On Thu, 5 Dec 2013 16:27:37 +0100 Jiri Pirko <jiri@xxxxxxxxxxx> wrote: > br_stp_rcv() is reached by non-rx_handler path. That means there is no > guarantee that dev is bridge port and therefore simple NULL check of > ->rx_handler_data is not enough. There is need to check if dev is really > bridge port and since only rcu read lock is held here, do it by checking > ->rx_handler pointer. > > Note that synchronize_net() in netdev_rx_handler_unregister() ensures > this approach as valid. > I think this patch is simpler/better, it restores the old logic. Ps. submitting patches to bugzilla is a good way to have them ignored. >From Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> Check that incoming STP packet is received on a port assigned to bridge before processing. It is possible to receive packet on non-bridge port because they are multicast. See: https://bugzilla.kernel.org/show_bug.cgi?id=64911 Regression introduced by: commit 716ec052d2280d511e10e90ad54a86f5b5d4dcc2 Author: Hong Zhiguo <zhiguohong@xxxxxxxxxxx> Date: Sat Sep 14 22:42:28 2013 +0800 bridge: fix NULL pointer deref of br_port_get_rcu Reported-by: Alexander Y. Fomichev Signed-off-by: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> --- a/net/bridge/br_stp_bpdu.c 2013-06-11 09:50:21.522919061 -0700 +++ b/net/bridge/br_stp_bpdu.c 2013-12-05 08:46:56.090463702 -0800 @@ -153,6 +153,9 @@ void br_stp_rcv(const struct stp_proto * if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0) goto err; + if (!br_port_exists(dev)) + goto err; + p = br_port_get_rcu(dev); if (!p) goto err;
