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Commit d8d7218a authored by Toshiaki Makita's avatar Toshiaki Makita Committed by Alexei Starovoitov
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xdp: XDP_REDIRECT should check IFF_UP and MTU 



Otherwise we end up with attempting to send packets from down devices
or to send oversized packets, which may cause unexpected driver/device
behaviour. Generic XDP has already done this check, so reuse the logic
in native XDP.

Fixes: 814abfab ("xdp: add bpf_redirect helper function")
Signed-off-by: default avatarToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 4fb126cb

include/linux/filter.h

+3 −3
Original line number Diff line number Diff line
@@ -765,8 +765,8 @@ static inline bool bpf_dump_raw_ok(void) 
struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,

				       const struct bpf_insn *patch, u32 len);



static inline int __xdp_generic_ok_fwd_dev(struct sk_buff *skb,

					   struct net_device *fwd)

static inline int xdp_ok_fwd_dev(const struct net_device *fwd,

				 unsigned int pktlen)

{

	unsigned int len;
@@ -774,7 +774,7 @@ static inline int __xdp_generic_ok_fwd_dev(struct sk_buff *skb, 
		return -ENETDOWN;



	len = fwd->mtu + fwd->hard_header_len + VLAN_HLEN;

	if (skb->len > len)

	if (pktlen > len)

		return -EMSGSIZE;



	return 0;

kernel/bpf/devmap.c

+6 −1
Original line number Diff line number Diff line
@@ -334,10 +334,15 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, 
{

	struct net_device *dev = dst->dev;

	struct xdp_frame *xdpf;

	int err;



	if (!dev->netdev_ops->ndo_xdp_xmit)

		return -EOPNOTSUPP;



	err = xdp_ok_fwd_dev(dev, xdp->data_end - xdp->data);

	if (unlikely(err))

		return err;



	xdpf = convert_to_xdp_frame(xdp);

	if (unlikely(!xdpf))

		return -EOVERFLOW;
@@ -350,7 +355,7 @@ int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb, 
{

	int err;



	err = __xdp_generic_ok_fwd_dev(skb, dst->dev);

	err = xdp_ok_fwd_dev(dst->dev, skb->len);

	if (unlikely(err))

		return err;

	skb->dev = dst->dev;

net/core/filter.c

+7 −2
Original line number Diff line number Diff line
@@ -3128,12 +3128,16 @@ static int __bpf_tx_xdp(struct net_device *dev, 
			u32 index)

{

	struct xdp_frame *xdpf;

	int sent;

	int err, sent;



	if (!dev->netdev_ops->ndo_xdp_xmit) {

		return -EOPNOTSUPP;

	}



	err = xdp_ok_fwd_dev(dev, xdp->data_end - xdp->data);

	if (unlikely(err))

		return err;



	xdpf = convert_to_xdp_frame(xdp);

	if (unlikely(!xdpf))

		return -EOVERFLOW;
@@ -3367,7 +3371,8 @@ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb, 
		goto err;

	}



	if (unlikely((err = __xdp_generic_ok_fwd_dev(skb, fwd))))

	err = xdp_ok_fwd_dev(fwd, skb->len);

	if (unlikely(err))

		goto err;



	skb->dev = fwd;