netdev - Re: [PATCH net] pppoe: Fix memory leak in pppoe

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Message-ID: <Zc4TOy4FPn1YaKb/@debian>
Date: Thu, 15 Feb 2024 14:35:55 +0100
From: Guillaume Nault <gnault@...hat.com>
To: Gavrilov Ilia <Ilia.Gavrilov@...otecs.ru>
Cc: Michal Ostrowski <mostrows@...thlink.net>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"lvc-project@...uxtesting.org" <lvc-project@...uxtesting.org>,
	"syzbot+6bdfd184eac7709e5cc9@...kaller.appspotmail.com" <syzbot+6bdfd184eac7709e5cc9@...kaller.appspotmail.com>
Subject: Re: [PATCH net] pppoe: Fix memory leak in pppoe_sendmsg()

On Wed, Feb 14, 2024 at 09:01:50AM +0000, Gavrilov Ilia wrote:
> syzbot reports a memory leak in pppoe_sendmsg [1].
> 
> The problem is in the pppoe_recvmsg() function that handles errors
> in the wrong order. For the skb_recv_datagram() function, check
> the pointer to skb for NULL first, and then check the 'error' variable,
> because the skb_recv_datagram() function can set 'error'
> to -EAGAIN in a loop but return a correct pointer to socket buffer
> after a number of attempts, though 'error' remains set to -EAGAIN.

Reviewed-by: Guillaume Nault <gnault@...hat.com>