netlabel: Initial support for the CALIPSO netlink protocol.

CALIPSO is a packet labelling protocol for IPv6 which is very similar
to CIPSO.  It is specified in RFC 5570.  Much of the code is based on
the current CIPSO code.

This adds support for adding passthrough-type CALIPSO DOIs through the
NLBL_CALIPSO_C_ADD command.  It requires attributes:

 NLBL_CALIPSO_A_TYPE which must be CALIPSO_MAP_PASS.
 NLBL_CALIPSO_A_DOI.

In passthrough mode the CALIPSO engine will map MLS secattr levels
and categories directly to the packet label.

At this stage, the major difference between this and the CIPSO
code is that IPv6 may be compiled as a module.  To allow for
this the CALIPSO functions are registered at module init time.

Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

3 files changed, 178 insertions, 1 deletions

diff --git a/net/ipv6/Makefile b/net/ipv6/Makefile
index 2fbd90b..88ad447 100644
--- a/net/ipv6/Makefile
+++ b/net/ipv6/Makefile
@@ -21,6 +21,7 @@ ipv6-$(CONFIG_NETFILTER) += netfilter.o
 ipv6-$(CONFIG_IPV6_MULTIPLE_TABLES) += fib6_rules.o
 ipv6-$(CONFIG_PROC_FS) += proc.o
 ipv6-$(CONFIG_SYN_COOKIES) += syncookies.o
+ipv6-$(CONFIG_NETLABEL) += calipso.o
 
 ipv6-objs += $(ipv6-y)
 
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index b11c37c..c241c18 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -60,6 +60,7 @@
 #ifdef CONFIG_IPV6_TUNNEL
 #include <net/ip6_tunnel.h>
 #endif
+#include <net/calipso.h>
 
 #include <asm/uaccess.h>
 #include <linux/mroute6.h>
@@ -970,6 +971,10 @@ static int __init inet6_init(void)
 	if (err)
 		goto pingv6_fail;
 
+	err = calipso_init();
+	if (err)
+		goto calipso_fail;
+
 #ifdef CONFIG_SYSCTL
 	err = ipv6_sysctl_register();
 	if (err)
@@ -980,8 +985,10 @@ out:
 
 #ifdef CONFIG_SYSCTL
 sysctl_fail:
-	pingv6_exit();
+	calipso_exit();
 #endif
+calipso_fail:
+	pingv6_exit();
 pingv6_fail:
 	ipv6_packet_cleanup();
 ipv6_packet_fail:
diff --git a/net/ipv6/calipso.c b/net/ipv6/calipso.c
new file mode 100644
index 0000000..aa44310
--- /dev/null
+++ b/net/ipv6/calipso.c
@@ -0,0 +1,169 @@
+/*
+ * CALIPSO - Common Architecture Label IPv6 Security Option
+ *
+ * This is an implementation of the CALIPSO protocol as specified in
+ * RFC 5570.
+ *
+ * Authors: Paul Moore <paul.moore@hp.com>
+ *          Huw Davies <huw@codeweavers.com>
+ *
+ */
+
+/* (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
+ * (c) Copyright Huw Davies <huw@codeweavers.com>, 2015
+ *
+ * This program is free software;  you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY;  without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program;  if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/rcupdate.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/jhash.h>
+#include <linux/audit.h>
+#include <linux/slab.h>
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/tcp.h>
+#include <net/netlabel.h>
+#include <net/calipso.h>
+#include <linux/atomic.h>
+#include <linux/bug.h>
+#include <asm/unaligned.h>
+
+/* List of available DOI definitions */
+static DEFINE_SPINLOCK(calipso_doi_list_lock);
+static LIST_HEAD(calipso_doi_list);
+
+/* DOI List Functions
+ */
+
+/**
+ * calipso_doi_search - Searches for a DOI definition
+ * @doi: the DOI to search for
+ *
+ * Description:
+ * Search the DOI definition list for a DOI definition with a DOI value that
+ * matches @doi.  The caller is responsible for calling rcu_read_[un]lock().
+ * Returns a pointer to the DOI definition on success and NULL on failure.
+ */
+static struct calipso_doi *calipso_doi_search(u32 doi)
+{
+	struct calipso_doi *iter;
+
+	list_for_each_entry_rcu(iter, &calipso_doi_list, list)
+		if (iter->doi == doi && atomic_read(&iter->refcount))
+			return iter;
+	return NULL;
+}
+
+/**
+ * calipso_doi_add - Add a new DOI to the CALIPSO protocol engine
+ * @doi_def: the DOI structure
+ * @audit_info: NetLabel audit information
+ *
+ * Description:
+ * The caller defines a new DOI for use by the CALIPSO engine and calls this
+ * function to add it to the list of acceptable domains.  The caller must
+ * ensure that the mapping table specified in @doi_def->map meets all of the
+ * requirements of the mapping type (see calipso.h for details).  Returns
+ * zero on success and non-zero on failure.
+ *
+ */
+static int calipso_doi_add(struct calipso_doi *doi_def,
+			   struct netlbl_audit *audit_info)
+{
+	int ret_val = -EINVAL;
+	u32 doi;
+	u32 doi_type;
+	struct audit_buffer *audit_buf;
+
+	doi = doi_def->doi;
+	doi_type = doi_def->type;
+
+	if (doi_def->doi == CALIPSO_DOI_UNKNOWN)
+		goto doi_add_return;
+
+	atomic_set(&doi_def->refcount, 1);
+
+	spin_lock(&calipso_doi_list_lock);
+	if (calipso_doi_search(doi_def->doi)) {
+		spin_unlock(&calipso_doi_list_lock);
+		ret_val = -EEXIST;
+		goto doi_add_return;
+	}
+	list_add_tail_rcu(&doi_def->list, &calipso_doi_list);
+	spin_unlock(&calipso_doi_list_lock);
+	ret_val = 0;
+
+doi_add_return:
+	audit_buf = netlbl_audit_start(AUDIT_MAC_CALIPSO_ADD, audit_info);
+	if (audit_buf) {
+		const char *type_str;
+
+		switch (doi_type) {
+		case CALIPSO_MAP_PASS:
+			type_str = "pass";
+			break;
+		default:
+			type_str = "(unknown)";
+		}
+		audit_log_format(audit_buf,
+				 " calipso_doi=%u calipso_type=%s res=%u",
+				 doi, type_str, ret_val == 0 ? 1 : 0);
+		audit_log_end(audit_buf);
+	}
+
+	return ret_val;
+}
+
+/**
+ * calipso_doi_free - Frees a DOI definition
+ * @doi_def: the DOI definition
+ *
+ * Description:
+ * This function frees all of the memory associated with a DOI definition.
+ *
+ */
+static void calipso_doi_free(struct calipso_doi *doi_def)
+{
+	kfree(doi_def);
+}
+
+static const struct netlbl_calipso_ops ops = {
+	.doi_add          = calipso_doi_add,
+	.doi_free         = calipso_doi_free,
+};
+
+/**
+ * calipso_init - Initialize the CALIPSO module
+ *
+ * Description:
+ * Initialize the CALIPSO module and prepare it for use.  Returns zero on
+ * success and negative values on failure.
+ *
+ */
+int __init calipso_init(void)
+{
+	netlbl_calipso_ops_register(&ops);
+	return 0;
+}
+
+void calipso_exit(void)
+{
+	netlbl_calipso_ops_register(NULL);
+}