2020-07-08 22:59:38

by Jarod Wilson

Subject: [PATCH net-next] bonding: don't need RTNL for ipsec helpers

The bond_ipsec_* helpers don't need RTNL, and can potentially get called
without it being held, so switch from rtnl_dereference() to
rcu_dereference() to access bond struct data.

Lightly tested with xfrm bonding, no problems found, should address the
syzkaller bug referenced below.

Reported-by: [email protected]
CC: Huy Nguyen <[email protected]>
CC: Saeed Mahameed <[email protected]>
CC: Jay Vosburgh <[email protected]>
CC: Veaceslav Falico <[email protected]>
CC: Andy Gospodarek <[email protected]>
CC: "David S. Miller" <[email protected]>
CC: Jeff Kirsher <[email protected]>
CC: Jakub Kicinski <[email protected]>
CC: Steffen Klassert <[email protected]>
CC: Herbert Xu <[email protected]>
CC: [email protected]
CC: [email protected]
Signed-off-by: Jarod Wilson <[email protected]>
---
drivers/net/bonding/bond_main.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index f886d97c4359..e2d491c4378c 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -390,7 +390,7 @@ static int bond_ipsec_add_sa(struct xfrm_state *xs)
return -EINVAL;

bond = netdev_priv(bond_dev);
- slave = rtnl_dereference(bond->curr_active_slave);
+ slave = rcu_dereference(bond->curr_active_slave);
xs->xso.real_dev = slave->dev;
bond->xs = xs;

@@ -417,7 +417,7 @@ static void bond_ipsec_del_sa(struct xfrm_state *xs)
return;

bond = netdev_priv(bond_dev);
- slave = rtnl_dereference(bond->curr_active_slave);
+ slave = rcu_dereference(bond->curr_active_slave);

if (!slave)
return;
@@ -442,7 +442,7 @@ static bool bond_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
{
struct net_device *bond_dev = xs->xso.dev;
struct bonding *bond = netdev_priv(bond_dev);
- struct slave *curr_active = rtnl_dereference(bond->curr_active_slave);
+ struct slave *curr_active = rcu_dereference(bond->curr_active_slave);
struct net_device *slave_dev = curr_active->dev;

if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP)
--
2.20.1

2020-07-08 23:10:02

by David Miller

Subject: Re: [PATCH net-next] bonding: don't need RTNL for ipsec helpers

From: Jarod Wilson <[email protected]>
Date: Wed, 8 Jul 2020 18:58:49 -0400

> The bond_ipsec_* helpers don't need RTNL, and can potentially get called
> without it being held, so switch from rtnl_dereference() to
> rcu_dereference() to access bond struct data.
>
> Lightly tested with xfrm bonding, no problems found, should address the
> syzkaller bug referenced below.
>
> Reported-by: [email protected]
> Signed-off-by: Jarod Wilson <[email protected]>

Applied, thank you.