Commit a8801799 authored Apr 03, 2017 by Florian Larysch Committed by David S. Miller Apr 06, 2017

net: ipv4: fix multipath RTM_GETROUTE behavior when iif is given



inet_rtm_getroute synthesizes a skeletal ICMP skb, which is passed to
ip_route_input when iif is given. If a multipath route is present for
the designated destination, ip_multipath_icmp_hash ends up being called,
which uses the source/destination addresses within the skb to calculate
a hash. However, those are not set in the synthetic skb, causing it to
return an arbitrary and incorrect result.

Instead, use UDP, which gets no such special treatment.

Signed-off-by: Florian Larysch <fl@n621.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 0e4c0ee5

net/ipv4/route.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2620,7 +2620,7 @@ static int inet_rtm_getroute(struct sk_buff in_skb, struct nlmsghdr nlh)
		skb_reset_network_header(skb);

		/* Bugfix: need to give ip_route_input enough of an IP header to not gag. */
		ip_hdr(skb)->protocol = IPPROTO_ICMP;
		ip_hdr(skb)->protocol = IPPROTO_UDP;
		skb_reserve(skb, MAX_HEADER + sizeof(struct iphdr));

		src = tb[RTA_SRC] ? nla_get_in_addr(tb[RTA_SRC]) : 0;

Admin message