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Commit 7a94b8c2 authored by Dominik Brodowski's avatar Dominik Brodowski Committed by Johannes Berg
Browse files

nl80211: take RCU read lock when calling ieee80211_bss_get_ie() 



As ieee80211_bss_get_ie() derefences an RCU to return ssid_ie, both
the call to this function and any operation on this variable need
protection by the RCU read lock.

Fixes: 44905265 ("nl80211: don't expose wdev->ssid for most interfaces")
Signed-off-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent a48a52b7

net/wireless/nl80211.c

+7 −4
Original line number Diff line number Diff line
@@ -2618,12 +2618,13 @@ static int nl80211_send_iface(struct sk_buff *msg, u32 portid, u32 seq, int flag 
		const u8 *ssid_ie;

		if (!wdev->current_bss)

			break;

		rcu_read_lock();

		ssid_ie = ieee80211_bss_get_ie(&wdev->current_bss->pub,

					       WLAN_EID_SSID);

		if (!ssid_ie)

			break;

		if (nla_put(msg, NL80211_ATTR_SSID, ssid_ie[1], ssid_ie + 2))

			goto nla_put_failure_locked;

		if (ssid_ie &&

		    nla_put(msg, NL80211_ATTR_SSID, ssid_ie[1], ssid_ie + 2))

			goto nla_put_failure_rcu_locked;

		rcu_read_unlock();

		break;

		}

	default:
@@ -2635,6 +2636,8 @@ static int nl80211_send_iface(struct sk_buff *msg, u32 portid, u32 seq, int flag 
	genlmsg_end(msg, hdr);

	return 0;



 nla_put_failure_rcu_locked:

	rcu_read_unlock();

 nla_put_failure_locked:

	wdev_unlock(wdev);

 nla_put_failure: