cls_bpf: do eBPF invocation under non-bh RCU lock variant for maps
Currently, it is possible in cls_bpf to access eBPF maps only under
rcu_read_lock_bh() variants: while on ingress side, that is, handle_ing(),
the classifier would be called from __netif_receive_skb_core() under
rcu_read_lock(); on egress side, however, it's rcu_read_lock_bh() via
__dev_queue_xmit().
This rcu/rcu_bh mix doesn't work together with eBPF maps as they require
soley to be called under rcu_read_lock(). eBPF maps could also be shared
among various other eBPF programs (possibly even with other eBPF program
types, f.e. tracing) and user space processes, so any context is assumed.
Therefore, a possible fix for cls_bpf is to wrap/nest eBPF program
invocation under non-bh RCU lock variant.
Fixes: e2e9b6541d
("cls_bpf: add initial eBPF support for programmable classifiers")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
06741d055b
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54720df130
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@ -64,8 +64,10 @@ static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
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{
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struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
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struct cls_bpf_prog *prog;
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int ret;
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int ret = -1;
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/* Needed here for accessing maps. */
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rcu_read_lock();
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list_for_each_entry_rcu(prog, &head->plist, link) {
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int filter_res = BPF_PROG_RUN(prog->filter, skb);
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@ -80,10 +82,11 @@ static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
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if (ret < 0)
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continue;
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return ret;
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break;
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}
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rcu_read_unlock();
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return -1;
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return ret;
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}
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static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
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