ipv6: Initialize rt6_info properly in ip6_blackhole_route() (0a1f5962) · Commits · 戴 / test

ip6_blackhole_route() does not initialize the newly allocated rt6_info properly. This patch: 1. Call rt6_info_init() to initialize rt6i_siblings and rt6i_uncached 2. The current rt->dst._metrics init code is incorrect: - 'rt->dst._metrics = ort->dst._metris' is not always safe - Not sure what dst_copy_metrics() is trying to do here considering ip6_rt_blackhole_cow_metrics() always returns NULL Fix: - Always do dst_copy_metrics() - Replace ip6_rt_blackhole_cow_metrics() with dst_cow_metrics_generic() 3. Mask out the RTF_PCPU bit from the newly allocated blackhole route. This bug triggers an oops (reported by Phil Sutter) in rt6_get_cookie(). It is because RTF_PCPU is set while rt->dst.from is NULL. Fixes: ("ipv6: Create percpu rt6_info") Signed-off-by:

Martin KaFai Lau <kafai@fb.com> Reported-by:

Phil Sutter <phil@nwl.cc> Tested-by:

Phil Sutter <phil@nwl.cc> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Cc: Julian Anastasov <ja@ssi.bg> Cc: Phil Sutter <phil@nwl.cc> Cc: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv6/route.c

+5 −15

Original line number	Diff line number	Diff line
		@@ -248,12 +248,6 @@ static void ip6_rt_blackhole_redirect(struct dst_entry dst, struct sock sk,
		{
		}

		static u32 ip6_rt_blackhole_cow_metrics(struct dst_entry dst,
		unsigned long old)
		{
		return NULL;
		}

		static struct dst_ops ip6_dst_blackhole_ops = {
		.family = AF_INET6,
		.destroy = ip6_dst_destroy,
		@@ -262,7 +256,7 @@ static struct dst_ops ip6_dst_blackhole_ops = {
		.default_advmss = ip6_default_advmss,
		.update_pmtu = ip6_rt_blackhole_update_pmtu,
		.redirect = ip6_rt_blackhole_redirect,
		.cow_metrics = ip6_rt_blackhole_cow_metrics,
		.cow_metrics = dst_cow_metrics_generic,
		.neigh_lookup = ip6_neigh_lookup,
		};

		@@ -1219,24 +1213,20 @@ struct dst_entry ip6_blackhole_route(struct net net, struct dst_entry *dst_ori

		rt = dst_alloc(&ip6_dst_blackhole_ops, ort->dst.dev, 1, DST_OBSOLETE_NONE, 0);
		if (rt) {
		new = &rt->dst;

		memset(new + 1, 0, sizeof(rt) - sizeof(new));
		rt6_info_init(rt);

		new = &rt->dst;
		new->__use = 1;
		new->input = dst_discard;
		new->output = dst_discard_sk;

		if (dst_metrics_read_only(&ort->dst))
		new->_metrics = ort->dst._metrics;
		else
		dst_copy_metrics(new, &ort->dst);
		rt->rt6i_idev = ort->rt6i_idev;
		if (rt->rt6i_idev)
		in6_dev_hold(rt->rt6i_idev);

		rt->rt6i_gateway = ort->rt6i_gateway;
		rt->rt6i_flags = ort->rt6i_flags;
		rt->rt6i_flags = ort->rt6i_flags & ~RTF_PCPU;
		rt->rt6i_metric = 0;

		memcpy(&rt->rt6i_dst, &ort->rt6i_dst, sizeof(struct rt6key));

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