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cfg80211: fix wext iw_freq parsing 

The function to parse a struct iw_freq has a stupid bug,
it returns NULL when the channel cannot be found at all,
but NULL is supposed to mean "auto". Fix this by checking
the return value of ieee80211_get_channel() and returning
ERR_PTR(-EINVAL) if it returned NULL (channel not found).

This fixes an issue where you could say (in IBSS mode)
	iwconfig wlan0 channel 21
and it would use channel 1 instead because that's the
first available channel with IBSS allowed (which is what
the "auto" setting uses).

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg 2009-05-08 09:42:33 +02:00 committed by John W. Linville
parent aa837e1d6b
commit 0b258582fe
1 changed files with 18 additions and 6 deletions
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24
net/wireless/wext-compat.c
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@ -296,22 +296,34 @@ EXPORT_SYMBOL_GPL(cfg80211_wext_siwmlme);
struct ieee80211_channel *cfg80211_wext_freq(struct wiphy *wiphy,
struct iw_freq *freq)
{
struct ieee80211_channel *chan;
int f;
/*
* Parse frequency - return NULL for auto and
* -EINVAL for impossible things.
*/
if (freq->e == 0) {
if (freq->m < 0)
return NULL;
else
return ieee80211_get_channel(wiphy,
ieee80211_channel_to_frequency(freq->m));
f = ieee80211_channel_to_frequency(freq->m);
} else {
int i, div = 1000000;
for (i = 0; i < freq->e; i++)
div /= 10;
if (div > 0)
return ieee80211_get_channel(wiphy, freq->m / div);
else
if (div <= 0)
return ERR_PTR(-EINVAL);
f = freq->m / div;
}
/*
* Look up channel struct and return -EINVAL when
* it cannot be found.
*/
chan = ieee80211_get_channel(wiphy, f);
if (!chan)
return ERR_PTR(-EINVAL);
return chan;
}
EXPORT_SYMBOL_GPL(cfg80211_wext_freq);