USB: omninet: refactor read-urb processing

Refactor read-urb processing, and add sanity checks on header and data
lengths.

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

1 files changed, 18 insertions, 7 deletions

diff --git a/drivers/usb/serial/omninet.c b/drivers/usb/serial/omninet.c
index 9dcaa7727de5..7aaf9692b334 100644
--- a/drivers/usb/serial/omninet.c
+++ b/drivers/usb/serial/omninet.c
@@ -158,11 +158,26 @@ static void omninet_close(struct usb_serial_port *port)
 #define OMNINET_BULKOUTSIZE     64
 #define OMNINET_PAYLOADSIZE     (OMNINET_BULKOUTSIZE - OMNINET_HEADERLEN)
 
+static void omninet_process_read_urb(struct urb *urb)
+{
+        struct usb_serial_port *port = urb->context;
+        const struct omninet_header *hdr = urb->transfer_buffer;
+        const unsigned char *data;
+        size_t data_len;
+
+        if (urb->actual_length <= OMNINET_HEADERLEN || !hdr->oh_len)
+                return;
+
+        data = (char *)urb->transfer_buffer + OMNINET_HEADERLEN;
+        data_len = min_t(size_t, urb->actual_length - OMNINET_HEADERLEN,
+                                                                hdr->oh_len);
+        tty_insert_flip_string(&port->port, data, data_len);
+        tty_flip_buffer_push(&port->port);
+}
+
 static void omninet_read_bulk_callback(struct urb *urb)
 {
         struct usb_serial_port  *port   = urb->context;
-        unsigned char           *data   = urb->transfer_buffer;
-        struct omninet_header   *header = (struct omninet_header *) &data[0];
         int status = urb->status;
         int result;
 
@@ -172,11 +187,7 @@ static void omninet_read_bulk_callback(struct urb *urb)
                 return;
         }
 
-        if (urb->actual_length && header->oh_len) {
-                tty_insert_flip_string(&port->port, data + OMNINET_HEADERLEN,
-                                header->oh_len);
-                tty_flip_buffer_push(&port->port);
-        }
+        omninet_process_read_urb(urb);
 
         /* Continue trying to always read  */
         result = usb_submit_urb(urb, GFP_ATOMIC);