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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 9226DC07520 for ; Thu, 13 Sep 2018 13:54:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 533FB20854 for ; Thu, 13 Sep 2018 13:54:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 533FB20854 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731047AbeIMTEM (ORCPT ); Thu, 13 Sep 2018 15:04:12 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33866 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728671AbeIMTEL (ORCPT ); Thu, 13 Sep 2018 15:04:11 -0400 Received: from localhost (ip-213-127-77-73.ip.prioritytelecom.net [213.127.77.73]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id E1A11D1B; Thu, 13 Sep 2018 13:54:34 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Borkmann , John Fastabend , Song Liu , Alexei Starovoitov , Sasha Levin Subject: [PATCH 4.18 063/197] bpf, sockmap: fix map elem deletion race with smap_stop_sock Date: Thu, 13 Sep 2018 15:30:12 +0200 Message-Id: <20180913131844.047074315@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180913131841.568116777@linuxfoundation.org> References: <20180913131841.568116777@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review 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 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Borkmann [ Upstream commit 166ab6f0a0702fdd4d865ad5090bf3094ed83428 ] The smap_start_sock() and smap_stop_sock() are each protected under the sock->sk_callback_lock from their call-sites except in the case of sock_map_delete_elem() where we drop the old socket from the map slot. This is racy because the same sock could be part of multiple sock maps, so we run smap_stop_sock() in parallel, and given at that point psock->strp_enabled might be true on both CPUs, we might for example wrongly restore the sk->sk_data_ready / sk->sk_write_space. Therefore, hold the sock->sk_callback_lock as well on delete. Looks like 2f857d04601a ("bpf: sockmap, remove STRPARSER map_flags and add multi-map support") had this right, but later on e9db4ef6bf4c ("bpf: sockhash fix omitted bucket lock in sock_close") removed it again from delete leaving this smap_stop_sock() instance unprotected. Fixes: e9db4ef6bf4c ("bpf: sockhash fix omitted bucket lock in sock_close") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Song Liu Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/sockmap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -1784,8 +1784,11 @@ static int sock_map_delete_elem(struct b if (!psock) goto out; - if (psock->bpf_parse) + if (psock->bpf_parse) { + write_lock_bh(&sock->sk_callback_lock); smap_stop_sock(psock, sock); + write_unlock_bh(&sock->sk_callback_lock); + } smap_list_map_remove(psock, &stab->sock_map[k]); smap_release_sock(psock, sock); out: