Re: RX metadata kfuncs cause kernel panic with XDP generic mode

["Toke Høiland-Jørgensen" <toke@redhat.com>]

Marcus Wichelmann <marcus.wichelmann@hetzner-cloud.de> writes:

> There is probably a check missing somewhere that prevents the use of
> these kfuncs in the scope of do_xdp_generic?

Heh, yeah, we should definitely block device-bound programs from being
attached in generic mode. Something like the below, I guess. Care to
test that out?

-Toke

diff --git a/net/core/dev.c b/net/core/dev.c
index afa2282f2604..c1fa68264989 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -9924,6 +9924,10 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack
                        NL_SET_ERR_MSG(extack, "Program bound to different device");
                        return -EINVAL;
                }
+               if (bpf_prog_is_dev_bound(new_prog->aux) && mode == XDP_MODE_SKB) {
+                       NL_SET_ERR_MSG(extack, "Can't attach device-bound programs in generic mode");
+                       return -EINVAL;
+               }
                if (new_prog->expected_attach_type == BPF_XDP_DEVMAP) {
                        NL_SET_ERR_MSG(extack, "BPF_XDP_DEVMAP programs can not be attached to a device");
                        return -EINVAL;