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_input() (i.e., also
increment LINUX_MIB_XFRMINSTATEMODEERROR in case of error), 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:
v2: implement review comments from Steffen (thanks for the reply):
- return -EINVAL in case of error
- increment LINUX_MIB_XFRMINSTATEMODEERROR in case of error
Just to point that out, in case there are arguments against it:
this is done in the namespace of skb->dev and not in the
t(unnel)?->net namespace.
and update the commit message accordingly.
net/ipv4/ip_vti.c | 15 ++++++++++++++-
net/ipv6/ip6_vti.c | 15 ++++++++++++++-
2 files changed, 28 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index a917903..c9957ed 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 +106,19 @@ 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) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINSTATEMODEERROR);
+ return -EINVAL;
+ }
+ }
+
+ 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..52a2f73 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 +358,19 @@ 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) {
+ XFRM_INC_STATS(dev_net(skb->dev),
+ LINUX_MIB_XFRMINSTATEMODEERROR);
+ return -EINVAL;
+ }
+ }
+
+ 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
