Re: [PATCH 5.10 09/38] llc: fix netdevice reference leaks in llc_ui_bind()

Greg Kroah-Hartman
2022-03-27T09:53:25Z

On Sat, Mar 26, 2022 at 01:13:25PM -0700, Jakub Kicinski wrote:
> On Sat, 26 Mar 2022 21:09:22 +0100 Pavel Machek wrote:
> > Can someone check this? AFAICT this is buggy.
> >
> > static int llc_ui_autobind(struct socket *sock, struct sockaddr_llc *addr)
> > {
> > struct sock *sk = sock->sk;
> > struct llc_sock *llc = llc_sk(sk);
> > struct llc_sap *sap;
> > int rc = -EINVAL;
> >
> > if (!sock_flag(sk, SOCK_ZAPPED))
> > goto out;
> >
> > There are 'goto out's from both before dev_get() and after it,
> > dev_put() will be called with NULL pointer. dev_put() can't handle
> > NULL at least in the old kernels... this is simply confused.
> >
> > Mainline has dev_put_track() there, but I see same confusion.
> >
> > Best regards,
>
> commit 2d327a79ee17 ("llc: only change llc->dev when bind() succeeds"),
> https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=2d327a79ee176930dc72c131a970c891d367c1dc
>
> Should be in mainline on Thursday, LMK if we need to accelerate.
> IDK if anyone enables LLC2.

I'll queue this up now, thanks.

greg k-h