From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Horman Subject: Re: [PATCH net] sctp: add the missing sock_owned_by_user check in sctp_icmp_redirect Date: Wed, 18 Oct 2017 10:27:25 -0400 Message-ID: <20171018142725.GA14778@hmswarspite.think-freely.org> References: <7f2a5122d93d4b72115027690e89c0a164097452.1508333869.git.lucien.xin@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: network dev , linux-sctp@vger.kernel.org, davem@davemloft.net, Eric Dumazet , Marcelo Ricardo Leitner To: Xin Long Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:33759 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751039AbdJRO1v (ORCPT ); Wed, 18 Oct 2017 10:27:51 -0400 Content-Disposition: inline In-Reply-To: <7f2a5122d93d4b72115027690e89c0a164097452.1508333869.git.lucien.xin@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Oct 18, 2017 at 09:37:49PM +0800, Xin Long wrote: > Now sctp processes icmp redirect packet in sctp_icmp_redirect where > it calls sctp_transport_dst_check in which tp->dst can be released. > > The problem is before calling sctp_transport_dst_check, it doesn't > check sock_owned_by_user, which means tp->dst could be freed while > a process is accessing it with owning the socket. > > An use-after-free issue could be triggered by this. > > This patch is to fix it by checking sock_owned_by_user before calling > sctp_transport_dst_check in sctp_icmp_redirect, so that it would not > release tp->dst if users still hold sock lock. > > Besides, the same issue fixed in commit 45caeaa5ac0b ("dccp/tcp: fix > routing redirect race") on sctp also needs this check. > > Fixes: 55be7a9c6074 ("ipv4: Add redirect support to all protocol icmp error handlers") > Reported-by: Eric Dumazet > Signed-off-by: Xin Long > --- > net/sctp/input.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/sctp/input.c b/net/sctp/input.c > index 92a0714..34f10e7 100644 > --- a/net/sctp/input.c > +++ b/net/sctp/input.c > @@ -421,7 +421,7 @@ void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, > { > struct dst_entry *dst; > > - if (!t) > + if (sock_owned_by_user(sk) || !t) > return; > dst = sctp_transport_dst_check(t); > if (dst) > -- > 2.1.0 > > Acked-by: Neil Horman