initial_commit

1 files changed, 1383 insertions, 0 deletions

diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
new file mode 100644
index 00000000..f8277c80
--- /dev/null
+++ b/kernel/auditfilter.c
@@ -0,0 +1,1383 @@
+/* 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/slab.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)
+{
+	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->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 (old->watch) {
+		audit_get_watch(old->watch);
+		new->watch = old->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 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, &list);
+		if (err) {
+			mutex_unlock(&audit_filter_mutex);
+			goto error;
+		}
+	}
+	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;
+	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);
+
+	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);
+
+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;
+		u32 sid;
+
+		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(audit_get_loginuid(current),
+						  f->op, f->val);
+			break;
+		case AUDIT_SUBJ_USER:
+		case AUDIT_SUBJ_ROLE:
+		case AUDIT_SUBJ_TYPE:
+		case AUDIT_SUBJ_SEN:
+		case AUDIT_SUBJ_CLR:
+			if (f->lsm_rule) {
+				security_task_getsecid(current, &sid);
+				result = security_audit_rule_match(sid,
+								   f->type,
+								   f->op,
+								   f->lsm_rule,
+								   NULL);
+			}
+			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;
+	int err = 0;
+
+	if (!security_audit_rule_known(r))
+		return 0;
+
+	nentry = audit_dupe_rule(r);
+	if (IS_ERR(nentry)) {
+		/* save the first error encountered for the
+		 * return value */
+		err = PTR_ERR(nentry);
+		audit_panic("error updating LSM filters");
+		if (r->watch)
+			list_del(&r->rlist);
+		list_del_rcu(&entry->list);
+		list_del(&r->list);
+	} else {
+		if (r->watch || r->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;
+}