From 084dce9dc9d3aa8debd2e6aea6020be721be8908 Mon Sep 17 00:00:00 2001 From: Mahesh Bandewar Date: Mon, 9 Mar 2020 15:57:07 -0700 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 --- drivers/net/macvlan.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c index 277bbff..a8f338d 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(); } } -- 2.7.4