vti[6]: fix packet tx through bpf_redirect()
[ Upstream commit 95224166a9032ff5d08fca633d37113078ce7d01 ]
With an ebpf program that redirects packets through a vti[6] interface,
the packets are dropped because no dst is attached.
This could also be reproduced with an AF_PACKET socket, with the following
python script (vti1 is an ip_vti interface):
import socket
send_s = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, 0)
# scapy
# p = IP(src='10.100.0.2', dst='10.200.0.1')/ICMP(type='echo-request')
# raw(p)
req = b'E\x00\x00\x1c\x00\x01\x00\x00@\x01e\xb2\nd\x00\x02\n\xc8\x00\x01\x08\x00\xf7\xff\x00\x00\x00\x00'
send_s.sendto(req, ('vti1', 0x800, 0, 0))
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index c2b2ee7..a266fac 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -453,8 +453,17 @@
int err = -1;
int mtu;
- if (!dst)
- goto tx_err_link_failure;
+ if (!dst) {
+ fl->u.ip6.flowi6_oif = dev->ifindex;
+ fl->u.ip6.flowi6_flags |= FLOWI_FLAG_ANYSRC;
+ dst = ip6_route_output(dev_net(dev), NULL, &fl->u.ip6);
+ if (dst->error) {
+ dst_release(dst);
+ dst = NULL;
+ goto tx_err_link_failure;
+ }
+ skb_dst_set(skb, dst);
+ }
dst_hold(dst);
dst = xfrm_lookup(t->net, dst, fl, NULL, 0);