re: libertas: if_spi, driver for libertas GSPI devices

[Dan Carpenter <dan.carpenter@oracle.com>]

Hi Colin,

I was going through some old stuff and I had a question about a
potential overfow in if_spi_c2h_cmd().

   714          } else if (len > IF_SPI_CMD_BUF_SIZE) {
                           ^^^^^^^^^^^^^^^^^^^^^^^^^
We cap "len" at 2400 bytes here.

   715                  netdev_err(priv->dev,
   716                             "%s: error: response packet too large: %d bytes, but maximum is %d\n",
   717                             __func__, len, IF_SPI_CMD_BUF_SIZE);
   718                  err = -EINVAL;
   719                  goto out;
   720          }
   721  
   722          /* Read the data from the WLAN module into our command buffer */
   723          err = spu_read(card, IF_SPI_CMD_RDWRPORT_REG,
   724                                  card->cmd_buffer, ALIGN(len, 4));
   725          if (err)
   726                  goto out;
   727  
   728          spin_lock_irqsave(&priv->driver_lock, flags);
   729          i = (priv->resp_idx == 0) ? 1 : 0;
   730          BUG_ON(priv->resp_len[i]);
   731          priv->resp_len[i] = len;
   732          memcpy(priv->resp_buf[i], card->cmd_buffer, len);
                       ^^^^^^^^^^^^^^^^
But ->resp_buf[i] can only hold LBS_UPLD_SIZE (2312) bytes, so we could
write past the end of the array.

   733          lbs_notify_command_response(priv, i);

regards,
dan carpenter