Char: ipmi_bt_sm, fix infinite loop

commit a94cdd1f upstream.

In read_all_bytes, we do

  unsigned char i;
  ...
  bt->read_data[0] = BMC2HOST;
  bt->read_count = bt->read_data[0];
  ...
  for (i = 1; i <= bt->read_count; i++)
    bt->read_data[i] = BMC2HOST;

If bt->read_data[0] == bt->read_count == 255, we loop infinitely in the
'for' loop.  Make 'i' an 'int' instead of 'char' to get rid of the
overflow and finish the loop after 255 iterations every time.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-and-debugged-by: Rui Hui Dian <rhdian@novell.com>
Cc: Tomas Cech <tcech@suse.cz>
Cc: Corey Minyard <minyard@acm.org>
Cc: <openipmi-developer@lists.sourceforge.net>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/ipmi/ipmi_bt_sm.c

@@ -352,7 +352,7 @@ static inline void write_all_bytes(struct si_sm_data *bt)
 
 static inline int read_all_bytes(struct si_sm_data *bt)
 {
-	unsigned char i;
+	unsigned int i;
 
 	/*
 	 * length is "framing info", minimum = 4: NetFn, Seq, Cmd, cCode.