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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 61AD7C433FF for ; Mon, 29 Jul 2019 20:13:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 351BD205F4 for ; Mon, 29 Jul 2019 20:13:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564431197; bh=PyKlQJ2rHOcrBoZ4zSJoeq3lpGNSP6Q6qpHvyYDs3wE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=LQuXe0hRgxjbjFtruadF5AytCYbMpuVSaKBC1j0lGWOJi5W0WmQZMxVJDdw265eAt tV/zwgI8LiHKIKObTPW+acKkV+1yYrCn1FigXvBvoK8mZMdkzXvhjnM+xXLaiySp/Q X+zI3TMtnLaNosnoJ36MafCBeh9+jsuxqnmOrfDU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730553AbfG2UNQ (ORCPT ); Mon, 29 Jul 2019 16:13:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:43432 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729342AbfG2Tal (ORCPT ); Mon, 29 Jul 2019 15:30:41 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2D3BA217D4; Mon, 29 Jul 2019 19:30:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564428640; bh=PyKlQJ2rHOcrBoZ4zSJoeq3lpGNSP6Q6qpHvyYDs3wE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2cOf1QpXV9Hya8b9Un2qaZDBRp+8x0Tk7lBM/BXoD0WX8z2kvU79iDBM/tkKjv/ho Gxp0vnUZ67JagJZWdoVNCQ19SV6BBMGakejwHI1q08KxkGOU/KB3fmzA6YMe/qXIDC qf4g+a8Ya5UDNmCqD+DcXH7R1loxVS/u/OBgTQSM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Taehee Yoo , "David S. Miller" , Sasha Levin Subject: [PATCH 4.14 103/293] gtp: fix use-after-free in gtp_encap_destroy() Date: Mon, 29 Jul 2019 21:19:54 +0200 Message-Id: <20190729190832.541477515@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190820.321094988@linuxfoundation.org> References: <20190729190820.321094988@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 1788b8569f5de27da09087fa3f6580d2aa04cc75 ] gtp_encap_destroy() is called twice. 1. When interface is deleted. 2. When udp socket is destroyed. either gtp->sk0 or gtp->sk1u could be freed by sock_put() in gtp_encap_destroy(). so, when gtp_encap_destroy() is called again, it would uses freed sk pointer. patch makes gtp_encap_destroy() to set either gtp->sk0 or gtp->sk1u to null. in addition, both gtp->sk0 and gtp->sk1u pointer are protected by rtnl_lock. so, rtnl_lock() is added. Test command: gtp-link add gtp1 & killall gtp-link ip link del gtp1 Splat looks like: [ 83.182767] BUG: KASAN: use-after-free in __lock_acquire+0x3a20/0x46a0 [ 83.184128] Read of size 8 at addr ffff8880cc7d5360 by task ip/1008 [ 83.185567] CPU: 1 PID: 1008 Comm: ip Not tainted 5.2.0-rc6+ #50 [ 83.188469] Call Trace: [ ... ] [ 83.200126] lock_acquire+0x141/0x380 [ 83.200575] ? lock_sock_nested+0x3a/0xf0 [ 83.201069] _raw_spin_lock_bh+0x38/0x70 [ 83.201551] ? lock_sock_nested+0x3a/0xf0 [ 83.202044] lock_sock_nested+0x3a/0xf0 [ 83.202520] gtp_encap_destroy+0x18/0xe0 [gtp] [ 83.203065] gtp_encap_disable.isra.14+0x13/0x50 [gtp] [ 83.203687] gtp_dellink+0x56/0x170 [gtp] [ 83.204190] rtnl_delete_link+0xb4/0x100 [ ... ] [ 83.236513] Allocated by task 976: [ 83.236925] save_stack+0x19/0x80 [ 83.237332] __kasan_kmalloc.constprop.3+0xa0/0xd0 [ 83.237894] kmem_cache_alloc+0xd8/0x280 [ 83.238360] sk_prot_alloc.isra.42+0x50/0x200 [ 83.238874] sk_alloc+0x32/0x940 [ 83.239264] inet_create+0x283/0xc20 [ 83.239684] __sock_create+0x2dd/0x540 [ 83.240136] __sys_socket+0xca/0x1a0 [ 83.240550] __x64_sys_socket+0x6f/0xb0 [ 83.240998] do_syscall_64+0x9c/0x450 [ 83.241466] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 83.242061] [ 83.242249] Freed by task 0: [ 83.242616] save_stack+0x19/0x80 [ 83.243013] __kasan_slab_free+0x111/0x150 [ 83.243498] kmem_cache_free+0x89/0x250 [ 83.244444] __sk_destruct+0x38f/0x5a0 [ 83.245366] rcu_core+0x7e9/0x1c20 [ 83.245766] __do_softirq+0x213/0x8fa Fixes: 1e3a3abd8b28 ("gtp: make GTP sockets in gtp_newlink optional") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/gtp.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c index c751f87c935e..53fd66534e3a 100644 --- a/drivers/net/gtp.c +++ b/drivers/net/gtp.c @@ -289,13 +289,17 @@ static int gtp1u_udp_encap_recv(struct gtp_dev *gtp, struct sk_buff *skb) return gtp_rx(pctx, skb, hdrlen, gtp->role); } -static void gtp_encap_destroy(struct sock *sk) +static void __gtp_encap_destroy(struct sock *sk) { struct gtp_dev *gtp; lock_sock(sk); gtp = sk->sk_user_data; if (gtp) { + if (gtp->sk0 == sk) + gtp->sk0 = NULL; + else + gtp->sk1u = NULL; udp_sk(sk)->encap_type = 0; rcu_assign_sk_user_data(sk, NULL); sock_put(sk); @@ -303,12 +307,19 @@ static void gtp_encap_destroy(struct sock *sk) release_sock(sk); } +static void gtp_encap_destroy(struct sock *sk) +{ + rtnl_lock(); + __gtp_encap_destroy(sk); + rtnl_unlock(); +} + static void gtp_encap_disable_sock(struct sock *sk) { if (!sk) return; - gtp_encap_destroy(sk); + __gtp_encap_destroy(sk); } static void gtp_encap_disable(struct gtp_dev *gtp) @@ -1045,6 +1056,7 @@ static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info) return -EINVAL; } + rtnl_lock(); rcu_read_lock(); gtp = gtp_find_dev(sock_net(skb->sk), info->attrs); @@ -1069,6 +1081,7 @@ static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info) out_unlock: rcu_read_unlock(); + rtnl_unlock(); return err; } -- 2.20.1