From dbde1bae2933018c576abcc28daf082fcd17c8d3 Mon Sep 17 00:00:00 2001 From: Julian Anastasov Date: Sat, 4 Feb 2012 13:04:46 +0000 Subject: ipv4: reset flowi parameters on route connect [ Upstream commit e6b45241c57a83197e5de9166b3b0d32ac562609 ] Eric Dumazet found that commit 813b3b5db83 (ipv4: Use caller's on-stack flowi as-is in output route lookups.) that comes in 3.0 added a regression. The problem appears to be that resulting flowi4_oif is used incorrectly as input parameter to some routing lookups. The result is that when connecting to local port without listener if the IP address that is used is not on a loopback interface we incorrectly assign RTN_UNICAST to the output route because no route is matched by oif=lo. The RST packet can not be sent immediately by tcp_v4_send_reset because it expects RTN_LOCAL. So, change ip_route_connect and ip_route_newports to update the flowi4 fields that are input parameters because we do not want unnecessary binding to oif. To make it clear what are the input parameters that can be modified during lookup and to show which fields of floiw4 are reused add a new function to update the flowi4 structure: flowi4_update_output. Thanks to Yurij M. Plotnikov for providing a bug report including a program to reproduce the problem. Thanks to Eric Dumazet for tracking the problem down to tcp_v4_send_reset and providing initial fix. Reported-by: Yurij M. Plotnikov Signed-off-by: Julian Anastasov Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/net/flow.h | 10 ++++++++++ include/net/route.h | 4 ++++ 2 files changed, 14 insertions(+) (limited to 'include/net') diff --git a/include/net/flow.h b/include/net/flow.h index 32359fd..e37cfda 100644 --- a/include/net/flow.h +++ b/include/net/flow.h @@ -90,6 +90,16 @@ static inline void flowi4_init_output(struct flowi4 *fl4, int oif, fl4->fl4_dport = dport; fl4->fl4_sport = sport; } + +/* Reset some input parameters after previous lookup */ +static inline void flowi4_update_output(struct flowi4 *fl4, int oif, __u8 tos, + __be32 daddr, __be32 saddr) +{ + fl4->flowi4_oif = oif; + fl4->flowi4_tos = tos; + fl4->daddr = daddr; + fl4->saddr = saddr; +} struct flowi6 { diff --git a/include/net/route.h b/include/net/route.h index db7b343..5d7aae4 100644 --- a/include/net/route.h +++ b/include/net/route.h @@ -270,6 +270,7 @@ static inline struct rtable *ip_route_connect(struct flowi4 *fl4, if (IS_ERR(rt)) return rt; ip_rt_put(rt); + flowi4_update_output(fl4, oif, tos, fl4->daddr, fl4->saddr); } security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); return ip_route_output_flow(net, fl4, sk); @@ -284,6 +285,9 @@ static inline struct rtable *ip_route_newports(struct flowi4 *fl4, struct rtable fl4->fl4_dport = dport; fl4->fl4_sport = sport; ip_rt_put(rt); + flowi4_update_output(fl4, sk->sk_bound_dev_if, + RT_CONN_FLAGS(sk), fl4->daddr, + fl4->saddr); security_sk_classify_flow(sk, flowi4_to_flowi(fl4)); return ip_route_output_flow(sock_net(sk), fl4, sk); } -- cgit v1.1