From 8f917bba0042f1e3b7693743fbe9782709e936e7 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Tue, 11 Apr 2017 14:08:08 -0400 Subject: [PATCH] bpf: pass sk to helper functions BPF helper functions access socket fields through skb->sk. This is not set in ingress cgroup and socket filters. The association is only made in skb_set_owner_r once the filter has accepted the packet. Sk is available as socket lookup has taken place. Temporarily set skb->sk to sk in these cases. Signed-off-by: Willem de Bruijn Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- kernel/bpf/cgroup.c | 5 ++++- net/core/filter.c | 7 ++++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index da0f53690295..ea6033cba947 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -154,7 +154,7 @@ int __cgroup_bpf_update(struct cgroup *cgrp, struct cgroup *parent, /** * __cgroup_bpf_run_filter_skb() - Run a program for packet filtering - * @sk: The socken sending or receiving traffic + * @sk: The socket sending or receiving traffic * @skb: The skb that is being sent or received * @type: The type of program to be exectuted * @@ -189,10 +189,13 @@ int __cgroup_bpf_run_filter_skb(struct sock *sk, prog = rcu_dereference(cgrp->bpf.effective[type]); if (prog) { unsigned int offset = skb->data - skb_network_header(skb); + struct sock *save_sk = skb->sk; + skb->sk = sk; __skb_push(skb, offset); ret = bpf_prog_run_save_cb(prog, skb) == 1 ? 0 : -EPERM; __skb_pull(skb, offset); + skb->sk = save_sk; } rcu_read_unlock(); diff --git a/net/core/filter.c b/net/core/filter.c index bbe0cf415105..ce2a19da8aa4 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -92,8 +92,13 @@ int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap) rcu_read_lock(); filter = rcu_dereference(sk->sk_filter); if (filter) { - unsigned int pkt_len = bpf_prog_run_save_cb(filter->prog, skb); + struct sock *save_sk = skb->sk; + unsigned int pkt_len; + + skb->sk = sk; + pkt_len = bpf_prog_run_save_cb(filter->prog, skb); err = pkt_len ? pskb_trim(skb, max(cap, pkt_len)) : -EPERM; + skb->sk = save_sk; } rcu_read_unlock(); -- 2.20.1