Commit 584991dc authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville
Browse files

cfg80211: validate scan channels 



Currently it is possible to request a scan on only
disabled channels, which could be problematic for
some drivers. Reject such scans, and also ignore
disabled channels that are given. This resuls in
the scan begin/end event only including channels
that are actually used.

This makes the mac80211 check for disabled channels
superfluous. At the same time, remove the no-IBSS
check from mac80211 -- nothing says that we should
not find any networks on channels that cannot be
used for an IBSS, even when operating in IBSS mode.

Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 6c085227

net/mac80211/scan.c

+2 −11
Original line number Diff line number Diff line
@@ -614,22 +614,13 @@ static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, 
{

	int skip;

	struct ieee80211_channel *chan;

	struct ieee80211_sub_if_data *sdata = local->scan_sdata;



	skip = 0;

	chan = local->scan_req->channels[local->scan_channel_idx];



	if (chan->flags & IEEE80211_CHAN_DISABLED ||

	    (sdata->vif.type == NL80211_IFTYPE_ADHOC &&

	     chan->flags & IEEE80211_CHAN_NO_IBSS))

		skip = 1;



	if (!skip) {

	local->scan_channel = chan;

		if (ieee80211_hw_config(local,

					IEEE80211_CONF_CHANGE_CHANNEL))

	if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL))

		skip = 1;

	}



	/* advance state machine to next channel/band */

	local->scan_channel_idx++;

net/wireless/nl80211.c

+27 −7
Original line number Diff line number Diff line
@@ -2988,7 +2988,6 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info) 
		goto out;

	}



	request->n_channels = n_channels;

	if (n_ssids)

		request->ssids = (void *)&request->channels[n_channels];

	request->n_ssids = n_ssids;
@@ -2999,32 +2998,53 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info) 
			request->ie = (void *)(request->channels + n_channels);

	}



	i = 0;

	if (info->attrs[NL80211_ATTR_SCAN_FREQUENCIES]) {

		/* user specified, bail out if channel not found */

		request->n_channels = n_channels;

		i = 0;

		nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_FREQUENCIES], tmp) {

			request->channels[i] = ieee80211_get_channel(wiphy, nla_get_u32(attr));

			if (!request->channels[i]) {

			struct ieee80211_channel *chan;



			chan = ieee80211_get_channel(wiphy, nla_get_u32(attr));



			if (!chan) {

				err = -EINVAL;

				goto out_free;

			}



			/* ignore disabled channels */

			if (chan->flags & IEEE80211_CHAN_DISABLED)

				continue;



			request->channels[i] = chan;

			i++;

		}

	} else {

		/* all channels */

		i = 0;

		for (band = 0; band < IEEE80211_NUM_BANDS; band++) {

			int j;

			if (!wiphy->bands[band])

				continue;

			for (j = 0; j < wiphy->bands[band]->n_channels; j++) {

				request->channels[i] = &wiphy->bands[band]->channels[j];

				struct ieee80211_channel *chan;



				chan = &wiphy->bands[band]->channels[j];



				if (chan->flags & IEEE80211_CHAN_DISABLED)

					continue;



				request->channels[i] = chan;

				i++;

			}

		}

	}



	if (!i) {

		err = -EINVAL;

		goto out_free;

	}



	request->n_channels = i;



	i = 0;

	if (info->attrs[NL80211_ATTR_SCAN_SSIDS]) {

		nla_for_each_nested(attr, info->attrs[NL80211_ATTR_SCAN_SSIDS], tmp) {

net/wireless/scan.c

+6 −0
Original line number Diff line number Diff line
@@ -650,9 +650,15 @@ int cfg80211_wext_siwscan(struct net_device *dev, 
	i = 0;

	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {

		int j;



		if (!wiphy->bands[band])

			continue;



		for (j = 0; j < wiphy->bands[band]->n_channels; j++) {

			/* ignore disabled channels */

			if (wiphy->bands[band]->channels[j].flags &

						IEEE80211_CHAN_DISABLED)

				continue;



			/* If we have a wireless request structure and the

			 * wireless request specifies frequencies, then search

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