL-pointer dereference in write() by never marking a non-existent
write-urb as free.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>	# < v3.3
Signed-off-by: Johan Hovold <johan@kernel.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index e49ad0c63ad8..83523fcf6fb9 100644
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -699,6 +699,19 @@ MODULE_FIRMWARE("keyspan_pda/keyspan_pda.fw");
 MODULE_FIRMWARE("keyspan_pda/xircom_pgs.fw");
 #endif
 
+static int keyspan_pda_attach(struct usb_serial *serial)
+{
+        unsigned char num_ports = serial->num_ports;
+
+        if (serial->num_bulk_out < num_ports ||
+                        serial->num_interrupt_in < num_ports) {
+                dev_err(&serial->interface->dev, "missing endpoints\n");
+                return -ENODEV;
+        }
+
+        return 0;
+}
+
 static int keyspan_pda_port_probe(struct usb_serial_port *port)
 {
 
@@ -776,6 +789,7 @@ static struct usb_serial_driver keyspan_pda_device = {
         .break_ctl =            keyspan_pda_break_ctl,
         .tiocmget =             keyspan_pda_tiocmget,
         .tiocmset =             keyspan_pda_tiocmset,
+        .attach =               keyspan_pda_attach,
         .port_probe =           keyspan_pda_port_probe,
         .port_remove =          keyspan_pda_port_remove,
 };