3.16.55-rc1 review patch. If anyone has any objections, please let me know.
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From: Dominik Brodowski linux@dominikbrodowski.net
commit 7a94b8c2eee7083ddccd0515830f8c81a8e44b1a upstream.
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: 44905265bc15 ("nl80211: don't expose wdev->ssid for most interfaces") Signed-off-by: Dominik Brodowski linux@dominikbrodowski.net Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- net/wireless/nl80211.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
--- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -2354,12 +2354,13 @@ static int nl80211_send_iface(struct sk_ 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: @@ -2370,6 +2371,8 @@ static int nl80211_send_iface(struct sk_
return genlmsg_end(msg, hdr);
+ nla_put_failure_rcu_locked: + rcu_read_unlock(); nla_put_failure_locked: wdev_unlock(wdev); nla_put_failure: