vti4: Check the tunnel endpoints of the xfrm state and the vti interface

The tunnel endpoints of the xfrm_state we got from the xfrm_lookup
must match the tunnel endpoints of the vti interface. This patch
ensures this matching.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c
index 9369b7c03f1c3ff1053e5bfe2f1728fd46d16886..9471893df47c1607b30c2e5d8ab1a6bfb17a7ad7 100644 (file)
--- a/net/ipv4/ip_vti.c
+++ b/net/ipv4/ip_vti.c
@@ -123,10 +123,32 @@ static int vti_rcv_cb(struct sk_buff *skb, int err)
        return 0;
 }
 
+static bool vti_state_check(const struct xfrm_state *x, __be32 dst, __be32 src)
+{
+       xfrm_address_t *daddr = (xfrm_address_t *)&dst;
+       xfrm_address_t *saddr = (xfrm_address_t *)&src;
+
+       /* if there is no transform then this tunnel is not functional.
+        * Or if the xfrm is not mode tunnel.
+        */
+       if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
+           x->props.family != AF_INET)
+               return false;
+
+       if (!dst)
+               return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET);
+
+       if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET))
+               return false;
+
+       return true;
+}
+
 static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
                            struct flowi *fl)
 {
        struct ip_tunnel *tunnel = netdev_priv(dev);
+       struct ip_tunnel_parm *parms = &tunnel->parms;
        struct dst_entry *dst = skb_dst(skb);
        struct net_device *tdev;        /* Device to other host */
        int err;
@@ -143,15 +165,12 @@ static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
                goto tx_error_icmp;
        }
 
-       /* if there is no transform then this tunnel is not functional.
-        * Or if the xfrm is not mode tunnel.
-        */
-       if (!dst->xfrm ||
-           dst->xfrm->props.mode != XFRM_MODE_TUNNEL) {
+       if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) {
                dev->stats.tx_carrier_errors++;
                dst_release(dst);
                goto tx_error_icmp;
        }
+
        tdev = dst->dev;
 
        if (tdev == dev) {