cls_bpf: don't decrement net's refcount when offload fails (25415cec) · Commits · 戴 / test

When cls_bpf offload was added it seemed like a good idea to call cls_bpf_delete_prog() instead of extending the error handling path, since the software state is fully initialized at that point. This handling of errors without jumping to the end of the function is error prone, as proven by later commit missing that extra call to __cls_bpf_delete_prog(). __cls_bpf_delete_prog() is now expected to be invoked with a reference on exts->net or the field zeroed out. The call on the offload's error patch does not fullfil this requirement, leading to each error stealing a reference on net namespace. Create a function undoing what cls_bpf_set_parms() did and use it from __cls_bpf_delete_prog() and the error path. Fixes: ("cls_bpf: use tcf_exts_get_net() before call_rcu()") Signed-off-by:

Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by:

Simon Horman <simon.horman@netronome.com> Acked-by:

Daniel Borkmann <daniel@iogearbox.net> Acked-by:

Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/sched/cls_bpf.c

+13 −10

Original line number	Diff line number	Diff line
		@@ -258,11 +258,8 @@ static int cls_bpf_init(struct tcf_proto *tp)
		return 0;
		}

		static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
		static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
		{
		tcf_exts_destroy(&prog->exts);
		tcf_exts_put_net(&prog->exts);

		if (cls_bpf_is_ebpf(prog))
		bpf_prog_put(prog->filter);
		else
		@@ -270,6 +267,14 @@ static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)

		kfree(prog->bpf_name);
		kfree(prog->bpf_ops);
		}

		static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
		{
		tcf_exts_destroy(&prog->exts);
		tcf_exts_put_net(&prog->exts);

		cls_bpf_free_parms(prog);
		kfree(prog);
		}

		@@ -514,12 +519,8 @@ static int cls_bpf_change(struct net net, struct sk_buff in_skb,
		goto errout_idr;

		ret = cls_bpf_offload(tp, prog, oldprog);
		if (ret) {
		if (!oldprog)
		idr_remove_ext(&head->handle_idr, prog->handle);
		__cls_bpf_delete_prog(prog);
		return ret;
		}
		if (ret)
		goto errout_parms;

		if (!tc_in_hw(prog->gen_flags))
		prog->gen_flags \|= TCA_CLS_FLAGS_NOT_IN_HW;
		@@ -537,6 +538,8 @@ static int cls_bpf_change(struct net net, struct sk_buff in_skb,
		*arg = prog;
		return 0;

		errout_parms:
		cls_bpf_free_parms(prog);
		errout_idr:
		if (!oldprog)
		idr_remove_ext(&head->handle_idr, prog->handle);

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