In case of inter address family tunneling (IPv6 over vti4 or IPv4 over
vti6), the inbound policy checks in vti_rcv_cb and vti6_rcv_cb are using
the wrong address family. As a result, all inbound inter address family
traffic is dropped.
Use the xfrm_ip2inner_mode helper (as done in xfrm_prepare_input and
xfrm_input) to select the inner_mode that contains the right address family
for the inbound policy checks.
Signed-off-by: Thomas Zeitlhofer <thomas.zeitlhofer+l...@ze-it.at>
---
Notes:
The patch was developed by looking at the code, but without knowledge of
the XFRM code in the kernel. It has been successfully tested, but it is
more a guess that might be helpful for the maintainers to find a proper
solution.
net/ipv4/ip_vti.c | 12 +++++++++++-
net/ipv6/ip6_vti.c | 12 +++++++++++-
2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index a917903..44d5449 100644
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -88,6 +88,7 @@ static int vti_rcv_cb(struct sk_buff *skb, int err)
struct net_device *dev;
struct pcpu_sw_netstats *tstats;
struct xfrm_state *x;
+ struct xfrm_mode *inner_mode;
struct ip_tunnel *tunnel = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4;
u32 orig_mark = skb->mark;
int ret;
@@ -105,7 +106,16 @@ static int vti_rcv_cb(struct sk_buff *skb, int err)
}
x = xfrm_input_state(skb);
- family = x->inner_mode->afinfo->family;
+
+ inner_mode = x->inner_mode;
+
+ if (x->sel.family == AF_UNSPEC) {
+ inner_mode = xfrm_ip2inner_mode(x,
XFRM_MODE_SKB_CB(skb)->protocol);
+ if (inner_mode == NULL)
+ return -EPERM;
+ }
+
+ family = inner_mode->afinfo->family;
skb->mark = be32_to_cpu(tunnel->parms.i_key);
ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index d90a11f..3149757 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -340,6 +340,7 @@ static int vti6_rcv_cb(struct sk_buff *skb, int err)
struct net_device *dev;
struct pcpu_sw_netstats *tstats;
struct xfrm_state *x;
+ struct xfrm_mode *inner_mode;
struct ip6_tnl *t = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6;
u32 orig_mark = skb->mark;
int ret;
@@ -357,7 +358,16 @@ static int vti6_rcv_cb(struct sk_buff *skb, int err)
}
x = xfrm_input_state(skb);
- family = x->inner_mode->afinfo->family;
+
+ inner_mode = x->inner_mode;
+
+ if (x->sel.family == AF_UNSPEC) {
+ inner_mode = xfrm_ip2inner_mode(x,
XFRM_MODE_SKB_CB(skb)->protocol);
+ if (inner_mode == NULL)
+ return -EPERM;
+ }
+
+ family = inner_mode->afinfo->family;
skb->mark = be32_to_cpu(t->parms.i_key);
ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
--
2.1.4
