Net, mac80211: Fix resource leak in ieee80211_rx_h_mesh_fwding()

We may leak the 'fwd_skb' we skb_copy() in ieee80211_rx_h_mesh_fwding() if
we take the 'else' branch in the 'if' statement just below. If we take
that branch we'll end up returning from the function and since we've not
assigned 'fwd_skb' to anything at that point, we leak it when the variable
goes out of scope.

The simple fix seems to be to just kfree_skb(fwd_skb); just before we
return. That is what this patch does.
Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/rx.c

@@ -1979,6 +1979,7 @@ ieee80211_rx_h_mesh_fwding(struct ieee80211_rx_data *rx)
 		mesh_path_error_tx(ifmsh->mshcfg.element_ttl, fwd_hdr->addr3,
 				    0, reason, fwd_hdr->addr2, sdata);
 		IEEE80211_IFSTA_MESH_CTR_INC(ifmsh, dropped_frames_no_route);
+		kfree_skb(fwd_skb);
 		return RX_DROP_MONITOR;
 	}