Re: OOPS, ip -f inet6 route get fec0::1, linux-2.6.26, ip6_route_output, rt6_fill_node+0x175

[David Miller <davem@davemloft.net>]

From: Eugene Teo <eteo@redhat.com>
Date: Mon, 11 Aug 2008 16:40:24 +0800

> Brian Haley wrote:
> > Alexey Dobriyan wrote:
> >> On Thu, Aug 07, 2008 at 07:00:56PM +0200, John Gumb wrote:
> >>> Scenario: no ipv6 default route set.
> >>
> >>> # ip -f inet6 route get fec0::1
> >>>
> >>> BUG: unable to handle kernel NULL pointer dereference at 00000000
> >>> IP: [<c0369b85>] rt6_fill_node+0x175/0x3b0
> >>> EIP is at rt6_fill_node+0x175/0x3b0
> >>
> >> 0xffffffff80424dd3 is in rt6_fill_node (net/ipv6/route.c:2191).
> >> 2186                    } else
> >> 2187    #endif
> >> 2188                            NLA_PUT_U32(skb, RTA_IIF, iif);
> >> 2189            } else if (dst) {
> >> 2190                    struct in6_addr saddr_buf;
> >> 2191      ====>         if
> >> (ipv6_dev_get_saddr(ip6_dst_idev(&rt->u.dst)->dev,
> >>                            ^^^^^^^^^^^^^^^^^^^^^^^^
> >>                                    NULL
> >>
> >> 2192                                           dst, 0, &saddr_buf) == 0)
> >> 2193                            NLA_PUT(skb, RTA_PREFSRC, 16,
> >> &saddr_buf);
> >> 2194            }
> > 
> > The commit that changed this can't be reverted easily, but the patch
> > below works for me.
> > 
> > Fix NULL de-reference in rt6_fill_node() when there's no IPv6 input
> > device present in the dst entry.
> > 
> > Signed-off-by: Brian Haley <brian.haley@hp.com>
> 
> Cc: Stable <stable@kernel.org>

We've already determined from one tester that the behavior is
changing with Brian's patch.  Furthermore I haven't applied it
to mainline so it isn't anywhere near being submittable for
-stable.

I submit all relevant networking bug fixes to -stable when they are
ready and in a proper state to be submitted, you don't have to do it
for me.  Sending me a gentle reminder or nudge, on the other hand, is
fine.