Re: [PATCH v2] 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(a)umn.edu&gt; --- kernel/auditfilter.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)

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); +

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) { -- 2.7.4