[PATCH 4.9 18/59] cfg80211: fix a type issue in ieee80211_chandef_to_operating_class()

Greg Kroah-Hartman
2018-10-08T18:39:53Z

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 8442938c3a2177ba16043b3a935f2c78266ad399 ]

The "chandef->center_freq1" variable is a u32 but "freq" is a u16 so we
are truncating away the high bits. I noticed this bug because in commit
9cf0a0b4b64a ("cfg80211: Add support for 60GHz band channels 5 and 6")
we made "freq <= 56160 + 2160 * 6" a valid requency when before it was
only "freq <= 56160 + 2160 * 4" that was valid. It introduces a static
checker warning:

net/wireless/util.c:1571 ieee80211_chandef_to_operating_class()
warn: always true condition '(freq <= 56160 + 2160 * 6) => (0-u16max <= 69120)'

But really we probably shouldn't have been truncating the high bits
away to begin with.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/wireless/util.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1432,7 +1432,7 @@ bool ieee80211_chandef_to_operating_clas
u8 *op_class)
{
u8 vht_opclass;
- u16 freq = chandef->center_freq1;
+ u32 freq = chandef->center_freq1;

if (freq >= 2412 && freq <= 2472) {
if (chandef->width > NL80211_CHAN_WIDTH_40)