From bdff7bcb80da6e37e4fa216e97737d23aaafc856 Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Thu, 14 May 2020 12:51:35 +0200 Subject: [PATCH] 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: Jesper Dangaard Brouer Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/158945349549.97035.15316291762482444006.stgit@firesoul --- net/bpf/test_run.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index 29dbdd4c29f68..30ba7d38941d9 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -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: -- 2.39.5