Re: net: heap out-of-bounds in fib6_clean_node/rt6_fill_node/fib6_age/fib6_prune_clone

[Cong Wang <xiyou.wangcong@gmail.com>]

On Wed, Apr 19, 2017 at 9:12 AM, Andrey Konovalov <andreyknvl@google.com> wrote:
>
> Anyway, I just finished simplifying the reproducer. Give this one a try.

Thanks for providing such a minimal reproducer!

The following patch could fix this crash, but I am not 100% sure if we should
just clear these bits or reject them with an errno.

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 9db14189..cf524c2 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2086,7 +2086,7 @@ static struct rt6_info
*ip6_route_info_create(struct fib6_config *cfg)
        } else
                rt->rt6i_prefsrc.plen = 0;

-       rt->rt6i_flags = cfg->fc_flags;
+       rt->rt6i_flags = cfg->fc_flags & ~(RTF_PCPU | RTF_CACHE);

 install_route:
        rt->dst.dev = dev;