[PATCH AUTOSEL 4.14 33/72] audit: fix a net reference leak in audit_list_rules_send()

Sasha Levin
2020-06-08T23:31:56Z

From: Paul Moore <paul@paul-moore.com>

[ Upstream commit 3054d06719079388a543de6adb812638675ad8f5 ]

If audit_list_rules_send() fails when trying to create a new thread
to send the rules it also fails to cleanup properly, leaking a
reference to a net structure. This patch fixes the error patch and
renames audit_send_list() to audit_send_list_thread() to better
match its cousin, audit_send_reply_thread().

Reported-by: teroincn@gmail.com
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/audit.c | 2 +-
kernel/audit.h | 2 +-
kernel/auditfilter.c | 16 +++++++---------
3 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index 53224f399038..6faaa908544a 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -853,7 +853,7 @@ static int kauditd_thread(void *dummy)
return 0;
}

-int audit_send_list(void *_dest)
+int audit_send_list_thread(void *_dest)
{
struct audit_netlink_list *dest = _dest;
struct sk_buff *skb;
diff --git a/kernel/audit.h b/kernel/audit.h
index 9b110ae17ee3..1007773b0b81 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -248,7 +248,7 @@ struct audit_netlink_list {
struct sk_buff_head q;
};

-int audit_send_list(void *_dest);
+int audit_send_list_thread(void *_dest);

extern int selinux_audit_rule_update(void);

diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index 16cf396ea738..f26f4cb5d08d 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -1137,11 +1137,8 @@ int audit_rule_change(int type, int seq, void *data, size_t datasz)
*/
int audit_list_rules_send(struct sk_buff *request_skb, int seq)
{
- u32 portid = NETLINK_CB(request_skb).portid;
- struct net *net = sock_net(NETLINK_CB(request_skb).sk);
struct task_struct *tsk;
struct audit_netlink_list *dest;
- int err = 0;

/* We can't just spew out the rules here because we might fill
* the available socket buffer space and deadlock waiting for
@@ -1149,25 +1146,26 @@ int audit_list_rules_send(struct sk_buff *request_skb, int seq)
* happen if we're actually running in the context of auditctl
* trying to _send_ the stuff */

- dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL);
+ dest = kmalloc(sizeof(*dest), GFP_KERNEL);
if (!dest)
return -ENOMEM;
- dest->net = get_net(net);
- dest->portid = portid;
+ dest->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
+ dest->portid = NETLINK_CB(request_skb).portid;
skb_queue_head_init(&dest->q);

mutex_lock(&audit_filter_mutex);
audit_list_rules(seq, &dest->q);
mutex_unlock(&audit_filter_mutex);

- tsk = kthread_run(audit_send_list, dest, "audit_send_list");
+ tsk = kthread_run(audit_send_list_thread, dest, "audit_send_list");
if (IS_ERR(tsk)) {
skb_queue_purge(&dest->q);
+ put_net(dest->net);
kfree(dest);
- err = PTR_ERR(tsk);
+ return PTR_ERR(tsk);
}

- return err;
+ return 0;
}

int audit_comparator(u32 left, u32 op, u32 right)
--
2.25.1