From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA688C43460 for ; Mon, 26 Apr 2021 07:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADFF06105A for ; Mon, 26 Apr 2021 07:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232128AbhDZHba (ORCPT ); Mon, 26 Apr 2021 03:31:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:41350 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231171AbhDZHb2 (ORCPT ); Mon, 26 Apr 2021 03:31:28 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A90CF61041; Mon, 26 Apr 2021 07:30:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1619422246; bh=DVXXAnLoVWgZ+1YCkGZuJAOvDooxlpbEBfviWDTW2Fc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VobeJ3cqEGkeHZrs6IU13k46tU+pI0bW/SysdJ48PubcWEqAtiGwhNEtdn8BEfE89 b9atSaxba/BVqDZO9hjGK22L8YCCCfeXz0c7vjylbH+6OsBKIcYo3sgYweGzsmY7mv aChMjifQeHa9R/OC8hFWYn2b3XkGJjcZYGZNiqjw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Or Cohen , Xin Long , Marcelo Ricardo Leitner , "David S. Miller" Subject: [PATCH 4.4 01/32] net/sctp: fix race condition in sctp_destroy_sock Date: Mon, 26 Apr 2021 09:28:59 +0200 Message-Id: <20210426072816.631201988@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210426072816.574319312@linuxfoundation.org> References: <20210426072816.574319312@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Or Cohen commit b166a20b07382b8bc1dcee2a448715c9c2c81b5b upstream. If sctp_destroy_sock is called without sock_net(sk)->sctp.addr_wq_lock held and sp->do_auto_asconf is true, then an element is removed from the auto_asconf_splist without any proper locking. This can happen in the following functions: 1. In sctp_accept, if sctp_sock_migrate fails. 2. In inet_create or inet6_create, if there is a bpf program attached to BPF_CGROUP_INET_SOCK_CREATE which denies creation of the sctp socket. The bug is fixed by acquiring addr_wq_lock in sctp_destroy_sock instead of sctp_close. This addresses CVE-2021-23133. Reported-by: Or Cohen Reviewed-by: Xin Long Fixes: 610236587600 ("bpf: Add new cgroup attach type to enable sock modifications") Signed-off-by: Or Cohen Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/sctp/socket.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -1567,11 +1567,9 @@ static void sctp_close(struct sock *sk, /* Supposedly, no process has access to the socket, but * the net layers still may. - * Also, sctp_destroy_sock() needs to be called with addr_wq_lock - * held and that should be grabbed before socket lock. */ - spin_lock_bh(&net->sctp.addr_wq_lock); - bh_lock_sock_nested(sk); + local_bh_disable(); + bh_lock_sock(sk); /* Hold the sock, since sk_common_release() will put sock_put() * and we have just a little more cleanup. @@ -1580,7 +1578,7 @@ static void sctp_close(struct sock *sk, sk_common_release(sk); bh_unlock_sock(sk); - spin_unlock_bh(&net->sctp.addr_wq_lock); + local_bh_enable(); sock_put(sk); @@ -4161,9 +4159,6 @@ static int sctp_init_sock(struct sock *s sk_sockets_allocated_inc(sk); sock_prot_inuse_add(net, sk->sk_prot, 1); - /* Nothing can fail after this block, otherwise - * sctp_destroy_sock() will be called without addr_wq_lock held - */ if (net->sctp.default_auto_asconf) { spin_lock(&sock_net(sk)->sctp.addr_wq_lock); list_add_tail(&sp->auto_asconf_list, @@ -4198,7 +4193,9 @@ static void sctp_destroy_sock(struct soc if (sp->do_auto_asconf) { sp->do_auto_asconf = 0; + spin_lock_bh(&sock_net(sk)->sctp.addr_wq_lock); list_del(&sp->auto_asconf_list); + spin_unlock_bh(&sock_net(sk)->sctp.addr_wq_lock); } sctp_endpoint_free(sp->ep); local_bh_disable();