Smack: IPv6 host labeling

IPv6 appears to be (finally) coming of age with the
influx of autonomous devices. In support of this, add
the ability to associate a Smack label with IPv6 addresses.

This patch also cleans up some of the conditional
compilation associated with the introduction of
secmark processing. It's now more obvious which bit
of code goes with which feature.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

Documentation/security/Smack.txt

@@ -28,6 +28,10 @@ Smack kernels use the CIPSO IP option. Some network
 configurations are intolerant of IP options and can impede
 access to systems that use them as Smack does.
 
+Smack is used in the Tizen operating system. Please
+go to http://wiki.tizen.org for information about how
+Smack is used in Tizen.
+
 The current git repository for Smack user space is:
 
 	git://github.com/smack-team/smack.git
@@ -108,6 +112,8 @@ in the smackfs filesystem. This pseudo-filesystem is mounted
 on /sys/fs/smackfs.
 
 access
+	Provided for backward compatibility. The access2 interface
+	is preferred and should be used instead.
 	This interface reports whether a subject with the specified
 	Smack label has a particular access to an object with a
 	specified Smack label. Write a fixed format access rule to
@@ -136,6 +142,8 @@ change-rule
 	those in the fourth string. If there is no such rule it will be
 	created using the access specified in the third and the fourth strings.
 cipso
+	Provided for backward compatibility. The cipso2 interface
+	is preferred and should be used instead.
 	This interface allows a specific CIPSO header to be assigned
 	to a Smack label. The format accepted on write is:
 		"%24s%4d%4d"["%4d"]...
@@ -157,7 +165,19 @@ direct
 doi
 	This contains the CIPSO domain of interpretation used in
 	network packets.
+ipv6host
+	This interface allows specific IPv6 internet addresses to be
+	treated as single label hosts. Packets are sent to single
+	label hosts only from processes that have Smack write access
+	to the host label. All packets received from single label hosts
+	are given the specified label. The format accepted on write is:
+		"%h:%h:%h:%h:%h:%h:%h:%h label" or
+		"%h:%h:%h:%h:%h:%h:%h:%h/%d label".
+	The "::" address shortcut is not supported.
+	If label is "-DELETE" a matched entry will be deleted.
 load
+	Provided for backward compatibility. The load2 interface
+	is preferred and should be used instead.
 	This interface allows access control rules in addition to
 	the system defined rules to be specified. The format accepted
 	on write is:
@@ -181,6 +201,8 @@ load2
 	permissions that are not allowed. The string "r-x--" would
 	specify read and execute access.
 load-self
+	Provided for backward compatibility. The load-self2 interface
+	is preferred and should be used instead.
 	This interface allows process specific access rules to be
 	defined. These rules are only consulted if access would
 	otherwise be permitted, and are intended to provide additional
@@ -205,6 +227,8 @@ netlabel
 	received from single label hosts are given the specified
 	label. The format accepted on write is:
 		"%d.%d.%d.%d label" or "%d.%d.%d.%d/%d label".
+	If the label specified is "-CIPSO" the address is treated
+	as a host that supports CIPSO headers.
 onlycap
 	This contains labels processes must have for CAP_MAC_ADMIN
 	and CAP_MAC_OVERRIDE to be effective. If this file is empty
@@ -232,7 +256,8 @@ unconfined
 	is dangerous and can ruin the proper labeling of your system.
 	It should never be used in production.
 
-You can add access rules in /etc/smack/accesses. They take the form:
+If you are using the smackload utility
+you can add access rules in /etc/smack/accesses. They take the form:
 
     subjectlabel objectlabel access
 

security/smack/smack.h

@@ -17,11 +17,26 @@
 #include <linux/spinlock.h>
 #include <linux/lsm_hooks.h>
 #include <linux/in.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <linux/in6.h>
+#endif /* CONFIG_IPV6 */
 #include <net/netlabel.h>
 #include <linux/list.h>
 #include <linux/rculist.h>
 #include <linux/lsm_audit.h>
 
+/*
+ * Use IPv6 port labeling if IPv6 is enabled and secmarks
+ * are not being used.
+ */
+#if IS_ENABLED(CONFIG_IPV6) && !defined(CONFIG_SECURITY_SMACK_NETFILTER)
+#define SMACK_IPV6_PORT_LABELING 1
+#endif
+
+#if IS_ENABLED(CONFIG_IPV6) && defined(CONFIG_SECURITY_SMACK_NETFILTER)
+#define SMACK_IPV6_SECMARK_LABELING 1
+#endif
+
 /*
  * Smack labels were limited to 23 characters for a long time.
  */
@@ -118,15 +133,30 @@ struct smack_rule {
 };
 
 /*
- * An entry in the table identifying hosts.
+ * An entry in the table identifying IPv4 hosts.
  */
-struct smk_netlbladdr {
+struct smk_net4addr {
 	struct list_head	list;
-	struct sockaddr_in	smk_host;	/* network address */
+	struct in_addr		smk_host;	/* network address */
 	struct in_addr		smk_mask;	/* network mask */
+	int			smk_masks;	/* mask size */
+	struct smack_known	*smk_label;	/* label */
+};
+
+#if IS_ENABLED(CONFIG_IPV6)
+/*
+ * An entry in the table identifying IPv6 hosts.
+ */
+struct smk_net6addr {
+	struct list_head	list;
+	struct in6_addr		smk_host;	/* network address */
+	struct in6_addr		smk_mask;	/* network mask */
+	int			smk_masks;	/* mask size */
 	struct smack_known	*smk_label;	/* label */
 };
+#endif /* CONFIG_IPV6 */
 
+#ifdef SMACK_IPV6_PORT_LABELING
 /*
  * An entry in the table identifying ports.
  */
@@ -137,6 +167,7 @@ struct smk_port_label {
 	struct smack_known	*smk_in;	/* inbound label */
 	struct smack_known	*smk_out;	/* outgoing label */
 };
+#endif /* SMACK_IPV6_PORT_LABELING */
 
 struct smack_onlycap {
 	struct list_head	list;
@@ -170,6 +201,7 @@ enum {
 #define SMK_FSROOT	"smackfsroot="
 #define SMK_FSTRANS	"smackfstransmute="
 
+#define SMACK_DELETE_OPTION	"-DELETE"
 #define SMACK_CIPSO_OPTION 	"-CIPSO"
 
 /*
@@ -252,10 +284,6 @@ struct smk_audit_info {
 	struct smack_audit_data sad;
 #endif
 };
-/*
- * These functions are in smack_lsm.c
- */
-struct inode_smack *new_inode_smack(struct smack_known *);
 
 /*
  * These functions are in smack_access.c
@@ -285,7 +313,6 @@ extern struct smack_known *smack_syslog_label;
 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 extern struct smack_known *smack_unconfined;
 #endif
-extern struct smack_known smack_cipso_option;
 extern int smack_ptrace_rule;
 
 extern struct smack_known smack_known_floor;
@@ -297,7 +324,10 @@ extern struct smack_known smack_known_web;
 
 extern struct mutex	smack_known_lock;
 extern struct list_head smack_known_list;
-extern struct list_head smk_netlbladdr_list;
+extern struct list_head smk_net4addr_list;
+#if IS_ENABLED(CONFIG_IPV6)
+extern struct list_head smk_net6addr_list;
+#endif /* CONFIG_IPV6 */
 
 extern struct mutex     smack_onlycap_lock;
 extern struct list_head smack_onlycap_list;