Commit bc56c919 authored by Jesper Dangaard Brouer's avatar Jesper Dangaard Brouer Committed by Alexei Starovoitov
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bpf: Add xdp.frame_sz in bpf_prog_test_run_xdp(). 



Update the memory requirements, when adding xdp.frame_sz in BPF test_run
function bpf_prog_test_run_xdp() which e.g. is used by XDP selftests.

Specifically add the expected reserved tailroom, but also allocated a
larger memory area to reflect that XDP frames usually comes in this
format. Limit the provided packet data size to 4096 minus headroom +
tailroom, as this also reflect a common 3520 bytes MTU limit with XDP.

Note that bpf_test_init already use a memory allocation method that clears
memory.  Thus, this already guards against leaking uninit kernel memory.

Signed-off-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/158945349549.97035.15316291762482444006.stgit@firesoul
parent ddb47d51

net/bpf/test_run.c

+12 −4
Original line number Diff line number Diff line
@@ -470,25 +470,34 @@ out: 
int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,

			  union bpf_attr __user *uattr)

{

	u32 tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

	u32 headroom = XDP_PACKET_HEADROOM;

	u32 size = kattr->test.data_size_in;

	u32 repeat = kattr->test.repeat;

	struct netdev_rx_queue *rxqueue;

	struct xdp_buff xdp = {};

	u32 retval, duration;

	u32 max_data_sz;

	void *data;

	int ret;



	if (kattr->test.ctx_in || kattr->test.ctx_out)

		return -EINVAL;



	data = bpf_test_init(kattr, size, XDP_PACKET_HEADROOM + NET_IP_ALIGN, 0);

	/* XDP have extra tailroom as (most) drivers use full page */

	max_data_sz = 4096 - headroom - tailroom;

	if (size > max_data_sz)

		return -EINVAL;



	data = bpf_test_init(kattr, max_data_sz, headroom, tailroom);

	if (IS_ERR(data))

		return PTR_ERR(data);



	xdp.data_hard_start = data;

	xdp.data = data + XDP_PACKET_HEADROOM + NET_IP_ALIGN;

	xdp.data = data + headroom;

	xdp.data_meta = xdp.data;

	xdp.data_end = xdp.data + size;

	xdp.frame_sz = headroom + max_data_sz + tailroom;



	rxqueue = __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 0);

	xdp.rxq = &rxqueue->xdp_rxq;
@@ -496,8 +505,7 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr, 
	ret = bpf_test_run(prog, &xdp, repeat, &retval, &duration, true);

	if (ret)

		goto out;

	if (xdp.data != data + XDP_PACKET_HEADROOM + NET_IP_ALIGN ||

	    xdp.data_end != xdp.data + size)

	if (xdp.data != data + headroom || xdp.data_end != xdp.data + size)

		size = xdp.data_end - xdp.data;

	ret = bpf_test_finish(kattr, uattr, xdp.data, size, retval, duration);

out:

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