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=-14.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 1AADEC433ED for ; Thu, 15 Apr 2021 17:42:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC9FF611BF for ; Thu, 15 Apr 2021 17:42:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234325AbhDORm2 (ORCPT ); Thu, 15 Apr 2021 13:42:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52742 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233610AbhDORm1 (ORCPT ); Thu, 15 Apr 2021 13:42:27 -0400 Received: from mail-wr1-x42d.google.com (mail-wr1-x42d.google.com [IPv6:2a00:1450:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DCFDBC061574; Thu, 15 Apr 2021 10:42:02 -0700 (PDT) Received: by mail-wr1-x42d.google.com with SMTP id j5so23165711wrn.4; Thu, 15 Apr 2021 10:42:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:references:autocrypt:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=uEjbmIlAYJr/chkPHgEovS37j8EeMpHOWLqyA5kaHHk=; b=rg81Y52c74FFPUJHGbFwesSapImx1QoWoJI3kId+pUt7+4xA0yZcd/XjpzyPdlepxE 2yCeLR684plNnQxr0miHx8T+QLN63CPrKw+TOd6s2koNyJad+zQyvo3kPKIlmZuWolQS W3X3JeGLnDkG5hDfrsG27kw2p4jtuxuHIl1j0EQLARWcCwEaq2hZjPAw9zXjUp18p/MW aoVH2Ddxp9jh/NHe1zXCjeKpDxO+6+cd/wyEdiVy0e4042Emdl7naeP2CJpmFheJ+32G /nBj9vFH2SYYqlVUszpWTO5ErQuzCYyfh5dvcA2yN4Hsh0/idNv2L2cAZXlq0eVyrK0N dx0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=uEjbmIlAYJr/chkPHgEovS37j8EeMpHOWLqyA5kaHHk=; b=FtfZVpIBn1c3Su0NK5sNkM07D9fMXODQ8WMGPZKSHhwbyVGKqFqCpMS/H/OH49heMs cNuBE5nJCRr/TX4foXCXHRIISrZ266LkGYbYgPZigyh4Ug4b2sPA1gPQ6UAyauITlvND 1EZ2XCC9Fl3PVqFvARA+K8bC7a0wymfEZlwpFei0WKX0g3E28rW7Tts94nnWwVlSJwHt rB4H3uYJuuZBklEfnfkxZKoxJwM4cumM8ON1Y0jsHpgWt+tOykYMTHrif8Yz+Z105e2S TNYLKEtD41ngtF06zrZdw9rfOWWwjvdA44nGDPP34weOpfl6q86J3O+KAU1zJtvGk3pR hBlQ== X-Gm-Message-State: AOAM532jG78qC7QEUxNgrpL0V45Mh8vDxgsQaeRXmZf870/EXURdtqD1 qCKzeAWi9x465I/0qEoz6oc3c/9ZauJJSg== X-Google-Smtp-Source: ABdhPJzg1wWuONXjWedvc2gZqj9aFK0JFCeYfMzaOK/8Vn58gK7kr8Di8DcbNgeaBFYkQU6DPnzHbA== X-Received: by 2002:adf:f302:: with SMTP id i2mr4596297wro.423.1618508521460; Thu, 15 Apr 2021 10:42:01 -0700 (PDT) Received: from [192.168.8.188] ([185.69.144.21]) by smtp.gmail.com with ESMTPSA id 61sm5038669wrm.52.2021.04.15.10.41.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 15 Apr 2021 10:42:00 -0700 (PDT) Subject: Re: [PATCH] block: reexpand iov_iter after read/write From: Pavel Begunkov To: yangerkun , axboe@kernel.dk Cc: viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, io-uring@vger.kernel.org References: <20210401071807.3328235-1-yangerkun@huawei.com> Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Message-ID: <7ff7d1b7-8b6d-a684-1740-6a62565f77b6@gmail.com> Date: Thu, 15 Apr 2021 18:37:51 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 09/04/2021 15:49, Pavel Begunkov wrote: > On 01/04/2021 08:18, yangerkun wrote: >> We get a bug: >> >> BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x11c/0x404 >> lib/iov_iter.c:1139 >> Read of size 8 at addr ffff0000d3fb11f8 by task >> >> CPU: 0 PID: 12582 Comm: syz-executor.2 Not tainted >> 5.10.0-00843-g352c8610ccd2 #2 >> Hardware name: linux,dummy-virt (DT) >> Call trace: ... >> __asan_load8+0xb4/0xbc mm/kasan/generic.c:252 >> iov_iter_revert+0x11c/0x404 lib/iov_iter.c:1139 >> io_read fs/io_uring.c:3421 [inline] >> io_issue_sqe+0x2344/0x2d64 fs/io_uring.c:5943 >> __io_queue_sqe+0x19c/0x520 fs/io_uring.c:6260 >> io_queue_sqe+0x2a4/0x590 fs/io_uring.c:6326 >> io_submit_sqe fs/io_uring.c:6395 [inline] >> io_submit_sqes+0x4c0/0xa04 fs/io_uring.c:6624 ... >> >> blkdev_read_iter can truncate iov_iter's count since the count + pos may >> exceed the size of the blkdev. This will confuse io_read that we have >> consume the iovec. And once we do the iov_iter_revert in io_read, we >> will trigger the slab-out-of-bounds. Fix it by reexpand the count with >> size has been truncated. > > Looks right, > > Acked-by: Pavel Begunkov Fwiw, we need to forget to drag it through 5.13 + stable >> >> blkdev_write_iter can trigger the problem too. >> >> Signed-off-by: yangerkun >> --- >> fs/block_dev.c | 20 +++++++++++++++++--- >> 1 file changed, 17 insertions(+), 3 deletions(-) >> >> diff --git a/fs/block_dev.c b/fs/block_dev.c >> index 92ed7d5df677..788e1014576f 100644 >> --- a/fs/block_dev.c >> +++ b/fs/block_dev.c >> @@ -1680,6 +1680,7 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) >> struct inode *bd_inode = bdev_file_inode(file); >> loff_t size = i_size_read(bd_inode); >> struct blk_plug plug; >> + size_t shorted = 0; >> ssize_t ret; >> >> if (bdev_read_only(I_BDEV(bd_inode))) >> @@ -1697,12 +1698,17 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) >> if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) >> return -EOPNOTSUPP; >> >> - iov_iter_truncate(from, size - iocb->ki_pos); >> + size -= iocb->ki_pos; >> + if (iov_iter_count(from) > size) { >> + shorted = iov_iter_count(from) - size; >> + iov_iter_truncate(from, size); >> + } >> >> blk_start_plug(&plug); >> ret = __generic_file_write_iter(iocb, from); >> if (ret > 0) >> ret = generic_write_sync(iocb, ret); >> + iov_iter_reexpand(from, iov_iter_count(from) + shorted); >> blk_finish_plug(&plug); >> return ret; >> } >> @@ -1714,13 +1720,21 @@ ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) >> struct inode *bd_inode = bdev_file_inode(file); >> loff_t size = i_size_read(bd_inode); >> loff_t pos = iocb->ki_pos; >> + size_t shorted = 0; >> + ssize_t ret; >> >> if (pos >= size) >> return 0; >> >> size -= pos; >> - iov_iter_truncate(to, size); >> - return generic_file_read_iter(iocb, to); >> + if (iov_iter_count(to) > size) { >> + shorted = iov_iter_count(to) - size; >> + iov_iter_truncate(to, size); >> + } >> + >> + ret = generic_file_read_iter(iocb, to); >> + iov_iter_reexpand(to, iov_iter_count(to) + shorted); >> + return ret; >> } >> EXPORT_SYMBOL_GPL(blkdev_read_iter); >> >> > -- Pavel Begunkov