| Message ID | 20180115071215.GA2639@light.dominikbrodowski.net (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Johannes Berg |
| Headers | show |
On Mon, 2018-01-15 at 08:12 +0100, Dominik Brodowski wrote: > 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> > --- > > > but after, perhaps it's easier to just do > > > > if (ssid_ie && > > nla_put(...) > > goto nla_put_failure_rcu_locked; > > > > and avoid the extra label (but yeah, it's getting late) > > OK, done that (and updated the commit message), and testet it. > Applied, thanks! johannes
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 2b3dbcd40e46..ed87a97fcb0b 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -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:
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> --- > but after, perhaps it's easier to just do > > if (ssid_ie && > nla_put(...) > goto nla_put_failure_rcu_locked; > > and avoid the extra label (but yeah, it's getting late) OK, done that (and updated the commit message), and testet it. Thanks, Dominik