NetLabel: Introduce static network labels for unlabeled connections

Most trusted OSs, with the exception of Linux, have the ability to specify
static security labels for unlabeled networks.  This patch adds this ability to
the NetLabel packet labeling framework.

If the NetLabel subsystem is called to determine the security attributes of an
incoming packet it first checks to see if any recognized NetLabel packet
labeling protocols are in-use on the packet.  If none can be found then the
unlabled connection table is queried and based on the packets incoming
interface and address it is matched with a security label as configured by the
administrator using the netlabel_tools package.  The matching security label is
returned to the caller just as if the packet was explicitly labeled using a
labeling protocol.
Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>

include/net/netlabel.h

@@ -67,7 +67,11 @@
  * NetLabel NETLINK protocol
  */
 
-#define NETLBL_PROTO_VERSION            1
+/* NetLabel NETLINK protocol version
+ *  1: initial version
+ *  2: added static labels for unlabeled connections
+ */
+#define NETLBL_PROTO_VERSION            2
 
 /* NetLabel NETLINK types/families */
 #define NETLBL_NLTYPE_NONE              0

net/netlabel/netlabel_kapi.c

@@ -312,7 +312,7 @@ int netlbl_sock_setattr(struct sock *sk,
  * @secattr: the security attributes
  *
  * Description:
- * Examines the given sock to see any NetLabel style labeling has been
+ * Examines the given sock to see if any NetLabel style labeling has been
  * applied to the sock, if so it parses the socket label and returns the
  * security attributes in @secattr.  Returns zero on success, negative values
  * on failure.
@@ -320,13 +320,7 @@ int netlbl_sock_setattr(struct sock *sk,
  */
 int netlbl_sock_getattr(struct sock *sk, struct netlbl_lsm_secattr *secattr)
 {
-	int ret_val;
-
-	ret_val = cipso_v4_sock_getattr(sk, secattr);
-	if (ret_val == 0)
-		return 0;
-
-	return netlbl_unlabel_getattr(secattr);
+	return cipso_v4_sock_getattr(sk, secattr);
 }
 
 /**
@@ -350,7 +344,7 @@ int netlbl_skbuff_getattr(const struct sk_buff *skb,
 	    cipso_v4_skbuff_getattr(skb, secattr) == 0)
 		return 0;
 
-	return netlbl_unlabel_getattr(secattr);
+	return netlbl_unlabel_getattr(skb, family, secattr);
 }
 
 /**
@@ -434,6 +428,10 @@ static int __init netlbl_init(void)
 	if (ret_val != 0)
 		goto init_failure;
 
+	ret_val = netlbl_unlabel_init(NETLBL_UNLHSH_BITSIZE);
+	if (ret_val != 0)
+		goto init_failure;
+
 	ret_val = netlbl_netlink_init();
 	if (ret_val != 0)
 		goto init_failure;

net/netlabel/netlabel_unlabeled.h

@@ -36,6 +36,116 @@
 /*
  * The following NetLabel payloads are supported by the Unlabeled subsystem.
  *
+ * o STATICADD
+ *   This message is sent from an application to add a new static label for
+ *   incoming unlabeled connections.
+ *
+ *   Required attributes:
+ *
+ *     NLBL_UNLABEL_A_IFACE
+ *     NLBL_UNLABEL_A_SECCTX
+ *
+ *   If IPv4 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV4ADDR
+ *     NLBL_UNLABEL_A_IPV4MASK
+ *
+ *   If IPv6 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV6ADDR
+ *     NLBL_UNLABEL_A_IPV6MASK
+ *
+ * o STATICREMOVE
+ *   This message is sent from an application to remove an existing static
+ *   label for incoming unlabeled connections.
+ *
+ *   Required attributes:
+ *
+ *     NLBL_UNLABEL_A_IFACE
+ *
+ *   If IPv4 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV4ADDR
+ *     NLBL_UNLABEL_A_IPV4MASK
+ *
+ *   If IPv6 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV6ADDR
+ *     NLBL_UNLABEL_A_IPV6MASK
+ *
+ * o STATICLIST
+ *   This message can be sent either from an application or by the kernel in
+ *   response to an application generated STATICLIST message.  When sent by an
+ *   application there is no payload and the NLM_F_DUMP flag should be set.
+ *   The kernel should response with a series of the following messages.
+ *
+ *   Required attributes:
+ *
+ *     NLBL_UNLABEL_A_IFACE
+ *     NLBL_UNLABEL_A_SECCTX
+ *
+ *   If IPv4 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV4ADDR
+ *     NLBL_UNLABEL_A_IPV4MASK
+ *
+ *   If IPv6 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV6ADDR
+ *     NLBL_UNLABEL_A_IPV6MASK
+ *
+ * o STATICADDDEF
+ *   This message is sent from an application to set the default static
+ *   label for incoming unlabeled connections.
+ *
+ *   Required attribute:
+ *
+ *     NLBL_UNLABEL_A_SECCTX
+ *
+ *   If IPv4 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV4ADDR
+ *     NLBL_UNLABEL_A_IPV4MASK
+ *
+ *   If IPv6 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV6ADDR
+ *     NLBL_UNLABEL_A_IPV6MASK
+ *
+ * o STATICREMOVEDEF
+ *   This message is sent from an application to remove the existing default
+ *   static label for incoming unlabeled connections.
+ *
+ *   If IPv4 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV4ADDR
+ *     NLBL_UNLABEL_A_IPV4MASK
+ *
+ *   If IPv6 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV6ADDR
+ *     NLBL_UNLABEL_A_IPV6MASK
+ *
+ * o STATICLISTDEF
+ *   This message can be sent either from an application or by the kernel in
+ *   response to an application generated STATICLISTDEF message.  When sent by
+ *   an application there is no payload and the NLM_F_DUMP flag should be set.
+ *   The kernel should response with the following message.
+ *
+ *   Required attribute:
+ *
+ *     NLBL_UNLABEL_A_SECCTX
+ *
+ *   If IPv4 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV4ADDR
+ *     NLBL_UNLABEL_A_IPV4MASK
+ *
+ *   If IPv6 is specified the following attributes are required:
+ *
+ *     NLBL_UNLABEL_A_IPV6ADDR
+ *     NLBL_UNLABEL_A_IPV6MASK
+ *
  * o ACCEPT
  *   This message is sent from an application to specify if the kernel should
  *   allow unlabled packets to pass if they do not match any of the static
@@ -62,6 +172,12 @@ enum {
 	NLBL_UNLABEL_C_UNSPEC,
 	NLBL_UNLABEL_C_ACCEPT,
 	NLBL_UNLABEL_C_LIST,
+	NLBL_UNLABEL_C_STATICADD,
+	NLBL_UNLABEL_C_STATICREMOVE,
+	NLBL_UNLABEL_C_STATICLIST,
+	NLBL_UNLABEL_C_STATICADDDEF,
+	NLBL_UNLABEL_C_STATICREMOVEDEF,
+	NLBL_UNLABEL_C_STATICLISTDEF,
 	__NLBL_UNLABEL_C_MAX,
 };
 #define NLBL_UNLABEL_C_MAX (__NLBL_UNLABEL_C_MAX - 1)
@@ -73,6 +189,24 @@ enum {
 	/* (NLA_U8)
 	 * if true then unlabeled packets are allowed to pass, else unlabeled
 	 * packets are rejected */
+	NLBL_UNLABEL_A_IPV6ADDR,
+	/* (NLA_BINARY, struct in6_addr)
+	 * an IPv6 address */
+	NLBL_UNLABEL_A_IPV6MASK,
+	/* (NLA_BINARY, struct in6_addr)
+	 * an IPv6 address mask */
+	NLBL_UNLABEL_A_IPV4ADDR,
+	/* (NLA_BINARY, struct in_addr)
+	 * an IPv4 address */
+	NLBL_UNLABEL_A_IPV4MASK,
+	/* (NLA_BINARY, struct in_addr)
+	 * and IPv4 address mask */
+	NLBL_UNLABEL_A_IFACE,
+	/* (NLA_NULL_STRING)
+	 * network interface */
+	NLBL_UNLABEL_A_SECCTX,
+	/* (NLA_BINARY)
+	 * a LSM specific security context */
 	__NLBL_UNLABEL_A_MAX,
 };
 #define NLBL_UNLABEL_A_MAX (__NLBL_UNLABEL_A_MAX - 1)
@@ -80,8 +214,17 @@ enum {
 /* NetLabel protocol functions */
 int netlbl_unlabel_genl_init(void);
 
+/* Unlabeled connection hash table size */
+/* XXX - currently this number is an uneducated guess */
+#define NETLBL_UNLHSH_BITSIZE       7
+
+/* General Unlabeled init function */
+int netlbl_unlabel_init(u32 size);
+
 /* Process Unlabeled incoming network packets */
-int netlbl_unlabel_getattr(struct netlbl_lsm_secattr *secattr);
+int netlbl_unlabel_getattr(const struct sk_buff *skb,
+			   u16 family,
+			   struct netlbl_lsm_secattr *secattr);
 
 /* Set the default configuration to allow Unlabeled packets */
 int netlbl_unlabel_defconf(void);