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>
diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index 239c483..077a93d 100644
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -780,6 +780,9 @@
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) {
case IEEE80211_STYPE_PROBE_REQ:
ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);
@@ -797,6 +800,7 @@
break;
}
+ mgmt_out:
mutex_unlock(&sdata->u.ibss.mtx);
}