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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_NONE, USER_AGENT_GIT 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 2B4D0C41602 for ; Wed, 12 May 2021 15:28:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E22161CBA for ; Wed, 12 May 2021 15:28:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234887AbhELPZx (ORCPT ); Wed, 12 May 2021 11:25:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:47650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231588AbhELPMP (ORCPT ); Wed, 12 May 2021 11:12:15 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0294161920; Wed, 12 May 2021 15:03:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620831828; bh=lDaAdmeje9VmkeMIa0y5IagwgGb3hon+ePrSW+A/Uis=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PRGkZBTC0zFfImrcy45HovlJzvqanmfWemZxdHwEd/ca5gdRDixf9LiSJXFcVruc5 AnQMd4aP6EImBgK8gDCKMcwD27JcLiaNnECkBTt96lzwIJEmHAIuxpaaxgD+5ZPwLt 7fWzmWdzmBo/Xra43F9RnIgtlVvK3j11xCToiICk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thadeu Lima de Souza Cascardo , Jens Axboe Subject: [PATCH 5.10 004/530] io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers Date: Wed, 12 May 2021 16:41:54 +0200 Message-Id: <20210512144819.822281412@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210512144819.664462530@linuxfoundation.org> References: <20210512144819.664462530@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thadeu Lima de Souza Cascardo commit d1f82808877bb10d3deee7cf3374a4eb3fb582db upstream. Read and write operations are capped to MAX_RW_COUNT. Some read ops rely on that limit, and that is not guaranteed by the IORING_OP_PROVIDE_BUFFERS. Truncate those lengths when doing io_add_buffers, so buffer addresses still use the uncapped length. Also, take the chance and change struct io_buffer len member to __u32, so it matches struct io_provide_buffer len member. This fixes CVE-2021-3491, also reported as ZDI-CAN-13546. Fixes: ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") Reported-by: Billy Jheng Bing-Jhong (@st424204) Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- fs/io_uring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -222,7 +222,7 @@ struct fixed_file_data { struct io_buffer { struct list_head list; __u64 addr; - __s32 len; + __u32 len; __u16 bid; }; @@ -4034,7 +4034,7 @@ static int io_add_buffers(struct io_prov break; buf->addr = addr; - buf->len = pbuf->len; + buf->len = min_t(__u32, pbuf->len, MAX_RW_COUNT); buf->bid = bid; addr += pbuf->len; bid++;