[IPSEC]: Disallow combinations of RO and AH/ESP/IPCOMP

Combining RO and AH/ESP/IPCOMP does not make sense.  So this patch adds a
check in the state initialisation function to prevent this.

This allows us to safely remove the mode input function of RO since it
can never be called anymore.  Indeed, if somehow it does get called we'll
know about it through an OOPS instead of it slipping past silently.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 24 insertions, 12 deletions

diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index a8221d1da0ff..67cd06613a25 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -477,8 +477,15 @@ static int ah6_init_state(struct xfrm_state *x)
 
         x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
                                           ahp->icv_trunc_len);
-        if (x->props.mode == XFRM_MODE_TUNNEL)
+        switch (x->props.mode) {
+        case XFRM_MODE_BEET:
+        case XFRM_MODE_TRANSPORT:
+                break;
+        case XFRM_MODE_TUNNEL:
                 x->props.header_len += sizeof(struct ipv6hdr);
+        default:
+                goto error;
+        }
         x->data = ahp;
 
         return 0;
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 9eb928598351..b0715432e454 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -354,8 +354,15 @@ static int esp6_init_state(struct xfrm_state *x)
                                     (x->ealg->alg_key_len + 7) / 8))
                 goto error;
         x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
-        if (x->props.mode == XFRM_MODE_TUNNEL)
+        switch (x->props.mode) {
+        case XFRM_MODE_BEET:
+        case XFRM_MODE_TRANSPORT:
+                break;
+        case XFRM_MODE_TUNNEL:
                 x->props.header_len += sizeof(struct ipv6hdr);
+        default:
+                goto error;
+        }
         x->data = esp;
         return 0;
 
diff --git a/net/ipv6/ipcomp6.c b/net/ipv6/ipcomp6.c
index 28fc8edfdc3a..80ef2a1d39fd 100644
--- a/net/ipv6/ipcomp6.c
+++ b/net/ipv6/ipcomp6.c
@@ -411,8 +411,15 @@ static int ipcomp6_init_state(struct xfrm_state *x)
                 goto out;
 
         x->props.header_len = 0;
-        if (x->props.mode == XFRM_MODE_TUNNEL)
+        switch (x->props.mode) {
+        case XFRM_MODE_BEET:
+        case XFRM_MODE_TRANSPORT:
+                break;
+        case XFRM_MODE_TUNNEL:
                 x->props.header_len += sizeof(struct ipv6hdr);
+        default:
+                goto error;
+        }
 
         mutex_lock(&ipcomp6_resource_mutex);
         if (!ipcomp6_alloc_scratches())
diff --git a/net/ipv6/xfrm6_mode_ro.c b/net/ipv6/xfrm6_mode_ro.c
index 957ae36b6695..a7bc8c62317a 100644
--- a/net/ipv6/xfrm6_mode_ro.c
+++ b/net/ipv6/xfrm6_mode_ro.c
@@ -58,16 +58,7 @@ static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
         return 0;
 }
 
-/*
- * Do nothing about routing optimization header unlike IPsec.
- */
-static int xfrm6_ro_input(struct xfrm_state *x, struct sk_buff *skb)
-{
-        return 0;
-}
-
 static struct xfrm_mode xfrm6_ro_mode = {
-        .input = xfrm6_ro_input,
         .output = xfrm6_ro_output,
         .owner = THIS_MODULE,
         .encap = XFRM_MODE_ROUTEOPTIMIZATION,