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Commit 138437f5 authored by Hangbin Liu's avatar Hangbin Liu Committed by Steffen Klassert
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xfrm: move xfrm_garbage_collect out of xfrm_policy_flush 



Now we will force to do garbage collection if any policy removed in
xfrm_policy_flush(). But during xfrm_net_exit(). We call flow_cache_fini()
first and set set fc->percpu to NULL. Then after we call xfrm_policy_fini()
-> frxm_policy_flush() -> flow_cache_flush(), we will get NULL pointer
dereference when check percpu_empty. The code path looks like:

flow_cache_fini()
  - fc->percpu = NULL
xfrm_policy_fini()
  - xfrm_policy_flush()
    - xfrm_garbage_collect()
      - flow_cache_flush()
        - flow_cache_percpu_empty()
	  - fcp = per_cpu_ptr(fc->percpu, cpu)

To reproduce, just add ipsec in netns and then remove the netns.

v2:
As Xin Long suggested, since only two other places need to call it. move
xfrm_garbage_collect() outside xfrm_policy_flush().

v3:
Fix subject mismatch after v2 fix.

Fixes: 35db0691 ("xfrm: do the garbage collection after flushing policy")
Signed-off-by: default avatarHangbin Liu <liuhangbin@gmail.com>
Reviewed-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent b81f884a

net/key/af_key.c

+2 −0
Original line number Diff line number Diff line
@@ -2755,6 +2755,8 @@ static int pfkey_spdflush(struct sock *sk, struct sk_buff *skb, const struct sad 
	int err, err2;



	err = xfrm_policy_flush(net, XFRM_POLICY_TYPE_MAIN, true);

	if (!err)

		xfrm_garbage_collect(net);

	err2 = unicast_flush_resp(sk, hdr);

	if (err || err2) {

		if (err == -ESRCH) /* empty table - old silent behavior */

net/xfrm/xfrm_policy.c

+0 −4
Original line number Diff line number Diff line
@@ -1006,10 +1006,6 @@ int xfrm_policy_flush(struct net *net, u8 type, bool task_valid) 
		err = -ESRCH;

out:

	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);



	if (cnt)

		xfrm_garbage_collect(net);



	return err;

}

EXPORT_SYMBOL(xfrm_policy_flush);

net/xfrm/xfrm_user.c

+1 −0
Original line number Diff line number Diff line
@@ -2027,6 +2027,7 @@ static int xfrm_flush_policy(struct sk_buff *skb, struct nlmsghdr *nlh, 
			return 0;

		return err;

	}

	xfrm_garbage_collect(net);



	c.data.type = type;

	c.event = nlh->nlmsg_type;