From 85350871317a5adb35519d9dc6fc9e80809d42ad Mon Sep 17 00:00:00 2001 From: Xufeng Zhang Date: Fri, 25 Apr 2014 16:55:41 +0800 Subject: [PATCH] sctp: reset flowi4_oif parameter on route lookup commit 813b3b5db83 (ipv4: Use caller's on-stack flowi as-is in output route lookups.) introduces another regression which is very similar to the problem of commit e6b45241c (ipv4: reset flowi parameters on route connect) wants to fix: Before we call ip_route_output_key() in sctp_v4_get_dst() to get a dst that matches a bind address as the source address, we have already called this function previously and the flowi parameters have been initialized including flowi4_oif, so when we call this function again, the process in __ip_route_output_key() will be different because of the setting of flowi4_oif, and we'll get a networking device which corresponds to the inputted flowi4_oif as the output device, this is wrong because we'll never hit this place if the previously returned source address of dst match one of the bound addresses. To reproduce this problem, a vlan setting is enough: # ifconfig eth0 up # route del default # vconfig add eth0 2 # vconfig add eth0 3 # ifconfig eth0.2 10.0.1.14 netmask 255.255.255.0 # route add default gw 10.0.1.254 dev eth0.2 # ifconfig eth0.3 10.0.0.14 netmask 255.255.255.0 # ip rule add from 10.0.0.14 table 4 # ip route add table 4 default via 10.0.0.254 src 10.0.0.14 dev eth0.3 # sctp_darn -H 10.0.0.14 -P 36422 -h 10.1.4.134 -p 36422 -s -I You'll detect that all the flow are routed to eth0.2(10.0.1.254). Signed-off-by: Xufeng Zhang Signed-off-by: Julian Anastasov Acked-by: Vlad Yasevich Signed-off-by: David S. Miller --- net/sctp/protocol.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c index c09757fbf803..44cbb54c8574 100644 --- a/net/sctp/protocol.c +++ b/net/sctp/protocol.c @@ -491,8 +491,13 @@ static void sctp_v4_get_dst(struct sctp_transport *t, union sctp_addr *saddr, continue; if ((laddr->state == SCTP_ADDR_SRC) && (AF_INET == laddr->a.sa.sa_family)) { - fl4->saddr = laddr->a.v4.sin_addr.s_addr; fl4->fl4_sport = laddr->a.v4.sin_port; + flowi4_update_output(fl4, + asoc->base.sk->sk_bound_dev_if, + RT_CONN_FLAGS(asoc->base.sk), + daddr->v4.sin_addr.s_addr, + laddr->a.v4.sin_addr.s_addr); + rt = ip_route_output_key(sock_net(sk), fl4); if (!IS_ERR(rt)) { dst = &rt->dst; -- GitLab