M7350v1_en_gpl

kernel/security/smack/Kconfig

@@ -0,0 +1,10 @@
+config SECURITY_SMACK
+	bool "Simplified Mandatory Access Control Kernel Support"
+	depends on NETLABEL && 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.
+

kernel/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

kernel/security/smack/smack.h

@@ -0,0 +1,394 @@
+/*
+ * 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>
+
+/*
+ * 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_MAXLEN	23
+#define SMK_LABELLEN	(SMK_MAXLEN+1)
+
+struct superblock_smack {
+	char		*smk_root;
+	char		*smk_floor;
+	char		*smk_hat;
+	char		*smk_default;
+	int		smk_initialized;
+	spinlock_t	smk_sblock;	/* for initialization */
+};
+
+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 */
+
+/*
+ * 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 mapping smack values to
+ * CIPSO level/category-set values.
+ */
+struct smack_cipso {
+	int	smk_level;
+	char	smk_catset[SMK_LABELLEN];
+};
+
+/*
+ * 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.
+ *
+ * If there is a cipso value associated with the label it
+ * gets stored here, too. This will most likely be rare as
+ * the cipso direct mapping in used internally.
+ *
+ * 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[SMK_LABELLEN];
+	u32			smk_secid;
+	struct smack_cipso	*smk_cipso;
+	spinlock_t		smk_cipsolock;	/* for changing cipso map */
+	struct list_head	smk_rules;	/* access rules */
+	struct mutex		smk_rules_lock;	/* lock for the 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
+
+/*
+ * smackfs magic number
+ */
+#define SMACK_MAGIC	0x43415d53 /* "SMAC" */
+
+/*
+ * 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_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 *);
+int smack_to_cipso(const char *, struct smack_cipso *);
+char *smack_from_cipso(u32, char *);
+char *smack_from_secid(const u32);
+void smk_parse_smack(const char *string, int len, char *smack);
+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 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 list_head smack_known_list;
+extern struct list_head smk_netlbladdr_list;
+
+extern struct security_operations smack_ops;
+
+/*
+ * Stricly for CIPSO level manipulation.
+ * Set the category bit number in a smack label sized buffer.
+ */
+static inline void smack_catset_bit(int cat, char *catsetp)
+{
+	if (cat > SMK_LABELLEN * 8)
+		return;
+
+	catsetp[(cat - 1) / 8] |= 0x80 >> ((cat - 1) % 8);
+}
+
+/*
+ * 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());
+}
+
+/*
+ * 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, 0, sizeof(*a));
+	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 */

kernel/security/smack/smack_access.c

@@ -0,0 +1,557 @@
+/*
+ * 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,
+	.smk_cipso	= NULL,
+};
+
+struct smack_known smack_known_hat = {
+	.smk_known	= "^",
+	.smk_secid	= 3,
+	.smk_cipso	= NULL,
+};
+
+struct smack_known smack_known_star = {
+	.smk_known	= "*",
+	.smk_secid	= 4,
+	.smk_cipso	= NULL,
+};
+
+struct smack_known smack_known_floor = {
+	.smk_known	= "_",
+	.smk_secid	= 5,
+	.smk_cipso	= NULL,
+};
+
+struct smack_known smack_known_invalid = {
+	.smk_known	= "",
+	.smk_secid	= 6,
+	.smk_cipso	= NULL,
+};
+
+struct smack_known smack_known_web = {
+	.smk_known	= "@",
+	.smk_secid	= 7,
+	.smk_cipso	= NULL,
+};
+
+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;
+	}
+
+	/*
+	 * Return if a specific label has been designated as the
+	 * only one that gets privilege and current does not
+	 * have that label.
+	 */
+	if (smack_onlycap != NULL && smack_onlycap != sp)
+		goto out_audit;
+
+	if (capable(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';
+	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
+
+static 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 (strncmp(skp->smk_known, string, SMK_MAXLEN) == 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.
+ * @smack: parsed smack label, or NULL if parse error
+ */
+void smk_parse_smack(const char *string, int len, char *smack)
+{
+	int found;
+	int i;
+
+	if (len <= 0 || len > SMK_MAXLEN)
+		len = SMK_MAXLEN;
+
+	for (i = 0, found = 0; i < SMK_LABELLEN; i++) {
+		if (found)
+			smack[i] = '\0';
+		else if (i >= len || string[i] > '~' || string[i] <= ' ' ||
+			 string[i] == '/' || string[i] == '"' ||
+			 string[i] == '\\' || string[i] == '\'') {
+			smack[i] = '\0';
+			found = 1;
+		} else
+			smack[i] = string[i];
+	}
+}
+
+/**
+ * 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[SMK_LABELLEN];
+
+	smk_parse_smack(string, len, smack);
+	if (smack[0] == '\0')
+		return NULL;
+
+	mutex_lock(&smack_known_lock);
+
+	skp = smk_find_entry(smack);
+
+	if (skp == NULL) {
+		skp = kzalloc(sizeof(struct smack_known), GFP_KERNEL);
+		if (skp != NULL) {
+			strncpy(skp->smk_known, smack, SMK_MAXLEN);
+			skp->smk_secid = smack_next_secid++;
+			skp->smk_cipso = NULL;
+			INIT_LIST_HEAD(&skp->smk_rules);
+			spin_lock_init(&skp->smk_cipsolock);
+			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);
+		}
+	}
+
+	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;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(skp, &smack_known_list, list) {
+		if (strncmp(skp->smk_known, smack, SMK_MAXLEN) == 0) {
+			rcu_read_unlock();
+			return skp->smk_secid;
+		}
+	}
+	rcu_read_unlock();
+	return 0;
+}
+
+/**
+ * smack_from_cipso - find the Smack label associated with a CIPSO option
+ * @level: Bell & LaPadula level from the network
+ * @cp: Bell & LaPadula categories from the network
+ *
+ * This is a simple lookup in the label table.
+ *
+ * Return the matching label from the label list or NULL.
+ */
+char *smack_from_cipso(u32 level, char *cp)
+{
+	struct smack_known *kp;
+	char *final = NULL;
+
+	rcu_read_lock();
+	list_for_each_entry(kp, &smack_known_list, list) {
+		if (kp->smk_cipso == NULL)
+			continue;
+
+		spin_lock_bh(&kp->smk_cipsolock);
+
+		if (kp->smk_cipso->smk_level == level &&
+		    memcmp(kp->smk_cipso->smk_catset, cp, SMK_LABELLEN) == 0)
+			final = kp->smk_known;
+
+		spin_unlock_bh(&kp->smk_cipsolock);
+
+		if (final != NULL)
+			break;
+	}
+	rcu_read_unlock();
+
+	return final;
+}
+
+/**
+ * smack_to_cipso - find the CIPSO option to go with a Smack label
+ * @smack: a pointer to the smack label in question
+ * @cp: where to put the result
+ *
+ * Returns zero if a value is available, non-zero otherwise.
+ */
+int smack_to_cipso(const char *smack, struct smack_cipso *cp)
+{
+	struct smack_known *kp;
+	int found = 0;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(kp, &smack_known_list, list) {
+		if (kp->smk_known == smack ||
+		    strcmp(kp->smk_known, smack) == 0) {
+			found = 1;
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	if (found == 0 || kp->smk_cipso == NULL)
+		return -ENOENT;
+
+	memcpy(cp, kp->smk_cipso, sizeof(struct smack_cipso));
+	return 0;
+}