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audit: fix a net reference leak in audit_send_reply() 

[ Upstream commit a48b284b40 ]

If audit_send_reply() fails when trying to create a new thread to
send the reply it also fails to cleanup properly, leaking a reference
to a net structure.  This patch fixes the error path and makes a
handful of other cleanups that came up while fixing the code.

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>
5.4-rM2-2.2.x-imx-squashed
Paul Moore 2020-04-20 10:09:29 -04:00 committed by Greg Kroah-Hartman
parent 6315839f14
commit 189ca174b8
1 changed files with 29 additions and 21 deletions
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50
kernel/audit.c
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@ -923,19 +923,30 @@ out_kfree_skb:
return NULL;
}
static void audit_free_reply(struct audit_reply *reply)
{
if (!reply)
return;
if (reply->skb)
kfree_skb(reply->skb);
if (reply->net)
put_net(reply->net);
kfree(reply);
}
static int audit_send_reply_thread(void *arg)
{
struct audit_reply *reply = (struct audit_reply *)arg;
struct sock *sk = audit_get_sk(reply->net);
audit_ctl_lock();
audit_ctl_unlock();
/* Ignore failure. It'll only happen if the sender goes away,
because our timeout is set to infinite. */
netlink_unicast(sk, reply->skb, reply->portid, 0);
put_net(reply->net);
kfree(reply);
netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
reply->skb = NULL;
audit_free_reply(reply);
return 0;
}
@ -949,35 +960,32 @@ static int audit_send_reply_thread(void *arg)
* @payload: payload data
* @size: payload size
*
* Allocates an skb, builds the netlink message, and sends it to the port id.
* No failure notifications.
* Allocates a skb, builds the netlink message, and sends it to the port id.
*/
static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
int multi, const void *payload, int size)
{
struct net *net = sock_net(NETLINK_CB(request_skb).sk);
struct sk_buff *skb;
struct task_struct *tsk;
struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
GFP_KERNEL);
struct audit_reply *reply;
reply = kzalloc(sizeof(*reply), GFP_KERNEL);
if (!reply)
return;
skb = audit_make_reply(seq, type, done, multi, payload, size);
if (!skb)
goto out;
reply->net = get_net(net);
reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
if (!reply->skb)
goto err;
reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
reply->portid = NETLINK_CB(request_skb).portid;
reply->skb = skb;
tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
if (!IS_ERR(tsk))
return;
kfree_skb(skb);
out:
kfree(reply);
if (IS_ERR(tsk))
goto err;
return;
err:
audit_free_reply(reply);
}
/*