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=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 AA1A0ECE561 for ; Mon, 24 Sep 2018 12:28:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6E17521486 for ; Mon, 24 Sep 2018 12:28:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6E17521486 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 S2387636AbeIXSau (ORCPT ); Mon, 24 Sep 2018 14:30:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:57530 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732275AbeIXSat (ORCPT ); Mon, 24 Sep 2018 14:30:49 -0400 Received: from localhost (ip-213-127-77-73.ip.prioritytelecom.net [213.127.77.73]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 4125D1094; Mon, 24 Sep 2018 12:28:55 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+93a5839deb355537440f@syzkaller.appspotmail.com, Sowmini Varadhan , Santosh Shilimkar , rds-devel@oss.oracle.com, Cong Wang , Santosh Shilimkar , "David S. Miller" Subject: [PATCH 4.18 004/235] rds: fix two RCU related problems Date: Mon, 24 Sep 2018 13:49:50 +0200 Message-Id: <20180924113104.696412478@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180924113103.999624566@linuxfoundation.org> References: <20180924113103.999624566@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: Cong Wang [ Upstream commit cc4dfb7f70a344f24c1c71e298deea0771dadcb2 ] When a rds sock is bound, it is inserted into the bind_hash_table which is protected by RCU. But when releasing rds sock, after it is removed from this hash table, it is freed immediately without respecting RCU grace period. This could cause some use-after-free as reported by syzbot. Mark the rds sock with SOCK_RCU_FREE before inserting it into the bind_hash_table, so that it would be always freed after a RCU grace period. The other problem is in rds_find_bound(), the rds sock could be freed in between rhashtable_lookup_fast() and rds_sock_addref(), so we need to extend RCU read lock protection in rds_find_bound() to close this race condition. Reported-and-tested-by: syzbot+8967084bcac563795dc6@syzkaller.appspotmail.com Reported-by: syzbot+93a5839deb355537440f@syzkaller.appspotmail.com Cc: Sowmini Varadhan Cc: Santosh Shilimkar Cc: rds-devel@oss.oracle.com Signed-off-by: Cong Wang Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/rds/bind.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/rds/bind.c +++ b/net/rds/bind.c @@ -60,11 +60,13 @@ struct rds_sock *rds_find_bound(__be32 a u64 key = ((u64)addr << 32) | port; struct rds_sock *rs; - rs = rhashtable_lookup_fast(&bind_hash_table, &key, ht_parms); + rcu_read_lock(); + rs = rhashtable_lookup(&bind_hash_table, &key, ht_parms); if (rs && !sock_flag(rds_rs_to_sk(rs), SOCK_DEAD)) rds_sock_addref(rs); else rs = NULL; + rcu_read_unlock(); rdsdebug("returning rs %p for %pI4:%u\n", rs, &addr, ntohs(port)); @@ -157,6 +159,7 @@ int rds_bind(struct socket *sock, struct goto out; } + sock_set_flag(sk, SOCK_RCU_FREE); ret = rds_add_bound(rs, sin->sin_addr.s_addr, &sin->sin_port); if (ret) goto out;