Re: [PATCH net] bonding: initialize err for empty target lists

[Jay Vosburgh]

Ruoyu Wang <ruoyuw560@xxxxxxxxx> wrote:

>Empty NLA_NESTED attributes are valid, and bonding uses them to clear
>the ARP and NS target lists. When either target attribute is empty,
>nla_for_each_nested() does not execute, so err retains an uninitialized
>value before it is tested. The request can consequently return an
>unpredictable error after clearing the targets.
>
>Initialize err to zero so an empty target list completes successfully.
>Non-empty lists still propagate errors from __bond_opt_set() unchanged.
>
>This issue was found by a static analysis checker and confirmed by manual
>source review.
>
>Fixes: 4fb0ef585eb2 ("bonding: convert arp_ip_target to use the new option API")
>Signed-off-by: Ruoyu Wang <ruoyuw560@xxxxxxxxx>

Acked-by: Jay Vosburgh <jv@xxxxxxxxxxxxx>


>---
> drivers/net/bonding/bond_netlink.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c
>index 4a11572f663d31..87d92d3cce4a88 100644
>--- a/drivers/net/bonding/bond_netlink.c
>+++ b/drivers/net/bonding/bond_netlink.c
>@@ -220,7 +220,7 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[],
> 	struct bonding *bond = netdev_priv(bond_dev);
> 	struct bond_opt_value newval;
> 	int miimon = 0;
>-	int err;
>+	int err = 0;
> 
> 	if (!data)
> 		return 0;
>-- 
>2.51.0
>