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=-3.0 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 E78F8C46471 for ; Tue, 7 Aug 2018 18:56:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ABE7F2151D for ; Tue, 7 Aug 2018 18:56:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ABE7F2151D 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 S2404457AbeHGVMF (ORCPT ); Tue, 7 Aug 2018 17:12:05 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33894 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732347AbeHGVMF (ORCPT ); Tue, 7 Aug 2018 17:12:05 -0400 Received: from localhost (unknown [194.244.16.108]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 3270FD0E; Tue, 7 Aug 2018 18:56:21 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Noam Rathaus , Cong Wang , Jason Gunthorpe , Sasha Levin Subject: [PATCH 3.18 10/85] infiniband: fix a possible use-after-free bug Date: Tue, 7 Aug 2018 20:51:12 +0200 Message-Id: <20180807172357.740822417@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180807172357.357252052@linuxfoundation.org> References: <20180807172357.357252052@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cong Wang [ Upstream commit cb2595c1393b4a5211534e6f0a0fbad369e21ad8 ] ucma_process_join() will free the new allocated "mc" struct, if there is any error after that, especially the copy_to_user(). But in parallel, ucma_leave_multicast() could find this "mc" through idr_find() before ucma_process_join() frees it, since it is already published. So "mc" could be used in ucma_leave_multicast() after it is been allocated and freed in ucma_process_join(), since we don't refcnt it. Fix this by separating "publish" from ID allocation, so that we can get an ID first and publish it later after copy_to_user(). Fixes: c8f6a362bf3e ("RDMA/cma: Add multicast communication support") Reported-by: Noam Rathaus Signed-off-by: Cong Wang Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/core/ucma.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/infiniband/core/ucma.c +++ b/drivers/infiniband/core/ucma.c @@ -180,7 +180,7 @@ static struct ucma_multicast* ucma_alloc return NULL; mutex_lock(&mut); - mc->id = idr_alloc(&multicast_idr, mc, 0, 0, GFP_KERNEL); + mc->id = idr_alloc(&multicast_idr, NULL, 0, 0, GFP_KERNEL); mutex_unlock(&mut); if (mc->id < 0) goto error; @@ -1262,6 +1262,10 @@ static ssize_t ucma_process_join(struct goto err3; } + mutex_lock(&mut); + idr_replace(&multicast_idr, mc, mc->id); + mutex_unlock(&mut); + mutex_unlock(&file->mut); ucma_put_ctx(ctx); return 0;