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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_MUTT 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 683D3C282CE for ; Mon, 8 Apr 2019 08:15:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 35C8D208E3 for ; Mon, 8 Apr 2019 08:15:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="sdrIBkcp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726487AbfDHIPg (ORCPT ); Mon, 8 Apr 2019 04:15:36 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:56444 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726343AbfDHIPg (ORCPT ); Mon, 8 Apr 2019 04:15:36 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x388Drhh143445; Mon, 8 Apr 2019 08:15:25 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=p8SPSjCn008e07/4+WJbLSruNtiI92Hx8qaumPKlQbY=; b=sdrIBkcpORRohOOZBxziQBn3Gh6QXCPN5DcpKga7R9kTDg748mXZQ+JK6ajuKuOWeAVZ NRfHTD1tSOK6rQPedUNxqxu9IIWv/h5IMBNTP6vSYDBMMLqiwiJzC6DNxvk6JYhvwIux SpXK2e5QYSmIV3WR6N6GdGyvbqPCUJSv4m6OsG1NXJPWH3kNNP8uCT//JxUD1/Gp5FiG 0VBDaSjg4U8b4D0t/uLvv2Z9PjWLu2i9VQzMXUbOxAVA93gKdtE/AMrYjeqeH41JfHKN 2+DL1HmhmjlJjxfRGXHSA7Ot4edPwkPWxr+K1+fRcjEa/KtlXhVZoSKR3KGJIdHwGb5W KA== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2130.oracle.com with ESMTP id 2rpkhsmpph-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 08 Apr 2019 08:15:25 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x388DmtZ104387; Mon, 8 Apr 2019 08:15:25 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3020.oracle.com with ESMTP id 2rpkehjxxw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 08 Apr 2019 08:15:25 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x388FN8B024630; Mon, 8 Apr 2019 08:15:24 GMT Received: from kadam (/41.202.241.3) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 08 Apr 2019 01:15:22 -0700 Date: Mon, 8 Apr 2019 11:15:13 +0300 From: Dan Carpenter To: "David S. Miller" , Alexander Viro , Jens Axboe Cc: Amritha Nambiar , Willem de Bruijn , kernel-janitors@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra Subject: [PATCH v2 2/2] io_uring: Potential Oops in io_sq_offload_start() Message-ID: <20190408081513.GB15239@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190404104527.GX4038@hirez.programming.kicks-ass.net> X-Mailer: git-send-email haha only kidding User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9220 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904080077 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9220 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904080077 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The "p->sq_thread_cpu" variable is an integer which comes from the user. We can't pass values greater than NR_CPUS to cpu_possible() or it could lead to an out of bound read and possibly an Oops. The recently added cpu_possible_safe() function can handle unfiltered input so lets use that instead. This patch also removes the call to array_index_nospec() since that is handled in cpu_possible_safe(). Fixes: 6c271ce2f1d5 ("io_uring: add submission polling") Signed-off-by: Dan Carpenter --- No change. fs/io_uring.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index c0fecb9d889f..9789887b0d36 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2240,16 +2240,13 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx, ctx->sq_thread_idle = HZ; ret = -EINVAL; - if (!cpu_possible(p->sq_thread_cpu)) + if (!cpu_possible_safe(p->sq_thread_cpu)) goto err; if (ctx->flags & IORING_SETUP_SQPOLL) { if (p->flags & IORING_SETUP_SQ_AFF) { - int cpu; - - cpu = array_index_nospec(p->sq_thread_cpu, NR_CPUS); ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread, - ctx, cpu, + ctx, p->sq_thread_cpu, "io_uring-sq"); } else { ctx->sqo_thread = kthread_create(io_sq_thread, ctx, -- 2.17.1