i2o: check copy_from_user() size parameter

Limit the size of the copy so we don't corrupt memory.  Hopefully this
can only be called by root, but fixing this makes the static checkers
happier.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Masanari Iida <standby24x7@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: Dan Carpenter

drivers/message/i2o/i2o_config.c

@@ -687,6 +687,11 @@ static int i2o_cfg_passthru32(struct file *file, unsigned cmnd,
 		}
 		size = size >> 16;
 		size *= 4;
+		if (size > sizeof(rmsg)) {
+			rcode = -EINVAL;
+			goto sg_list_cleanup;
+		}
+
 		/* Copy in the user's I2O command */
 		if (copy_from_user(rmsg, user_msg, size)) {
 			rcode = -EFAULT;
@@ -922,6 +927,11 @@ static int i2o_cfg_passthru(unsigned long arg)
 		}
 		size = size >> 16;
 		size *= 4;
+		if (size > sizeof(rmsg)) {
+			rcode = -EFAULT;
+			goto sg_list_cleanup;
+		}
+
 		/* Copy in the user's I2O command */
 		if (copy_from_user(rmsg, user_msg, size)) {
 			rcode = -EFAULT;