auditfilter.c

Kernel code of linux kernel

		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)
					&& (f->op != AUDIT_NEGATE) && (f->op)) {
				err = -EINVAL;
				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;
		}

		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;
		}
	}

	ino_f = entry->rule.inode_f;
	if (ino_f) {
		switch(ino_f->op) {
		case AUDIT_NOT_EQUAL:
			entry->rule.inode_f = NULL;
		case AUDIT_EQUAL:
			break;
		default:
			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;
	struct audit_field *ino_f;
	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;
		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];
		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;
		}
	}

	ino_f = entry->rule.inode_f;
	if (ino_f) {
		switch(ino_f->op) {
		case AUDIT_NOT_EQUAL:
			entry->rule.inode_f = NULL;
		case AUDIT_EQUAL:
			break;
		default:
			err = -EINVAL;
			goto exit_free;
		}
	}

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] |= 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] = 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, krule->watch->path);
			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(a->watch->path, b->watch->path))
				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 the given audit watch.  The new watch's rules list is initialized
 * to an empty list and wlist is undefined. */
static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
{
	char *path;
	struct audit_watch *new;

	path = kstrdup(old->path, GFP_KERNEL);
	if (unlikely(!path))
		return ERR_PTR(-ENOMEM);

	new = audit_init_watch(path);
	if (IS_ERR(new)) {
		kfree(path);
		goto out;
	}

	new->dev = old->dev;
	new->ino = old->ino;
	get_inotify_watch(&old->parent->wdata);
	new->parent = old->parent;

out:
	return new;
}

/* 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. */
static 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->buflen = old->buflen;
	new->inode_f = old->inode_f;
	new->watch = NULL;
	new->field_count = old->field_count;
	/*