From: Hong Zhiguo Date: Sat, 14 Sep 2013 14:42:28 +0000 (+0800) Subject: bridge: fix NULL pointer deref of br_port_get_rcu X-Git-Tag: v3.12-rc2~14^2~31 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=716ec052d2280d511e10e90ad54a86f5b5d4dcc2;p=pandora-kernel.git bridge: fix NULL pointer deref of br_port_get_rcu The NULL deref happens when br_handle_frame is called between these 2 lines of del_nbp: dev->priv_flags &= ~IFF_BRIDGE_PORT; /* --> br_handle_frame is called at this time */ netdev_rx_handler_unregister(dev); In br_handle_frame the return of br_port_get_rcu(dev) is dereferenced without check but br_port_get_rcu(dev) returns NULL if: !(dev->priv_flags & IFF_BRIDGE_PORT) Eric Dumazet pointed out the testing of IFF_BRIDGE_PORT is not necessary here since we're in rcu_read_lock and we have synchronize_net() in netdev_rx_handler_unregister. So remove the testing of IFF_BRIDGE_PORT and by the previous patch, make sure br_port_get_rcu is called in bridging code. Signed-off-by: Hong Zhiguo Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- Reading git-diff-tree failed