[net] net/ipv4: Set oif in fib_compute_spec_dst

Message ID 20180707231526.19173-1-dsahern@kernel.org
State Accepted
Delegated to: David Miller
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Series
  • [net] net/ipv4: Set oif in fib_compute_spec_dst
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Commit Message

dsahern@kernel.org July 7, 2018, 11:15 p.m.
From: David Ahern <dsahern@gmail.com>

Xin reported that icmp replies may not use the address on the device the
echo request is received if the destination address is broadcast. Instead
a route lookup is done without considering VRF context. Fix by setting
oif in flow struct to the master device if it is enslaved. That directs
the lookup to the VRF table. If the device is not enslaved, oif is still
0 so no affect.

Fixes: cd2fbe1b6b51 ("net: Use VRF device index for lookups on RX")
Reported-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
---
 net/ipv4/fib_frontend.c | 1 +
 1 file changed, 1 insertion(+)

Comments

David Miller July 8, 2018, 1:55 a.m. | #1
From: dsahern@kernel.org
Date: Sat,  7 Jul 2018 16:15:26 -0700

> From: David Ahern <dsahern@gmail.com>
> 
> Xin reported that icmp replies may not use the address on the device the
> echo request is received if the destination address is broadcast. Instead
> a route lookup is done without considering VRF context. Fix by setting
> oif in flow struct to the master device if it is enslaved. That directs
> the lookup to the VRF table. If the device is not enslaved, oif is still
> 0 so no affect.
> 
> Fixes: cd2fbe1b6b51 ("net: Use VRF device index for lookups on RX")
> Reported-by: Xin Long <lucien.xin@gmail.com>
> Signed-off-by: David Ahern <dsahern@gmail.com>

Applied and queued up for -stable, thanks David.

Patch

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index b21833651394..e46cdd310e5f 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -300,6 +300,7 @@  __be32 fib_compute_spec_dst(struct sk_buff *skb)
 	if (!ipv4_is_zeronet(ip_hdr(skb)->saddr)) {
 		struct flowi4 fl4 = {
 			.flowi4_iif = LOOPBACK_IFINDEX,
+			.flowi4_oif = l3mdev_master_ifindex_rcu(dev),
 			.daddr = ip_hdr(skb)->saddr,
 			.flowi4_tos = RT_TOS(ip_hdr(skb)->tos),
 			.flowi4_scope = scope,