Commit c926d006 authored Dec 09, 2010 by Tim Harvey Committed by John W. Linville Dec 13, 2010

mac80211: Fix NULL-pointer deference on ibss merge when not ready



dev_open will eventually call ieee80211_ibss_join which sets up the
skb used for beacons/probe-responses however it is possible to
receive beacons that attempt to merge before this occurs causing
a null pointer dereference.  Check ssid_len as that is the last
thing set in ieee80211_ibss_join.

This occurs quite easily in the presence of adhoc nodes with hidden SSID's

revised previous patch to check further up based on irc feedback

Signed-off-by: Tim Harvey <harvey.tim@gmail.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

parent 4a55d585

net/mac80211/ibss.c

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -780,6 +780,9 @@ void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,

	mutex_lock(&sdata->u.ibss.mtx);		mutex_lock(&sdata->u.ibss.mtx);

			if (!sdata->u.ibss.ssid_len)
			goto mgmt_out; /* not ready to merge yet */

	switch (fc & IEEE80211_FCTL_STYPE) {		switch (fc & IEEE80211_FCTL_STYPE) {
	case IEEE80211_STYPE_PROBE_REQ:		case IEEE80211_STYPE_PROBE_REQ:
	ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);		ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);
	@@ -797,6 +800,7 @@ void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
	break;		break;
	}		}

			mgmt_out:
	mutex_unlock(&sdata->u.ibss.mtx);		mutex_unlock(&sdata->u.ibss.mtx);
	}		}