ipvs: do not use random local source address for tunnels

commit 4754957f04f5f368792a0eb7dab0ae89fb93dcfd upstream.

Michael Vallaly reports about wrong source address used
in rare cases for tunneled traffic. Looks like
__ip_vs_get_out_rt in 3.10+ is providing uninitialized
dest_dst->dst_saddr.ip because ip_vs_dest_dst_alloc uses
kmalloc. While we retry after seeing EINVAL from routing
for data that does not look like valid local address, it
still succeeded when this memory was previously used from
other dests and with different local addresses. As result,
we can use valid local address that is not suitable for
our real server.

Fix it by providing 0.0.0.0 every time our cache is refreshed.
By this way we will get preferred source address from routing.

Reported-by: Michael Vallaly <lvs@nolatency.com>
Fixes: 026ace060dfe ("ipvs: optimize dst usage for real server")
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index 1692e75347593c04bd8cd93aa6d0e6887437eaf2..c3d204973dbc4779520d70ea8e703f218564510b 100644 (file)
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -129,7 +129,6 @@ static struct rtable *do_output_route4(struct net *net, __be32 daddr,
 
        memset(&fl4, 0, sizeof(fl4));
        fl4.daddr = daddr;
-       fl4.saddr = (rt_mode & IP_VS_RT_MODE_CONNECT) ? *saddr : 0;
        fl4.flowi4_flags = (rt_mode & IP_VS_RT_MODE_KNOWN_NH) ?
                           FLOWI_FLAG_KNOWN_NH : 0;