Commit 70c4cf17 authored Apr 19, 2019 by Wenwen Wang Committed by Paul Moore Apr 22, 2019

audit: fix a memory leak bug



In audit_rule_change(), audit_data_to_entry() is firstly invoked to
translate the payload data to the kernel's rule representation. In
audit_data_to_entry(), depending on the audit field type, an audit tree may
be created in audit_make_tree(), which eventually invokes kmalloc() to
allocate the tree.  Since this tree is a temporary tree, it will be then
freed in the following execution, e.g., audit_add_rule() if the message
type is AUDIT_ADD_RULE or audit_del_rule() if the message type is
AUDIT_DEL_RULE. However, if the message type is neither AUDIT_ADD_RULE nor
AUDIT_DEL_RULE, i.e., the default case of the switch statement, this
temporary tree is not freed.

To fix this issue, only allocate the tree when the type is AUDIT_ADD_RULE
or AUDIT_DEL_RULE.

Signed-off-by: Wenwen Wang <wang6495@umn.edu>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

parent 7e8eda73

kernel/auditfilter.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -1114,22 +1114,24 @@ int audit_rule_change(int type, int seq, void *data, size_t datasz)
		int err = 0;
		struct audit_entry *entry;

		switch (type) {
		case AUDIT_ADD_RULE:
		entry = audit_data_to_entry(data, datasz);
		if (IS_ERR(entry))
		return PTR_ERR(entry);

		switch (type) {
		case AUDIT_ADD_RULE:
		err = audit_add_rule(entry);
		audit_log_rule_change("add_rule", &entry->rule, !err);
		break;
		case AUDIT_DEL_RULE:
		entry = audit_data_to_entry(data, datasz);
		if (IS_ERR(entry))
		return PTR_ERR(entry);
		err = audit_del_rule(entry);
		audit_log_rule_change("remove_rule", &entry->rule, !err);
		break;
		default:
		err = -EINVAL;
		WARN_ON(1);
		return -EINVAL;
		}

		if (err \|\| type == AUDIT_DEL_RULE) {

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