rt2x00: fix memory corruption in rf cache, add a sanity check

commit 6b26dead3ce97d016b57724b01974d5ca5c84bd5 upstream.

Change rt2x00_rf_read() and rt2x00_rf_write() to subtract 1 from the rf
register number.  This is needed because the rf registers are enumerated
starting with one.  The size of the rf register cache is just enough to
hold all registers, so writing to the highest register was corrupting
memory.  Add a check to make sure that the rf register number is valid.

Signed-off-by: Pavel Roskin <proski@gnu.org>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index 84bd6f19acb0749be1dd6200a99fbe595ca8da49..c242b540cf5be84464b2ea2187cdbb5e323f82f0 100644 (file)
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -814,13 +814,15 @@ struct rt2x00_dev {
 static inline void rt2x00_rf_read(struct rt2x00_dev *rt2x00dev,
                                  const unsigned int word, u32 *data)
 {
-       *data = rt2x00dev->rf[word];
+       BUG_ON(word < 1 || word > rt2x00dev->ops->rf_size / sizeof(u32));
+       *data = rt2x00dev->rf[word - 1];
 }
 
 static inline void rt2x00_rf_write(struct rt2x00_dev *rt2x00dev,
                                   const unsigned int word, u32 data)
 {
-       rt2x00dev->rf[word] = data;
+       BUG_ON(word < 1 || word > rt2x00dev->ops->rf_size / sizeof(u32));
+       rt2x00dev->rf[word - 1] = data;
 }
 
 /*