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audit: fix a memory leak bug

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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>
This commit is contained in:
Wenwen Wang 2019-04-19 20:49:29 -05:00 committed by Paul Moore
parent 7e8eda734d
commit 70c4cf17e4
1 changed files with 7 additions and 5 deletions
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10
kernel/auditfilter.c
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@ -1114,22 +1114,24 @@ int audit_rule_change(int type, int seq, void *data, size_t datasz)
int err = 0; int err = 0;
struct audit_entry *entry; struct audit_entry *entry;
switch (type) {
case AUDIT_ADD_RULE:
entry = audit_data_to_entry(data, datasz); entry = audit_data_to_entry(data, datasz);
if (IS_ERR(entry)) if (IS_ERR(entry))
return PTR_ERR(entry); return PTR_ERR(entry);
switch (type) {
case AUDIT_ADD_RULE:
err = audit_add_rule(entry); err = audit_add_rule(entry);
audit_log_rule_change("add_rule", &entry->rule, !err); audit_log_rule_change("add_rule", &entry->rule, !err);
break; break;
case AUDIT_DEL_RULE: case AUDIT_DEL_RULE:
entry = audit_data_to_entry(data, datasz);
if (IS_ERR(entry))
return PTR_ERR(entry);
err = audit_del_rule(entry); err = audit_del_rule(entry);
audit_log_rule_change("remove_rule", &entry->rule, !err); audit_log_rule_change("remove_rule", &entry->rule, !err);
break; break;
default: default:
err = -EINVAL;
WARN_ON(1); WARN_ON(1);
return -EINVAL;
} }
if (err || type == AUDIT_DEL_RULE) { if (err || type == AUDIT_DEL_RULE) {