[NetLabel]: CIPSOv4 and Unlabeled packet integration

Add CIPSO/IPv4 and unlabeled packet management to the NetLabel
subsystem.  The CIPSO/IPv4 changes allow the configuration of
CIPSO/IPv4 within the overall NetLabel framework.  The unlabeled
packet changes allows NetLabel to pass unlabeled packets without
error.
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netlabel/netlabel_unlabeled.c

+/*
+ * NetLabel Unlabeled Support
+ *
+ * This file defines functions for dealing with unlabeled packets for the
+ * NetLabel system.  The NetLabel system manages static and dynamic label
+ * mappings for network protocols such as CIPSO and RIPSO.
+ *
+ * Author: Paul Moore <paul.moore@hp.com>
+ *
+ */
+
+/*
+ * (c) Copyright Hewlett-Packard Development Company, L.P., 2006
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/rcupdate.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/socket.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+#include <net/netlabel.h>
+#include <asm/bug.h>
+
+#include "netlabel_user.h"
+#include "netlabel_domainhash.h"
+#include "netlabel_unlabeled.h"
+
+/* Accept unlabeled packets flag */
+static atomic_t netlabel_unlabel_accept_flg = ATOMIC_INIT(0);
+
+/* NetLabel Generic NETLINK CIPSOv4 family */
+static struct genl_family netlbl_unlabel_gnl_family = {
+	.id = GENL_ID_GENERATE,
+	.hdrsize = 0,
+	.name = NETLBL_NLTYPE_UNLABELED_NAME,
+	.version = NETLBL_PROTO_VERSION,
+	.maxattr = 0,
+};
+
+
+/*
+ * NetLabel Command Handlers
+ */
+
+/**
+ * netlbl_unlabel_accept - Handle an ACCEPT message
+ * @skb: the NETLINK buffer
+ * @info: the Generic NETLINK info block
+ *
+ * Description:
+ * Process a user generated ACCEPT message and set the accept flag accordingly.
+ * Returns zero on success, negative values on failure.
+ *
+ */
+static int netlbl_unlabel_accept(struct sk_buff *skb, struct genl_info *info)
+{
+	int ret_val;
+	struct nlattr *data = netlbl_netlink_payload_data(skb);
+	u32 value;
+
+	ret_val = netlbl_netlink_cap_check(skb, CAP_NET_ADMIN);
+	if (ret_val != 0)
+		return ret_val;
+
+	if (netlbl_netlink_payload_len(skb) == NETLBL_LEN_U32) {
+		value = nla_get_u32(data);
+		if (value == 1 || value == 0) {
+			atomic_set(&netlabel_unlabel_accept_flg, value);
+			netlbl_netlink_send_ack(info,
+						netlbl_unlabel_gnl_family.id,
+						NLBL_UNLABEL_C_ACK,
+						NETLBL_E_OK);
+			return 0;
+		}
+	}
+
+	netlbl_netlink_send_ack(info,
+				netlbl_unlabel_gnl_family.id,
+				NLBL_UNLABEL_C_ACK,
+				EINVAL);
+	return -EINVAL;
+}
+
+/**
+ * netlbl_unlabel_list - Handle a LIST message
+ * @skb: the NETLINK buffer
+ * @info: the Generic NETLINK info block
+ *
+ * Description:
+ * Process a user generated LIST message and respond with the current status.
+ * Returns zero on success, negative values on failure.
+ *
+ */
+static int netlbl_unlabel_list(struct sk_buff *skb, struct genl_info *info)
+{
+	int ret_val = -ENOMEM;
+	struct sk_buff *ans_skb;
+
+	ans_skb = netlbl_netlink_alloc_skb(0,
+					   GENL_HDRLEN + NETLBL_LEN_U32,
+					   GFP_KERNEL);
+	if (ans_skb == NULL)
+		goto list_failure;
+
+	if (netlbl_netlink_hdr_put(ans_skb,
+				   info->snd_pid,
+				   0,
+				   netlbl_unlabel_gnl_family.id,
+				   NLBL_UNLABEL_C_LIST) == NULL)
+		goto list_failure;
+
+	ret_val = nla_put_u32(ans_skb,
+			      NLA_U32,
+			      atomic_read(&netlabel_unlabel_accept_flg));
+	if (ret_val != 0)
+		goto list_failure;
+
+	ret_val = netlbl_netlink_snd(ans_skb, info->snd_pid);
+	if (ret_val != 0)
+		goto list_failure;
+
+	return 0;
+
+list_failure:
+	netlbl_netlink_send_ack(info,
+				netlbl_unlabel_gnl_family.id,
+				NLBL_UNLABEL_C_ACK,
+				-ret_val);
+	return ret_val;
+}
+
+
+/*
+ * NetLabel Generic NETLINK Command Definitions
+ */
+
+static struct genl_ops netlbl_unlabel_genl_c_accept = {
+	.cmd = NLBL_UNLABEL_C_ACCEPT,
+	.flags = 0,
+	.doit = netlbl_unlabel_accept,
+	.dumpit = NULL,
+};
+
+static struct genl_ops netlbl_unlabel_genl_c_list = {
+	.cmd = NLBL_UNLABEL_C_LIST,
+	.flags = 0,
+	.doit = netlbl_unlabel_list,
+	.dumpit = NULL,
+};
+
+
+/*
+ * NetLabel Generic NETLINK Protocol Functions
+ */
+
+/**
+ * netlbl_unlabel_genl_init - Register the Unlabeled NetLabel component
+ *
+ * Description:
+ * Register the unlabeled packet NetLabel component with the Generic NETLINK
+ * mechanism.  Returns zero on success, negative values on failure.
+ *
+ */
+int netlbl_unlabel_genl_init(void)
+{
+	int ret_val;
+
+	ret_val = genl_register_family(&netlbl_unlabel_gnl_family);
+	if (ret_val != 0)
+		return ret_val;
+
+	ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
+				    &netlbl_unlabel_genl_c_accept);
+	if (ret_val != 0)
+		return ret_val;
+
+	ret_val = genl_register_ops(&netlbl_unlabel_gnl_family,
+				    &netlbl_unlabel_genl_c_list);
+	if (ret_val != 0)
+		return ret_val;
+
+	return 0;
+}
+
+/*
+ * NetLabel KAPI Hooks
+ */
+
+/**
+ * netlbl_unlabel_getattr - Get the security attributes for an unlabled packet
+ * @secattr: the security attributes
+ *
+ * Description:
+ * Determine the security attributes, if any, for an unlabled packet and return
+ * them in @secattr.  Returns zero on success and negative values on failure.
+ *
+ */
+int netlbl_unlabel_getattr(struct netlbl_lsm_secattr *secattr)
+{
+	if (atomic_read(&netlabel_unlabel_accept_flg) == 1) {
+		memset(secattr, 0, sizeof(*secattr));
+		return 0;
+	}
+
+	return -ENOMSG;
+}
+
+/**
+ * netlbl_unlabel_defconf - Set the default config to allow unlabeled packets
+ *
+ * Description:
+ * Set the default NetLabel configuration to allow incoming unlabeled packets
+ * and to send unlabeled network traffic by default.
+ *
+ */
+int netlbl_unlabel_defconf(void)
+{
+	int ret_val;
+	struct netlbl_dom_map *entry;
+
+	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	if (entry == NULL)
+		return -ENOMEM;
+	entry->type = NETLBL_NLTYPE_UNLABELED;
+	ret_val = netlbl_domhsh_add_default(entry);
+	if (ret_val != 0)
+		return ret_val;
+
+	atomic_set(&netlabel_unlabel_accept_flg, 1);
+
+	return 0;
+}