[MLSXFRM]: Add flow labeling

This labels the flows that could utilize IPSec xfrms at the points the
flows are defined so that IPSec policy and SAs at the right label can
be used.

The following protos are currently not handled, but they should
continue to be able to use single-labeled IPSec like they currently
do.

ipmr
ip_gre
ipip
igmp
sit
sctp
ip6_tunnel (IPv6 over IPv6 tunnel device)
decnet

Signed-off-by: Venkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 28 insertions, 13 deletions

diff --git a/include/linux/security.h b/include/linux/security.h
index 2c4921d79d19..f3909d189fe0 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -32,6 +32,7 @@
 #include <linux/sched.h>
 #include <linux/key.h>
 #include <linux/xfrm.h>
+#include <net/flow.h>
 
 struct ctl_table;
 
@@ -815,8 +816,8 @@ struct swap_info_struct;
  *	Deallocate security structure.
  * @sk_clone_security:
  *	Clone/copy security structure.
- * @sk_getsid:
- *	Retrieve the LSM-specific sid for the sock to enable caching of network
+ * @sk_getsecid:
+ *	Retrieve the LSM-specific secid for the sock to enable caching of network
  *	authorizations.
  *
  * Security hooks for XFRM operations.
@@ -882,8 +883,9 @@ struct swap_info_struct;
  *	Return 1 if there is a match.
  * @xfrm_decode_session:
  *	@skb points to skb to decode.
- *	@fl points to the flow key to set.
- *	Return 0 if successful decoding.
+ *	@secid points to the flow key secid to set.
+ *	@ckall says if all xfrms used should be checked for same secid.
+ *	Return 0 if ckall is zero or all xfrms used have the same secid.
  *
  * Security hooks affecting all Key Management operations
  *
@@ -1353,7 +1355,7 @@ struct security_operations {
 	int (*sk_alloc_security) (struct sock *sk, int family, gfp_t priority);
 	void (*sk_free_security) (struct sock *sk);
 	void (*sk_clone_security) (const struct sock *sk, struct sock *newsk);
-	unsigned int (*sk_getsid) (struct sock *sk, struct flowi *fl, u8 dir);
+	void (*sk_getsecid) (struct sock *sk, u32 *secid);
 #endif	/* CONFIG_SECURITY_NETWORK */
 
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
@@ -1370,7 +1372,7 @@ struct security_operations {
 	int (*xfrm_state_pol_flow_match)(struct xfrm_state *x,
 			struct xfrm_policy *xp, struct flowi *fl);
 	int (*xfrm_flow_state_match)(struct flowi *fl, struct xfrm_state *xfrm);
-	int (*xfrm_decode_session)(struct sk_buff *skb, struct flowi *fl);
+	int (*xfrm_decode_session)(struct sk_buff *skb, u32 *secid, int ckall);
 #endif	/* CONFIG_SECURITY_NETWORK_XFRM */
 
 	/* key management security hooks */
@@ -2917,9 +2919,9 @@ static inline void security_sk_clone(const struct sock *sk, struct sock *newsk)
 	return security_ops->sk_clone_security(sk, newsk);
 }
 
-static inline unsigned int security_sk_sid(struct sock *sk, struct flowi *fl, u8 dir)
+static inline void security_sk_classify_flow(struct sock *sk, struct flowi *fl)
 {
-	return security_ops->sk_getsid(sk, fl, dir);
+	security_ops->sk_getsecid(sk, &fl->secid);
 }
 #else	/* CONFIG_SECURITY_NETWORK */
 static inline int security_unix_stream_connect(struct socket * sock,
@@ -3047,9 +3049,8 @@ static inline void security_sk_clone(const struct sock *sk, struct sock *newsk)
 {
 }
 
-static inline unsigned int security_sk_sid(struct sock *sk, struct flowi *fl, u8 dir)
+static inline void security_sk_classify_flow(struct sock *sk, struct flowi *fl)
 {
-	return 0;
 }
 #endif	/* CONFIG_SECURITY_NETWORK */
 
@@ -3114,9 +3115,16 @@ static inline int security_xfrm_flow_state_match(struct flowi *fl, struct xfrm_s
 	return security_ops->xfrm_flow_state_match(fl, xfrm);
 }
 
-static inline int security_xfrm_decode_session(struct sk_buff *skb, struct flowi *fl)
+static inline int security_xfrm_decode_session(struct sk_buff *skb, u32 *secid)
+{
+	return security_ops->xfrm_decode_session(skb, secid, 1);
+}
+
+static inline void security_skb_classify_flow(struct sk_buff *skb, struct flowi *fl)
 {
-	return security_ops->xfrm_decode_session(skb, fl);
+	int rc = security_ops->xfrm_decode_session(skb, &fl->secid, 0);
+
+	BUG_ON(rc);
 }
 #else	/* CONFIG_SECURITY_NETWORK_XFRM */
 static inline int security_xfrm_policy_alloc(struct xfrm_policy *xp, struct xfrm_user_sec_ctx *sec_ctx)
@@ -3176,11 +3184,15 @@ static inline int security_xfrm_flow_state_match(struct flowi *fl,
 	return 1;
 }
 
-static inline int security_xfrm_decode_session(struct sk_buff *skb, struct flowi *fl)
+static inline int security_xfrm_decode_session(struct sk_buff *skb, u32 *secid)
 {
 	return 0;
 }
 
+static inline void security_skb_classify_flow(struct sk_buff *skb, struct flowi *fl)
+{
+}
+
 #endif	/* CONFIG_SECURITY_NETWORK_XFRM */
 
 #ifdef CONFIG_KEYS
diff --git a/include/net/route.h b/include/net/route.h
index c4a068692dcc..7f93ac0e0899 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -32,6 +32,7 @@
 #include <linux/route.h>
 #include <linux/ip.h>
 #include <linux/cache.h>
+#include <linux/security.h>
 
 #ifndef __KERNEL__
 #warning This file is not supposed to be used outside of kernel.
@@ -166,6 +167,7 @@ static inline int ip_route_connect(struct rtable **rp, u32 dst,
 		ip_rt_put(*rp);
 		*rp = NULL;
 	}
+	security_sk_classify_flow(sk, &fl);
 	return ip_route_output_flow(rp, &fl, sk, 0);
 }
 
@@ -182,6 +184,7 @@ static inline int ip_route_newports(struct rtable **rp, u8 protocol,
 		fl.proto = protocol;
 		ip_rt_put(*rp);
 		*rp = NULL;
+		security_sk_classify_flow(sk, &fl);
 		return ip_route_output_flow(rp, &fl, sk, 0);
 	}
 	return 0;