xfrm: Add xfrm_tunnel_skb_cb to the skb common buffer

IPsec vti_rcv needs to remind the tunnel pointer to
check it later at the vti_rcv_cb callback. So add
this pointer to the IPsec common buffer, initialize
it and check it to avoid transport state matching of
a tunneled packet.

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

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 345a150..3311259 100644 (file)
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -599,16 +599,27 @@ struct xfrm_mgr {
 int xfrm_register_km(struct xfrm_mgr *km);
 int xfrm_unregister_km(struct xfrm_mgr *km);
 
+struct xfrm_tunnel_skb_cb {
+       union {
+               struct inet_skb_parm h4;
+               struct inet6_skb_parm h6;
+       } header;
+
+       union {
+               struct ip_tunnel *ip4;
+               struct ip6_tnl *ip6;
+       } tunnel;
+};
+
+#define XFRM_TUNNEL_SKB_CB(__skb) ((struct xfrm_tunnel_skb_cb *)&((__skb)->cb[0]))
+
 /*
  * This structure is used for the duration where packets are being
  * transformed by IPsec.  As soon as the packet leaves IPsec the
  * area beyond the generic IP part may be overwritten.
  */
 struct xfrm_skb_cb {
-       union {
-               struct inet_skb_parm h4;
-               struct inet6_skb_parm h6;
-        } header;
+       struct xfrm_tunnel_skb_cb header;
 
         /* Sequence number for replay protection. */
        union {
@@ -630,10 +641,7 @@ struct xfrm_skb_cb {
  * to transmit header information to the mode input/output functions.
  */
 struct xfrm_mode_skb_cb {
-       union {
-               struct inet_skb_parm h4;
-               struct inet6_skb_parm h6;
-       } header;
+       struct xfrm_tunnel_skb_cb header;
 
        /* Copied from header for IPv4, always set to zero and DF for IPv6. */
        __be16 id;
@@ -665,10 +673,7 @@ struct xfrm_mode_skb_cb {
  * related information.
  */
 struct xfrm_spi_skb_cb {
-       union {
-               struct inet_skb_parm h4;
-               struct inet6_skb_parm h6;
-       } header;
+       struct xfrm_tunnel_skb_cb header;
 
        unsigned int daddroff;
        unsigned int family;
@@ -1510,6 +1515,7 @@ int xfrm4_rcv(struct sk_buff *skb);
 
 static inline int xfrm4_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi)
 {
+       XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
        XFRM_SPI_SKB_CB(skb)->family = AF_INET;
        XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
        return xfrm_input(skb, nexthdr, spi, 0);
@@ -1781,4 +1787,24 @@ static inline int xfrm_rcv_cb(struct sk_buff *skb, unsigned int family,
        return 0;
 }
 
+static inline int xfrm_tunnel_check(struct sk_buff *skb, struct xfrm_state *x,
+                                   unsigned int family)
+{
+       bool tunnel = false;
+
+       switch(family) {
+       case AF_INET:
+               if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4)
+                       tunnel = true;
+               break;
+       case AF_INET6:
+               if (XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6)
+                       tunnel = true;
+               break;
+       }
+       if (tunnel && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL))
+               return -EINVAL;
+
+       return 0;
+}
 #endif /* _NET_XFRM_H */

diff --git a/net/ipv4/xfrm4_protocol.c b/net/ipv4/xfrm4_protocol.c
index 862a26c..cdc09ef 100644 (file)
--- a/net/ipv4/xfrm4_protocol.c
+++ b/net/ipv4/xfrm4_protocol.c
@@ -65,6 +65,7 @@ int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
        int ret;
        struct xfrm4_protocol *handler;
 
+       XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
        XFRM_SPI_SKB_CB(skb)->family = AF_INET;
        XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
 
@@ -84,6 +85,8 @@ static int xfrm4_esp_rcv(struct sk_buff *skb)
        int ret;
        struct xfrm4_protocol *handler;
 
+       XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
+
        for_each_protocol_rcu(esp4_handlers, handler)
                if ((ret = handler->handler(skb)) != -EINVAL)
                        return ret;
@@ -108,6 +111,8 @@ static int xfrm4_ah_rcv(struct sk_buff *skb)
        int ret;
        struct xfrm4_protocol *handler;
 
+       XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
+
        for_each_protocol_rcu(ah4_handlers, handler)
                if ((ret = handler->handler(skb)) != -EINVAL)
                        return ret;;
@@ -132,6 +137,8 @@ static int xfrm4_ipcomp_rcv(struct sk_buff *skb)
        int ret;
        struct xfrm4_protocol *handler;
 
+       XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
+
        for_each_protocol_rcu(ipcomp4_handlers, handler)
                if ((ret = handler->handler(skb)) != -EINVAL)
                        return ret;

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 99e3a9e..4218164 100644 (file)
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -163,6 +163,11 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
 
                skb->sp->xvec[skb->sp->len++] = x;
 
+               if (xfrm_tunnel_check(skb, x, family)) {
+                       XFRM_INC_STATS(net, LINUX_MIB_XFRMINSTATEMODEERROR);
+                       goto drop;
+               }
+
                spin_lock(&x->lock);
                if (unlikely(x->km.state == XFRM_STATE_ACQ)) {
                        XFRM_INC_STATS(net, LINUX_MIB_XFRMACQUIREERROR);