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Commit 8f917bba authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

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: default avatarWillem de Bruijn <willemb@google.com>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cb6bf9cf

kernel/bpf/cgroup.c

+4 −1
Original line number Diff line number Diff line
@@ -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();

net/core/filter.c

+6 −1
Original line number Diff line number Diff line
@@ -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();