selinux: Add new NetLabel glue code to handle labeling of connection requests

[NOTE: based on 389fb800ac8be2832efedd19978a2b8ced37eb61]

This patch provides the missing functions to properly handle the labeling of
responses to incoming connection requests within SELinux.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 72 insertions, 67 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index e210b212da7f..5f740cceb256 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -3799,7 +3799,7 @@ static int selinux_socket_post_create(struct socket *sock, int family,
 		sksec = sock->sk->sk_security;
 		sksec->sid = isec->sid;
 		sksec->sclass = isec->sclass;
-		err = selinux_netlbl_socket_post_create(sock);
+		err = selinux_netlbl_socket_post_create(sock->sk, family);
 	}
 
 	return err;
@@ -4467,8 +4467,6 @@ static void selinux_inet_conn_established(struct sock *sk, struct sk_buff *skb)
 		family = PF_INET;
 
 	selinux_skb_peerlbl_sid(skb, family, &sksec->peer_sid);
-
-	selinux_netlbl_inet_conn_established(sk, family);
 }
 
 static void selinux_req_classify_flow(const struct request_sock *req,
diff --git a/security/selinux/include/netlabel.h b/security/selinux/include/netlabel.h
index b913c8d06038..9fca7b5069e8 100644
--- a/security/selinux/include/netlabel.h
+++ b/security/selinux/include/netlabel.h
@@ -32,6 +32,7 @@
 #include <linux/net.h>
 #include <linux/skbuff.h>
 #include <net/sock.h>
+#include <net/request_sock.h>
 
 #include "avc.h"
 #include "objsec.h"
@@ -53,8 +54,9 @@ int selinux_netlbl_skbuff_setsid(struct sk_buff *skb,
 				 u16 family,
 				 u32 sid);
 
-void selinux_netlbl_inet_conn_established(struct sock *sk, u16 family);
-int selinux_netlbl_socket_post_create(struct socket *sock);
+int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family);
+void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family);
+int selinux_netlbl_socket_post_create(struct sock *sk, u16 family);
 int selinux_netlbl_inode_permission(struct inode *inode, int mask);
 int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
 				struct sk_buff *skb,
@@ -113,12 +115,17 @@ static inline int selinux_netlbl_conn_setsid(struct sock *sk,
 	return 0;
 }
 
-static inline void selinux_netlbl_inet_conn_established(struct sock *sk,
-							u16 family)
+static inline int selinux_netlbl_inet_conn_request(struct request_sock *req,
+						   u16 family)
+{
+	return 0;
+}
+static inline void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
 {
 	return;
 }
-static inline int selinux_netlbl_socket_post_create(struct socket *sock)
+static inline int selinux_netlbl_socket_post_create(struct sock *sk,
+						    u16 family)
 {
 	return 0;
 }
diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c
index 350794ab9b42..8fcb2d56bdcf 100644
--- a/security/selinux/netlabel.c
+++ b/security/selinux/netlabel.c
@@ -281,73 +281,52 @@ skbuff_setsid_return:
 }
 
 /**
- * selinux_netlbl_inet_conn_established - Netlabel the newly accepted connection
- * @sk: the new connection
+ * selinux_netlbl_inet_conn_request - Label an incoming stream connection
+ * @req: incoming connection request socket
  *
  * Description:
- * A new connection has been established on @sk so make sure it is labeled
- * correctly with the NetLabel susbsystem.
+ * A new incoming connection request is represented by @req, we need to label
+ * the new request_sock here and the stack will ensure the on-the-wire label
+ * will get preserved when a full sock is created once the connection handshake
+ * is complete.  Returns zero on success, negative values on failure.
  *
  */
-void selinux_netlbl_inet_conn_established(struct sock *sk, u16 family)
+int selinux_netlbl_inet_conn_request(struct request_sock *req, u16 family)
 {
 	int rc;
-	struct sk_security_struct *sksec = sk->sk_security;
-	struct netlbl_lsm_secattr *secattr;
-	struct inet_sock *sk_inet = inet_sk(sk);
-	struct sockaddr_in addr;
+	struct netlbl_lsm_secattr secattr;
 
-	if (sksec->nlbl_state != NLBL_REQUIRE)
-		return;
+	if (family != PF_INET)
+		return 0;
 
-	secattr = selinux_netlbl_sock_genattr(sk);
-	if (secattr == NULL)
-		return;
+	netlbl_secattr_init(&secattr);
+	rc = security_netlbl_sid_to_secattr(req->secid, &secattr);
+	if (rc != 0)
+		goto inet_conn_request_return;
+	rc = netlbl_req_setattr(req, &secattr);
+inet_conn_request_return:
+	netlbl_secattr_destroy(&secattr);
+	return rc;
+}
 
-	rc = netlbl_sock_setattr(sk, secattr);
-	switch (rc) {
-	case 0:
+/**
+ * selinux_netlbl_inet_csk_clone - Initialize the newly created sock
+ * @sk: the new sock
+ *
+ * Description:
+ * A new connection has been established using @sk, we've already labeled the
+ * socket via the request_sock struct in selinux_netlbl_inet_conn_request() but
+ * we need to set the NetLabel state here since we now have a sock structure.
+ *
+ */
+void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
+{
+	struct sk_security_struct *sksec = sk->sk_security;
+
+	if (family == PF_INET)
 		sksec->nlbl_state = NLBL_LABELED;
-		break;
-	case -EDESTADDRREQ:
-		/* no PF_INET6 support yet because we don't support any IPv6
-		 * labeling protocols */
-		if (family != PF_INET) {
-			sksec->nlbl_state = NLBL_UNSET;
-			return;
-		}
-
-		addr.sin_family = family;
-		addr.sin_addr.s_addr = sk_inet->daddr;
-		if (netlbl_conn_setattr(sk, (struct sockaddr *)&addr,
-					secattr) != 0) {
-			/* we failed to label the connected socket (could be
-			 * for a variety of reasons, the actual "why" isn't
-			 * important here) so we have to go to our backup plan,
-			 * labeling the packets individually in the netfilter
-			 * local output hook.  this is okay but we need to
-			 * adjust the MSS of the connection to take into
-			 * account any labeling overhead, since we don't know
-			 * the exact overhead at this point we'll use the worst
-			 * case value which is 40 bytes for IPv4 */
-			struct inet_connection_sock *sk_conn = inet_csk(sk);
-			sk_conn->icsk_ext_hdr_len += 40 -
-				      (sk_inet->opt ? sk_inet->opt->optlen : 0);
-			sk_conn->icsk_sync_mss(sk, sk_conn->icsk_pmtu_cookie);
-
-			sksec->nlbl_state = NLBL_REQSKB;
-		} else
-			sksec->nlbl_state = NLBL_CONNLABELED;
-		break;
-	default:
-		/* note that we are failing to label the socket which could be
-		 * a bad thing since it means traffic could leave the system
-		 * without the desired labeling, however, all is not lost as
-		 * we have a check in selinux_netlbl_inode_permission() to
-		 * pick up the pieces that we might drop here because we can't
-		 * return an error code */
-		break;
-	}
+	else
+		sksec->nlbl_state = NLBL_UNSET;
 }
 
 /**
@@ -359,9 +338,30 @@ void selinux_netlbl_inet_conn_established(struct sock *sk, u16 family)
  * SID.  Returns zero values on success, negative values on failure.
  *
  */
-int selinux_netlbl_socket_post_create(struct socket *sock)
+int selinux_netlbl_socket_post_create(struct sock *sk, u16 family)
 {
-	return selinux_netlbl_sock_setsid(sock->sk);
+	int rc;
+	struct sk_security_struct *sksec = sk->sk_security;
+	struct netlbl_lsm_secattr *secattr;
+
+	if (family != PF_INET)
+		return 0;
+
+	secattr = selinux_netlbl_sock_genattr(sk);
+	if (secattr == NULL)
+		return -ENOMEM;
+	rc = netlbl_sock_setattr(sk, secattr);
+	switch (rc) {
+	case 0:
+		sksec->nlbl_state = NLBL_LABELED;
+		break;
+	case -EDESTADDRREQ:
+		sksec->nlbl_state = NLBL_REQSKB;
+		rc = 0;
+		break;
+	}
+
+	return rc;
 }
 
 /**