From edafeb3a074bd38141008dd4e0f1344d3bb5f1dc Mon Sep 17 00:00:00 2001 From: Mahesh Bandewar Date: Fri, 17 Apr 2020 15:37:12 +0800 Subject: [PATCH] macvlan: add cond_resched() during multicast processing [ Upstream commit ce9a4186f9ac475c415ffd20348176a4ea366670 ] The Rx bound multicast packets are deferred to a workqueue and macvlan can also suffer from the same attack that was discovered by Syzbot for IPvlan. This solution is not as effective as in IPvlan. IPvlan defers all (Tx and Rx) multicast packet processing to a workqueue while macvlan does this way only for the Rx. This fix should address the Rx codition to certain extent. Tx is still suseptible. Tx multicast processing happens when .ndo_start_xmit is called, hence we cannot add cond_resched(). However, it's not that severe since the user which is generating / flooding will be affected the most. Fixes: 412ca1550cbe ("macvlan: Move broadcasts into a work queue") Signed-off-by: Mahesh Bandewar Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman Signed-off-by: Yang Yingliang --- drivers/net/macvlan.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index 277bbff53cff..a8f338dc0dfa 100644 --- a/drivers/net/macvlan.c +++ b/drivers/net/macvlan.c @@ -338,6 +338,8 @@ static void macvlan_process_broadcast(struct work_struct *w) if (src) dev_put(src->dev); kfree_skb(skb); + + cond_resched(); } } -- GitLab