cfg80211: fix wext iw_freq parsing (0b258582) · Commits · 戴 / test

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>

net/wireless/wext-compat.c

+18 −6

Original line number	Diff line number	Diff line
		@@ -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);

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