litmus-rt.git - The LITMUS^RT kernel.

The LITMUS^RT kernel.

Bjoern Brandenburg

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author	Mao, Junjie <junjie.mao@intel.com>	2012-07-01 21:18:48 -0400
committer	Avi Kivity <avi@redhat.com>	2012-07-12 06:07:34 -0400
commit	ad756a1603c5fac207758faaac7f01c34c9d0b7b (patch)
tree	0b01513f1e3434362ab9faf8394cbd158b31386d /lib/mpi/mpi-bit.c
parent	fc73373b33f5f965f2f82bfbc40ef8e6072e986d (diff)

KVM: VMX: Implement PCID/INVPCID for guests with EPT

This patch handles PCID/INVPCID for guests. Process-context identifiers (PCIDs) are a facility by which a logical processor may cache information for multiple linear-address spaces so that the processor may retain cached information when software switches to a different linear address space. Refer to section 4.10.1 in IA32 Intel Software Developer's Manual Volume 3A for details. For guests with EPT, the PCID feature is enabled and INVPCID behaves as running natively. For guests without EPT, the PCID feature is disabled and INVPCID triggers #UD. Signed-off-by: Junjie Mao <junjie.mao@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>

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/* 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/mutex.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/netlink.h>
#include <linux/sched.h>
#include <linux/security.h>
#include "audit.h"

/*
 * Locking model:
 *
 * audit_filter_mutex:
 * 		Synchronizes writes and blocking reads of audit's filterlist
 * 		data.  Rcu is used to traverse the filterlist and access
 * 		contents of structs audit_entry, audit_watch and opaque
 * 		LSM rules during filtering.  If modified, these structures
 * 		must be copied and replace their counterparts in the filterlist.
 * 		An audit_parent struct is not accessed during filtering, so may
 * 		be written directly provided audit_filter_mutex is held.
 */

/* Audit filter lists, defined in <linux/audit.h> */
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 struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
	LIST_HEAD_INIT(audit_rules_list[0]),
	LIST_HEAD_INIT(audit_rules_list[1]),
	LIST_HEAD_INIT(audit_rules_list[2]),
	LIST_HEAD_INIT(audit_rules_list[3]),
	LIST_HEAD_INIT(audit_rules_list[4]),
	LIST_HEAD_INIT(audit_rules_list[5]),
};

DEFINE_MUTEX(audit_filter_mutex);

static inline void audit_free_rule(struct audit_entry *e)
{
	int i;
	struct audit_krule *erule = &e->rule;
	/* some rules don't have associated watches */
	if (erule->watch)
		audit_put_watch(erule->watch);
	if (erule->fields)
		for (i = 0; i < erule->field_count; i++) {
			struct audit_field *f = &erule->fields[i];
			kfree(f->lsm_str);
			security_audit_rule_free(f->lsm_rule);
		}
	kfree(erule->fields);
	kfree(erule->filterkey);
	kfree(e);
}

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

/* Initialize an audit filterlist entry. */
static inline struct audit_entry *audit_init_entry(u32 field_count)
{
	struct audit_entry *entry;
	struct audit_field *fields;

	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
	if (unlikely(!entry))
		return NULL;

	fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL);
	if (unlikely(!fields)) {
		kfree(entry);
		return NULL;
	}
	entry->rule.fields = fields;

	return entry;
}

/* Unpack a filter field's string representation from user-space
 * buffer. */
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;
}

/* Translate an inode field to kernel respresentation. */
static inline int audit_to_inode(struct audit_krule *krule,
				 struct audit_field *f)
{
	if (krule->listnr != AUDIT_FILTER_EXIT ||
	    krule->watch || krule->inode_f || krule->tree ||
	    (f->op != Audit_equal && f->op != Audit_not_equal))
		return -EINVAL;

	krule->inode_f = f;
	return 0;
}

static __u32 *classes[AUDIT_SYSCALL_CLASSES];

int __init audit_register_class(int class, unsigned *list)
{
	__u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL);
	if (!p)
		return -ENOMEM;
	while (*list != ~0U) {
		unsigned n = *list++;
		if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) {
			kfree(p);
			return -EINVAL;
		}
		p[AUDIT_WORD(n)] |= AUDIT_BIT(n);
	}
	if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) {
		kfree(p);
		return -EINVAL;
	}
	classes[class] = p;
	return 0;
}

int audit_match_class(int class, unsigned syscall)
{
	if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32))
		return 0;
	if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class]))
		return 0;
	return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall);
}

#ifdef CONFIG_AUDITSYSCALL
static inline int audit_match_class_bits(int class, u32 *mask)
{
	int i;

	if (classes[class]) {
		for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
			if (mask[i] & classes[class][i])
				return 0;
	}
	return 1;
}

static int audit_match_signal(struct audit_entry *entry)
{
	struct audit_field *arch = entry->rule.arch_f;

	if (!arch) {
		/* When arch is unspecified, we must check both masks on biarch
		 * as syscall number alone is ambiguous. */
		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
					       entry->rule.mask) &&
			audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
					       entry->rule.mask));
	}

	switch(audit_classify_arch(arch->val)) {
	case 0: /* native */
		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL,
					       entry->rule.mask));
	case 1: /* 32bit on biarch */
		return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32,
					       entry->rule.mask));
	default:
		return 1;
	}
}
#endif

/* 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;
	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 (unlikely(rule->action == AUDIT_POSSIBLE)) {
		printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n");
		goto exit_err;
	}
	if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS)
		goto exit_err;
	if (rule->field_count > AUDIT_MAX_FIELDS)
		goto exit_err;

	err = -ENOMEM;
	entry = audit_init_entry(rule->field_count);
	if (!entry)
		goto exit_err;

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

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

	for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) {
		int bit = AUDIT_BITMASK_SIZE * 32 - i - 1;
		__u32 *p = &entry->rule.mask[AUDIT_WORD(bit)];
		__u32 *class;

		if (!(*p & AUDIT_BIT(bit)))
			continue;
		*p &= ~AUDIT_BIT(bit);
		class = classes[i];
		if (class) {
			int j;
			for (j = 0; j < AUDIT_BITMASK_SIZE; j++)
				entry->rule.mask[j] |= class[j];
		}
	}

	return entry;

exit_err:
	return ERR_PTR(err);
}

static u32 audit_ops[] =
{
	[Audit_equal] = AUDIT_EQUAL,
	[Audit_not_equal] = AUDIT_NOT_EQUAL,
	[Audit_bitmask] = AUDIT_BIT_MASK,
	[Audit_bittest] = AUDIT_BIT_TEST,
	[Audit_lt] = AUDIT_LESS_THAN,
	[Audit_gt] = AUDIT_GREATER_THAN,
	[Audit_le] = AUDIT_LESS_THAN_OR_EQUAL,
	[Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL,
};

static u32 audit_to_op(u32 op)
{
	u32 n;
	for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++)
		;
	return n;
}


/* 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];
		u32 n;

		n = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS);

		/* Support for legacy operators where
		 * AUDIT_NEGATE bit signifies != and otherwise assumes == */
		if (n & AUDIT_NEGATE)
			f->op = Audit_not_equal;
		else if (!n)
			f->op = Audit_equal;
		else
			f->op = audit_to_op(n);

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

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

		err = -EINVAL;
		if (f->op == Audit_bad)
			goto exit_free;

		switch(f->type) {
		default:
			goto exit_free;
		case AUDIT_PID:
		case AUDIT_UID:
		case AUDIT_EUID:
		case AUDIT_SUID:
		case AUDIT_FSUID:
		case AUDIT_GID:
		case AUDIT_EGID:
		case AUDIT_SGID:
		case AUDIT_FSGID:
		case AUDIT_LOGINUID:
		case AUDIT_PERS:
		case AUDIT_MSGTYPE:
		case AUDIT_PPID:
		case AUDIT_DEVMAJOR:
		case AUDIT_DEVMINOR:
		case AUDIT_EXIT:
		case AUDIT_SUCCESS:
			/* bit ops are only useful on syscall args */
			if (f->op == Audit_bitmask || f->op == Audit_bittest)
				goto exit_free;
			break;
		case AUDIT_ARG0:
		case AUDIT_ARG1:
		case AUDIT_ARG2:
		case AUDIT_ARG3:
			break;
		/* arch is only allowed to be = or != */
		case AUDIT_ARCH:
			if (f->op != Audit_not_equal && f->op != Audit_equal)
				goto exit_free;
			entry->rule.arch_f = f;
			break;
		case AUDIT_PERM:
			if (f->val & ~15)
				goto exit_free;
			break;
		case AUDIT_FILETYPE:
			if ((f->val & ~S_IFMT) > S_IFMT)
				goto exit_free;
			break;
		case AUDIT_INODE:
			err = audit_to_inode(&entry->rule, f);
			if (err)
				goto exit_free;
			break;
		}
	}

	if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
		entry->rule.inode_f = NULL;

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;
	char *str;

	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;

		f->op = audit_to_op(data->fieldflags[i]);
		if (f->op == Audit_bad)
			goto exit_free;

		f->type = data->fields[i];
		f->val = data->values[i];
		f->lsm_str = NULL;
		f->lsm_rule = NULL;
		switch(f->type) {
		case AUDIT_PID:
		case AUDIT_UID:
		case AUDIT_EUID:
		case AUDIT_SUID:
		case AUDIT_FSUID:
		case AUDIT_GID:
		case AUDIT_EGID:
		case AUDIT_SGID:
		case AUDIT_FSGID:
		case AUDIT_LOGINUID:
		case AUDIT_PERS:
		case AUDIT_MSGTYPE:
		case AUDIT_PPID:
		case AUDIT_DEVMAJOR:
		case AUDIT_DEVMINOR:
		case AUDIT_EXIT:
		case AUDIT_SUCCESS:
		case AUDIT_ARG0:
		case AUDIT_ARG1:
		case AUDIT_ARG2:
		case AUDIT_ARG3:
			break;
		case AUDIT_ARCH:
			entry->rule.arch_f = f;
			break;
		case AUDIT_SUBJ_USER:
		case AUDIT_SUBJ_ROLE:
		case AUDIT_SUBJ_TYPE:
		case AUDIT_SUBJ_SEN:
		case AUDIT_SUBJ_CLR:
		case AUDIT_OBJ_USER:
		case AUDIT_OBJ_ROLE:
		case AUDIT_OBJ_TYPE:
		case AUDIT_OBJ_LEV_LOW:
		case AUDIT_OBJ_LEV_HIGH:
			str = audit_unpack_string(&bufp, &remain, f->val);
			if (IS_ERR(str))
				goto exit_free;
			entry->rule.buflen += f->val;

			err = security_audit_rule_init(f->type, f->op, str,
						       (void **)&f->lsm_rule);
			/* Keep currently invalid fields around in case they
			 * become valid after a policy reload. */
			if (err == -EINVAL) {
				printk(KERN_WARNING "audit rule for LSM "
				       "\'%s\' is invalid\n",  str);
				err = 0;
			}
			if (err) {
				kfree(str);
				goto exit_free;
			} else
				f->lsm_str = str;
			break;
		case AUDIT_WATCH:
			str = audit_unpack_string(&bufp, &remain, f->val);
			if (IS_ERR(str))
				goto exit_free;
			entry->rule.buflen += f->val;

			err = audit_to_watch(&entry->rule, str, f->val, f->op);
			if (err) {
				kfree(str);
				goto exit_free;
			}
			break;
		case AUDIT_DIR:
			str = audit_unpack_string(&bufp, &remain, f->val);
			if (IS_ERR(str))
				goto exit_free;
			entry->rule.buflen += f->val;

			err = audit_make_tree(&entry->rule, str, f->op);
			kfree(str);
			if (err)
				goto exit_free;
			break;
		case AUDIT_INODE:
			err = audit_to_inode(&entry->rule, f);
			if (err)
				goto exit_free;
			break;
		case AUDIT_FILTERKEY:
			err = -EINVAL;
			if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
				goto exit_free;
			str = audit_unpack_string(&bufp, &remain, f->val);
			if (IS_ERR(str))
				goto exit_free;
			entry->rule.buflen += f->val;
			entry->rule.filterkey = str;
			break;
		case AUDIT_PERM:
			if (f->val & ~15)
				goto exit_free;
			break;
		case AUDIT_FILETYPE:
			if ((f->val & ~S_IFMT) > S_IFMT)
				goto exit_free;
			break;
		default:
			goto exit_free;
		}
	}

	if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal)
		entry->rule.inode_f = NULL;

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, const 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 = kzalloc(sizeof(*rule), GFP_KERNEL);
	if (unlikely(!rule))
		return NULL;

	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] |= audit_ops[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 NULL;
	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] = audit_ops[f->op];
		switch(f->type) {
		case AUDIT_SUBJ_USER:
		case AUDIT_SUBJ_ROLE:
		case AUDIT_SUBJ_TYPE:
		case AUDIT_SUBJ_SEN:
		case AUDIT_SUBJ_CLR:
		case AUDIT_OBJ_USER:
		case AUDIT_OBJ_ROLE:
		case AUDIT_OBJ_TYPE:
		case AUDIT_OBJ_LEV_LOW:
		case AUDIT_OBJ_LEV_HIGH:
			data->buflen += data->values[i] =
				audit_pack_string(&bufp, f->lsm_str);
			break;
		case AUDIT_WATCH:
			data->buflen += data->values[i] =
				audit_pack_string(&bufp,
						  audit_watch_path(krule->watch));
			break;
		case AUDIT_DIR:
			data->buflen += data->values[i] =
				audit_pack_string(&bufp,
						  audit_tree_path(krule->tree));
			break;
		case AUDIT_FILTERKEY:
			data->buflen += data->values[i] =
				audit_pack_string(&bufp, krule->filterkey);
			break;
		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) {
		case AUDIT_SUBJ_USER:
		case AUDIT_SUBJ_ROLE:
		case AUDIT_SUBJ_TYPE:
		case AUDIT_SUBJ_SEN:
		case AUDIT_SUBJ_CLR:
		case AUDIT_OBJ_USER:
		case AUDIT_OBJ_ROLE:
		case AUDIT_OBJ_TYPE:
		case AUDIT_OBJ_LEV_LOW:
		case AUDIT_OBJ_LEV_HIGH:
			if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str))
				return 1;
			break;
		case AUDIT_WATCH:
			if (strcmp(audit_watch_path(a->watch),
				   audit_watch_path(b->watch)))
				return 1;
			break;
		case AUDIT_DIR:
			if (strcmp(audit_tree_path(a->tree),
				   audit_tree_path(b->tree)))
				return 1;
			break;
		case AUDIT_FILTERKEY:
			/* both filterkeys exist based on above type compare */
			if (strcmp(a->filterkey, b->filterkey))
				return 1;
			break;
		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;
}

/* Duplicate LSM field information.  The lsm_rule is opaque, so must be
 * re-initialized. */
static inline int audit_dupe_lsm_field(struct audit_field *df,
					   struct audit_field *sf)
{
	int ret = 0;
	char *lsm_str;

	/* our own copy of lsm_str */
	lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL);
	if (unlikely(!lsm_str))
		return -ENOMEM;
	df->lsm_str = lsm_str;

	/* our own (refreshed) copy of lsm_rule */
	ret = security_audit_rule_init(df->type, df->op, df->lsm_str,
				       (void **)&df->lsm_rule);
	/* Keep currently invalid fields around in case they
	 * become valid after a policy reload. */
	if (ret == -EINVAL) {
		printk(KERN_WARNING "audit rule for LSM \'%s\' is "
		       "invalid\n", df->lsm_str);
		ret = 0;
	}

	return ret;
}

/* Duplicate an audit rule.  This will be a deep copy with the exception
 * of the watch - that pointer is carried over.  The LSM specific fields
 * will be updated in the copy.  The point is to be able to replace the old
 * rule with the new rule in the filterlist, then free the old rule.
 * The rlist element is undefined; list manipulations are handled apart from
 * the initial copy. */
struct audit_entry *audit_dupe_rule(struct audit_krule *old,
				    struct audit_watch *watch)
{
	u32 fcount = old->field_count;
	struct audit_entry *entry;
	struct audit_krule *new;
	char *fk;
	int i, err = 0;

	entry = audit_init_entry(fcount);
	if (unlikely(!entry))
		return ERR_PTR(-ENOMEM);

	new = &entry->rule;
	new->vers_ops = old->vers_ops;
	new->flags = old->flags;
	new->listnr = old->listnr;
	new->action = old->action;
	for (i = 0; i < AUDIT_BITMASK_SIZE; i++)
		new->mask[i] = old->mask[i];
	new->prio = old->prio;
	new->buflen = old->buflen;
	new->inode_f = old->inode_f;
	new->watch = NULL;
	new->field_count = old->field_count;
	/*
	 * note that we are OK with not refcounting here; audit_match_tree()
	 * never dereferences tree and we can't get false positives there
	 * since we'd have to have rule gone from the list *and* removed
	 * before the chunks found by lookup had been allocated, i.e. before
	 * the beginning of list scan.
	 */
	new->tree = old->tree;
	memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount);

	/* deep copy this information, updating the lsm_rule fields, because
	 * the originals will all be freed when the old rule is freed. */
	for (i = 0; i < fcount; i++) {
		switch (new->fields[i].type) {
		case AUDIT_SUBJ_USER:
		case AUDIT_SUBJ_ROLE:
		case AUDIT_SUBJ_TYPE:
		case AUDIT_SUBJ_SEN:
		case AUDIT_SUBJ_CLR:
		case AUDIT_OBJ_USER:
		case AUDIT_OBJ_ROLE:
		case AUDIT_OBJ_TYPE:
		case AUDIT_OBJ_LEV_LOW:
		case AUDIT_OBJ_LEV_HIGH:
			err = audit_dupe_lsm_field(&new->fields[i],
						       &old->fields[i]);
			break;
		case AUDIT_FILTERKEY:
			fk = kstrdup(old->filterkey, GFP_KERNEL);
			if (unlikely(!fk))
				err = -ENOMEM;
			else
				new->filterkey = fk;
		}
		if (err) {
			audit_free_rule(entry);
			return ERR_PTR(err);
		}
	}

	if (watch) {
		audit_get_watch(watch);
		new->watch = watch;
	}

	return entry;
}

/* Find an existing audit rule.
 * Caller must hold audit_filter_mutex to prevent stale rule data. */
static struct audit_entry *audit_find_rule(struct audit_entry *entry,
					   struct list_head **p)
{
	struct audit_entry *e, *found = NULL;
	struct list_head *list;
	int h;

	if (entry->rule.inode_f) {
		h = audit_hash_ino(entry->rule.inode_f->val);
		*p = list = &audit_inode_hash[h];
	} else if (entry->rule.watch) {
		/* we don't know the inode number, so must walk entire hash */
		for (h = 0; h < AUDIT_INODE_BUCKETS; h++) {
			list = &audit_inode_hash[h];
			list_for_each_entry(e, list, list)
				if (!audit_compare_rule(&entry->rule, &e->rule)) {
					found = e;
					goto out;
				}
		}
		goto out;
	} else {
		*p = list = &audit_filter_list[entry->rule.listnr];
	}

	list_for_each_entry(e, list, list)
		if (!audit_compare_rule(&entry->rule, &e->rule)) {
			found = e;
			goto out;
		}

out:
	return found;
}

static u64 prio_low = ~0ULL/2;
static u64 prio_high = ~0ULL/2 - 1;

/* Add rule to given filterlist if not a duplicate. */
static inline int audit_add_rule(struct audit_entry *entry)
{
	struct audit_entry *e;
	struct audit_watch *watch = entry->rule.watch;
	struct audit_tree *tree = entry->rule.tree;
	struct list_head *list;
	int h, err;
#ifdef CONFIG_AUDITSYSCALL
	int dont_count = 0;

	/* If either of these, don't count towards total */
	if (entry->rule.listnr == AUDIT_FILTER_USER ||
		entry->rule.listnr == AUDIT_FILTER_TYPE)
		dont_count = 1;
#endif

	mutex_lock(&audit_filter_mutex);
	e = audit_find_rule(entry, &list);
	if (e) {
		mutex_unlock(&audit_filter_mutex);
		err = -EEXIST;
		/* normally audit_add_tree_rule() will free it on failure */
		if (tree)
			audit_put_tree(tree);
		goto error;
	}

	if (watch) {
		/* audit_filter_mutex is dropped and re-taken during this call */
		err = audit_add_watch(&entry->rule);
		if (err) {
			mutex_unlock(&audit_filter_mutex);
			goto error;
		}
		/* entry->rule.watch may have changed during audit_add_watch() */
		watch = entry->rule.watch;
		h = audit_hash_ino((u32)audit_watch_inode(watch));
		list = &audit_inode_hash[h];
	}
	if (tree) {
		err = audit_add_tree_rule(&entry->rule);
		if (err) {
			mutex_unlock(&audit_filter_mutex);
			goto error;
		}
	}

	entry->rule.prio = ~0ULL;
	if (entry->rule.listnr == AUDIT_FILTER_EXIT) {
		if (entry->rule.flags & AUDIT_FILTER_PREPEND)
			entry->rule.prio = ++prio_high;
		else
			entry->rule.prio = --prio_low;
	}

	if (entry->rule.flags & AUDIT_FILTER_PREPEND) {
		list_add(&entry->rule.list,
			 &audit_rules_list[entry->rule.listnr]);
		list_add_rcu(&entry->list, list);
		entry->rule.flags &= ~AUDIT_FILTER_PREPEND;
	} else {
		list_add_tail(&entry->rule.list,
			      &audit_rules_list[entry->rule.listnr]);
		list_add_tail_rcu(&entry->list, list);
	}
#ifdef CONFIG_AUDITSYSCALL
	if (!dont_count)
		audit_n_rules++;

	if (!audit_match_signal(entry))
		audit_signals++;
#endif
	mutex_unlock(&audit_filter_mutex);

 	return 0;

error:
	if (watch)
		audit_put_watch(watch); /* tmp watch, matches initial get */
	return err;
}

/* Remove an existing rule from filterlist. */
static inline int audit_del_rule(struct audit_entry *entry)
{
	struct audit_entry  *e;
	struct audit_watch *watch = entry->rule.watch;
	struct audit_tree *tree = entry->rule.tree;
	struct list_head *list;
	LIST_HEAD(inotify_list);
	int ret = 0;
#ifdef CONFIG_AUDITSYSCALL
	int dont_count = 0;

	/* If either of these, don't count towards total */
	if (entry->rule.listnr == AUDIT_FILTER_USER ||
		entry->rule.listnr == AUDIT_FILTER_TYPE)
		dont_count = 1;
#endif

	mutex_lock(&audit_filter_mutex);
	e = audit_find_rule(entry, &list);
	if (!e) {
		mutex_unlock(&audit_filter_mutex);
		ret = -ENOENT;
		goto out;
	}

	if (e->rule.watch)
		audit_remove_watch_rule(&e->rule, &inotify_list);

	if (e->rule.tree)
		audit_remove_tree_rule(&e->rule);

	list_del_rcu(&e->list);
	list_del(&e->rule.list);
	call_rcu(&e->rcu, audit_free_rule_rcu);

#ifdef CONFIG_AUDITSYSCALL
	if (!dont_count)
		audit_n_rules--;

	if (!audit_match_signal(entry))
		audit_signals--;
#endif
	mutex_unlock(&audit_filter_mutex);

	if (!list_empty(&inotify_list))
		audit_inotify_unregister(&inotify_list);

out:
	if (watch)
		audit_put_watch(watch); /* match initial get */
	if (tree)
		audit_put_tree(tree);	/* that's the temporary one */

	return ret;
}

/* List rules using struct audit_rule.  Exists for backward
 * compatibility with userspace. */
static void audit_list(int pid, int seq, struct sk_buff_head *q)
{
	struct sk_buff *skb;
	struct audit_krule *r;
	int i;

	/* This is a blocking read, so use audit_filter_mutex instead of rcu
	 * iterator to sync with list writers. */
	for (i=0; i<AUDIT_NR_FILTERS; i++) {
		list_for_each_entry(r, &audit_rules_list[i], list) {
			struct audit_rule *rule;

			rule = audit_krule_to_rule(r);
			if (unlikely(!rule))
				break;
			skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1,
					 rule, sizeof(*rule));
			if (skb)
				skb_queue_tail(q, skb);
			kfree(rule);
		}
	}
	skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0);
	if (skb)
		skb_queue_tail(q, skb);
}

/* List rules using struct audit_rule_data. */
static void audit_list_rules(int pid, int seq, struct sk_buff_head *q)
{
	struct sk_buff *skb;
	struct audit_krule *r;
	int i;

	/* This is a blocking read, so use audit_filter_mutex instead of rcu
	 * iterator to sync with list writers. */
	for (i=0; i<AUDIT_NR_FILTERS; i++) {
		list_for_each_entry(r, &audit_rules_list[i], list) {
			struct audit_rule_data *data;

			data = audit_krule_to_data(r);
			if (unlikely(!data))
				break;
			skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1,
					 data, sizeof(*data) + data->buflen);
			if (skb)
				skb_queue_tail(q, skb);
			kfree(data);
		}
	}
	skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0);
	if (skb)
		skb_queue_tail(q, skb);
}

/* Log rule additions and removals */
static void audit_log_rule_change(uid_t loginuid, u32 sessionid, u32 sid,
				  char *action, struct audit_krule *rule,
				  int res)
{
	struct audit_buffer *ab;

	if (!audit_enabled)
		return;

	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
	if (!ab)
		return;
	audit_log_format(ab, "auid=%u ses=%u", loginuid, sessionid);
	if (sid) {
		char *ctx = NULL;
		u32 len;
		if (security_secid_to_secctx(sid, &ctx, &len))
			audit_log_format(ab, " ssid=%u", sid);
		else {
			audit_log_format(ab, " subj=%s", ctx);
			security_release_secctx(ctx, len);
		}
	}
	audit_log_format(ab, " op=");
	audit_log_string(ab, action);
	audit_log_key(ab, rule->filterkey);
	audit_log_format(ab, " list=%d res=%d", rule->listnr, res);
	audit_log_end(ab);
}

/**
 * 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
 * @sessionid: sessionid for netlink audit message
 * @sid: SE Linux Security ID of sender
 */
int audit_receive_filter(int type, int pid, int uid, int seq, void *data,
			 size_t datasz, uid_t loginuid, u32 sessionid, u32 sid)
{
	struct task_struct *tsk;
	struct audit_netlink_list *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(sizeof(struct audit_netlink_list), GFP_KERNEL);
		if (!dest)
			return -ENOMEM;
		dest->pid = pid;
		skb_queue_head_init(&dest->q);

		mutex_lock(&audit_filter_mutex);
		if (type == AUDIT_LIST)
			audit_list(pid, seq, &dest->q);
		else
			audit_list_rules(pid, seq, &dest->q);
		mutex_unlock(&audit_filter_mutex);

		tsk = kthread_run(audit_send_list, dest, "audit_send_list");
		if (IS_ERR(tsk)) {
			skb_queue_purge(&dest->q);
			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_log_rule_change(loginuid, sessionid, sid, "add rule",
				      &entry->rule, !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_log_rule_change(loginuid, sessionid, sid, "remove rule",
				      &entry->rule, !err);

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

	return err;
}

int audit_comparator(u32 left, u32 op, u32 right)
{
	switch (op) {
	case Audit_equal:
		return (left == right);
	case Audit_not_equal:
		return (left != right);
	case Audit_lt:
		return (left < right);
	case Audit_le:
		return (left <= right);
	case Audit_gt:
		return (left > right);
	case Audit_ge:
		return (left >= right);
	case Audit_bitmask:
		return (left & right);
	case Audit_bittest:
		return ((left & right) == right);
	default:
		BUG();
		return 0;
	}
}

/* Compare given dentry name with last component in given path,
 * return of 0 indicates a match. */
int audit_compare_dname_path(const char *dname, const char *path,
			     int *dirlen)
{
	int dlen, plen;
	const char *p;

	if (!dname || !path)
		return 1;

	dlen = strlen(dname);
	plen = strlen(path);
	if (plen < dlen)
		return 1;

	/* disregard trailing slashes */
	p = path + plen - 1;
	while ((*p == '/') && (p > path))
		p--;

	/* find last path component */
	p = p - dlen + 1;
	if (p < path)
		return 1;
	else if (p > path) {
		if (*--p != '/')
			return 1;
		else
			p++;
	}

	/* return length of path's directory component */
	if (dirlen)
		*dirlen = p - path;
	return strncmp(p, dname, dlen);
}

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_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
	}
	return 1;
}

int audit_filter_user(struct netlink_skb_parms *cb)
{
	enum audit_state state = AUDIT_DISABLED;
	struct audit_entry *e;
	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;
}

static int update_lsm_rule(struct audit_krule *r)
{
	struct audit_entry *entry = container_of(r, struct audit_entry, rule);
	struct audit_entry *nentry;
	struct audit_watch *watch;
	struct audit_tree *tree;
	int err = 0;

	if (!security_audit_rule_known(r))
		return 0;

	watch = r->watch;
	tree = r->tree;
	nentry = audit_dupe_rule(r, watch);
	if (IS_ERR(nentry)) {
		/* save the first error encountered for the
		 * return value */
		err = PTR_ERR(nentry);
		audit_panic("error updating LSM filters");
		if (watch)
			list_del(&r->rlist);
		list_del_rcu(&entry->list);
		list_del(&r->list);
	} else {
		if (watch) {
			list_add(&nentry->rule.rlist, audit_watch_rules(watch));
			list_del(&r->rlist);
		} else if (tree)
			list_replace_init(&r->rlist, &nentry->rule.rlist);
		list_replace_rcu(&entry->list, &nentry->list);
		list_replace(&r->list, &nentry->rule.list);
	}
	call_rcu(&entry->rcu, audit_free_rule_rcu);

	return err;
}

/* This function will re-initialize the lsm_rule field of all applicable rules.
 * It will traverse the filter lists serarching for rules that contain LSM
 * specific filter fields.  When such a rule is found, it is copied, the
 * LSM field is re-initialized, and the old rule is replaced with the
 * updated rule. */
int audit_update_lsm_rules(void)
{
	struct audit_krule *r, *n;
	int i, err = 0;

	/* audit_filter_mutex synchronizes the writers */
	mutex_lock(&audit_filter_mutex);

	for (i = 0; i < AUDIT_NR_FILTERS; i++) {
		list_for_each_entry_safe(r, n, &audit_rules_list[i], list) {
			int res = update_lsm_rule(r);
			if (!err)
				err = res;
		}
	}
	mutex_unlock(&audit_filter_mutex);

	return err;
}


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