Re: [PATCH] net: ipv4: fix multipath RTM_GETROUTE behavior when iif is given
From: Florian Larysch Date: Mon, 3 Apr 2017 16:46:09 +0200 > 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 Applied and queued up for -stable. Please submit the net-next variant you mentioned, thank you.
Re: [PATCH] net: ipv4: fix multipath RTM_GETROUTE behavior when iif is given
On Mon, Apr 03, 2017 at 01:33:39PM -0400, David Ahern wrote: > that function no longer exists since Nik's recent work > (bf4e0a3db97eb882368fd82980b3b1fa0b5b9778) Didn't notice that as I was looking at Linus' tree. Thanks. > So does the problem you noted still exist? Yes. And in fact, that change invalidates the fix I proposed. I'll submit something new for net-next. Florian
Re: [PATCH] net: ipv4: fix multipath RTM_GETROUTE behavior when iif is given
On 4/3/17 10:46 AM, Florian Larysch wrote: > 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, that function no longer exists since Nik's recent work (bf4e0a3db97eb882368fd82980b3b1fa0b5b9778) So does the problem you noted still exist?
[PATCH] 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 --- net/ipv4/route.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 8471dd116771..acd69cfe2951 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -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; -- 2.12.0
