Re: [PATCH v2] audit: fix a memory leak bug

On Fri, Apr 19, 2019 at 11:10 AM Wenwen Wang <wang6495(a)umn.edu&gt; wrote: > > 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(a)umn.edu&gt; > --- > kernel/auditfilter.c | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) This looks good, it just needs some minor vertical whitespace fixes (see below). > diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c > index 63f8b3f..923b858 100644 > --- a/kernel/auditfilter.c > +++ b/kernel/auditfilter.c > @@ -1114,22 +1114,28 @@ int audit_rule_change(int type, int seq, void *data, size_t datasz) > int err = 0; > struct audit_entry *entry; > > - entry = audit_data_to_entry(data, datasz); > - if (IS_ERR(entry)) > - return PTR_ERR(entry); > - > switch (type) { > case AUDIT_ADD_RULE: > + entry = audit_data_to_entry(data, datasz); > + if (IS_ERR(entry)) > + return PTR_ERR(entry); > + I realize you are taking the blank line from the code above, but we probably don't need it here. > err = audit_add_rule(entry); > audit_log_rule_change("add_rule", &entry->rule, !err); > break; > + Definitely do not add this blank line. > 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; > + Same here.