[MLSXFRM]: Add security context to acquire messages using netlink

This includes the security context of a security association created
for use by IKE in the acquire messages sent to IKE daemons using
netlink/xfrm_user. This would allow the daemons to include the
security context in the negotiation, so that the resultant association
is unique to that security context.
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/xfrm/xfrm_user.c

@@ -911,27 +911,40 @@ rtattr_failure:
 	return -1;
 }
 
-static int copy_to_user_sec_ctx(struct xfrm_policy *xp, struct sk_buff *skb)
+static int copy_sec_ctx(struct xfrm_sec_ctx *s, struct sk_buff *skb)
 {
-	if (xp->security) {
-		int ctx_size = sizeof(struct xfrm_sec_ctx) +
-				xp->security->ctx_len;
+	int ctx_size = sizeof(struct xfrm_sec_ctx) + s->ctx_len;
 	struct rtattr *rt = __RTA_PUT(skb, XFRMA_SEC_CTX, ctx_size);
 	struct xfrm_user_sec_ctx *uctx = RTA_DATA(rt);
 
 	uctx->exttype = XFRMA_SEC_CTX;
 	uctx->len = ctx_size;
-		uctx->ctx_doi = xp->security->ctx_doi;
-		uctx->ctx_alg = xp->security->ctx_alg;
-		uctx->ctx_len = xp->security->ctx_len;
-		memcpy(uctx + 1, xp->security->ctx_str, xp->security->ctx_len);
-	}
+	uctx->ctx_doi = s->ctx_doi;
+	uctx->ctx_alg = s->ctx_alg;
+	uctx->ctx_len = s->ctx_len;
+	memcpy(uctx + 1, s->ctx_str, s->ctx_len);
  	return 0;
 
  rtattr_failure:
 	return -1;
 }
 
+static inline int copy_to_user_state_sec_ctx(struct xfrm_state *x, struct sk_buff *skb)
+{
+	if (x->security) {
+		return copy_sec_ctx(x->security, skb);
+	}
+	return 0;
+}
+
+static inline int copy_to_user_sec_ctx(struct xfrm_policy *xp, struct sk_buff *skb)
+{
+	if (xp->security) {
+		return copy_sec_ctx(xp->security, skb);
+	}
+	return 0;
+}
+
 static int dump_one_policy(struct xfrm_policy *xp, int dir, int count, void *ptr)
 {
 	struct xfrm_dump_info *sp = ptr;
@@ -1710,7 +1723,7 @@ static int build_acquire(struct sk_buff *skb, struct xfrm_state *x,
 
 	if (copy_to_user_tmpl(xp, skb) < 0)
 		goto nlmsg_failure;
-	if (copy_to_user_sec_ctx(xp, skb))
+	if (copy_to_user_state_sec_ctx(x, skb))
 		goto nlmsg_failure;
 
 	nlh->nlmsg_len = skb->tail - b;