Re: [PATCH] net: memory leak in nr_rx_frame

[Bragatheswaran Manickavel]

On 11/11/23 03:01, Kuniyuki Iwashima wrote:
> From: Bragatheswaran Manickavel <bragathemanick0908@xxxxxxxxx>
> Date: Fri, 10 Nov 2023 23:06:32 +0530
> > The condition (make = nr_make_new(sk)) == NULL suggests
> > that nr_make_new allocates memory and returns a pointer.
> > If this allocation fails (returns NULL), it indicates a
> > potential memory leak.
> If make is NULL, nothing is allocated and leaked here, and
> your code will never be executed as "if (make)" is always false.
>
>
> > Added sock_put() for make which can potentially solve
> > this issue
> Sounds like the patch is not tested with kmemleak.

Yes, Had some issue with reproducer. So, haven't tested it

> > Reported-by: syzbot+0145ea560de205bc09f0@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Closes: https://syzkaller.appspot.com/bug?extid=0145ea560de205bc09f0
> > Signed-off-by: Bragatheswaran Manickavel <bragathemanick0908@xxxxxxxxx>
> > ---
> >   net/netrom/af_netrom.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/net/netrom/af_netrom.c b/net/netrom/af_netrom.c
> > index 0eed00184adf..7d7cda4ae300 100644
> > --- a/net/netrom/af_netrom.c
> > +++ b/net/netrom/af_netrom.c
> > @@ -970,6 +970,8 @@ int nr_rx_frame(struct sk_buff *skb, struct net_device *dev)
> >   		nr_transmit_refusal(skb, 0);
> >   		if (sk)
> >   			sock_put(sk);
> > +		if (make)
> > +			sock_put(make);
> Also, make could be uninitialised here if the first two
> condition is true.
>
>     if (sk == NULL || sk_acceptq_is_full(sk) ||
>
>
> >   		return 0;
> >   	}
> >   
> > --
> > 2.34.1


Sorry for the inconvenience, let me check the code and get back properly.

Thanks,
Bragathe