Initial commit; kernel source import

security/smack/Kconfig

@@ -0,0 +1,14 @@
+config SECURITY_SMACK
+	bool "Simplified Mandatory Access Control Kernel Support"
+	depends on NET
+	depends on INET
+	depends on SECURITY
+	select NETLABEL
+	select SECURITY_NETWORK
+	default n
+	help
+	  This selects the Simplified Mandatory Access Control Kernel.
+	  Smack is useful for sensitivity, integrity, and a variety
+	  of other mandatory security schemes.
+	  If you are unsure how to answer this question, answer N.
+

security/smack/Makefile

@@ -0,0 +1,7 @@
+#
+# Makefile for the SMACK LSM
+#
+
+obj-$(CONFIG_SECURITY_SMACK) := smack.o
+
+smack-y := smack_lsm.o smack_access.o smackfs.o

security/smack/smack.h

@@ -0,0 +1,386 @@
+/*
+ * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
+ *
+ *      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, version 2.
+ *
+ * Author:
+ *      Casey Schaufler <casey@schaufler-ca.com>
+ *
+ */
+
+#ifndef _SECURITY_SMACK_H
+#define _SECURITY_SMACK_H
+
+#include <linux/capability.h>
+#include <linux/spinlock.h>
+#include <linux/security.h>
+#include <linux/in.h>
+#include <net/netlabel.h>
+#include <linux/list.h>
+#include <linux/rculist.h>
+#include <linux/lsm_audit.h>
+
+/*
+ * Smack labels were limited to 23 characters for a long time.
+ */
+#define SMK_LABELLEN	24
+#define SMK_LONGLABEL	256
+
+/*
+ * Maximum number of bytes for the levels in a CIPSO IP option.
+ * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
+ * bigger than can be used, and 24 is the next lower multiple
+ * of 8, and there are too many issues if there isn't space set
+ * aside for the terminating null byte.
+ */
+#define SMK_CIPSOLEN	24
+
+struct superblock_smack {
+	char		*smk_root;
+	char		*smk_floor;
+	char		*smk_hat;
+	char		*smk_default;
+	int		smk_initialized;
+};
+
+struct socket_smack {
+	char		*smk_out;	/* outbound label */
+	char		*smk_in;	/* inbound label */
+	char		*smk_packet;	/* TCP peer label */
+};
+
+/*
+ * Inode smack data
+ */
+struct inode_smack {
+	char		*smk_inode;	/* label of the fso */
+	char		*smk_task;	/* label of the task */
+	char		*smk_mmap;	/* label of the mmap domain */
+	struct mutex	smk_lock;	/* initialization lock */
+	int		smk_flags;	/* smack inode flags */
+};
+
+struct task_smack {
+	char			*smk_task;	/* label for access control */
+	char			*smk_forked;	/* label when forked */
+	struct list_head	smk_rules;	/* per task access rules */
+	struct mutex		smk_rules_lock;	/* lock for the rules */
+};
+
+#define	SMK_INODE_INSTANT	0x01	/* inode is instantiated */
+#define	SMK_INODE_TRANSMUTE	0x02	/* directory is transmuting */
+#define	SMK_INODE_CHANGED	0x04	/* smack was transmuted */
+
+/*
+ * A label access rule.
+ */
+struct smack_rule {
+	struct list_head	list;
+	char			*smk_subject;
+	char			*smk_object;
+	int			smk_access;
+};
+
+/*
+ * An entry in the table identifying hosts.
+ */
+struct smk_netlbladdr {
+	struct list_head	list;
+	struct sockaddr_in	smk_host;	/* network address */
+	struct in_addr		smk_mask;	/* network mask */
+	char			*smk_label;	/* label */
+};
+
+/*
+ * This is the repository for labels seen so that it is
+ * not necessary to keep allocating tiny chuncks of memory
+ * and so that they can be shared.
+ *
+ * Labels are never modified in place. Anytime a label
+ * is imported (e.g. xattrset on a file) the list is checked
+ * for it and it is added if it doesn't exist. The address
+ * is passed out in either case. Entries are added, but
+ * never deleted.
+ *
+ * Since labels are hanging around anyway it doesn't
+ * hurt to maintain a secid for those awkward situations
+ * where kernel components that ought to use LSM independent
+ * interfaces don't. The secid should go away when all of
+ * these components have been repaired.
+ *
+ * The cipso value associated with the label gets stored here, too.
+ *
+ * Keep the access rules for this subject label here so that
+ * the entire set of rules does not need to be examined every
+ * time.
+ */
+struct smack_known {
+	struct list_head		list;
+	char				*smk_known;
+	u32				smk_secid;
+	struct netlbl_lsm_secattr	smk_netlabel;	/* on wire labels */
+	struct list_head		smk_rules;	/* access rules */
+	struct mutex			smk_rules_lock;	/* lock for rules */
+};
+
+/*
+ * Mount options
+ */
+#define SMK_FSDEFAULT	"smackfsdef="
+#define SMK_FSFLOOR	"smackfsfloor="
+#define SMK_FSHAT	"smackfshat="
+#define SMK_FSROOT	"smackfsroot="
+
+#define SMACK_CIPSO_OPTION 	"-CIPSO"
+
+/*
+ * How communications on this socket are treated.
+ * Usually it's determined by the underlying netlabel code
+ * but there are certain cases, including single label hosts
+ * and potentially single label interfaces for which the
+ * treatment can not be known in advance.
+ *
+ * The possibility of additional labeling schemes being
+ * introduced in the future exists as well.
+ */
+#define SMACK_UNLABELED_SOCKET	0
+#define SMACK_CIPSO_SOCKET	1
+
+/*
+ * CIPSO defaults.
+ */
+#define SMACK_CIPSO_DOI_DEFAULT		3	/* Historical */
+#define SMACK_CIPSO_DOI_INVALID		-1	/* Not a DOI */
+#define SMACK_CIPSO_DIRECT_DEFAULT	250	/* Arbitrary */
+#define SMACK_CIPSO_MAPPED_DEFAULT	251	/* Also arbitrary */
+#define SMACK_CIPSO_MAXCATVAL		63	/* Bigger gets harder */
+#define SMACK_CIPSO_MAXLEVEL            255     /* CIPSO 2.2 standard */
+#define SMACK_CIPSO_MAXCATNUM           239     /* CIPSO 2.2 standard */
+
+/*
+ * Flag for transmute access
+ */
+#define MAY_TRANSMUTE	64
+/*
+ * Just to make the common cases easier to deal with
+ */
+#define MAY_ANYREAD	(MAY_READ | MAY_EXEC)
+#define MAY_READWRITE	(MAY_READ | MAY_WRITE)
+#define MAY_NOT		0
+
+/*
+ * Number of access types used by Smack (rwxat)
+ */
+#define SMK_NUM_ACCESS_TYPE 5
+
+/* SMACK data */
+struct smack_audit_data {
+	const char *function;
+	char *subject;
+	char *object;
+	char *request;
+	int result;
+};
+
+/*
+ * Smack audit data; is empty if CONFIG_AUDIT not set
+ * to save some stack
+ */
+struct smk_audit_info {
+#ifdef CONFIG_AUDIT
+	struct common_audit_data a;
+	struct smack_audit_data sad;
+#endif
+};
+/*
+ * These functions are in smack_lsm.c
+ */
+struct inode_smack *new_inode_smack(char *);
+
+/*
+ * These functions are in smack_access.c
+ */
+int smk_access_entry(char *, char *, struct list_head *);
+int smk_access(char *, char *, int, struct smk_audit_info *);
+int smk_curacc(char *, u32, struct smk_audit_info *);
+char *smack_from_secid(const u32);
+char *smk_parse_smack(const char *string, int len);
+int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
+char *smk_import(const char *, int);
+struct smack_known *smk_import_entry(const char *, int);
+struct smack_known *smk_find_entry(const char *);
+u32 smack_to_secid(const char *);
+
+/*
+ * Shared data.
+ */
+extern int smack_cipso_direct;
+extern int smack_cipso_mapped;
+extern char *smack_net_ambient;
+extern char *smack_onlycap;
+extern const char *smack_cipso_option;
+
+extern struct smack_known smack_known_floor;
+extern struct smack_known smack_known_hat;
+extern struct smack_known smack_known_huh;
+extern struct smack_known smack_known_invalid;
+extern struct smack_known smack_known_star;
+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 security_operations smack_ops;
+
+/*
+ * Is the directory transmuting?
+ */
+static inline int smk_inode_transmutable(const struct inode *isp)
+{
+	struct inode_smack *sip = isp->i_security;
+	return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
+}
+
+/*
+ * Present a pointer to the smack label in an inode blob.
+ */
+static inline char *smk_of_inode(const struct inode *isp)
+{
+	struct inode_smack *sip = isp->i_security;
+	return sip->smk_inode;
+}
+
+/*
+ * Present a pointer to the smack label in an task blob.
+ */
+static inline char *smk_of_task(const struct task_smack *tsp)
+{
+	return tsp->smk_task;
+}
+
+/*
+ * Present a pointer to the forked smack label in an task blob.
+ */
+static inline char *smk_of_forked(const struct task_smack *tsp)
+{
+	return tsp->smk_forked;
+}
+
+/*
+ * Present a pointer to the smack label in the current task blob.
+ */
+static inline char *smk_of_current(void)
+{
+	return smk_of_task(current_security());
+}
+
+/*
+ * Is the task privileged and allowed to be privileged
+ * by the onlycap rule.
+ */
+static inline int smack_privileged(int cap)
+{
+	if (!capable(cap))
+		return 0;
+	if (smack_onlycap == NULL || smack_onlycap == smk_of_current())
+		return 1;
+	return 0;
+}
+
+/*
+ * logging functions
+ */
+#define SMACK_AUDIT_DENIED 0x1
+#define SMACK_AUDIT_ACCEPT 0x2
+extern int log_policy;
+
+void smack_log(char *subject_label, char *object_label,
+		int request,
+		int result, struct smk_audit_info *auditdata);
+
+#ifdef CONFIG_AUDIT
+
+/*
+ * some inline functions to set up audit data
+ * they do nothing if CONFIG_AUDIT is not set
+ *
+ */
+static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
+			       char type)
+{
+	memset(&a->sad, 0, sizeof(a->sad));
+	a->a.type = type;
+	a->a.smack_audit_data = &a->sad;
+	a->a.smack_audit_data->function = func;
+}
+
+static inline void smk_ad_init_net(struct smk_audit_info *a, const char *func,
+				   char type, struct lsm_network_audit *net)
+{
+	smk_ad_init(a, func, type);
+	memset(net, 0, sizeof(*net));
+	a->a.u.net = net;
+}
+
+static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
+					 struct task_struct *t)
+{
+	a->a.u.tsk = t;
+}
+static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
+						    struct dentry *d)
+{
+	a->a.u.dentry = d;
+}
+static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
+					      struct inode *i)
+{
+	a->a.u.inode = i;
+}
+static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
+					     struct path p)
+{
+	a->a.u.path = p;
+}
+static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
+					    struct sock *sk)
+{
+	a->a.u.net->sk = sk;
+}
+
+#else /* no AUDIT */
+
+static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
+			       char type)
+{
+}
+static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,
+					 struct task_struct *t)
+{
+}
+static inline void smk_ad_setfield_u_fs_path_dentry(struct smk_audit_info *a,
+						    struct dentry *d)
+{
+}
+static inline void smk_ad_setfield_u_fs_path_mnt(struct smk_audit_info *a,
+						 struct vfsmount *m)
+{
+}
+static inline void smk_ad_setfield_u_fs_inode(struct smk_audit_info *a,
+					      struct inode *i)
+{
+}
+static inline void smk_ad_setfield_u_fs_path(struct smk_audit_info *a,
+					     struct path p)
+{
+}
+static inline void smk_ad_setfield_u_net_sk(struct smk_audit_info *a,
+					    struct sock *sk)
+{
+}
+#endif
+
+#endif  /* _SECURITY_SMACK_H */

security/smack/smack_access.c

@@ -0,0 +1,553 @@
+/*
+ * Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
+ *
+ *      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, version 2.
+ *
+ * Author:
+ *      Casey Schaufler <casey@schaufler-ca.com>
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include "smack.h"
+
+struct smack_known smack_known_huh = {
+	.smk_known	= "?",
+	.smk_secid	= 2,
+};
+
+struct smack_known smack_known_hat = {
+	.smk_known	= "^",
+	.smk_secid	= 3,
+};
+
+struct smack_known smack_known_star = {
+	.smk_known	= "*",
+	.smk_secid	= 4,
+};
+
+struct smack_known smack_known_floor = {
+	.smk_known	= "_",
+	.smk_secid	= 5,
+};
+
+struct smack_known smack_known_invalid = {
+	.smk_known	= "",
+	.smk_secid	= 6,
+};
+
+struct smack_known smack_known_web = {
+	.smk_known	= "@",
+	.smk_secid	= 7,
+};
+
+LIST_HEAD(smack_known_list);
+
+/*
+ * The initial value needs to be bigger than any of the
+ * known values above.
+ */
+static u32 smack_next_secid = 10;
+
+/*
+ * what events do we log
+ * can be overwritten at run-time by /smack/logging
+ */
+int log_policy = SMACK_AUDIT_DENIED;
+
+/**
+ * smk_access_entry - look up matching access rule
+ * @subject_label: a pointer to the subject's Smack label
+ * @object_label: a pointer to the object's Smack label
+ * @rule_list: the list of rules to search
+ *
+ * This function looks up the subject/object pair in the
+ * access rule list and returns the access mode. If no
+ * entry is found returns -ENOENT.
+ *
+ * NOTE:
+ *
+ * Earlier versions of this function allowed for labels that
+ * were not on the label list. This was done to allow for
+ * labels to come over the network that had never been seen
+ * before on this host. Unless the receiving socket has the
+ * star label this will always result in a failure check. The
+ * star labeled socket case is now handled in the networking
+ * hooks so there is no case where the label is not on the
+ * label list. Checking to see if the address of two labels
+ * is the same is now a reliable test.
+ *
+ * Do the object check first because that is more
+ * likely to differ.
+ */
+int smk_access_entry(char *subject_label, char *object_label,
+			struct list_head *rule_list)
+{
+	int may = -ENOENT;
+	struct smack_rule *srp;
+
+	list_for_each_entry_rcu(srp, rule_list, list) {
+		if (srp->smk_object == object_label &&
+		    srp->smk_subject == subject_label) {
+			may = srp->smk_access;
+			break;
+		}
+	}
+
+	return may;
+}
+
+/**
+ * smk_access - determine if a subject has a specific access to an object
+ * @subject_label: a pointer to the subject's Smack label
+ * @object_label: a pointer to the object's Smack label
+ * @request: the access requested, in "MAY" format
+ * @a : a pointer to the audit data
+ *
+ * This function looks up the subject/object pair in the
+ * access rule list and returns 0 if the access is permitted,
+ * non zero otherwise.
+ *
+ * Smack labels are shared on smack_list
+ */
+int smk_access(char *subject_label, char *object_label, int request,
+	       struct smk_audit_info *a)
+{
+	struct smack_known *skp;
+	int may = MAY_NOT;
+	int rc = 0;
+
+	/*
+	 * Hardcoded comparisons.
+	 *
+	 * A star subject can't access any object.
+	 */
+	if (subject_label == smack_known_star.smk_known) {
+		rc = -EACCES;
+		goto out_audit;
+	}
+	/*
+	 * An internet object can be accessed by any subject.
+	 * Tasks cannot be assigned the internet label.
+	 * An internet subject can access any object.
+	 */
+	if (object_label == smack_known_web.smk_known ||
+	    subject_label == smack_known_web.smk_known)
+		goto out_audit;
+	/*
+	 * A star object can be accessed by any subject.
+	 */
+	if (object_label == smack_known_star.smk_known)
+		goto out_audit;
+	/*
+	 * An object can be accessed in any way by a subject
+	 * with the same label.
+	 */
+	if (subject_label == object_label)
+		goto out_audit;
+	/*
+	 * A hat subject can read any object.
+	 * A floor object can be read by any subject.
+	 */
+	if ((request & MAY_ANYREAD) == request) {
+		if (object_label == smack_known_floor.smk_known)
+			goto out_audit;
+		if (subject_label == smack_known_hat.smk_known)
+			goto out_audit;
+	}
+	/*
+	 * Beyond here an explicit relationship is required.
+	 * If the requested access is contained in the available
+	 * access (e.g. read is included in readwrite) it's
+	 * good. A negative response from smk_access_entry()
+	 * indicates there is no entry for this pair.
+	 */
+	skp = smk_find_entry(subject_label);
+	rcu_read_lock();
+	may = smk_access_entry(subject_label, object_label, &skp->smk_rules);
+	rcu_read_unlock();
+
+	if (may > 0 && (request & may) == request)
+		goto out_audit;
+
+	rc = -EACCES;
+out_audit:
+#ifdef CONFIG_AUDIT
+	if (a)
+		smack_log(subject_label, object_label, request, rc, a);
+#endif
+	return rc;
+}
+
+/**
+ * smk_curacc - determine if current has a specific access to an object
+ * @obj_label: a pointer to the object's Smack label
+ * @mode: the access requested, in "MAY" format
+ * @a : common audit data
+ *
+ * This function checks the current subject label/object label pair
+ * in the access rule list and returns 0 if the access is permitted,
+ * non zero otherwise. It allows that current may have the capability
+ * to override the rules.
+ */
+int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a)
+{
+	struct task_smack *tsp = current_security();
+	char *sp = smk_of_task(tsp);
+	int may;
+	int rc;
+
+	/*
+	 * Check the global rule list
+	 */
+	rc = smk_access(sp, obj_label, mode, NULL);
+	if (rc == 0) {
+		/*
+		 * If there is an entry in the task's rule list
+		 * it can further restrict access.
+		 */
+		may = smk_access_entry(sp, obj_label, &tsp->smk_rules);
+		if (may < 0)
+			goto out_audit;
+		if ((mode & may) == mode)
+			goto out_audit;
+		rc = -EACCES;
+	}
+
+	/*
+	 * Allow for priviliged to override policy.
+	 */
+	if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
+		rc = 0;
+
+out_audit:
+#ifdef CONFIG_AUDIT
+	if (a)
+		smack_log(sp, obj_label, mode, rc, a);
+#endif
+	return rc;
+}
+
+#ifdef CONFIG_AUDIT
+/**
+ * smack_str_from_perm : helper to transalate an int to a
+ * readable string
+ * @string : the string to fill
+ * @access : the int
+ *
+ */
+static inline void smack_str_from_perm(char *string, int access)
+{
+	int i = 0;
+	if (access & MAY_READ)
+		string[i++] = 'r';
+	if (access & MAY_WRITE)
+		string[i++] = 'w';
+	if (access & MAY_EXEC)
+		string[i++] = 'x';
+	if (access & MAY_APPEND)
+		string[i++] = 'a';
+	if (access & MAY_TRANSMUTE)
+		string[i++] = 't';
+	string[i] = '\0';
+}
+/**
+ * smack_log_callback - SMACK specific information
+ * will be called by generic audit code
+ * @ab : the audit_buffer
+ * @a  : audit_data
+ *
+ */
+static void smack_log_callback(struct audit_buffer *ab, void *a)
+{
+	struct common_audit_data *ad = a;
+	struct smack_audit_data *sad = ad->smack_audit_data;
+	audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
+			 ad->smack_audit_data->function,
+			 sad->result ? "denied" : "granted");
+	audit_log_format(ab, " subject=");
+	audit_log_untrustedstring(ab, sad->subject);
+	audit_log_format(ab, " object=");
+	audit_log_untrustedstring(ab, sad->object);
+	audit_log_format(ab, " requested=%s", sad->request);
+}
+
+/**
+ *  smack_log - Audit the granting or denial of permissions.
+ *  @subject_label : smack label of the requester
+ *  @object_label  : smack label of the object being accessed
+ *  @request: requested permissions
+ *  @result: result from smk_access
+ *  @a:  auxiliary audit data
+ *
+ * Audit the granting or denial of permissions in accordance
+ * with the policy.
+ */
+void smack_log(char *subject_label, char *object_label, int request,
+	       int result, struct smk_audit_info *ad)
+{
+	char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
+	struct smack_audit_data *sad;
+	struct common_audit_data *a = &ad->a;
+
+	/* check if we have to log the current event */
+	if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
+		return;
+	if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
+		return;
+
+	sad = a->smack_audit_data;
+
+	if (sad->function == NULL)
+		sad->function = "unknown";
+
+	/* end preparing the audit data */
+	smack_str_from_perm(request_buffer, request);
+	sad->subject = subject_label;
+	sad->object  = object_label;
+	sad->request = request_buffer;
+	sad->result  = result;
+
+	common_lsm_audit(a, smack_log_callback, NULL);
+}
+#else /* #ifdef CONFIG_AUDIT */
+void smack_log(char *subject_label, char *object_label, int request,
+               int result, struct smk_audit_info *ad)
+{
+}
+#endif
+
+DEFINE_MUTEX(smack_known_lock);
+
+/**
+ * smk_find_entry - find a label on the list, return the list entry
+ * @string: a text string that might be a Smack label
+ *
+ * Returns a pointer to the entry in the label list that
+ * matches the passed string.
+ */
+struct smack_known *smk_find_entry(const char *string)
+{
+	struct smack_known *skp;
+
+	list_for_each_entry_rcu(skp, &smack_known_list, list) {
+		if (strcmp(skp->smk_known, string) == 0)
+			return skp;
+	}
+
+	return NULL;
+}
+
+/**
+ * smk_parse_smack - parse smack label from a text string
+ * @string: a text string that might contain a Smack label
+ * @len: the maximum size, or zero if it is NULL terminated.
+ *
+ * Returns a pointer to the clean label, or NULL
+ */
+char *smk_parse_smack(const char *string, int len)
+{
+	char *smack;
+	int i;
+
+	if (len <= 0)
+		len = strlen(string) + 1;
+
+	/*
+	 * Reserve a leading '-' as an indicator that
+	 * this isn't a label, but an option to interfaces
+	 * including /smack/cipso and /smack/cipso2
+	 */
+	if (string[0] == '-')
+		return NULL;
+
+	for (i = 0; i < len; i++)
+		if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
+		    string[i] == '"' || string[i] == '\\' || string[i] == '\'')
+			break;
+
+	if (i == 0 || i >= SMK_LONGLABEL)
+		return NULL;
+
+	smack = kzalloc(i + 1, GFP_KERNEL);
+	if (smack != NULL) {
+		strncpy(smack, string, i + 1);
+		smack[i] = '\0';
+	}
+	return smack;
+}
+
+/**
+ * smk_netlbl_mls - convert a catset to netlabel mls categories
+ * @catset: the Smack categories
+ * @sap: where to put the netlabel categories
+ *
+ * Allocates and fills attr.mls
+ * Returns 0 on success, error code on failure.
+ */
+int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
+			int len)
+{
+	unsigned char *cp;
+	unsigned char m;
+	int cat;
+	int rc;
+	int byte;
+
+	sap->flags |= NETLBL_SECATTR_MLS_CAT;
+	sap->attr.mls.lvl = level;
+	sap->attr.mls.cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
+	sap->attr.mls.cat->startbit = 0;
+
+	for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
+		for (m = 0x80; m != 0; m >>= 1, cat++) {
+			if ((m & *cp) == 0)
+				continue;
+			rc = netlbl_secattr_catmap_setbit(sap->attr.mls.cat,
+							  cat, GFP_ATOMIC);
+			if (rc < 0) {
+				netlbl_secattr_catmap_free(sap->attr.mls.cat);
+				return rc;
+			}
+		}
+
+	return 0;
+}
+
+/**
+ * smk_import_entry - import a label, return the list entry
+ * @string: a text string that might be a Smack label
+ * @len: the maximum size, or zero if it is NULL terminated.
+ *
+ * Returns a pointer to the entry in the label list that
+ * matches the passed string, adding it if necessary.
+ */
+struct smack_known *smk_import_entry(const char *string, int len)
+{
+	struct smack_known *skp;
+	char *smack;
+	int slen;
+	int rc;
+
+	smack = smk_parse_smack(string, len);
+	if (smack == NULL)
+		return NULL;
+
+	mutex_lock(&smack_known_lock);
+
+	skp = smk_find_entry(smack);
+	if (skp != NULL)
+		goto freeout;
+
+	skp = kzalloc(sizeof(*skp), GFP_KERNEL);
+	if (skp == NULL)
+		goto freeout;
+
+	skp->smk_known = smack;
+	skp->smk_secid = smack_next_secid++;
+	skp->smk_netlabel.domain = skp->smk_known;
+	skp->smk_netlabel.flags =
+		NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
+	/*
+	 * If direct labeling works use it.
+	 * Otherwise use mapped labeling.
+	 */
+	slen = strlen(smack);
+	if (slen < SMK_CIPSOLEN)
+		rc = smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
+			       &skp->smk_netlabel, slen);
+	else
+		rc = smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
+			       &skp->smk_netlabel, sizeof(skp->smk_secid));
+
+	if (rc >= 0) {
+		INIT_LIST_HEAD(&skp->smk_rules);
+		mutex_init(&skp->smk_rules_lock);
+		/*
+		 * Make sure that the entry is actually
+		 * filled before putting it on the list.
+		 */
+		list_add_rcu(&skp->list, &smack_known_list);
+		goto unlockout;
+	}
+	/*
+	 * smk_netlbl_mls failed.
+	 */
+	kfree(skp);
+	skp = NULL;
+freeout:
+	kfree(smack);
+unlockout:
+	mutex_unlock(&smack_known_lock);
+
+	return skp;
+}
+
+/**
+ * smk_import - import a smack label
+ * @string: a text string that might be a Smack label
+ * @len: the maximum size, or zero if it is NULL terminated.
+ *
+ * Returns a pointer to the label in the label list that
+ * matches the passed string, adding it if necessary.
+ */
+char *smk_import(const char *string, int len)
+{
+	struct smack_known *skp;
+
+	/* labels cannot begin with a '-' */
+	if (string[0] == '-')
+		return NULL;
+	skp = smk_import_entry(string, len);
+	if (skp == NULL)
+		return NULL;
+	return skp->smk_known;
+}
+
+/**
+ * smack_from_secid - find the Smack label associated with a secid
+ * @secid: an integer that might be associated with a Smack label
+ *
+ * Returns a pointer to the appropriate Smack label if there is one,
+ * otherwise a pointer to the invalid Smack label.
+ */
+char *smack_from_secid(const u32 secid)
+{
+	struct smack_known *skp;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(skp, &smack_known_list, list) {
+		if (skp->smk_secid == secid) {
+			rcu_read_unlock();
+			return skp->smk_known;
+		}
+	}
+
+	/*
+	 * If we got this far someone asked for the translation
+	 * of a secid that is not on the list.
+	 */
+	rcu_read_unlock();
+	return smack_known_invalid.smk_known;
+}
+
+/**
+ * smack_to_secid - find the secid associated with a Smack label
+ * @smack: the Smack label
+ *
+ * Returns the appropriate secid if there is one,
+ * otherwise 0
+ */
+u32 smack_to_secid(const char *smack)
+{
+	struct smack_known *skp = smk_find_entry(smack);
+
+	if (skp == NULL)
+		return 0;
+	return skp->smk_secid;
+}