USB: keyspan_pda: fix DMA buffers on stack

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 33 insertions, 12 deletions

diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index 1296a097f5c3..427d377c9d3e 100644
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -429,13 +429,20 @@ static int keyspan_pda_get_modem_info(struct usb_serial *serial,
                                       unsigned char *value)
 {
         int rc;
-        unsigned char data;
+        u8 *data;
+
+        data = kmalloc(1, GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+
         rc = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
                              3, /* get pins */
                              USB_TYPE_VENDOR|USB_RECIP_INTERFACE|USB_DIR_IN,
-                             0, 0, &data, 1, 2000);
+                             0, 0, data, 1, 2000);
         if (rc >= 0)
-                *value = data;
+                *value = *data;
+
+        kfree(data);
         return rc;
 }
 
@@ -543,7 +550,14 @@ static int keyspan_pda_write(struct tty_struct *tty,
            device how much room it really has.  This is done only on
            scheduler time, since usb_control_msg() sleeps. */
         if (count > priv->tx_room && !in_interrupt()) {
-                unsigned char room;
+                u8 *room;
+
+                room = kmalloc(1, GFP_KERNEL);
+                if (!room) {
+                        rc = -ENOMEM;
+                        goto exit;
+                }
+
                 rc = usb_control_msg(serial->dev,
                                      usb_rcvctrlpipe(serial->dev, 0),
                                      6, /* write_room */
@@ -551,9 +565,14 @@ static int keyspan_pda_write(struct tty_struct *tty,
                                      | USB_DIR_IN,
                                      0, /* value: 0 means "remaining room" */
                                      0, /* index */
-                                     &room,
+                                     room,
                                      1,
                                      2000);
+                if (rc > 0) {
+                        dbg(" roomquery says %d", *room);
+                        priv->tx_room = *room;
+                }
+                kfree(room);
                 if (rc < 0) {
                         dbg(" roomquery failed");
                         goto exit;
@@ -563,8 +582,6 @@ static int keyspan_pda_write(struct tty_struct *tty,
                         rc = -EIO; /* device didn't return any data */
                         goto exit;
                 }
-                dbg(" roomquery says %d", room);
-                priv->tx_room = room;
         }
         if (count > priv->tx_room) {
                 /* we're about to completely fill the Tx buffer, so
@@ -684,18 +701,22 @@ static int keyspan_pda_open(struct tty_struct *tty,
                                         struct usb_serial_port *port)
 {
         struct usb_serial *serial = port->serial;
-        unsigned char room;
+        u8 *room;
         int rc = 0;
         struct keyspan_pda_private *priv;
 
         /* find out how much room is in the Tx ring */
+        room = kmalloc(1, GFP_KERNEL);
+        if (!room)
+                return -ENOMEM;
+
         rc = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
                              6, /* write_room */
                              USB_TYPE_VENDOR | USB_RECIP_INTERFACE
                              | USB_DIR_IN,
                              0, /* value */
                              0, /* index */
-                             &room,
+                             room,
                              1,
                              2000);
         if (rc < 0) {
@@ -708,8 +729,8 @@ static int keyspan_pda_open(struct tty_struct *tty,
                 goto error;
         }
         priv = usb_get_serial_port_data(port);
-        priv->tx_room = room;
-        priv->tx_throttled = room ? 0 : 1;
+        priv->tx_room = *room;
+        priv->tx_throttled = *room ? 0 : 1;
 
         /*Start reading from the device*/
         port->interrupt_in_urb->dev = serial->dev;
@@ -718,8 +739,8 @@ static int keyspan_pda_open(struct tty_struct *tty,
                 dbg("%s - usb_submit_urb(read int) failed", __func__);
                 goto error;
         }
-
 error:
+        kfree(room);
         return rc;
 }
 static void keyspan_pda_close(struct usb_serial_port *port)