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=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,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 1A258C47256 for ; Tue, 5 May 2020 08:29:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0437B206CC for ; Tue, 5 May 2020 08:29:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728569AbgEEI3G (ORCPT ); Tue, 5 May 2020 04:29:06 -0400 Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:39077 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728556AbgEEI3G (ORCPT ); Tue, 5 May 2020 04:29:06 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04397;MF=xiaoguang.wang@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0TxYdNBh_1588667335; Received: from localhost(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0TxYdNBh_1588667335) by smtp.aliyun-inc.com(127.0.0.1); Tue, 05 May 2020 16:29:04 +0800 From: Xiaoguang Wang To: io-uring@vger.kernel.org Cc: axboe@kernel.dk, joseph.qi@linux.alibaba.com, Xiaoguang Wang Subject: [PATCH v2] io_uring: handle -EFAULT properly in io_uring_setup() Date: Tue, 5 May 2020 16:28:53 +0800 Message-Id: <20200505082853.28411-1-xiaoguang.wang@linux.alibaba.com> X-Mailer: git-send-email 2.17.2 Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org If copy_to_user() in io_uring_setup() failed, we'll leak many kernel resources, which will be recycled until process terminates. This bug can be reproduced by using mprotect to set params to PROT_READ. To fix this issue, refactor io_uring_create() a bit to add a new 'struct io_uring_params __user *params' parameter and move the copy_to_user() in io_uring_setup() to io_uring_setup(), if copy_to_user() failed, we can free kernel resource properly. Suggested-by: Jens Axboe Signed-off-by: Xiaoguang Wang --- fs/io_uring.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 0b91b0631173..ec0aa6957882 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -7761,7 +7761,8 @@ static int io_uring_get_fd(struct io_ring_ctx *ctx) return ret; } -static int io_uring_create(unsigned entries, struct io_uring_params *p) +static int io_uring_create(unsigned entries, struct io_uring_params *p, + struct io_uring_params __user *params) { struct user_struct *user = NULL; struct io_ring_ctx *ctx; @@ -7853,6 +7854,14 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p) p->cq_off.overflow = offsetof(struct io_rings, cq_overflow); p->cq_off.cqes = offsetof(struct io_rings, cqes); + p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP | + IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS | + IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL; + + if (copy_to_user(params, p, sizeof(*p))) { + ret = -EFAULT; + goto err; + } /* * Install ring fd as the very last thing, so we don't risk someone * having closed it before we finish setup @@ -7861,9 +7870,6 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p) if (ret < 0) goto err; - p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP | - IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS | - IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL; trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags); return ret; err: @@ -7879,7 +7885,6 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p) static long io_uring_setup(u32 entries, struct io_uring_params __user *params) { struct io_uring_params p; - long ret; int i; if (copy_from_user(&p, params, sizeof(p))) @@ -7894,14 +7899,7 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ)) return -EINVAL; - ret = io_uring_create(entries, &p); - if (ret < 0) - return ret; - - if (copy_to_user(params, &p, sizeof(p))) - return -EFAULT; - - return ret; + return io_uring_create(entries, &p, params); } SYSCALL_DEFINE2(io_uring_setup, u32, entries, -- 2.17.2