From: Paul Moore paul@paul-moore.com

commit a48b284b403a4a073d8beb72d2bb33e54df67fb6 upstream.

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 Cc: stable@vger.kernel.org # 4.9.x Signed-off-by: Wen Yang wenyang@linux.alibaba.com --- kernel/audit.c | 46 ++++++++++++++++++++++++++++------------------ 1 file changed, 28 insertions(+), 18 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c index af1e00f..55ccd842 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -580,6 +580,18 @@ struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done, 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; @@ -592,8 +604,8 @@ static int audit_send_reply_thread(void *arg) /* Ignore failure. It'll only happen if the sender goes away, because our timeout is set to infinite. */ netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0); - put_net(net); - kfree(reply); + reply->skb = NULL; + audit_free_reply(reply); return 0; } /** @@ -606,36 +618,34 @@ 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) { u32 portid = NETLINK_CB(request_skb).portid; - 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(portid, seq, type, done, multi, payload, size); - if (!skb) - goto out; + reply->skb = audit_make_reply(portid, seq, type, done, multi, payload, size); + if (!reply->skb) + goto err;

- reply->net = get_net(net); + reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk)); reply->portid = 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); }

/*