Commit 0b258582 authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville

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: default avatarJohannes Berg <>
Signed-off-by: default avatarJohn W. Linville <>
parent aa837e1d
......@@ -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;
return ieee80211_get_channel(wiphy,
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);
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;
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