From db58ba45920255e967cc1d62a430cebd634b5046 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 5 May 2016 19:49:12 -0700 Subject: bpf: wire in data and data_end for cls_act_bpf allow cls_bpf and act_bpf programs access skb->data and skb->data_end pointers. The bpf helpers that change skb->data need to update data_end pointer as well. The verifier checks that programs always reload data, data_end pointers after calls to such bpf helpers. We cannot add 'data_end' pointer to struct qdisc_skb_cb directly, since it's embedded as-is by infiniband ipoib, so wrapper struct is needed. Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- include/linux/filter.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux') diff --git a/include/linux/filter.h b/include/linux/filter.h index 43aa1f8855c7..ec1411c89105 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -352,6 +352,22 @@ struct sk_filter { #define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN +struct bpf_skb_data_end { + struct qdisc_skb_cb qdisc_cb; + void *data_end; +}; + +/* compute the linear packet data range [data, data_end) which + * will be accessed by cls_bpf and act_bpf programs + */ +static inline void bpf_compute_data_end(struct sk_buff *skb) +{ + struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb; + + BUILD_BUG_ON(sizeof(*cb) > FIELD_SIZEOF(struct sk_buff, cb)); + cb->data_end = skb->data + skb_headlen(skb); +} + static inline u8 *bpf_skb_cb(struct sk_buff *skb) { /* eBPF programs may read/write skb->cb[] area to transfer meta -- cgit v1.3-14-g43fede