On Fri, 2019-05-31 at 16:34 +0800, Young Xiao wrote:
> There is a possible null pointer deference bug in vxlan_fdb_info(),
> which is similar to the bug which was fixed in commit 6adc5fd6a142
> ("net/neighbour: fix crash at dumping device-agnostic proxy entries").
>
> Signed-off-by: Young Xiao <[email protected]>
> ---
> drivers/net/vxlan.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
> index 5994d54..1ba5977 100644
> --- a/drivers/net/vxlan.c
> +++ b/drivers/net/vxlan.c
> @@ -274,7 +274,7 @@ static int vxlan_fdb_info(struct sk_buff *skb, struct
> vxlan_dev *vxlan,
> } else
> ndm->ndm_family = AF_BRIDGE;
> ndm->ndm_state = fdb->state;
> - ndm->ndm_ifindex = vxlan->dev->ifindex;
> + ndm->ndm_ifindex = vxlan->dev ? vxlan->dev->ifindex : 0;
> ndm->ndm_flags = fdb->flags;
> if (rdst->offloaded)
> ndm->ndm_flags |= NTF_OFFLOADED;
vxlan->dev points to the struct net_device for this vxlan device. It
can't be NULL.
I suggest to look for working reproducer for this kind of issue before
adding additional, unneeded, checks. We want to avoid as many unneeded
conditionals as possible.
Thanks,
Paolo
