Re: [Openvpn-users] Assertion failed at mroute.c:349

[James Yonan <jim@xxxxxxxxx>]

On Tue, 2 Aug 2005, Erich Titl wrote:

> Paul
> 
> I looked at the assertion error, it appears to be triggered by a call to
>  multi_del_iroutes and hence mroute_helper_del_iroute. just before the
> assertion net_len_refcount is decremented and thus may become negative.
> 
> I believe the following code is not entirely correct and does not
> rgenerate the refcount if it becomes zero.
> 
> mroute.c:
> 
>       if (!mh->net_len_refcount[ir->netbits])
>         mroute_helper_regenerate (mh);
> 
> IMHO should read
> 
>       if (mh->net_len_refcount[ir->netbits] < 1)
>         mroute_helper_regenerate (mh);
> 
> because this regeneration takes place when the first iroute ets added
> too. It may be possible that the regeneration code is not executed in a
> previous call to mroute_helper_del_iroute call and thus the refcount
> gets decremented below zero in a subsequent call.
> 
> James, would you mind to comment on this?

No, that's not the problem.

The code in mroute_helper_{add,del}_iroute is correct.

The assertion is being thrown by design because mroute_helper_del_iroute 
is being called for a given netbits value, without a corresponding earlier 
call to mroute_helper_add_iroute for that same netbits value.

Think of it as a test to prevent a double free.  Your patch above would 
allow the double free, and therefore mask the underlying problem which is 
occuring in the code which calls mroute_helper_{add,del}_iroute.

I've figured out a recipe to reproduce this, and I should have a fix 
shortly.

James

____________________________________________
Openvpn-users mailing list
Openvpn-users@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/openvpn-users