Hi,

YOSHIFUJI Hideaki wrote:
> In article <[EMAIL PROTECTED]> (at Mon, 06 Mar 2006 21:50:33 +0100), 
> Jean-Mickael Guerin <[EMAIL PROTECTED]> says:
> > This patch fixes potential null pointer dereference (I never experiment 
> > such crash).
> > The patch is made for net-2.6.17.
> 
> I disagree.
> 
> It never happen, because (void *)&rt->u.dst is equal to (void *)rt,
> and dst_release() checks its argument.

Since I see nothing, that guarantees that struct rtable will not be reorganized
to get better cache access patterns or similiar, I would not trust this very 
much.

What about sth. like this simple defensive patch instead 
(against Linux 2.6.16-rc4)?

Regards 

Ingo Oeser

--- net/ipv6/addrconf.c~        2006-02-17 23:23:45.000000000 +0100
+++ net/ipv6/addrconf.c 2006-03-07 11:19:50.000000000 +0100
@@ -713,7 +713,8 @@
                                rt->rt6i_flags |= RTF_EXPIRES;
                        }
                }
-               dst_release(&rt->u.dst);
+               if (rt)
+                       dst_release(&rt->u.dst);
        }
 
        in6_ifa_put(ifp);
-
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