From: Eric Dumazet <eric.dumazet@gmail.com>
To: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Cc: Jason Baron <jbaron@akamai.com>,
davem@davemloft.net, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, minipli@googlemail.com,
normalperson@yhbt.net, viro@zeniv.linux.org.uk,
davidel@xmailserver.org, dave@stgolabs.net, olivier@mauras.ch,
pageexec@freemail.hu, torvalds@linux-foundation.org,
peterz@infradead.org
Subject: Re: [PATCH v2 1/3] unix: fix use-after-free in unix_dgram_poll()
Date: Mon, 05 Oct 2015 09:54:34 -0700 [thread overview]
Message-ID: <1444064074.9555.4.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <87bncdxool.fsf@doppelsaurus.mobileactivedefense.com>
On Mon, 2015-10-05 at 17:31 +0100, Rainer Weikusat wrote:
> atomic_long_set(&u->inflight, 0);
> INIT_LIST_HEAD(&u->link);
> @@ -2135,8 +2139,16 @@ static unsigned int unix_poll(struct fil
> static unsigned int unix_dgram_poll(struct file *file, struct socket *sock,
> poll_table *wait)
> {
> - struct sock *sk = sock->sk, *other;
> - unsigned int mask, writable;
> + struct sock *sk = sock->sk, *other, *pp;
> + struct unix_sock *u;
> + unsigned int mask, writable, dead;
> +
> + u = unix_sk(sk);
> + pp = u->poll_peer;
> + if (pp) {
> + u->poll_peer = NULL;
> + sock_put(pp);
> + }
This looks racy.
Multiple threads could use poll() at the same time,
and you would have too many sock_put()
next prev parent reply other threads:[~2015-10-05 16:54 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-02 20:43 [PATCH v2 0/3] af_unix: fix use-after-free Jason Baron
2015-10-02 20:43 ` [PATCH v2 1/3] unix: fix use-after-free in unix_dgram_poll() Jason Baron
2015-10-03 5:46 ` Mathias Krause
2015-10-03 17:02 ` Rainer Weikusat
2015-10-04 17:41 ` Rainer Weikusat
2015-10-05 16:31 ` Rainer Weikusat
2015-10-05 16:54 ` Eric Dumazet [this message]
2015-10-05 17:20 ` Rainer Weikusat
2015-10-05 17:55 ` Jason Baron
2015-10-12 20:41 ` Rainer Weikusat
2015-10-14 3:44 ` Jason Baron
2015-10-14 17:47 ` Rainer Weikusat
2015-10-15 2:54 ` Jason Baron
2015-10-18 20:58 ` Rainer Weikusat
2015-10-19 15:07 ` Jason Baron
2015-10-20 22:29 ` Rainer Weikusat
2015-10-21 17:34 ` Rainer Weikusat
2015-10-28 16:46 ` [RFC] " Rainer Weikusat
2015-10-28 17:57 ` Jason Baron
2015-10-29 14:23 ` Rainer Weikusat
2015-10-30 20:52 ` [RFC] unix: fix use-after-free in unix_dgram_poll()/ 4.2.5 Rainer Weikusat
[not found] ` <57d2f5b6aae251957bff7a1a52b8bf2c@core-hosting.net>
2015-11-02 21:55 ` Rainer Weikusat
2015-10-02 20:43 ` [PATCH v2 2/3] af_unix: Convert gc_flags to flags Jason Baron
2015-10-02 20:44 ` [PATCH v2 3/3] af_unix: optimize the unix_dgram_recvmsg() Jason Baron
2015-10-05 7:41 ` Peter Zijlstra
2015-10-05 17:13 ` Jason Baron
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