kernel/auditfilter.c - third_party/linux - Git at Google

 /* auditfilter.c -- filtering of audit events
  *
  * Copyright 2003-2004 Red Hat, Inc.
  * Copyright 2005 Hewlett-Packard Development Company, L.P.
  * Copyright 2005 IBM Corporation
  *
  * 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/kernel.h>
 #include <linux/audit.h>
 #include <linux/kthread.h>
 #include <linux/netlink.h>
 #include "audit.h"

 /* There are three lists of rules -- one to search at task creation
  * time, one to search at syscall entry time, and another to search at
  * syscall exit time. */
 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
 	LIST_HEAD_INIT(audit_filter_list[0]),
 	LIST_HEAD_INIT(audit_filter_list[1]),
 	LIST_HEAD_INIT(audit_filter_list[2]),
 	LIST_HEAD_INIT(audit_filter_list[3]),
 	LIST_HEAD_INIT(audit_filter_list[4]),
 	LIST_HEAD_INIT(audit_filter_list[5]),
 #if AUDIT_NR_FILTERS != 6
 #error Fix audit_filter_list initialiser
 #endif
 };

 static inline void audit_free_rule(struct audit_entry *e)
 {
 	kfree(e->rule.fields);
 	kfree(e);
 }

 static inline void audit_free_rule_rcu(struct rcu_head *head)
 {
 	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
 	audit_free_rule(e);
 }

 /* Unpack a filter field's string representation from user-space
  * buffer. */
 static __attribute__((unused)) char *audit_unpack_string(void **bufp, size_t *remain, size_t len)
 {
 	char *str;

 	if (!*bufp || (len == 0) || (len > *remain))
 		return ERR_PTR(-EINVAL);

 	/* Of the currently implemented string fields, PATH_MAX
 	 * defines the longest valid length.
 	 */
 	if (len > PATH_MAX)
 		return ERR_PTR(-ENAMETOOLONG);

 	str = kmalloc(len + 1, GFP_KERNEL);
 	if (unlikely(!str))
 		return ERR_PTR(-ENOMEM);

 	memcpy(str, *bufp, len);
 	str[len] = 0;
 	*bufp += len;
 	*remain -= len;

 	return str;
 }

 /* Common user-space to kernel rule translation. */
 static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule)
 {
 	unsigned listnr;
 	struct audit_entry *entry;
 	struct audit_field *fields;
 	int i, err;

 	err = -EINVAL;
 	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
 	switch(listnr) {
 	default:
 		goto exit_err;
 	case AUDIT_FILTER_USER:
 	case AUDIT_FILTER_TYPE:
 #ifdef CONFIG_AUDITSYSCALL
 	case AUDIT_FILTER_ENTRY:
 	case AUDIT_FILTER_EXIT:
 	case AUDIT_FILTER_TASK:
 #endif
 		;
 	}
 	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_POSSIBLE &&
 	    rule->action != AUDIT_ALWAYS)
 		goto exit_err;
 	if (rule->field_count > AUDIT_MAX_FIELDS)
 		goto exit_err;

 	err = -ENOMEM;
 	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 	if (unlikely(!entry))
 		goto exit_err;
 	fields = kmalloc(sizeof(*fields) * rule->field_count, GFP_KERNEL);
 	if (unlikely(!fields)) {
 		kfree(entry);
 		goto exit_err;
 	}

 	memset(&entry->rule, 0, sizeof(struct audit_krule));
 	memset(fields, 0, sizeof(struct audit_field));

 	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
 	entry->rule.listnr = listnr;
 	entry->rule.action = rule->action;
 	entry->rule.field_count = rule->field_count;
 	entry->rule.fields = fields;

 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 		entry->rule.mask[i] = rule->mask[i];

 	return entry;

 exit_err:
 	return ERR_PTR(err);
 }

 /* Translate struct audit_rule to kernel's rule respresentation.
  * Exists for backward compatibility with userspace. */
 static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule)
 {
 	struct audit_entry *entry;
 	int err = 0;
 	int i;

 	entry = audit_to_entry_common(rule);
 	if (IS_ERR(entry))
 		goto exit_nofree;

 	for (i = 0; i < rule->field_count; i++) {
 		struct audit_field *f = &entry->rule.fields[i];

 		if (rule->fields[i] & AUDIT_UNUSED_BITS) {
 			err = -EINVAL;
 			goto exit_free;
 		}

 		f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);
 		f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS);
 		f->val = rule->values[i];

 		entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;

 		/* Support for legacy operators where
 		 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
 		if (f->op & AUDIT_NEGATE)
 			f->op = AUDIT_NOT_EQUAL;
 		else if (!f->op)
 			f->op = AUDIT_EQUAL;
 		else if (f->op == AUDIT_OPERATORS) {
 			err = -EINVAL;
 			goto exit_free;
 		}
 	}

 exit_nofree:
 	return entry;

 exit_free:
 	audit_free_rule(entry);
 	return ERR_PTR(err);
 }

 /* Translate struct audit_rule_data to kernel's rule respresentation. */
 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
 					       size_t datasz)
 {
 	int err = 0;
 	struct audit_entry *entry;
 	void *bufp;
 	/* size_t remain = datasz - sizeof(struct audit_rule_data); */
 	int i;

 	entry = audit_to_entry_common((struct audit_rule *)data);
 	if (IS_ERR(entry))
 		goto exit_nofree;

 	bufp = data->buf;
 	entry->rule.vers_ops = 2;
 	for (i = 0; i < data->field_count; i++) {
 		struct audit_field *f = &entry->rule.fields[i];

 		err = -EINVAL;
 		if (!(data->fieldflags[i] & AUDIT_OPERATORS) ||
 		    data->fieldflags[i] & ~AUDIT_OPERATORS)
 			goto exit_free;

 		f->op = data->fieldflags[i] & AUDIT_OPERATORS;
 		f->type = data->fields[i];
 		switch(f->type) {
 		/* call type-specific conversion routines here */
 		default:
 			f->val = data->values[i];
 		}
 	}

 exit_nofree:
 	return entry;

 exit_free:
 	audit_free_rule(entry);
 	return ERR_PTR(err);
 }

 /* Pack a filter field's string representation into data block. */
 static inline size_t audit_pack_string(void **bufp, char *str)
 {
 	size_t len = strlen(str);

 	memcpy(*bufp, str, len);
 	*bufp += len;

 	return len;
 }

 /* Translate kernel rule respresentation to struct audit_rule.
  * Exists for backward compatibility with userspace. */
 static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule)
 {
 	struct audit_rule *rule;
 	int i;

 	rule = kmalloc(sizeof(*rule), GFP_KERNEL);
 	if (unlikely(!rule))
 		return ERR_PTR(-ENOMEM);
 	memset(rule, 0, sizeof(*rule));

 	rule->flags = krule->flags | krule->listnr;
 	rule->action = krule->action;
 	rule->field_count = krule->field_count;
 	for (i = 0; i < rule->field_count; i++) {
 		rule->values[i] = krule->fields[i].val;
 		rule->fields[i] = krule->fields[i].type;

 		if (krule->vers_ops == 1) {
 			if (krule->fields[i].op & AUDIT_NOT_EQUAL)
 				rule->fields[i] |= AUDIT_NEGATE;
 		} else {
 			rule->fields[i] |= krule->fields[i].op;
 		}
 	}
 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];

 	return rule;
 }

 /* Translate kernel rule respresentation to struct audit_rule_data. */
 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 {
 	struct audit_rule_data *data;
 	void *bufp;
 	int i;

 	data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
 	if (unlikely(!data))
 		return ERR_PTR(-ENOMEM);
 	memset(data, 0, sizeof(*data));

 	data->flags = krule->flags | krule->listnr;
 	data->action = krule->action;
 	data->field_count = krule->field_count;
 	bufp = data->buf;
 	for (i = 0; i < data->field_count; i++) {
 		struct audit_field *f = &krule->fields[i];

 		data->fields[i] = f->type;
 		data->fieldflags[i] = f->op;
 		switch(f->type) {
 		/* call type-specific conversion routines here */
 		default:
 			data->values[i] = f->val;
 		}
 	}
 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];

 	return data;
 }

 /* Compare two rules in kernel format.  Considered success if rules
  * don't match. */
 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 {
 	int i;

 	if (a->flags != b->flags ||
 	    a->listnr != b->listnr ||
 	    a->action != b->action ||
 	    a->field_count != b->field_count)
 		return 1;

 	for (i = 0; i < a->field_count; i++) {
 		if (a->fields[i].type != b->fields[i].type ||
 		    a->fields[i].op != b->fields[i].op)
 			return 1;

 		switch(a->fields[i].type) {
 		/* call type-specific comparison routines here */
 		default:
 			if (a->fields[i].val != b->fields[i].val)
 				return 1;
 		}
 	}

 	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
 		if (a->mask[i] != b->mask[i])
 			return 1;

 	return 0;
 }

 /* Add rule to given filterlist if not a duplicate.  Protected by
  * audit_netlink_mutex. */
 static inline int audit_add_rule(struct audit_entry *entry,
 				  struct list_head *list)
 {
 	struct audit_entry *e;

 	/* Do not use the _rcu iterator here, since this is the only
 	 * addition routine. */
 	list_for_each_entry(e, list, list) {
 		if (!audit_compare_rule(&entry->rule, &e->rule))
 			return -EEXIST;
 	}

 	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
 		list_add_rcu(&entry->list, list);
 	} else {
 		list_add_tail_rcu(&entry->list, list);
 	}

 	return 0;
 }

 /* Remove an existing rule from filterlist.  Protected by
  * audit_netlink_mutex. */
 static inline int audit_del_rule(struct audit_entry *entry,
 				 struct list_head *list)
 {
 	struct audit_entry  *e;

 	/* Do not use the _rcu iterator here, since this is the only
 	 * deletion routine. */
 	list_for_each_entry(e, list, list) {
 		if (!audit_compare_rule(&entry->rule, &e->rule)) {
 			list_del_rcu(&e->list);
 			call_rcu(&e->rcu, audit_free_rule_rcu);
 			return 0;
 		}
 	}
 	return -ENOENT;		/* No matching rule */
 }

 /* List rules using struct audit_rule.  Exists for backward
  * compatibility with userspace. */
 static int audit_list(void *_dest)
 {
 	int pid, seq;
 	int *dest = _dest;
 	struct audit_entry *entry;
 	int i;

 	pid = dest[0];
 	seq = dest[1];
 	kfree(dest);

 	mutex_lock(&audit_netlink_mutex);

 	/* The *_rcu iterators not needed here because we are
 	   always called with audit_netlink_mutex held. */
 	for (i=0; i<AUDIT_NR_FILTERS; i++) {
 		list_for_each_entry(entry, &audit_filter_list[i], list) {
 			struct audit_rule *rule;

 			rule = audit_krule_to_rule(&entry->rule);
 			if (unlikely(!rule))
 				break;
 			audit_send_reply(pid, seq, AUDIT_LIST, 0, 1,
 					 rule, sizeof(*rule));
 			kfree(rule);
 		}
 	}
 	audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);

 	mutex_unlock(&audit_netlink_mutex);
 	return 0;
 }

 /* List rules using struct audit_rule_data. */
 static int audit_list_rules(void *_dest)
 {
 	int pid, seq;
 	int *dest = _dest;
 	struct audit_entry *e;
 	int i;

 	pid = dest[0];
 	seq = dest[1];
 	kfree(dest);

 	mutex_lock(&audit_netlink_mutex);

 	/* The *_rcu iterators not needed here because we are
 	   always called with audit_netlink_mutex held. */
 	for (i=0; i<AUDIT_NR_FILTERS; i++) {
 		list_for_each_entry(e, &audit_filter_list[i], list) {
 			struct audit_rule_data *data;

 			data = audit_krule_to_data(&e->rule);
 			if (unlikely(!data))
 				break;
 			audit_send_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
 					 data, sizeof(*data));
 			kfree(data);
 		}
 	}
 	audit_send_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);

 	mutex_unlock(&audit_netlink_mutex);
 	return 0;
 }

 /**
  * audit_receive_filter - apply all rules to the specified message type
  * @type: audit message type
  * @pid: target pid for netlink audit messages
  * @uid: target uid for netlink audit messages
  * @seq: netlink audit message sequence (serial) number
  * @data: payload data
  * @datasz: size of payload data
  * @loginuid: loginuid of sender
  */
 int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
 			 size_t datasz, uid_t loginuid)
 {
 	struct task_struct *tsk;
 	int *dest;
 	int err = 0;
 	struct audit_entry *entry;

 	switch (type) {
 	case AUDIT_LIST:
 	case AUDIT_LIST_RULES:
 		/* We can't just spew out the rules here because we might fill
 		 * the available socket buffer space and deadlock waiting for
 		 * auditctl to read from it... which isn't ever going to
 		 * happen if we're actually running in the context of auditctl
 		 * trying to _send_ the stuff */

 		dest = kmalloc(2 * sizeof(int), GFP_KERNEL);
 		if (!dest)
 			return -ENOMEM;
 		dest[0] = pid;
 		dest[1] = seq;

 		if (type == AUDIT_LIST)
 			tsk = kthread_run(audit_list, dest, "audit_list");
 		else
 			tsk = kthread_run(audit_list_rules, dest,
 					  "audit_list_rules");
 		if (IS_ERR(tsk)) {
 			kfree(dest);
 			err = PTR_ERR(tsk);
 		}
 		break;
 	case AUDIT_ADD:
 	case AUDIT_ADD_RULE:
 		if (type == AUDIT_ADD)
 			entry = audit_rule_to_entry(data);
 		else
 			entry = audit_data_to_entry(data, datasz);
 		if (IS_ERR(entry))
 			return PTR_ERR(entry);

 		err = audit_add_rule(entry,
 				     &audit_filter_list[entry->rule.listnr]);
 		audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
 			"auid=%u add rule to list=%d res=%d\n",
 			loginuid, entry->rule.listnr, !err);

 		if (err)
 			audit_free_rule(entry);
 		break;
 	case AUDIT_DEL:
 	case AUDIT_DEL_RULE:
 		if (type == AUDIT_DEL)
 			entry = audit_rule_to_entry(data);
 		else
 			entry = audit_data_to_entry(data, datasz);
 		if (IS_ERR(entry))
 			return PTR_ERR(entry);

 		err = audit_del_rule(entry,
 				     &audit_filter_list[entry->rule.listnr]);
 		audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
 			"auid=%u remove rule from list=%d res=%d\n",
 			loginuid, entry->rule.listnr, !err);

 		audit_free_rule(entry);
 		break;
 	default:
 		return -EINVAL;
 	}

 	return err;
 }

 int audit_comparator(const u32 left, const u32 op, const u32 right)
 {
 	switch (op) {
 	case AUDIT_EQUAL:
 		return (left == right);
 	case AUDIT_NOT_EQUAL:
 		return (left != right);
 	case AUDIT_LESS_THAN:
 		return (left < right);
 	case AUDIT_LESS_THAN_OR_EQUAL:
 		return (left <= right);
 	case AUDIT_GREATER_THAN:
 		return (left > right);
 	case AUDIT_GREATER_THAN_OR_EQUAL:
 		return (left >= right);
 	}
 	BUG();
 	return 0;
 }


 static int audit_filter_user_rules(struct netlink_skb_parms *cb,
 				   struct audit_krule *rule,
 				   enum audit_state *state)
 {
 	int i;

 	for (i = 0; i < rule->field_count; i++) {
 		struct audit_field *f = &rule->fields[i];
 		int result = 0;

 		switch (f->type) {
 		case AUDIT_PID:
 			result = audit_comparator(cb->creds.pid, f->op, f->val);
 			break;
 		case AUDIT_UID:
 			result = audit_comparator(cb->creds.uid, f->op, f->val);
 			break;
 		case AUDIT_GID:
 			result = audit_comparator(cb->creds.gid, f->op, f->val);
 			break;
 		case AUDIT_LOGINUID:
 			result = audit_comparator(cb->loginuid, f->op, f->val);
 			break;
 		}

 		if (!result)
 			return 0;
 	}
 	switch (rule->action) {
 	case AUDIT_NEVER:    *state = AUDIT_DISABLED;	    break;
 	case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT;  break;
 	case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
 	}
 	return 1;
 }

 int audit_filter_user(struct netlink_skb_parms *cb, int type)
 {
 	struct audit_entry *e;
 	enum audit_state   state;
 	int ret = 1;

 	rcu_read_lock();
 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
 		if (audit_filter_user_rules(cb, &e->rule, &state)) {
 			if (state == AUDIT_DISABLED)
 				ret = 0;
 			break;
 		}
 	}
 	rcu_read_unlock();

 	return ret; /* Audit by default */
 }

 int audit_filter_type(int type)
 {
 	struct audit_entry *e;
 	int result = 0;

 	rcu_read_lock();
 	if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
 		goto unlock_and_return;

 	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
 				list) {
 		int i;
 		for (i = 0; i < e->rule.field_count; i++) {
 			struct audit_field *f = &e->rule.fields[i];
 			if (f->type == AUDIT_MSGTYPE) {
 				result = audit_comparator(type, f->op, f->val);
 				if (!result)
 					break;
 			}
 		}
 		if (result)
 			goto unlock_and_return;
 	}
 unlock_and_return:
 	rcu_read_unlock();
 	return result;
 }
	/* auditfilter.c -- filtering of audit events
	*
	* Copyright 2003-2004 Red Hat, Inc.
	* Copyright 2005 Hewlett-Packard Development Company, L.P.
	* Copyright 2005 IBM Corporation
	*
	* 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/kernel.h>
	#include <linux/audit.h>
	#include <linux/kthread.h>
	#include <linux/netlink.h>
	#include "audit.h"

	/* There are three lists of rules -- one to search at task creation
	* time, one to search at syscall entry time, and another to search at
	* syscall exit time. */
	struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
	LIST_HEAD_INIT(audit_filter_list[0]),
	LIST_HEAD_INIT(audit_filter_list[1]),
	LIST_HEAD_INIT(audit_filter_list[2]),
	LIST_HEAD_INIT(audit_filter_list[3]),
	LIST_HEAD_INIT(audit_filter_list[4]),
	LIST_HEAD_INIT(audit_filter_list[5]),
	#if AUDIT_NR_FILTERS != 6
	#error Fix audit_filter_list initialiser
	#endif
	};

	static inline void audit_free_rule(struct audit_entry *e)
	{
	kfree(e->rule.fields);
	kfree(e);
	}

	static inline void audit_free_rule_rcu(struct rcu_head *head)
	{
	struct audit_entry *e = container_of(head, struct audit_entry, rcu);
	audit_free_rule(e);
	}

	/* Unpack a filter field's string representation from user-space
	* buffer. */
	static __attribute__((unused)) char audit_unpack_string(void bufp, size_t remain, size_t len)
	{
	char *str;

	if (!bufp \|\| (len == 0) \|\| (len > remain))
	return ERR_PTR(-EINVAL);

	/* Of the currently implemented string fields, PATH_MAX
	* defines the longest valid length.
	*/
	if (len > PATH_MAX)
	return ERR_PTR(-ENAMETOOLONG);

	str = kmalloc(len + 1, GFP_KERNEL);
	if (unlikely(!str))
	return ERR_PTR(-ENOMEM);

	memcpy(str, *bufp, len);
	str[len] = 0;
	*bufp += len;
	*remain -= len;

	return str;
	}

	/* Common user-space to kernel rule translation. */
	static inline struct audit_entry audit_to_entry_common(struct audit_rule rule)
	{
	unsigned listnr;
	struct audit_entry *entry;
	struct audit_field *fields;
	int i, err;

	err = -EINVAL;
	listnr = rule->flags & ~AUDIT_FILTER_PREPEND;
	switch(listnr) {
	default:
	goto exit_err;
	case AUDIT_FILTER_USER:
	case AUDIT_FILTER_TYPE:
	#ifdef CONFIG_AUDITSYSCALL
	case AUDIT_FILTER_ENTRY:
	case AUDIT_FILTER_EXIT:
	case AUDIT_FILTER_TASK:
	#endif
	;
	}
	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_POSSIBLE &&
	rule->action != AUDIT_ALWAYS)
	goto exit_err;
	if (rule->field_count > AUDIT_MAX_FIELDS)
	goto exit_err;

	err = -ENOMEM;
	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
	if (unlikely(!entry))
	goto exit_err;
	fields = kmalloc(sizeof(fields) rule->field_count, GFP_KERNEL);
	if (unlikely(!fields)) {
	kfree(entry);
	goto exit_err;
	}

	memset(&entry->rule, 0, sizeof(struct audit_krule));
	memset(fields, 0, sizeof(struct audit_field));

	entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND;
	entry->rule.listnr = listnr;
	entry->rule.action = rule->action;
	entry->rule.field_count = rule->field_count;
	entry->rule.fields = fields;

	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
	entry->rule.mask[i] = rule->mask[i];

	return entry;

	exit_err:
	return ERR_PTR(err);
	}

	/* Translate struct audit_rule to kernel's rule respresentation.
	* Exists for backward compatibility with userspace. */
	static struct audit_entry audit_rule_to_entry(struct audit_rule rule)
	{
	struct audit_entry *entry;
	int err = 0;
	int i;

	entry = audit_to_entry_common(rule);
	if (IS_ERR(entry))
	goto exit_nofree;

	for (i = 0; i < rule->field_count; i++) {
	struct audit_field *f = &entry->rule.fields[i];

	if (rule->fields[i] & AUDIT_UNUSED_BITS) {
	err = -EINVAL;
	goto exit_free;
	}

	f->op = rule->fields[i] & (AUDIT_NEGATE\|AUDIT_OPERATORS);
	f->type = rule->fields[i] & ~(AUDIT_NEGATE\|AUDIT_OPERATORS);
	f->val = rule->values[i];

	entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1;

	/* Support for legacy operators where
	* AUDIT_NEGATE bit signifies != and otherwise assumes == */
	if (f->op & AUDIT_NEGATE)
	f->op = AUDIT_NOT_EQUAL;
	else if (!f->op)
	f->op = AUDIT_EQUAL;
	else if (f->op == AUDIT_OPERATORS) {
	err = -EINVAL;
	goto exit_free;
	}
	}

	exit_nofree:
	return entry;

	exit_free:
	audit_free_rule(entry);
	return ERR_PTR(err);
	}

	/* Translate struct audit_rule_data to kernel's rule respresentation. */
	static struct audit_entry audit_data_to_entry(struct audit_rule_data data,
	size_t datasz)
	{
	int err = 0;
	struct audit_entry *entry;
	void *bufp;
	/* size_t remain = datasz - sizeof(struct audit_rule_data); */
	int i;

	entry = audit_to_entry_common((struct audit_rule *)data);
	if (IS_ERR(entry))
	goto exit_nofree;

	bufp = data->buf;
	entry->rule.vers_ops = 2;
	for (i = 0; i < data->field_count; i++) {
	struct audit_field *f = &entry->rule.fields[i];

	err = -EINVAL;
	if (!(data->fieldflags[i] & AUDIT_OPERATORS) \|\|
	data->fieldflags[i] & ~AUDIT_OPERATORS)
	goto exit_free;

	f->op = data->fieldflags[i] & AUDIT_OPERATORS;
	f->type = data->fields[i];
	switch(f->type) {
	/* call type-specific conversion routines here */
	default:
	f->val = data->values[i];
	}
	}

	exit_nofree:
	return entry;

	exit_free:
	audit_free_rule(entry);
	return ERR_PTR(err);
	}

	/* Pack a filter field's string representation into data block. */
	static inline size_t audit_pack_string(void *bufp, char str)
	{
	size_t len = strlen(str);

	memcpy(*bufp, str, len);
	*bufp += len;

	return len;
	}

	/* Translate kernel rule respresentation to struct audit_rule.
	* Exists for backward compatibility with userspace. */
	static struct audit_rule audit_krule_to_rule(struct audit_krule krule)
	{
	struct audit_rule *rule;
	int i;

	rule = kmalloc(sizeof(*rule), GFP_KERNEL);
	if (unlikely(!rule))
	return ERR_PTR(-ENOMEM);
	memset(rule, 0, sizeof(*rule));

	rule->flags = krule->flags \| krule->listnr;
	rule->action = krule->action;
	rule->field_count = krule->field_count;
	for (i = 0; i < rule->field_count; i++) {
	rule->values[i] = krule->fields[i].val;
	rule->fields[i] = krule->fields[i].type;

	if (krule->vers_ops == 1) {
	if (krule->fields[i].op & AUDIT_NOT_EQUAL)
	rule->fields[i] \|= AUDIT_NEGATE;
	} else {
	rule->fields[i] \|= krule->fields[i].op;
	}
	}
	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i];

	return rule;
	}

	/* Translate kernel rule respresentation to struct audit_rule_data. */
	static struct audit_rule_data audit_krule_to_data(struct audit_krule krule)
	{
	struct audit_rule_data *data;
	void *bufp;
	int i;

	data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL);
	if (unlikely(!data))
	return ERR_PTR(-ENOMEM);
	memset(data, 0, sizeof(*data));

	data->flags = krule->flags \| krule->listnr;
	data->action = krule->action;
	data->field_count = krule->field_count;
	bufp = data->buf;
	for (i = 0; i < data->field_count; i++) {
	struct audit_field *f = &krule->fields[i];

	data->fields[i] = f->type;
	data->fieldflags[i] = f->op;
	switch(f->type) {
	/* call type-specific conversion routines here */
	default:
	data->values[i] = f->val;
	}
	}
	for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i];

	return data;
	}

	/* Compare two rules in kernel format. Considered success if rules
	* don't match. */
	static int audit_compare_rule(struct audit_krule a, struct audit_krule b)
	{
	int i;

	if (a->flags != b->flags \|\|
	a->listnr != b->listnr \|\|
	a->action != b->action \|\|
	a->field_count != b->field_count)
	return 1;

	for (i = 0; i < a->field_count; i++) {
	if (a->fields[i].type != b->fields[i].type \|\|
	a->fields[i].op != b->fields[i].op)
	return 1;

	switch(a->fields[i].type) {
	/* call type-specific comparison routines here */
	default:
	if (a->fields[i].val != b->fields[i].val)
	return 1;
	}
	}

	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
	if (a->mask[i] != b->mask[i])
	return 1;

	return 0;
	}

	/* Add rule to given filterlist if not a duplicate. Protected by
	* audit_netlink_mutex. */
	static inline int audit_add_rule(struct audit_entry *entry,
	struct list_head *list)
	{
	struct audit_entry *e;

	/* Do not use the _rcu iterator here, since this is the only
	* addition routine. */
	list_for_each_entry(e, list, list) {
	if (!audit_compare_rule(&entry->rule, &e->rule))
	return -EEXIST;
	}

	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
	list_add_rcu(&entry->list, list);
	} else {
	list_add_tail_rcu(&entry->list, list);
	}

	return 0;
	}

	/* Remove an existing rule from filterlist. Protected by
	* audit_netlink_mutex. */
	static inline int audit_del_rule(struct audit_entry *entry,
	struct list_head *list)
	{
	struct audit_entry *e;

	/* Do not use the _rcu iterator here, since this is the only
	* deletion routine. */
	list_for_each_entry(e, list, list) {
	if (!audit_compare_rule(&entry->rule, &e->rule)) {
	list_del_rcu(&e->list);
	call_rcu(&e->rcu, audit_free_rule_rcu);
	return 0;
	}
	}
	return -ENOENT; /* No matching rule */
	}

	/* List rules using struct audit_rule. Exists for backward
	* compatibility with userspace. */
	static int audit_list(void *_dest)
	{
	int pid, seq;
	int *dest = _dest;
	struct audit_entry *entry;
	int i;

	pid = dest[0];
	seq = dest[1];
	kfree(dest);

	mutex_lock(&audit_netlink_mutex);

	/* The *_rcu iterators not needed here because we are
	always called with audit_netlink_mutex held. */
	for (i=0; i<AUDIT_NR_FILTERS; i++) {
	list_for_each_entry(entry, &audit_filter_list[i], list) {
	struct audit_rule *rule;

	rule = audit_krule_to_rule(&entry->rule);
	if (unlikely(!rule))
	break;
	audit_send_reply(pid, seq, AUDIT_LIST, 0, 1,
	rule, sizeof(*rule));
	kfree(rule);
	}
	}
	audit_send_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);

	mutex_unlock(&audit_netlink_mutex);
	return 0;
	}

	/* List rules using struct audit_rule_data. */
	static int audit_list_rules(void *_dest)
	{
	int pid, seq;
	int *dest = _dest;
	struct audit_entry *e;
	int i;

	pid = dest[0];
	seq = dest[1];
	kfree(dest);

	mutex_lock(&audit_netlink_mutex);

	/* The *_rcu iterators not needed here because we are
	always called with audit_netlink_mutex held. */
	for (i=0; i<AUDIT_NR_FILTERS; i++) {
	list_for_each_entry(e, &audit_filter_list[i], list) {
	struct audit_rule_data *data;

	data = audit_krule_to_data(&e->rule);
	if (unlikely(!data))
	break;
	audit_send_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
	data, sizeof(*data));
	kfree(data);
	}
	}
	audit_send_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);

	mutex_unlock(&audit_netlink_mutex);
	return 0;
	}

	/**
	* audit_receive_filter - apply all rules to the specified message type
	* @type: audit message type
	* @pid: target pid for netlink audit messages
	* @uid: target uid for netlink audit messages
	* @seq: netlink audit message sequence (serial) number
	* @data: payload data
	* @datasz: size of payload data
	* @loginuid: loginuid of sender
	*/
	int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
	size_t datasz, uid_t loginuid)
	{
	struct task_struct *tsk;
	int *dest;
	int err = 0;
	struct audit_entry *entry;

	switch (type) {
	case AUDIT_LIST:
	case AUDIT_LIST_RULES:
	/* We can't just spew out the rules here because we might fill
	* the available socket buffer space and deadlock waiting for
	* auditctl to read from it... which isn't ever going to
	* happen if we're actually running in the context of auditctl
	* trying to _send_ the stuff */

	dest = kmalloc(2 * sizeof(int), GFP_KERNEL);
	if (!dest)
	return -ENOMEM;
	dest[0] = pid;
	dest[1] = seq;

	if (type == AUDIT_LIST)
	tsk = kthread_run(audit_list, dest, "audit_list");
	else
	tsk = kthread_run(audit_list_rules, dest,
	"audit_list_rules");
	if (IS_ERR(tsk)) {
	kfree(dest);
	err = PTR_ERR(tsk);
	}
	break;
	case AUDIT_ADD:
	case AUDIT_ADD_RULE:
	if (type == AUDIT_ADD)
	entry = audit_rule_to_entry(data);
	else
	entry = audit_data_to_entry(data, datasz);
	if (IS_ERR(entry))
	return PTR_ERR(entry);

	err = audit_add_rule(entry,
	&audit_filter_list[entry->rule.listnr]);
	audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
	"auid=%u add rule to list=%d res=%d\n",
	loginuid, entry->rule.listnr, !err);

	if (err)
	audit_free_rule(entry);
	break;
	case AUDIT_DEL:
	case AUDIT_DEL_RULE:
	if (type == AUDIT_DEL)
	entry = audit_rule_to_entry(data);
	else
	entry = audit_data_to_entry(data, datasz);
	if (IS_ERR(entry))
	return PTR_ERR(entry);

	err = audit_del_rule(entry,
	&audit_filter_list[entry->rule.listnr]);
	audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
	"auid=%u remove rule from list=%d res=%d\n",
	loginuid, entry->rule.listnr, !err);

	audit_free_rule(entry);
	break;
	default:
	return -EINVAL;
	}

	return err;
	}

	int audit_comparator(const u32 left, const u32 op, const u32 right)
	{
	switch (op) {
	case AUDIT_EQUAL:
	return (left == right);
	case AUDIT_NOT_EQUAL:
	return (left != right);
	case AUDIT_LESS_THAN:
	return (left < right);
	case AUDIT_LESS_THAN_OR_EQUAL:
	return (left <= right);
	case AUDIT_GREATER_THAN:
	return (left > right);
	case AUDIT_GREATER_THAN_OR_EQUAL:
	return (left >= right);
	}
	BUG();
	return 0;
	}



	static int audit_filter_user_rules(struct netlink_skb_parms *cb,
	struct audit_krule *rule,
	enum audit_state *state)
	{
	int i;

	for (i = 0; i < rule->field_count; i++) {
	struct audit_field *f = &rule->fields[i];
	int result = 0;

	switch (f->type) {
	case AUDIT_PID:
	result = audit_comparator(cb->creds.pid, f->op, f->val);
	break;
	case AUDIT_UID:
	result = audit_comparator(cb->creds.uid, f->op, f->val);
	break;
	case AUDIT_GID:
	result = audit_comparator(cb->creds.gid, f->op, f->val);
	break;
	case AUDIT_LOGINUID:
	result = audit_comparator(cb->loginuid, f->op, f->val);
	break;
	}

	if (!result)
	return 0;
	}
	switch (rule->action) {
	case AUDIT_NEVER: *state = AUDIT_DISABLED; break;
	case AUDIT_POSSIBLE: *state = AUDIT_BUILD_CONTEXT; break;
	case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break;
	}
	return 1;
	}

	int audit_filter_user(struct netlink_skb_parms *cb, int type)
	{
	struct audit_entry *e;
	enum audit_state state;
	int ret = 1;

	rcu_read_lock();
	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) {
	if (audit_filter_user_rules(cb, &e->rule, &state)) {
	if (state == AUDIT_DISABLED)
	ret = 0;
	break;
	}
	}
	rcu_read_unlock();

	return ret; /* Audit by default */
	}

	int audit_filter_type(int type)
	{
	struct audit_entry *e;
	int result = 0;

	rcu_read_lock();
	if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE]))
	goto unlock_and_return;

	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE],
	list) {
	int i;
	for (i = 0; i < e->rule.field_count; i++) {
	struct audit_field *f = &e->rule.fields[i];
	if (f->type == AUDIT_MSGTYPE) {
	result = audit_comparator(type, f->op, f->val);
	if (!result)
	break;
	}
	}
	if (result)
	goto unlock_and_return;
	}
	unlock_and_return:
	rcu_read_unlock();
	return result;
	}