From: Nikolay Aleksandrov nikolay@cumulusnetworks.com

mainline inclusion from mainline-v5.9-rc1 commit fd65e5a95d08389444e8591a20538b3edece0e15 category: bugfix bugzilla: 186114 CVE: NA

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We need to clear all of the bridge private skb variables as they can be stale due to the packet being recirculated through the stack and then transmitted through the bridge device. Similar memset is already done on bridge's input. We've seen cases where proxyarp_replied was 1 on routed multicast packets transmitted through the bridge to ports with neigh suppress which were getting dropped. Same thing can in theory happen with the port isolation bit as well.

Fixes: 821f1b21cabb ("bridge: add new BR_NEIGH_SUPPRESS port flag to suppress arp and nd flood") Signed-off-by: Nikolay Aleksandrov nikolay@cumulusnetworks.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Huang Guobin huangguobin4@huawei.com Reviewed-by: Yue Haibing yuehaibing@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/bridge/br_device.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c index 7b7784bb1cb99..9475e0443ff92 100644 --- a/net/bridge/br_device.c +++ b/net/bridge/br_device.c @@ -41,6 +41,8 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev) const unsigned char *dest; u16 vid = 0;

+ memset(skb->cb, 0, sizeof(struct br_input_skb_cb)); + rcu_read_lock(); nf_ops = rcu_dereference(nf_br_ops); if (nf_ops && nf_ops->br_dev_xmit_hook(skb)) {