netlabel: Label incoming TCP connections correctly in SELinux

The current NetLabel/SELinux behavior for incoming TCP connections works but
only through a series of happy coincidences that rely on the limited nature of
standard CIPSO (only able to convey MLS attributes) and the write equality
imposed by the SELinux MLS constraints.  The problem is that network sockets
created as the result of an incoming TCP connection were not on-the-wire
labeled based on the security attributes of the parent socket but rather based
on the wire label of the remote peer.  The issue had to do with how IP options
were managed as part of the network stack and where the LSM hooks were in
relation to the code which set the IP options on these newly created child
sockets.  While NetLabel/SELinux did correctly set the socket's on-the-wire
label it was promptly cleared by the network stack and reset based on the IP
options of the remote peer.

This patch, in conjunction with a prior patch that adjusted the LSM hook
locations, works to set the correct on-the-wire label format for new incoming
connections through the security_inet_conn_request() hook.  Besides the
correct behavior there are many advantages to this change, the most significant
is that all of the NetLabel socket labeling code in SELinux now lives in hooks
which can return error codes to the core stack which allows us to finally get
ride of the selinux_netlbl_inode_permission() logic which greatly simplfies
the NetLabel/SELinux glue code.  In the process of developing this patch I
also ran into a small handful of AF_INET6 cleanliness issues that have been
fixed which should make the code safer and easier to extend in the future.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 13 insertions, 14 deletions

diff --git a/security/selinux/include/netlabel.h b/security/selinux/include/netlabel.h
index b913c8d..b4b5b9b 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"
@@ -42,8 +43,7 @@ void selinux_netlbl_cache_invalidate(void);
 void selinux_netlbl_err(struct sk_buff *skb, int error, int gateway);
 
 void selinux_netlbl_sk_security_free(struct sk_security_struct *ssec);
-void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec,
-				      int family);
+void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec);
 
 int selinux_netlbl_skbuff_getsid(struct sk_buff *skb,
 				 u16 family,
@@ -53,9 +53,9 @@ 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_inode_permission(struct inode *inode, int mask);
+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_sock_rcv_skb(struct sk_security_struct *sksec,
 				struct sk_buff *skb,
 				u16 family,
@@ -85,8 +85,7 @@ static inline void selinux_netlbl_sk_security_free(
 }
 
 static inline void selinux_netlbl_sk_security_reset(
-					       struct sk_security_struct *ssec,
-					       int family)
+					       struct sk_security_struct *ssec)
 {
 	return;
 }
@@ -113,17 +112,17 @@ 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;
+	return 0;
 }
-static inline int selinux_netlbl_socket_post_create(struct socket *sock)
+static inline void selinux_netlbl_inet_csk_clone(struct sock *sk, u16 family)
 {
-	return 0;
+	return;
 }
-static inline int selinux_netlbl_inode_permission(struct inode *inode,
-						  int mask)
+static inline int selinux_netlbl_socket_post_create(struct sock *sk,
+						    u16 family)
 {
 	return 0;
 }